But [climate scientists] say that aspects of the case of Hurricane Harvey—and the recent history of tropical cyclones worldwide—suggest global warming is making a bad situation worse.

Effects of global warming

Global warming not only causes changes in tropical cyclones, it may also make some impacts from them worse via sea level rise.

Hurricane Harvey

"It's a fact: climate change made Hurricane Harvey more deadly".

Hurricane Harvey

The Gulf of Mexico is known for hurricanes in August, so their incidence alone cannot be attributed to global warming, but the warming climate does influence certain attributes of storms.

Hurricane Harvey

Weather events are due to multiple factors, and so cannot be said to be caused by one precondition, but climate change affects aspects of extreme events, and very likely worsened some of the impacts of Harvey.

Hurricane Harvey

"Storm Harvey: impacts likely worsened due to global warming".


The human contribution can be up to 30 percent or so of the total rainfall coming out of the storm

Physical impacts of climate change

For 2 °C of warming the fraction of precipitation extremes attributable to human influence rises to about 40%.

Physical impacts of climate change

We show that at the present-day warming of 0.85 °C about 18% of the moderate daily precipitation extremes over land are attributable to the observed temperature increase since pre-industrial times, which in turn primarily results from human influence.

Puerto Rico

On average, a quarter of its annual rainfall is contributed from tropical cyclones, which are more prevalent during periods of La Niña than El Niño.

Saudi Arabia

An average of 300 mm (12 in) of rainfall occurs during this period, which is about 60 percent of the annual precipitation.

Urban heat island

Some cities show a total precipitation increase of 51%.


Global Ocean Circulation Appears To Be Collapsing Due To A Warming Planet

Climate

Alterations in the quantity of atmospheric greenhouse gases determines the amount of solar energy retained by the planet, leading to global warming or global cooling.

Eocene

Isotopes of carbon and oxygen indicate a shift to a global cooling climate.

Eocene

that the Eocene hothouse world was caused by runaway global warming from released methane clathrates deep in the oceans.

Ice age

Additional fresh water flowing into the North Atlantic during a warming cycle may also reduce the global ocean water circulation.

Little Ice Age

There is some concern that a shutdown of thermohaline circulation could happen again as a result of the present warming period.


Evidence is growing that the comparatively cold zone within the Northern Atlantic could be due to a slowdown of this global ocean water circulation.

Atlantic Ocean

The subpolar gyre forms an important part of the global thermohaline circulation.

Global warming

Another example is the possibility for the Atlantic Meridional Overturning Circulation to slow or shut down (see also shutdown of thermohaline circulation).

Ice age

Shutdown of thermohaline circulation

A shutdown or slowdown of the thermohaline circulation is a hypothesized effect of global warming on a major ocean circulation.

Thermohaline circulation

The Gulf Stream, together with its northern extension towards Europe, the North Atlantic Drift, is a powerful, warm, and swift Atlantic ocean current that originates at the tip of Florida, and follows the eastern coastlines of the United States and Newfoundland before crossing the Atlantic Ocean.


While geologists have studied events in the past similar to what appears to be happening today, scientists are largely unsure of what lies ahead.

Anoxic event

Although anoxic events have not happened for millions of years, the geological record shows that they happened many times in the past.

Geologist

Geochronology: the study of isotope geology specifically toward determining the date within the past of rock formation, metamorphism, mineralization and geological events (notably, meteorite impacts).

Geologist

Their studies are used to warn the general public of the occurrence of these events.

Geology

Other scientists perform stable-isotope studies on the rocks to gain information about past climate.

Geology

In Hutton's words: "the past history of our globe must be explained by what can be seen to be happening now."


Scientists have long known about the anomalous ‘warming hole‘ in the North Atlantic Ocean, an area immune to warming of Earth’s oceans.

Atlantic Ocean

The NADW is fed by a flow of warm shallow water into the northern North Atlantic which is responsible for the anomalous warm climate in Europe.

Climate

Other climate determinants are more dynamic: the thermohaline circulation of the ocean leads to a 5 °C (9 °F) warming of the northern Atlantic Ocean compared to other ocean basins.

Cretaceous

The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas.

Cretaceous

Meanwhile, deep ocean temperatures were as much as 15 to 20 °C (27 to 36 °F) warmer than today's.

Little Ice Age

In the North Atlantic, sediments accumulated since the end of the last ice age, nearly 12,000 years ago, show regular increases in the amount of coarse sediment grains deposited from icebergs melting in the now open ocean, indicating a series of 1–2 °C (2–4 °F) cooling events recurring every 1,500 years or so.


Carbon dioxide

Concentrations of 7% to 10% (70,000 to 100,000 ppm) may cause suffocation, even in the presence of sufficient oxygen, manifesting as dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour.

Carbon dioxide

There are few studies of the health effects of long-term continuous CO 2 exposure on humans and animals at levels below 1%.

Carbon dioxide

At this CO 2 concentration, International Space Station crew experienced headaches, lethargy, mental slowness, emotional irritation, and sleep disruption.

Smog

When inhaled, these particles can settle in the lungs and respiratory tract and cause health problems.

Smog

Smog is a serious problem in many cities and continues to harm human health.


Climate change need not endanger anyone”

Climate change and ecosystems

The species said to be most at risk for endangerment or extinction are populations that are not of conservation concern.

Scientific consensus on climate change:166

Scientific consensus on climate change

Given the potential threat to marine ecosystems and its ensuing impact on human society and economy, especially as it acts in conjunction with anthropogenic global warming, there is an urgent need for immediate action."

Scientific consensus on climate change:197

Scientific consensus on climate change

Mitigation will reduce the amount of future climate change and the risk of impacts that are potentially large and dangerous.

Scientific consensus on climate change:562

Scientific consensus on climate change

The threats are serious and action is urgently needed to mitigate the risks of climate change.

The Daily Caller

Other news outlets confirmed Halper's identity but did not report his identity because US intelligence officials warned that it would endanger him and his contacts.


“Healthy societies do not fall apart over slow, widely predicted, relatively small economic adjustments of the sort painted by climate analysis.

Economic growth

The Stern Review notes that the prediction that, "Under business as usual, global emissions will be sufficient to propel greenhouse gas concentrations to over 550 ppm CO 2 by 2050 and over 650–700 ppm by the end of this century is robust to a wide range of changes in model assumptions."

Low-carbon economy

GHG emissions due to anthropogenic (human) activity are the dominant cause of observed global warming (climate change) since the mid-20th century.

Low-carbon economy

Estimates from the International Labour Organization’s Global Economic Linkages model suggest that unmitigated climate change, with associated negative impacts on enterprises and workers, will have negative effects on output in many industries, with drops in output of 2.4% by 2030 and 7.2% by 2050.

Sustainability

In 2019, 2 weeks before the elections to the European Parlament, the World Wide Fund for Nature stated that the European Union is unsustainable in his current mode of life and economy and asked him to fix it by "Shift to sustainable consumption and food systems, make Europe climate-neutral by 2040, restore our Nature, protect the Ocean, invest in a sustainable future" At a March 2009 meeting of the Copenhagen Climate Council, 2,500 climate experts from 80 countries issued a keynote statement that there is now "no excuse" for failing to act on global warming and that without strong carbon reduction "abrupt or irreversible" shifts in climate may occur that "will be very difficult for contemporary societies to cope with".

Sustainability

Several key areas have been targeted for economic analysis and reform: the environmental effects of unconstrained economic growth; the consequences of nature being treated as an economic externality; and the possibility of an economics that takes greater account of the social and environmental consequences of market behavior.


Societies do fall apart from war, disease or chaos.

American Civil War

It proved to be the death struggle of a society, which went down in ruins.

Apocalyptic and post-apocalyptic fiction:138

In René Barjavel's novel Ravage (1943), written and published during the German occupation of France, a future France is devastated by the sudden failure of electricity, causing chaos, disease, and famine, with a small band of survivors desperately struggling for survival.

Vietnam War

World War I

By 1929, the Great Depression arrived, causing political chaos throughout the world.

World War I

Diseases flourished in the chaotic wartime conditions.


Climate policy must compete with other long-term threats for always-scarce resources.”

Climate change policy of the United States:307

Spokespeople within these groups argue that universal access to a clean and healthy environment and access to critical natural resources are basic human rights.

Habitat destruction

Any efforts to protect the world's remaining natural habitat and biodiversity will compete directly with humans’ growing demand for natural resources, especially new agricultural lands.

List of ecoregions in North America (CEC):1108

The white-tailed deer competes with other herbivores for limited food resources directly affecting the ecosystem, as well as indirectly affecting the area by altering habitats for small vertebrates and mammals.

List of ecoregions in North America (CEC):1179

Therefore, as species that thrive in the lower areas of the region are expanding into a greater space, they are beginning to compete for resources and nutrients with pre-existing native species.

Sustainability

Depletion of natural resources including fresh water increases the likelihood of "resource wars".


’Extremely remarkable’ 2017 heads toward record for hottest year without an El Niño episode.

El Niño

When this warming occurs for seven to nine months, it is classified as El Niño "conditions"; when its duration is longer, it is classified as an El Niño "episode".

Instrumental temperature record

2016's record meant that 16 of the 17 warmest years have occurred since 2000, 2017 being the third-hottest year on record meant that 17 of the last 18 warmest years have occurred since 2000.

Instrumental temperature record

Of the 2015 and 2016 records, Schmidt stated that the 2014–16 El Niño event was "a factor ... but both 2015 and 2016 would have been records even without it"; he attributed about 90% of the warming in 2016 to anthropogenic climate change.

Instrumental temperature record

This long-term trend is the main cause for the record warmth of 2015 and 2016, surpassing all previous years—even ones with strong El Niño events."

La Niña

It was the second-coolest year of the 21st century to date, and tied with the second-warmest year of the 20th century.


So it’s been a surprise to climate scientists that 2017 has been so remarkably warm — because the last El Niño ended a year ago.

2014–16 El Niño event

The 2014–16 El Niño was a warming of the eastern equatorial Pacific Ocean that resulted in unusually warm waters developing between the coast of South America and the International Date Line.

El Niño

However, over time the term has evolved and now refers to the warm and negative phase of the El Niño–Southern Oscillation and is the warming of the ocean surface or above-average sea surface temperatures in either the central and eastern tropical Pacific Ocean.

