The IPCC blames human emissions of carbon dioxide for the last  warming.

Carbon dioxide

Since the Industrial Revolution anthropogenic emissions – primarily from use of fossil fuels and deforestation – have rapidly increased its concentration in the atmosphere, leading to global warming.

Greenhouse gas

Cumulative anthropogenic (i.e., human-emitted) emissions of CO 2 from fossil fuel use are a major cause of global warming, and give some indication of which countries have contributed most to human-induced climate change.

Intergovernmental Panel on Climate Change:229

Deep reductions in non-CO2 emissions (such as nitrous oxide and methane) will also be required to limit warming to 1.5 °C.

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

The global warming observed over the past 50 years is due primarily to human-induced emissions of heat-trapping gases.


Greenhouse gases have been the main contributor of warming since 1970.

Global warming

In the scientific literature, there is an overwhelming consensus that global surface temperatures have increased in recent decades and that the trend is caused mainly by human-induced emissions of greenhouse gases.

Global warming

Before the Industrial Revolution, naturally occurring amounts of greenhouse gases caused the air near the surface to be warmer by about 33 °C (59 °F) than it would be in their absence.

Global warming

Global anthropogenic greenhouse gas emissions in 2010 were equivalent to 49 billion tonnes of carbon dioxide (using the most recent global warming potentials over 100 years from the AR5 report).

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.

Scientific consensus on climate change:150

Scientific consensus on climate change


Furthermore, it is physically incorrect to state that the planet is simply "recovering" from the Little Ice Age.

Earth

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.

Little Ice Age

This trend could be extrapolated to continue into the future, possibly leading to a full ice age, but the twentieth-century instrumental temperature record shows a sudden reversal of this trend, with a rise in global temperatures attributed to greenhouse gas emissions.

Little Ice Age

According to JM Lamb of Cambridge University the little ice age was already under way in Canada and Switzerland and in the wider North Atlantic region in the thirteenth and fourteenth centuries "Worldwide glacier retreat".

Little Ice Age

Thus current evidence does not support globally synchronous periods of anomalous cold or warmth over this interval, and the conventional terms of "Little Ice Age" and "Medieval Warm Period" appear to have limited utility in describing trends in hemispheric or global mean temperature changes in past centuries.... [Viewed] hemispherically, the "Little Ice Age" can only be considered as a modest cooling of the Northern Hemisphere during this period of less than 1°C relative to late twentieth century levels.


There are a number of forcings which affect climate (eg - stratospheric aerosols, solar variations).

Climate change (general concept)

These include processes such as variations in solar radiation, variations in the Earth's orbit, variations in the albedo or reflectivity of the continents, atmosphere, and oceans, mountain-building and continental drift and changes in greenhouse gas concentrations.

Climate system

Volcanic eruptions, solar variations and anthropogenic changes in the composition of the atmosphere and land use change are external forcings.

Climate system

These external forcings can be natural, such as variations in solar intensity and volcanic eruptions, or caused by humans.

Climate

Suggested causes of ice age periods include the positions of the continents, variations in the Earth's orbit, changes in the solar output, and volcanism.

Earth's energy budget

Natural climate forcings include changes in the Sun's brightness, Milankovitch cycles (small variations in the shape of Earth's orbit and its axis of rotation that occur over thousands of years) and volcanic eruptions that inject light-reflecting particles as high as the stratosphere.


When all forcings are combined, they show good correlation to global temperature throughout the 20th century including the mid-century cooling period.

20th century

The average global temperature on Earth has increased by about 0.8° Celsius (1.4° Fahrenheit) since 1880; Two-thirds of the warming has occurred since 1975, at a rate of roughly 0.15-0.20 °C per decade.

Global warming

IPCC AR4 WG1 Ch9 2007, p. 690: "Recent estimates indicate a relatively small combined effect of natural forcings on the global mean temperature evolution of the second half of the 20th century, with a small net cooling from the combined effects of solar and volcanic forcings."

Little Ice Age

The major differences between the various proxy reconstructions relate to the magnitude of past cool excursions, principally during the twelfth to fourteenth, seventeenth and nineteenth centuries.

Little Ice Age

There is still a very poor understanding of the correlation between low sunspot activity and cooling temperatures.

Solar activity and climate

Stott's group found that combining these factors enabled them to closely simulate global temperature changes throughout the 20th century.


The main reason behind this mid-century cooling was global dimming due to anthropogenic sulfate aerosol emissions.

Global cooling

Although the temperature drops foreseen by this mechanism have now been discarded in light of better theory and the observed warming, aerosols are thought to have contributed a cooling tendency (outweighed by increases in greenhouse gases) and also have contributed to "Global Dimming."

Global dimming

While most of the earth has warmed, the regions that are downwind from major sources