El Niño

A study of climate records has shown that El Niño events in the equatorial Pacific are generally associated with a warm tropical North Atlantic in the following spring and summer.

El Niño

About half of El Niño events persist sufficiently into the spring months for the Western Hemisphere Warm Pool to become unusually large in summer.

La Niña

La Niña (/lɑːˈniːnjə/, Spanish pronunciation: [la ˈniɲa]) is a coupled ocean-atmosphere phenomenon that is the colder counterpart of El Niño, as part of the broader El Niño–Southern Oscillation climate pattern.


The latest NOAA report is “a reminder that climate change has not, despite the insistence of climate contrarians ‘paused’ or even slowed down,” Mann said..

Abrupt climate change

The term is also used within the context of global warming to describe sudden climate change that is detectable over the time-scale of a human lifetime, possibly as the result of feedback loops within the climate system.

Climate change denial

"Details the findings of a new report that confirms NOAA data about climate change."

Climate change denial

Such disagreements are not new but the emails provided climate sceptics, in the sense of deniers or contrarians, with a golden opportunity to mount a sustained effort aimed at demonstrating the legitimacy of their views.

Climate change denial

I shall use "climate sceptics" here in the sense of "climate deniers", although there are obvious differences between scepticism and denial (see Shermer, 2010; Kemp, et al., 2010).

Scientific consensus on climate change:107

Scientific consensus on climate change

The statement references the IPCC's Fourth Assessment of 2007, and asserts that "climate change is happening even faster than previously estimated; global CO 2 emissions since 2000 have been higher than even the highest predictions, Arctic sea ice has been melting at rates much faster than predicted, and the rise in the sea level has become more rapid".


Famine, economic collapse, a sun that cooks us: What climate change could wreak — sooner than you think.

Global warming

"Reducing risks to food security from climate change".

Global warming

Abrupt climate change, tipping points in the climate system: Climate change could result in global, large-scale changes.

Global warming

"Climate change could impact the poor much more than previously thought".

Global warming

In November 2017, a second warning to humanity signed by 15,364 scientists from 184 countries stated that "the current trajectory of potentially catastrophic climate change due to rising greenhouse gases from burning fossil fuels, deforestation, and agricultural production – particularly from farming ruminants for meat consumption" is "especially troubling".

New York Harbor Storm-Surge Barrier

David Wallace-Wells, "The Uninhabitable Earth: Famine, economic collapse, a sun that cooks us: What climate change could wreak — sooner than you think," New York Magazine, July 9, 2017.


parts of the Earth will likely become close to uninhabitable

Effects of global warming

In July 2019, they issued a declaration "affirming that climate change poses the single greatest threat to the human rights and security of present and future generations of Pacific Island peoples" and claim their lands could become uninhabitable as early as 2030.

Sea level rise

At current rates, sea level would be high enough to make the Maldives uninhabitable by 2100.

Sea level rise

In the case all islands of an island nation become uninhabitable or completely submerged by the sea, the states themselves would also become dissolved.

Solar System

The expanding Sun is expected to vaporize Mercury and render Earth uninhabitable.

Space and survival

Eventually the Earth will be uninhabitable, at the latest when the Sun becomes a red giant in about 5 billion years.


Or the news from Antarctica this past May, when a crack in an ice shelf grew 11 miles in six days, then kept going; the break now has just three miles to go — by the time you read this, it may already have met the open water, where it will drop into the sea one of the biggest icebergs ever, a process known poetically as ‘calving.’

Antarctica

The ice was being held back by a "thread" of ice about 6 km (4 mi) wide, prior to its collapse on 5 April 2009.

Iceberg

"An Iceberg 30 Times the Size of Manhattan Is About to Break Off Antarctica".

Larsen Ice Shelf

"A giant crack in Antarctic ice is 'days or weeks' from breaking off a Delaware-size iceberg".

Larsen Ice Shelf

Scientists with Swansea University in the UK say the crack lengthened 18 km (11 mi) from 25 May to 31 May, and that less than 13 km (8 mi) of ice is all that prevents the birth of an enormous iceberg.

Ross Ice Shelf

Four days later, they found their way into open water and were hoping that they would have a clear passage to their destination.


“Even if we meet the Paris goals of two degrees warming, cities like Karachi and Kolkata will become close to uninhabitable, annually encountering deadly heat waves like those that crippled them in 2015.

Climate change mitigation

The Paris Agreement's long-term temperature goal is to keep the increase in global average temperature to well below 2°C above pre-industrial levels; and to pursue efforts to limit the increase to 1.5°C.

Global warming

In 2015 all UN countries negotiated the Paris Agreement, which aims to keep climate change well below 2 °C.

Karachi

While the summers are hot and humid, cool sea breezes typically provide relief during hot summer months, though Karachi is prone to deadly heat waves, though a text-message based early warning system is now in place that helped prevent any fatalities during an unusually strong heatwave in October 2017.

Paris Agreement

The aim of the agreement is to decrease global warming described in its Article 2, "enhancing the implementation" of the UNFCCC through: (a) Holding the increase in the global average temperature to well below 2 °C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 °C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change; (b) Increasing the ability to adapt to the adverse impacts of climate change and foster climate resilience and low greenhouse gas emissions development, in a manner that does not threaten food production; (c) Making finance flows consistent with a pathway towards low greenhouse gas emissions and climate-resilient development.

Paris Agreement

The Paris Agreement's long-term temperature goal is to keep the increase in global average temperature to well below 2 °C above pre-industrial levels; and to pursue efforts to limit the increase to 1.5 °C, recognizing that this would substantially reduce the risks and impacts of climate change.


At four degrees, the deadly European heat wave of 2003, which killed as many as 2,000 people a day, will be a normal summer.

2006 North American heat wave

The Summer 2006 North American heat wave was a severe heat wave that affected most of the United States and Canada, killing at least 225 people and bringing extreme heat to many locations.

2019 heat wave in India and Pakistan

For comparison, the 2003 European heat wave killed an estimated 35,000–70,000 people, with temperatures slightly less than in India and Pakistan.

Cold wave

Overall it was the coldest winter since 1978–79, with a mean temperature of 1.5 °C (34.7 °F).

List of heat waves

The European heat wave of 2006 was the second massive heat wave to hit the continent in four years, with temperatures rising to 40 °C (104 °F) in Paris; in Ireland, which has a moderate maritime climate, temperatures of over 32 °C (90 °F) were reported.

List of heat waves

The European heat wave of 2007 affected primarily south-eastern Europe during late June through August.


In other words, we have, trapped in Arctic permafrost, twice as much carbon as is currently wrecking the atmosphere of the planet, all of it scheduled to be released at a date that keeps getting moved up, partially in the form of a gas that multiplies its warming power 86 times over.

Arctic methane emissions

(2008) estimate that not less than 1,400 gigatonnes (Gt) of carbon is presently locked up as methane and methane hydrates under the Arctic submarine permafrost, and 5–10% of that area is subject to puncturing by open taliks.

Arctic methane emissions

Melting of this ice may release large quantities of methane, a powerful greenhouse gas into the atmosphere, causing further warming in a strong positive feedback cycle.

Arctic

Release of methane and carbon dioxide stored in permafrost could cause abrupt and severe global warming, as they are potent greenhouse gases.

Permafrost

The amount of carbon sequestered in permafrost is four times the carbon that has been released to the atmosphere due to human activities in modern time.

Tundra

When the permafrost melts, it releases carbon in the form of carbon dioxide and methane, both of which are greenhouse gases.


“The IPCC reports also don’t fully account for the albedo effect (less ice means less reflected and more absorbed sunlight, hence more warming); more cloud cover (which traps heat); or the dieback of forests and other flora (which extract carbon from the atmosphere).

Albedo

This has been a concern since arctic ice and snow has been melting at higher rates due to higher temperatures, creating regions in the arctic that are notably darker (being water or ground which is darker color) and reflects less heat back into space.

Global warming

The reduction of snow cover and sea ice in the Arctic reduces the albedo of the Earth's surface.

Global warming

If cloud cover increases, more sunlight will be reflected back into space, cooling the planet.

Global warming

Changing the type of vegetation in a region impacts the local temperature by changing how much sunlight gets reflected back into space, called albedo, and how much heat is lost by evaporation.

Tipping points in the climate system

The IPCC reports that feedbacks to increased temperatures are net positive for the remainder of this century, with the impact of cloud cover the largest uncertainty.


The most notorious was 252 million years ago; it began when carbon warmed the planet by five degrees, accelerated when that warming triggered the release of methane in the Arctic, and ended with 97 percent of all life on Earth dead.”

Arctic

The current Arctic warming is leading to ancient carbon being released from thawing permafrost, leading to methane and carbon dioxide production by micro-organisms.

Earth

The last continental glaciation ended 10,000 years ago.

Eocene

that the Eocene hothouse world was caused by runaway global warming from released methane clathrates deep in the oceans.

Permafrost

Global warming accelerates its release due to release of methane from both existing stores and methanogenesis in rotting biomass.

Tundra


The last time the planet was even four degrees warmer, Peter Brannen points out in The Ends of the World, his new history of the planet’s major extinction events, the oceans were hundreds of feet higher.

Devonian

Sea levels were high worldwide, and much of the land lay under shallow seas, where tropical reef organisms lived.

Earth

The elevation of the land surface varies from the low point of −418 m (−1,371 ft) at the Dead Sea, to a maximum altitude of 8,848 m (29,029 ft) at the top of Mount Everest.

Earth

As a result, the mean annual air temperature at sea level decreases by about 0.4 °C (0.7 °F) per degree of latitude from the equator.

Ordovician

In the early and middle Ordovician, temperatures were mild, but at the beginning of the Late Ordovician, from 460 to 450 Ma, volcanoes along the margin of the Iapetus Ocean spewed massive amounts of carbon dioxide, a greenhouse gas, into the atmosphere, turning the planet into a hothouse.

Ordovician

The Ordovician saw the highest sea levels of the Paleozoic, and the low relief of the continents led to many shelf deposits being formed under hundreds of metres of water.


Which means that if the planet is five degrees warmer at the end of the century, we may have as many as 50 percent more people to feed and 50 percent less grain to give them.”

Human overpopulation

To keep the numbers of starving constant, the percentage would have dropped by more than half.

Human overpopulation

The global consumption of meat is projected to rise by as much as 76% by 2050 as the global population surges to more than 9 billion, resulting in further biodiversity loss and increased GHG emissions.

Human overpopulation

Although plants produce 54 billion metric tons of carbohydrates per year, when the population is expected to grow to 9 billion by 2050, the plants may not be able to keep up (Biello).

Human overpopulation

The British scientist John Beddington predicted in 2009 that supplies of energy, food, and water will need to be increased by 50% to reach demand levels of 2030.

Human overpopulation

In 2019, a warning on climate change signed by 11,000 scientists from 153 nations said that human population growth adds 80 million humans annually, and "the world population must be stabilized—and, ideally, gradually reduced—within a framework that ensures social integrity" to reduce the impact of "population growth on GHG emissions and biodiversity loss."


as the pathbreaking work by Rosamond Naylor and David Battisti has shown, the tropics are already too hot to efficiently grow grain, and those places where grain is produced today are already at optimal growing temperature — which means even a small warming will push them down the slope of declining productivity.

Climate change and agriculture

In Africa and Latin America many rainfed crops are near their maximum temperature tolerance, so that yields are likely to fall sharply for even small climate changes; falls in agricultural productivity of up to 30% over the 21st century are projected.

Climate change and agriculture

Rice becomes sterile if exposed to temperatures above 35 degrees for more than one hour during flowering and consequently produces no grain.

Eocene

The models, while accurately predicting the tropics, tend to produce significantly cooler temperatures of up to 20 °C (36 °F) colder than the actual determined temperature at the poles.

Eocene

The polar stratospheric clouds had a warming effect on the poles, increasing temperatures by up to 20 °C in the winter months.

Tropics

In terms of climate, the tropics receive sunlight that is more direct than the rest of Earth and are generally hotter and wetter.


By 2080, without dramatic reductions in emissions, southern Europe will be in permanent extreme drought, much worse than the American dust bowl ever was.

Europe

There are frequent summer droughts in this region.

Global warming

Since the 1950s, droughts and heat waves have appeared simultaneously with increasing frequency.

Global warming

Climate change can be mitigated through the reduction of greenhouse gas emissions or the enhancement of the capacity of carbon sinks to absorb greenhouse gases from the atmosphere.

Severe weather

Another form of severe weather is drought, which is a prolonged period of persistently dry weather (that is, absence of precipitation).

Severe weather

A drought in the 1930s known as the Dust Bowl affected 50 million acres of farmland in the central United States.


None of these places, which today supply much of the world’s food, will be reliable sources of any.

Biodiversity

Biodiversity is also important to the security of resources such as water, timber, paper, fiber, and food.

Florida

The state produces about 75% of the phosphate required by farmers in the United States and 25% of the world supply, with about 95% used for agriculture (90% for fertilizer and 5% for livestock feed supplements) and 5% used for other products.

Hong Kong

With few natural lakes and rivers, high population density, inaccessible groundwater sources, and extremely seasonal rainfall, the territory does not have a reliable source of fresh water.

Human nutrition

Human nutrition deals with the provision of essential nutrients in food that are necessary to support human life and health.

Melbourne

It was an important meeting place for the clans of the Kulin nation alliance and a vital source of food and water.


In the sugarcane region of El Salvador, as much as one-fifth of the population has chronic kidney disease, including over a quarter of the men, the presumed result of dehydration from working the fields they were able to comfortably harvest as recently as two decades ago.

El Salvador

In the summer of 2001 a severe drought destroyed 80% of El Salvador's crops, causing famine in the countryside.

Hypertension

Serum creatinine is measured to assess for the presence of kidney disease, which can be either the cause or the result of hypertension.

Kidney

Only when the amount of functioning kidney tissue is greatly diminished does one develop chronic kidney disease.

Mesoamerican nephropathy

In El Salvador and Nicaragua alone, the reported number of men dying from this painful disease has risen five-fold in the last 20 years, although some researchers believe hidden cases have always been there and this increment in official data could be partially due to the recent increase in reports and improved case search, pushed by the growing social and political interest in the disease.

Mesoamerican nephropathy

In El Salvador, the disease has become the second leading cause of death among adult men, and according to a recent editorial, it has been estimated that this largely unknown epidemic has caused the premature death of at least 20,000 men in the region.


The warmer the planet gets, the more ozone forms, and by mid-century, Americans will likely suffer a 70 percent increase in unhealthy ozone smog, the National Center for Atmospheric Research has projected.

Global warming

Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further 0.3 to 1.7 °C (0.5 to 3.1 °F) in a moderate scenario, or as much as 2.6 to 4.8 °C (4.7 to 8.6 °F) in an extreme scenario, depending on the rate of future greenhouse gas emissions and on climate feedback effects.

Ozone depletion

So far, ozone depletion in most locations has been typically a few percent and, as noted above, no direct evidence of health damage is available in most latitudes.

Ozone depletion

Reductions of up to 70 percent in the ozone column observed in the austral (southern hemispheric) spring over Antarctica and first reported in 1985 (Farman et al.)

Ozone depletion

Some stratospheric cooling is also predicted from increases in greenhouse gases such as CO 2 and CFCs themselves; however, the ozone-induced cooling appears to be dominant.

Philadelphia

According to the same report, the city experienced a significant reduction in high ozone days since 2001—from nearly 50 days per year to fewer than 10—along with fewer days of high particle pollution since 2000—from about 19 days per year to about 3—and an approximate 30% reduction in annual levels of particle pollution since 2000.


“[Carbon dioxide] just crossed 400 parts per million, and high-end estimates extrapolating from current trends suggest it will hit 1,000 ppm by 2100.

Carbon dioxide

For an ideal gas mixture this is equivalent to parts per million by volume (ppmv).

Eocene

For contrast, today the carbon dioxide levels are at 400 ppm or 0.04%.

Greenhouse effect

Measurements of CO 2 from the Mauna Loa observatory show that concentrations have increased from about 313 parts per million (ppm) in 1960, passing the 400 ppm milestone on May 9, 2013.

Greenhouse gas

Carbon dioxide mole fractions in the atmosphere have gone up by approximately 35 percent since the 1900s, rising from 280 parts per million by volume to 387 parts per million in 2009.

Greenhouse gas

The oft-cited Mauna Loa average for 2012 is 393.8 ppm, which is a good approximation although typically about 1 ppm higher than the spatial average given above.


In Alaska, already, researchers have discovered remnants of the 1918 flu that infected as many as 500 million and killed as many as 100 million”

Spanish flu

It infected 500 million people around the world, or about 27% of the then world population of about 1.8 billion, including people on remote Pacific islands and in the Arctic.

Spanish flu

The death toll is estimated to have been 50 million, and possibly as high as 100 million (about 3 to 6 percent of Earth's population at the time), making it one of the deadliest epidemics in human history.

Spanish flu

"1918 Flu Pandemic That Killed 50 Million Originated in China, Historians Say".

Spanish flu

Older estimates say it killed 40–50 million people, while current estimates put the death toll at probably 50 million (less than 3% of the global population), and possibly as high as 100 million (more than 5%).

Spanish flu

In the U.S., about 28% of the population of 105 million became infected, and 500,000 to 675,000 died (0.48 to 0.64 percent of the population).


“As it happens, Zika may also be a good model of the second worrying effect — disease mutation.

Gene

Genetic disorders are the result of deleterious mutations and can be due to spontaneous mutation in the affected individual, or can be inherited.

Genetics

These errors, called mutations, can affect the phenotype of an organism, especially if they occur within the protein coding sequence of a gene.

Mutation

This is especially useful studying diseases in adults by allowing expression after a certain period of growth, thus eliminating the deleterious effect of gene expression seen during stages of development in model organisms.

Zika fever

In addition, research was needed to determine the mechanism by which Zika produced these effects.

Zika fever

Zika also appears to have an equal tropism for cells of the developing eye, leading to high rates of eye abnormalities as well.


The peer-reviewed study by two scientists and a veteran statistician looked at the global average temperature datasets[…]

Global warming

Scientific discussion takes place in journal articles that are peer-reviewed, which scientists subject to assessment every couple of years in the Intergovernmental Panel on Climate Change reports.

Hockey stick controversy

In a paper published by PNAS on 9 September 2008, Mann and colleagues produced updated reconstructions of Earth surface temperature for the past two millennia.

Hockey stick graph

The report was not properly peer reviewed.

Instrumental temperature record

An examination of the average global temperature changes by decades reveals continuing climate change, and AR5 reports "Each of the last three decades has been successively warmer at the Earth's surface than any preceding decade since 1850 (see Figure SPM.1).

The Daily Caller

In 2017, The Daily Caller published a story falsely claiming that a "peer-reviewed study" by "two scientists and a veteran statistician" found that recent years have not been the warmest ever.


the mild warming of around 0.8 degrees Celsius that the planet has experienced since the middle of the 19th century

Earth

Without this heat-retention effect, the average surface temperature would be −18 °C (0 °F), in contrast to the current +15 °C (59 °F), and life on Earth probably would not exist in its current form.

Earth

As a result, the mean annual air temperature at sea level decreases by about 0.4 °C (0.7 °F) per degree of latitude from the equator.

Earth

Consequently, summers are 2.3 °C (4 °F) warmer in the Northern Hemisphere than in the Southern Hemisphere under similar conditions.

Uppsala

The second warmest is 2018, with 8.0 °C (46 °F).

Uppsala

If compared to the period 1861–1890, the annual increase in temperature is 1.8 °C.


“Several of the papers note that the primary influence on warming appears to be solar activity.

Attribution of recent climate change:236

Attribution of recent climate change

(2009) found that the evidence showed that connections between solar variation and climate were more likely to be mediated by direct variation of insolation rather than cosmic rays, and concluded: "Hence within our assumptions, the effect of varying solar activity, either by direct solar irradiance or by varying cosmic ray rates, must be less than 0.07 °C since 1956, i.e.

Attribution of recent climate change

"From new estimates of the combined anthropogenic forcing due to greenhouse gases, aerosols, and land surface changes, it is extremely likely (>95%) that human activities have exerted a substantial net warming influence on climate since 1750."

Attribution of recent climate change

Natural forces alone (such as solar and volcanic activity) cannot explain the observed warming.

Global warming

The scientific consensus as of 2013[update], as stated in the IPCC Fifth Assessment Report, is that it "is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century".

Solar activity and climate

Patterns of solar irradiance and solar variation has been a main driver of climate change over the millennia to gigayears of the geologic time scale, but its role in the recent warming has been found to be insignificant.


Despite recent attempts to paint the United States as a major global polluter, according to the World Health Organization (WHO), the U.S. is among the cleanest nations on the planet.

United States

The most prominent is the Environmental Protection Agency (EPA), created by presidential order in 1970.

United States

It is the only country in the world, other than Eritrea, to do so.

United States

Since 2007, the total greenhouse gas emissions by the United States are the second highest by country, exceeded only by China.

United States

The United States has historically been the world's largest producer of greenhouse gases and greenhouse gas emissions per capita remain high.

United States

Issues that affect water supply in the United States include droughts in the West, water scarcity, pollution, a backlog of investment, concerns about the affordability of water for the poorest, and a rapidly retiring workforce.


While France and other G7 countries lamented the U.S. exit from the Paris climate accord, America’s air is already cleaner than that of any other country in the G7, except Canada with its scant population.

Canada

The most densely populated part of the country, accounting for nearly 50 percent, is the Quebec City–Windsor Corridor in Southern Quebec and Southern Ontario along the Great Lakes and the Saint Lawrence River.

France

Being the host country of the 2015 Paris Climate Change Conference, the French government was instrumental in securing the 2015 Paris agreement, a success that has been credited to its"openness and experience in diplomacy" (though the US, after the election of President Trump in 2016, then announced it will withdraw from the agreement).

United States withdrawal from the Paris Agreement:0

On June 1, 2017, United States President Donald Trump announced that the U.S. would cease all participation in the 2015 Paris Agreement on climate change mitigation.

United States withdrawal from the Paris Agreement:39

The communique issued at the conclusion of the summit stated that the United States "is not in a position to join the consensus" of the other G7 countries on policies regarding climate change and the Paris Agreement.

United States withdrawal from the Paris Agreement:729

"French PM blasts Trump's decision to pull US out of Paris climate accord as 'calamitous'".


According to the WHO, exposure to particulate matter increases the risk of acute lower respiratory infection, chronic obstructive pulmonary disease, heart disease, stroke and lung cancer.

Air pollution

Causes of deaths include strokes, heart disease, COPD, lung cancer, and lung infections.

Air pollution

Air pollution is a significant risk factor for a number of pollution-related diseases, including respiratory infections, heart disease, COPD, stroke and lung cancer.

Particulates

The effects of inhaling particulate matter that has been widely studied in humans and animals include asthma, lung cancer, respiratory diseases, cardiovascular disease, premature delivery, birth defects, low birth weight, and premature death.

Particulates

Bronchial asthma, chronic obstructive pulmonary disease, and interstitial pneumonia were the most common ailments treated by area hospitals.

Particulates

Worldwide exposure to PM2.5 contributed to 4.1 million deaths from heart disease and stroke, lung cancer, chronic lung disease, and respiratory infections in 2016.


The report […] found that the United States was one of the most pollution-free nations in the world.”

Developing country

For example, with regards to health risks, they commonly have: low levels of access to safe drinking water, sanitation and hygiene; energy poverty; high levels of pollution (e.g.

Developing country

Tropical and infectious diseases (neglected tropical diseases) Unsafe drinking water, poor sanitation and hygiene Indoor air pollution in developing nations Pollution (e.g.

Developing country

Water pollution is a major problem in many developing countries.

United States

United States


CO2 is colorless, odorless and completely non-toxic.

Carbon dioxide

Carbon dioxide (chemical formula CO 2) is a colorless gas with a density about 60% higher than that of dry air.

Carbon dioxide

Carbon dioxide

At low concentrations the gas is odorless; however, at sufficiently-high concentrations, it has a sharp, acidic odor.

Carbon dioxide

Carbon dioxide is odorless at normally encountered concentrations, but at high concentrations, it has a sharp and acidic odor.

Exhaust gas

Carbon monoxide is colorless, odorless and tasteless, but highly toxic.


Growers regularly pump CO2 into greenhouses, raising levels to three times that of the natural environment, to produce stronger, greener, healthier plants.”

Cannabis cultivation

Adequate levels of CO2 must be maintained for the plants to grow efficiently.

Carbon dioxide

Plants can grow as much as 50 percent faster in concentrations of 1,000 ppm CO 2 when compared with ambient conditions, though this assumes no change in climate and no limitation on other nutrients.

Greenhouse

Secondary metabolites, e.g., cardiac glycosides in Digitalis lanata, are produced in higher amounts by greenhouse cultivation at enhanced temperature and at enhanced carbon dioxide concentration.

Hydroponics

To increase yield further, some sealed greenhouses inject CO2 into their environment to help improve growth and plant fertility.

Vertical farming

Greenhouses commonly supplement carbon dioxide levels to 3–4 times the atmospheric rate.


Without human intervention, the concentration of CO2 has climbed as high as 7,000 parts per million (ppm) in prior eras, whereas at present the concentration is just over 400 ppm.

Carbon dioxide in Earth's atmosphere

Global annual mean CO 2 concentration has increased by more than 45% since the start of the Industrial Revolution, from 280 ppm during the 10,000 years up to the mid-18th century to 415 ppm as of May 2019.

Carbon dioxide

Carbon dioxide in Earth's atmosphere is a trace gas, currently (mid 2018) having a global average concentration of 409 parts per million by volume (or 622 parts per million by mass).

Carbon dioxide

The current concentration is about 0.04% (410 ppm) by volume, having risen from pre-industrial levels of 280 ppm.

Greenhouse gas

Measured atmospheric concentrations of carbon dioxide are currently 100 ppm higher than pre-industrial levels.

Greenhouse gas

Human activities since the beginning of the Industrial Revolution (around 1750) have produced a 45% increase in the atmospheric concentration of carbon dioxide, from 280 ppm in 1750 to 415 ppm in 2019.


“Some experts, such as UN climate scientist Dr. Indur Goklany, have defended rising CO2 levels as a good thing for humanity.

Carbon dioxide in Earth's atmosphere:128

Carbon dioxide in Earth's atmosphere

A 2017 Politico article states that increased CO 2 levels may have a negative impact on the nutritional quality of various human food crops, by increasing the levels of carbohydrates, such as glucose, while decreasing the levels of important nutrients such as protein, iron, and zinc.

Global warming

While increased CO 2 levels help crop growth at lower temperature increases, those crops do become less nutritious.

Greenhouse gas

It is likely that anthropogenic (i.e., human-induced) warming, such as that due to elevated greenhouse gas levels, has had a discernible influence on many physical and biological systems.

Greenhouse gas

During the late 20th century, a scientific consensus evolved that increasing concentrations of greenhouse gases in the atmosphere cause a substantial rise in global temperatures and changes to other parts of the climate system, with consequences for the environment and for human health.

Indur M. Goklany

In an op-ed for The New York Times, he wrote, "Ironically, much of the hysteria over global warming is itself fueled by concerns that it may drive numerous species to extinction and increase hunger worldwide, especially in developing countries.


Goklany has argued that the rising level of carbon dioxide in the earth’s atmosphere ‘is currently net beneficial for both humanity and the biosphere generally.”

Carbon dioxide in Earth's atmosphere

Since global warming is attributed to increasing atmospheric concentrations of greenhouse gases such as CO 2 and methane, scientists closely monitor atmospheric CO 2 concentrations and their impact on the present-day biosphere.

Carbon dioxide removal

Both have the same net effect, but for achieving carbon dioxide concentration levels below present levels, carbon dioxide removal is critical.

Carbon dioxide

Increases in atmospheric concentrations of CO 2 and other long-lived greenhouse gases such as methane, nitrous oxide and ozone have correspondingly strengthened their absorption and emission of infrared radiation, causing the rise in average global temperature since the mid-20th century.

Global warming

As stated in the Convention, this requires that greenhouse gas concentrations are stabilized in the atmosphere at a level where ecosystems can adapt naturally to climate change, food production is not threatened, and economic development can be sustained.

Snowball Earth

"High levels of atmospheric carbon dioxide necessary for the termination of global glaciation".


Meeting the 2025 emissions reduction target alone could subtract $250 billion from our GDP and eliminate 2.7 million jobs.

Air pollution

This would save about $600 billion in health costs a year due to reduced air pollution in 2050, or about 3.6% of the 2014 U.S. gross domestic product.

Biodiesel

Judging by the continued growth in the Renewable Fuel Standard and the extension of the biodiesel tax incentive, the number of jobs can increase to 50,725, $2.7 billion in income, and reaching $5 billion in GDP by 2012 and 2013.

Carbon tax

The goal is to reduce carbon emissions to those outlined in the Kyoto Protocol; specifically to reduce their emissions by 7% below 1990 levels by 2012.

Kyoto Protocol and government action:125

Kyoto Protocol and government action

The country has a national objective to reduce emissions by 25% from their 1990 levels by 2020, and a long-term target to reduce emissions 75–80% by 2050.

Kyoto Protocol and government action:157

Kyoto Protocol and government action

Informed by the Energy White Paper 2003, the bill aims to achieve a mandatory reduction of 60% in the carbon emission from the 1990 level by 2050, with an intermediate target of between 26% and 32% by 2020.


The cement, iron and steel, and petroleum refining industries could see their production cut by 21% 19%, and 11% respectively.”

Economy of Venezuela

The hardest hit sectors in the worst recession years (2002–2003) were construction (−55.9%), petroleum (−26.5%), commerce (−23.6%) and manufacturing (−22.5%).

Economy of Venezuela

By the first half of 2016, only 10 vehicles were manufactured per day in Venezuela with production dropping 86%.

Mineral industry of Africa

The 2012 share of world production from African soil was bauxite 7%; aluminium 5%; chromite 38%; cobalt 60%; copper 9%; gold 20%; iron ore 2%; steel 1%; lead (Pb) 2%; manganese 38%; zinc 1%; cement 4%; natural diamond 56%; graphite 2%; phosphate rock 21%; coal 4%; mineral fuels (including coal) & petroleum 47%; uranium 18%.platinum 69.4%.

Mineral industry of Africa

Crude steel production was expected to rise by an average of about 5% per year from 2005 to 2011.

Technological and industrial history of China:126

Improvements in existing plants reduced steel-industry energy consumption from 73.8 million tons of coal in 1978 to 69.1 million tons in 1983, and production increased by 26 percent.


The Clean Power Plan, a major component of fulfilling the agreement, would spike energy costs for working and middle-class Texans by 16% by 2030, according to the Economic Reliability Council of Texas

Efficient energy use

At an EU summit in October 2014, EU countries agreed on a new energy efficiency target of 27% or greater by 2030.

Efficient energy use

They are: To help households and businesses transition to a low carbon future To streamline the adoption of efficient energy To make buildings more energy-efficient For governments to work in partnership and lead the way to energy efficiency The overriding agreement that governs this strategy is the National Partnership Agreement on Energy Efficiency.

Energy policy of the United States

On August 31, 2006, the California Legislature reached an agreement with Governor Arnold Schwarzenegger to reduce the state's greenhouse-gas emissions, which rank at 12th-largest carbon emitter in the world, by 25 percent by the year 2020.

Smart grid

The increased efficiency and reliability of the smart grid is expected to save consumers money and help reduce CO 2 emissions.

Wind power

ESB National Grid, Ireland's electric utility, in a 2004 study that, concluded that to meet the renewable energy targets set by the EU in 2001 would "increase electricity generation costs by a modest 15%" "Impact of Wind Power Generation in Ireland on the Operation of Conventional Plant and the Economic Implications" (PDF).


The acceleration is making some scientists fear that Antarctica’s ice sheet may have entered the early stages of an unstoppable disintegration.

Antarctica

As a result, the continental mass of the East Antarctic ice sheet is held at lower temperatures, and the peripheral areas of Antarctica, especially the Antarctic Peninsula, are subject to higher temperatures, which promote accelerated melting.

Antarctica

The sheet has been of recent concern because of the small possibility of its collapse.

Pine Island Glacier

Scientists have found that the flow of these ice streams has accelerated in recent years, and suggested that if they were to melt, global sea levels would rise by 1 to 2 m (3 ft 3 in to 6 ft 7 in), destabilising the entire West Antarctic Ice Sheet and perhaps sections of the East Antarctic Ice Sheet.

Retreat of glaciers since 1850

The acceleration of the rate of retreat since 1995 of key outlet glaciers of the Greenland and West Antarctic ice sheets may foreshadow a rise in sea level, which would affect coastal regions.

Sea level rise

"Antarctica ice melt has accelerated by 280% in the last 4 decades".


Because the collapse of vulnerable parts of the ice sheet could raise the sea level dramatically, the continued existence of the world’s great coastal cities — Miami, New York, Shanghai and many more — is tied to Antarctica’s fate.

Antarctica

However, it is the outflow of the ice from the land to form the ice shelf which causes a rise in global sea level.

Ice sheet

Around 90% of the Earth's ice mass is in Antarctica, which, if melted, would cause sea levels to rise by 58 meters.

Sea level rise

A rapid collapse of the West Antarctic Ice Sheet could raise sea level by 3.3 metres (11 ft).

Sea level rise

The world's largest potential source of sea level rise is the East Antarctic Ice Sheet, which holds enough ice to raise global sea levels by 53.3 m (175 ft).

Sea level rise

The lead scientist Eric Rignot told CNN: "melting is taking place in the most vulnerable parts of Antarctica ... parts that hold the potential for multiple meters of sea level rise in the coming century or two."


an airplane is contributing to the emissions that put the frozen continent at risk.

Airplane

This enables the entire craft to contribute to lift generation with the result of potentially increased fuel economy.

Boeing

The airline industry is responsible for about 11% of greenhouse gases emitted by the U.S. transportation sector.

Boeing

Aviation's share of the greenhouse gas emissions is poised to grow, as air travel increases and ground vehicles use more alternative fuels like ethanol and biodiesel.

Boeing

Boeing estimates that biofuels could reduce flight-related greenhouse-gas emissions by 60 to 80%.

Global catastrophic risk

In November 2017, a statement by 15,364 scientists from 184 countries indicated that increasing levels of greenhouse gases from use of fossil fuels, human population growth, deforestation, and overuse of land for agricultural production, particularly by farming ruminants for meat consumption, are trending in ways that forecast an increase in human misery over coming decades.


If those emissions continue unchecked and the world is allowed to heat up enough, scientists have no doubt that large parts of Antarctica will melt into the sea.

Antarctica

As a result of continued warming, the polar ice caps melted and much of Gondwana became a desert.

Antarctica

Antarctica

If all of this ice were melted, sea levels would rise about 60 m (200 ft).

Sea level rise

Continued carbon dioxide emissions from fossil fuel sources could cause additional tens of metres of sea level rise, over the next millennia, and the available fossil fuel on Earth is even enough to ultimately melt the entire Antarctic ice sheet, causing about 58 m (190 ft) of sea level rise.

Sea level rise

Also, a report by the Royal Netherlands Institute for Sea Research stated that around three million years ago, levels of carbon dioxide in the Earth’s atmosphere were similar to today’s levels which increased temperature by two to three degrees Celsius and melted one third of Antarctica’s ice sheets.


About 120,000 years ago, before the last ice age, the planet went through a natural warm period, with temperatures similar to those expected in coming decades.

Global warming

"The next five years will be 'anomalously warm,' scientists predict".

Holocene

[citation needed] The Holocene climatic optimum (HCO) was a period of warming in which the global climate became warmer.

Holocene

This period of warmth ended about 5,500 years ago with the descent into the Neoglacial and concomitant Neopluvial.

Ice age

An ice age is a long period of reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers.

Ice age

The last cold episode of the last glacial period ended about 10,000 years ago.


The sea level was 20 to 30 feet higher than it is today, implying that the ice sheets in both Greenland and Antarctica must have partly disintegrated, a warning of what could occur in the relatively near future if the heating of the planet continues unchecked.”

Sea level rise

There is a threshold in surface warming beyond which a partial or near-complete melting of the Greenland ice sheet occurs.

Sea level rise

Both the Greenland ice sheet and Antarctica have tipping points for warming levels that could be reached before the end of the 21st century.

Sea level rise

The warming was sustained over a period of thousands of years and the magnitude of the rise in sea level implies a large contribution from the Antarctic and Greenland ice sheets.

Tipping points in the climate system

Runaway climate change of 4–5 °C can make swathes of the planet around the equator uninhabitable, with sea levels up to 60 metres (197 ft) higher than they are today.

West Antarctic Ice Sheet

In 2018, scientists concluded that high sea levels some 125,000 years ago, which were 6–9 m (20–30 ft) higher than today, were most likely due to the absence of the WAIS, and found evidence that the ice sheet collapsed under climate conditions similar to those of today.


“Right now, the shelf works like a giant bottle-stopper that slows down ice trying to flow from the land into the sea.

Antarctica

However, it is the outflow of the ice from the land to form the ice shelf which causes a rise in global sea level.

Ice shelf

An ice shelf is a large floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface.

Ice shelf

This new source of ice volume flows down from above sea level, displacing sea water and so contributing to sea level rise.

Ice shelf

That flow continually moves ice from the grounding line to the seaward front of the shelf.

Ross Ice Shelf

The Ross Ice Shelf pushes out into the sea at between 1.5 and 3 m (5 and 10 ft) a day.


The most vulnerable parts of the West Antarctic ice sheet could raise the sea level by 10 to 15 feet, inundating many of the world’s coastal cities, though most scientists think that would take well over a century, or perhaps longer.

Sea level rise

A rapid collapse of the West Antarctic Ice Sheet could raise sea level by 3.3 metres (11 ft).

West Antarctic Ice Sheet

It has been hypothesised that this disintegration could raise sea levels by approximately 3.3 metres (11 ft).

West Antarctic Ice Sheet

On 12 May 2014, it was announced that two teams of scientists said the long-feared collapse of the Ice Sheet had begun, kicking off what they say will be a centuries-long, "unstoppable" process that could raise sea levels by 1.2 to 3.6 metres (3.9 to 11.8 ft) They estimate that rapid drawdown of Thwaites Glacier will begin in 200 – 1000 years.

West Antarctic Ice Sheet

In 2016, improved computer modeling revealed that the breakup of glaciers could lead to a steep rise in sea levels much more quickly than previously projected.

West Antarctic Ice Sheet


The winds around the continent seem to be strengthening, stirring the ocean and bringing up a layer of warmer water that has most likely been there for centuries.

Arctic Ocean

Atlantic Water has the same salinity as Arctic Bottom Water but is much warmer (up to 3 °C).

Arctic Ocean

In fact, this water mass is actually warmer than the surface water, and remains submerged only due to the role of salinity in density.

El Niño

The low-level surface trade winds, which normally blow from east to west along the equator, either weaken or start blowing from the other direction.

El Niño

Within the Atlantic Ocean vertical wind shear is increased, which inhibits tropical cyclone genesis and intensification, by causing the westerly winds in the atmosphere to be stronger.

Southern Ocean

Strong westerly (eastward) winds blow around Antarctica, driving a significant flow of water northwards.


We’re not sure because we don’t have enough data, for long enough, to separate signal from noise,” said Eric J. Steig, a scientist at the University of Washington who has studied temperature trends in Antarctica.

Antarctica cooling controversy

In a study released in 2009, historical weather station data was combined with satellite measurements to deduce past temperatures over large regions of the continent, and these temperatures indicate an overall warming trend.

Antarctica cooling controversy

One of the paper's authors, Eric Steig of the University of Washington, stated "We now see warming is taking place on all seven of the earth’s continents in accord with what models predict as a response to greenhouse gases."

Antarctica

A study by Eric Steig published in 2009 noted for the first time that the continent-wide average surface temperature trend of Antarctica is slightly positive at >0.05 °C (0.09 °F) per decade from 1957 to 2006.

Global warming controversy

Using the long-term temperature trends for the earth scientists and statisticians conclude that it continues to warm through time.

Global warming in Antarctica

Research published in 2009 found that overall the continent had become warmer since the 1950s, a finding consistent with the influence of man-made climate change: "We can't pin it down, but it certainly is consistent with the influence of greenhouse gases from fossil fuels", said NASA scientist Drew Shindell, another study co-author.


“Recent computer forecasts suggest that if greenhouse gas emissions continue at a high level, parts of Antarctica could break up rapidly, causing the ocean to rise six feet or more by the end of this century.

Antarctica

If the sheet were to break down, ocean levels would rise by several metres in a relatively geologically short period of time, perhaps a matter of centuries.

Global warming

Over the 21st century, the IPCC projects that in a very high emissions scenario the sea level could rise by 61–110 cm.

Sea level rise

Sea level rise

If emissions remain very high, the IPCC projects sea level will rise by 52–98 cm (20–39 in).

Sea level rise

Continued carbon dioxide emissions from fossil fuel sources could cause additional tens of metres of sea level rise, over the next millennia, and the available fossil fuel on Earth is even enough to ultimately melt the entire Antarctic ice sheet, causing about 58 m (190 ft) of sea level rise.


‘We could be decades too fast, or decades too slow,’said one of them, Robert M. DeConto of the University of Massachusetts, Amherst.

Cambridge, Massachusetts

University of Massachusetts Amherst

from year to year, made possible the new M.A.C.

University of Massachusetts Amherst

Last of the ‘Big Four’ was President Henry H. Goodell—classicist, modern thinker, lover of literature and the arts, disciplinarian, sympathizer, self-forgetter.

University of Massachusetts Amherst

University of Massachusetts Amherst


In their worst-case scenario, the sea level could rise by six feet by the end of this century, and the pace could pick up drastically in the 22nd century.

Global warming

Intergovernmental Panel on Climate Change:237

Among other findings, the report concluded that sea level rises could be up to two feet higher by the year 2100, even if efforts to reduce greenhouse gas emissions and to limit global warming are successful; coastal cities across the world could see so-called "storm[s] of the century" at least once a year.

Sea level rise

According to the Fourth (2017) National Climate Assessment (NCA) of the United States it is very likely sea level will rise between 30 and 130 cm (1.0–4.3 feet) in 2100 compared to the year 2000.

Sea level rise

In 2019, a study projected that in low emission scenario, sea level will rise 30 centimeters by 2050 and 69 centimetres by 2100, relatively to the level in 2000.

Sea level rise

A number of later studies have concluded that a global sea level rise of 200 to 270 cm (6.6 to 8.9 ft) this century is "physically plausible".


In a study last year, Robert M. DeConto of the University of Massachusetts, Amherst, and David Pollard of Pennsylvania State University used their computer model to predict what would happen if emissions were reduced sharply over the next few decades, in line with international climate goals.

Emissions trading

These studies used mathematical models of several cities and their emission sources in order to compare the cost and effectiveness of various control strategies.

Global warming

Decision 1/CP.16, paragraph 4, in UNFCCC: Cancun 2010: "deep cuts in global greenhouse gas emissions are required according to science, and as documented in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, with a view to reducing global greenhouse gas emissions so as to hold the increase in global average temperature below 2 °C above preindustrial levels".

Global warming

The 10th Emissions Gap Report issued by the United Nations Environment Programme (UNEP) predicts that if emissions continue to increase at the same rate as they have in 2010–2020, global temperatures would rise by as much as 4° by 2100.

Global warming

Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further 0.3 to 1.7 °C (0.5 to 3.1 °F) in a moderate scenario, or as much as 2.6 to 4.8 °C (4.7 to 8.6 °F) in an extreme scenario, depending on the rate of future greenhouse gas emissions and on climate feedback effects.

University of Massachusetts Amherst

He and colleagues at the Political Economy Research Institute have developed a plan for national recovery that shows, for example, that investing in clean energy (wind power, solar, and biofuels) will create about three times as many good-paying jobs than conventional projects will, while reducing greenhouse gas emissions and dependence on foreign oil.


Under the most ambitious scenarios, they found a strong likelihood that Antarctica would remain fairly stable.”

Antarctica

The sheet has been of recent concern because of the small possibility of its collapse.

Global warming

Intergovernmental Panel on Climate Change:128

Projections based on the Special Report on Emissions Scenarios suggest warming over the 21st century at a more rapid rate than that experienced for at least the last 10,000 years.

Intergovernmental Panel on Climate Change:193

Pledges made as part of the Cancún Agreements are broadly consistent with cost-effective scenarios that give a "likely" chance (66-100% probability) of limiting global warming (in 2100) to below 3 °C, relative to pre-industrial levels.

Intergovernmental Panel on Climate Change:209

(2007) stated that the SRES represented "a substantial advance from prior scenarios".


The Alaskan tundra is warming so quickly it has become a net emitter of carbon dioxide ahead of schedule, a new study finds

Arctic

The current Arctic warming is leading to ancient carbon being released from thawing permafrost, leading to methane and carbon dioxide production by micro-organisms.

Carbon dioxide in Earth's atmosphere

The greenhouse effect is a process by which thermal radiation from a planetary atmosphere warms the planet's surface beyond the temperature it would have in the absence of its atmosphere.

Coal

The largest and most long term effect of coal use is the release of carbon dioxide, a greenhouse gas that causes climate change and global warming.

Fossil fuel power station

Fossil fueled power stations are major emitters of carbon dioxide (CO2), a greenhouse gas which is a major contributor to global warming.

Global warming

One potential source of abrupt climate change would be the rapid release of methane and carbon dioxide from permafrost, which would amplify global warming.


Melting permafrost can release not just CO2, but also methane, a much stronger heat-trapping gas.

Permafrost

Permafrost and clathrates degrade on warming, and thus, large releases of methane from these sources may arise as a result of global warming.

Permafrost

It is thought that permafrost thawing could exacerbate global warming by releasing methane and other hydrocarbons, which are powerful greenhouse gases.

Permafrost

It also contains gas hydrates in places, which are a "potential abundant source of energy" but may also destabilize as subsea permafrost warms and thaws, producing large amounts of methane gas, which is a potent greenhouse gas.

Permafrost

The consequence is thawing soil, which may be weaker, and release of methane, which contributes to an increased rate of global warming as part of a feedback loop.

Tundra

When the permafrost melts, it releases carbon in the form of carbon dioxide and methane, both of which are greenhouse gases.


Data from NOAA’s Barrow Alaska station ‘indicate that October through December emissions of CO2 from surrounding tundra increased by 73 percent since 1975, supporting the view that rising temperatures have made Arctic ecosystems a net source of CO2.’”

Carbon dioxide

Increases in atmospheric concentrations of CO 2 and other long-lived greenhouse gases such as methane, nitrous oxide and ozone have correspondingly strengthened their absorption and emission of infrared radiation, causing the rise in average global temperature since the mid-20th century.

Greenhouse gas

The spread of land plants is thought to have reduced CO 2 concentrations during the late Devonian, and plant activities as both sources and sinks of CO 2 have since been important in providing stabilising feedbacks.

Greenhouse gas

The seven sources of CO 2 from fossil fuel combustion are (with percentage contributions for 2000–2004): Carbon dioxide, methane, nitrous oxide (N 2O) and three groups of fluorinated gases (sulfur hexafluoride (SF 6), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs)) are the major anthropogenic greenhouse gases, and are regulated under the Kyoto Protocol international treaty, which came into force in 2005.

Greenhouse gas

Between the period 1970 to 2004, greenhouse gas emissions (measured in CO 2-equivalent) increased at an average rate of 1.6% per year, with CO 2 emissions from the use of fossil fuels growing at a rate of 1.9% per year.

Greenhouse gas

The sharp acceleration in CO 2 emissions since 2000 to more than a 3% increase per year (more than 2 ppm per year) from 1.1% per year during the 1990s is attributable to the lapse of formerly declining trends in carbon intensity of both developing and developed nations.


ever since December temperatures in the Arctic have consistently been lower than minus 20 C

Arctic Ocean

As recently as 55 million years ago, during the Paleocene–Eocene Thermal Maximum, the region reached an average annual temperature of 10–20 °C (50–68 °F).

Arctic

Another definition of the Arctic is the region where the average temperature for the warmest month (July) is below 10 °C (50 °F); the northernmost tree line roughly follows the isotherm at the boundary of this region.

Arctic

Average winter temperatures can go as low as −40 °C (−40 °F), and the coldest recorded temperature is approximately −68 °C (−90 °F).

North Pole

It was estimated that the temperature at the North Pole was between 30 and 35 °F (−1 and 2 °C) during the storm.

North Pole

The highest temperature yet recorded is 13 °C (55 °F), much warmer than the South Pole's record high of only −12.3 °C (9.9 °F).


This means the global temperature trend has now shown no further warming for 19 years

Global warming

Multiple independently produced instrumental datasets confirm that the 2009–2018 decade was 0.93 ± 0.07 °C warmer than the pre-industrial baseline (1850–1900).

Global warming

Currently, surface temperatures are rising by about 0.2 °C per decade.

Scientific consensus on climate change:150

Scientific consensus on climate change

Human-caused increases in greenhouse gases are responsible for most of the observed global average surface warming of roughly 0.8 °C (1.5 °F) over the past 140 years.

Scientific consensus on climate change:48

Scientific consensus on climate change

Global warming in this case was indicated by an increase of 0.75 degrees in average global temperatures over the last 100 years.

Scientific consensus on climate change:507

Scientific consensus on climate change

Since the start of the 20th century, the global mean surface temperature of the Earth has increased by more than 0.7°C and the rate of warming has been largest in the last 30 years.


In April the extent of Arctic sea ice was back to where it was in April 13 years ago

Arctic Ocean

Estimates vary for when the last time the Arctic was ice-free: 65 million years ago when fossils indicate that plants existed there to as recently as 5,500 years ago; ice and ocean cores going back 8,000 years to the last warm period or 125,000 during the last intraglacial period.

Ice age

The last cold episode of the last glacial period ended about 10,000 years ago.

Norwegian Sea

The Norwegian Sea (Norwegian: Norskehavet) is a marginal sea in the Arctic Ocean, northwest of Norway between the North Sea and the Greenland Sea, adjoining the Barents Sea to the northeast.

Norwegian Sea

Sea ice is a common problem in the Arctic seas, but ice-free conditions along the entire northern route were observed at the end of August 2008.

Sea

Increased melting of Arctic ice since 2007 enables ships to travel the Northwest Passage for some weeks in summertime, avoiding the longer routes via the Suez Canal or the Panama Canal.


He said: ‘We have had five warming cycles since about 900AD, each followed by a dramatic cooling cycle.’

Ice age

The reflection of energy into space resulted in a global cooling, triggering the Pleistocene Ice Age.

John D. Hamaker

In Paul Kelbie's article Remineralization Might Save Us From Global Warming, in The Independent, he wrote that since the last ice age, three million years ago, the Earth has gone through 25 glaciations, each lasting about 90,000 years, and that we are now 10,800 years into an interglacial – a hiatus between ice–ages.

Little Ice Age

In the North Atlantic, sediments accumulated since the end of the last ice age, nearly 12,000 years ago, show regular increases in the amount of coarse sediment grains deposited from icebergs melting in the now open ocean, indicating a series of 1–2 °C (2–4 °F) cooling events recurring every 1,500 years or so.

Little Ice Age

The Spörer Minimum has also been identified with a significant cooling period between 1460 and 1550.

Little Ice Age

This may have caused the initial cooling, and the 1452–53 eruption of Kuwae in Vanuatu triggered a second pulse of cooling.


Sea ice has diminished much faster than scientists and climate models anticipated.

Arctic sea ice decline

A 2007 study found the decline to be "faster than forecasted" by model simulations.

Arctic sea ice decline

However, these models do tend to underestimate the rate of sea ice loss since 2007.

Effects of global warming

Since 1979, satellite records indicate the decline in summer sea ice coverage has been about 13% per decade.

Global warming

Past models have underestimated the rate of Arctic shrinkage and underestimated the rate of precipitation increase.

Sea level rise

However scientists have found that ice is being lost, and at an accelerating rate.


“Arctic land stores about twice as much carbon as the atmosphere.

Atmospheric methane

Permafrost contains almost twice as much carbon as is present in the atmosphere.

Climate change feedback

The carbon currently stored in peatlands (390–455 gigatonnes, one-third of the total land-based carbon store) is over half the amount of carbon already in the atmosphere.

Mars

The atmosphere of Mars consists of about 96% carbon dioxide, 1.93% argon and 1.89% nitrogen along with traces of oxygen and water.

Permafrost

The amount of carbon sequestered in permafrost is four times the carbon that has been released to the atmosphere due to human activities in modern time.

Sperm whale

By reducing the abundance of sperm whales in the Southern Ocean, whaling has resulted in an extra 2 million tonnes of carbon remaining in the atmosphere each year.


The gas builds up in the soil, forming mounds called ‘pingoes.’

Effigy Mounds National Monument

However, mounds in the shape of mammals, birds, or reptiles, known as effigies, apparently were constructed primarily by peoples in what is now known as southern Wisconsin, northeast Iowa, and small parts of Minnesota and Illinois.

Soil

At the next larger scale, soil structures called peds or more commonly soil aggregates are created from the soil separates when iron oxides, carbonates, clay, silica and humus, coat particles and cause them to adhere into larger, relatively stable secondary structures.

Soil

The clumping of the soil textural components of sand, silt and clay causes aggregates to form and the further association of those aggregates into larger units creates soil structures called peds (a contraction of the word pedolith).

Soil

At the same time, root hairs and fungal hyphae create microscopic tunnels that break up peds.

Soil

Phosphorus is largely immobile in the soil and is not leached but actually builds up in the surface layer if not cropped.


The extreme cycles of dry and wet weather appear to have been intensifying over the last three decades.

Effects of global warming

In the last 30–40 years, heat waves with high humidity have become more frequent and severe.

El Niño–Southern Oscillation

The western side of the equatorial Pacific is characterized by warm, wet, low-pressure weather as the collected moisture is dumped in the form of typhoons and thunderstorms.

Global warming

Since the 1950s, droughts and heat waves have appeared simultaneously with increasing frequency.

Little Ice Age

Disease tends to intensify under the same conditions that unemployment and economic difficulties arise: prolonged, cold, dry seasons.

Sahara

The climate of the Sahara has undergone enormous variations between wet and dry over the last few hundred thousand years, believed to be caused by long-term changes in the North African climate cycle that alters the path of the North African Monsoon – usually southward.


“Warm weather worsened the most recent five-year drought, which included the driest four-year period on record in terms of statewide precipitation.

2006 European heat wave

The Environment Agency claimed that the UK may have had the most severe drought in 100 years.

2006 European heat wave

Despite the low rainfall, drought was not an issue in Ireland.

2006 European heat wave

The Netherlands also had to deal with extreme drought in June and July.

Climate change in Australia

He says that the drought in Australia is already 8 years long.

Drought in the United Kingdom

A significant hydrological drought occurred in the United Kingdom between 1995 and 1998, when the warm, dry summers were followed by dry, cool winters.


Not everyone is convinced that the evidence is in that climate change is responsible for extreme swings between drought and deluge.

Physical impacts of climate change

Scientists have found evidence that increased evaporation could result in more extreme weather as global warming progresses.

Scientific consensus on climate change:134

Scientific consensus on climate change

Scientific consensus on climate change:307

Scientific consensus on climate change

Network of African Science Academies: "A consensus, based on current evidence, now exists within the global scientific community that human activities are the main source of climate change and that the burning of fossil fuels is largely responsible for driving this change."

Scientific consensus on climate change:667

Scientific consensus on climate change

Rises in temperature will have complex and frequently localised effects on weather, but an overall increase in extreme weather conditions and changes in precipitation patterns are probable, resulting in flooding and drought.

Scientific consensus on climate change:693

Scientific consensus on climate change

Health impacts of climate change include the direct impacts of extreme events such as storms, floods, heatwaves and fires and the indirect effects of longer-term changes, such as drought, changes to the food and water supply, resource conflicts and population shifts.


‘The dry periods are drier and the wet periods are wetter,’ said Jeffrey Mount, a water expert and senior fellow at the Public Policy Institute of California.

Effects of global warming

In other words, regions which are dry at present will in general become even drier, while regions that are currently wet will in general become even wetter.

Kalahari Desert

In certain areas where the climate is drier, it becomes a true semi-desert with ground not entirely covered by vegetation: "open" as opposed to "closed" vegetation.

Physical impacts of climate change

In other words, regions which are dry at present will generally become even drier, while regions that are currently wet will generally become even wetter.

Water cycle

Will the wet get wetter and the dry drier?

Wetland

Wetlands can be dry during the dry season and abnormally dry periods during the wet season, but under normal environmental conditions the soils in a wetland will be saturated to the surface or inundated such that the soils become anaerobic, and those conditions will persist through the wet portion of the growing season.


The unlikely scenarios are now, all of a sudden, becoming more probable than they once were thought to be,’ says Sweet.”

Anglo-Saxon settlement of Britain

In recent decades, a few specialists have continued to support this interpretation, and Peter Schrijver has said that 'to a large extent, it is linguistics that is responsible for thinking in terms of drastic scenarios' about demographic change in late Roman Britain.

Anglo-Saxon settlement of Britain

Many feasible scenarios can be constructed to account for evidence.

Anglo-Saxon settlement of Britain

Therefore, scenarios that are not justified by other evidence or are created to account for the historical evidence have not been universally accepted.

Indo-Aryan migration

The reverse possibility, that a small group broke off and wandered from India into Western Asia is readily dismissed as an improbably long migration, again without the least bit of evidence.

July Crisis

On the contrary, there are reasons to believe that this is altogether out of the question."


many of south Florida’s drainage systems and seawalls are no longer enough

Beach nourishment

The restoration was complicated by the presence of old seawalls, groins, piles of rocks and other structures.

Beach nourishment

The structural alternative involves constructing a seawall, revetment, groyne or breakwater.

Hurricane Donna

Heavy rains and poor drainage in some areas flooded basements, lawns, and streets.

Lake Worth Beach, Florida

As in the flatwoods, these soils are poorly drained for many purposes unless drainage systems are installed.

Seawall

A seawall (or sea wall) is a form of coastal defense constructed where the sea, and associated coastal processes, impact directly upon the landforms of the coast.


Sea level rise

Since at least the start of the 20th century, the average global sea level has been rising.

Sea level rise

With continued melt and retreat they contribute to raising global sea levels.

Sea level rise

Sea ice melt contributes very slightly to global sea level rise.

Sea level rise

"One of the most striking trends – over a century of global-average sea level change".

Sea level rise

"20th century acceleration in global sea-level rise".


While there has been a mean rise of a little more than 3mm per year worldwide since the 1990s, in the last decade, the NOAA Virginia Key tide gauge just south of Miami Beach has measured a 9mm rise annually.”

Global warming

Between 1993 and 2017, the global mean sea level rose on average by 3.1 ± 0.3 mm per year, with an acceleration detected as well.

Sea level rise

This could mean rapid sea level rise of up to 19 mm (0.75 in) per year by the end of the century.

Sea level rise

Current rates of sea level rise from satellite altimetry have been estimated to be 3.0 ± 0.4 millimetres (0.118 ± 0.016 in) per year for the period 1993–2017.

Sea level rise

This network was used, in combination with satellite altimeter data, to establish that global mean sea-level rose 19.5 cm (7.7 in) between 1870 and 2004 at an average rate of about 1.44 mm/yr (1.7 mm/yr during the 20th century).

Sea level rise

Data collected by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia show the current global mean sea level trend to be 3.2 mm (0.13 in) per year, a doubling of the rate during the 20th century.


says Sweet, who has authored several sea-level rise studies.

Global warming

Global warming

"Contribution of Antarctica to past and future sea-level rise".

Global warming

Global warming

Over the 21st century, the IPCC projects that in a very high emissions scenario the sea level could rise by 61–110 cm.

Global warming

Sea level rise will continue over many centuries.


“The Northern Hemisphere jet stream […] flow is stronger when that temperature difference is large.

Jet stream

This in turn reduces the temperature gradient that drives jet stream winds, which may eventually cause the jet stream to become weaker and more variable in its course.

Jet stream

If two air masses of different temperatures or densities meet, the resulting pressure difference caused by the density difference (which ultimately causes wind) is highest within the transition zone.

Jet stream

Therefore, the strong eastward moving jet streams are in part a simple consequence of the fact that the Equator is warmer than the North and South poles.

Pacific Ocean

The Westerlies and associated jet stream within the Mid-Latitudes can be particularly strong, especially in the Southern Hemisphere, due to the temperature difference between the tropics and Antarctica, which records the coldest temperature readings on the planet.

Weather

The strong temperature contrast between polar and tropical air gives rise to the large scale atmospheric circulation cells and the jet stream.


But when the Arctic warms up faster than the equator does […] the jet stream’s flow can become weakened and elongated.

Jet stream

During the Dust Bowl, the jet stream weakened and changed course traveling farther south than normal.

Jet stream

Jet stream

With a weaker jet stream, the Polar vortex has a higher probability to leak out of the polar area and bring extremely cold weather to the middle latitude regions.

Jet stream

During these dark months the air high over the poles becomes much colder than the air over the Equator.

Jet stream


Ever since 2012, scientists have been debating a complex and frankly explosive idea about how a warming planet will alter our weather — one that, if it’s correct, would have profound implications across the Northern Hemisphere and especially in its middle latitudes

Global cooling

Whether this be due directly to the health, disposition or constitution of our globe itself, or to the weather from without, as the new glacial cosmogony would teach us, must remain a question for experts to debate, if not settle.

Global warming controversy

Public disputes that also reflect scientific debate include estimates of how responsive the climate system might be to any given level of greenhouse gases (climate sensitivity), how the climate will change at local and regional scales, and what the consequences of global warming will be.

Scientific consensus on climate change:110

Scientific consensus on climate change

Problems of global warming, climate change, and their various negative impacts on human life and on the functioning of entire societies are one of the most dramatic challenges of modern times.

Scientific consensus on climate change:228

Scientific consensus on climate change

The letter goes on to warn of predicted impacts on the United States such as sea level rise and increases in extreme weather events, water scarcity, heat waves, wildfires, and the disturbance of biological systems.

Scientific consensus on climate change:38

Scientific consensus on climate change

It said that Continued emission of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems.


‘This study goes beyond statistical correlations and explores a specific process that can plausibly explain how enhanced high-latitude warming trends may trigger remote weather impacts,’ he said.

Arctic sea ice decline

This relationship has been documented through observation evidence and model responses to sea ice loss according to the 2017 Wiley Periodicals Article, Amplified Arctic warming and mid latitude weather: new perspectives on emerging connections.

Arctic sea ice decline

Correlations have been identified between high-latitude cryosphere changes, hemispheric wind patterns and mid-latitude extreme weather events for the Northern Hemisphere.

Climate of Mars

K. I. Abdusamatov has proposed that "parallel global warmings" observed simultaneously on Mars and on Earth can only be a consequence of the same factor: a long-time change in solar irradiance."

Granger causality

Ordinarily, regressions reflect "mere" correlations, but Clive Granger argued that causality in economics could be tested for by measuring the ability to predict the future values of a time series using prior values of another time series.

Psychology

Observational studies analyze uncontrolled data in search of correlations; multivariate statistics are typically used to interpret the more complex situation.


A recent study in Nature Geoscience, for instance, called into question whether the Arctic’s melting, and in particular its sea ice loss, has been causing winter cooling over Eurasia, another idea that has been swept up in the debate over the jet stream and weather extremes.”

Arctic sea ice decline

In a 2017 study conducted by climatologist Dr. Judah Cohen and several of his research associates, Cohen wrote that "[the] shift in polar vortex states can account for most of the recent winter cooling trends over Eurasian midlatitudes".

Global warming

Various mechanisms have been identified that might explain extreme weather in mid-latitudes from the rapidly warming Arctic, such as the jet stream becoming more erratic.

Polar amplification

Studies published in 2017 and 2018 identified stalling patterns of rossby waves, in the northern hemisphere jet stream, to have caused almost stationary extreme weather events, such as the 2018 European heatwave, the 2003 European heat wave, 2010 Russian heat wave, 2010 Pakistan floods - these events have been linked to global warming, the rapid heating of the Arctic.

Polar amplification

Cold Arctic air intrudes into the warmer lower latitudes more rapidly today during autumn and winter, a trend projected to continue in the future except during summer, thus calling into question whether winters will bring more cold extremes.

Rossby wave

In 2011, a Nature Geoscience study using general circulation models linked Pacific Rossby waves generated by increasing central tropical Pacific temperatures to warming of the Amundsen Sea region, leading to winter and spring continental warming of Ellsworth Land and Marie Byrd Land in West Antarctica via an increase in advection.


‘With levels of carbon dioxide in the atmosphere consistently breaking new records, the influence of human activities on the climate system has become more and more evident,’ said Taalas.

Carbon dioxide in Earth's atmosphere:140

Carbon dioxide in Earth's atmosphere

While CO 2 absorption and release is always happening as a result of natural processes, the recent rise in CO 2 levels in the atmosphere is known to be mainly due to human (anthropogenic) activity.

SUPPORTS SUPPORTS SUPPORTS NOT_ENOUGH_INFO SUPPORTS

Global warming

The Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report concluded, "It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century".

SUPPORTS SUPPORTS SUPPORTS SUPPORTS SUPPORTS

Greenhouse gas

It is likely that anthropogenic (i.e., human-induced) warming, such as that due to elevated greenhouse gas levels, has had a discernible influence on many physical and biological systems.

Scientific consensus on climate change:571

Scientific consensus on climate change

Because the complexity of the climate makes accurate prediction difficult, the APS urges an enhanced effort to understand the effects of human activity on the Earth's climate, and to provide the technological options for meeting the climate challenge in the near and longer terms.

Scientific consensus on climate change:692

Scientific consensus on climate change

While ‘climate change’ can be due to natural forces or human activity, there is now substantial evidence to indicate that human activity – and specifically increased greenhouse gas (GHGs) emissions – is a key factor in the pace and extent of global temperature increases.


‘Arctic ice conditions have been tracking at record low conditions since October, persisting for six consecutive months’

Arctic sea ice decline

"Arctic Sea Ice Hits Record Low—Extreme Weather to Come?".

Arctic sea ice decline

Scientists recently measured sixteen-foot (five-meter) wave heights during a storm in the Beaufort Sea in mid-August until late October 2012.

Arctic sea ice decline

Given the estimated trend and the volume estimate for October–November of 2007 at less than 9,000 km3, one can project that at this rate it would take only 9 more years or until 2016 ± 3 years to reach a nearly ice-free Arctic Ocean in summer.

Arctic sea ice decline

The previous record of the lowest area of the Arctic Ocean covered by ice in 2012 saw a low of 1.58 million square miles (4.09 million square kilometers).

Methane

"Arctic sea ice reaches lowest extent for the year and the satellite record" (Press release).


“‘The Arctic may be remote, but changes that occur there directly affect us.

Arctic

The Arctic is especially vulnerable to the effects of any climate change, as has become apparent with the reduction of sea ice in recent years.

Arctic

Climate change is also predicted to have a large impact on Tundra vegetation, causing an increase of shrubs, and having a negative impact on bryophytes and lichens.

Climate change in the Arctic

Climate change is having a direct impact on the people that live in the Arctic, as well as other societies around the world.

Climate change in the United States

As an island Territory, we are directly and immediately impacted by global climate change.

El Niño

As a result of this change, Micronesia is more likely to be affected by tropical cyclones, while China has a decreased risk of being affected by tropical cyclones.


The melting of the Greenland ice sheet is already contributing significantly to sea level rise, and new research is highlighting that the melting of Arctic sea ice can alter weather conditions across Europe, Asia and North America.’”

Greenland ice sheet

The Greenland Ice Sheet has experienced record melting in recent years since detailed records have been kept and is likely to contribute substantially to sea level rise as well as to possible changes in ocean circulation in the future if this is sustained.

Greenland ice sheet

Ice sheet models project that such a warming would initiate the long-term melting of the ice sheet, leading to a complete melting of the ice sheet (over centuries), resulting in a global sea level rise of about 7 metres (23 ft).

Greenland ice sheet

Besides contributing to global sea level rise, the process adds freshwater to the ocean, which may disturb ocean circulation and thus regional climate.

Greenland

The glaciers of Greenland are also contributing to a rise in the global sea level faster than was previously believed.

Sea level rise

There is a threshold in surface warming beyond which a partial or near-complete melting of the Greenland ice sheet occurs.


Global sea level rise surged between November 2014 and February 2016, with the El Niño event helping the oceans rise by 15mm.

2014–16 El Niño event

The 2014–16 El Niño was a warming of the eastern equatorial Pacific Ocean that resulted in unusually warm waters developing between the coast of South America and the International Date Line.

2014–16 El Niño event

As El Niño conditions started to develop during early 2014, sea levels in western Micronesia including in waters surrounding the island nations of Palau and Guam dropped by 6–9 feet (1.8–2.7 m).

Sea level rise

Between 1900 and 2016, the sea level rose by 16–21 cm (6.3–8.3 in).

Sea level rise

This in turn caused sea-levels to rise 20 metres.

Sea level rise


Final data for 2016 sea level rise have yet to be published.

Effects of global warming

The IPCC's Special Report on the Ocean and Cryosphere concluded that global mean sea level rose by 0.16 metres between 1901 and 2016.

Effects of global warming

Global sea level rise is accelerating, rising 2.5 times faster between 2006 and 2016 than it did during the 20th century.

Sea level rise

Sea level rise

More precise data gathered from satellite radar measurements reveal an accelerating rise of 7.5 cm (3.0 in) from 1993 to 2017, which is a trend of roughly 30 cm (12 in) per century.

Sea level rise

A 2018 systematic review study estimated that ice loss across the entire continent was 43 gigatons (Gt) per year on average during the period from 1992 to 2002, but has accelerated to an average of 220 Gt per year during the five years from 2012 to 2017.


Our children and grandchildren will look back on the climate deniers and ask how they could have sacrificed the planet for the sake of cheap fossil fuel energy, when the cost of inaction exceeds the cost of a transition to a low-carbon economy,’ Watson said.

Climate change mitigation

At the core of most proposals is the reduction of greenhouse gas (GHG) emissions through reducing energy waste and switching to low-carbon power sources of energy.

Climate change mitigation

Examples of mitigation include reducing energy demand by increasing energy efficiency, phasing out fossil fuels by switching to low-carbon energy sources, and removing carbon dioxide from Earth's atmosphere.

Global warming controversy

Robert Watson found this "very disappointing" and said "We need the public to understand that climate change is serious so they will change their habits and help us move towards a low carbon economy."

Low-carbon economy

This would make the technologies more affordable and competitive in the global market, particularly when combined with a phasing out of fossil fuel subsidies.

Low-carbon economy

Recent advances in technology and policy will allow renewable energy and energy efficiency to play major roles in displacing fossil fuels, meeting global energy demand while reducing carbon dioxide emissions.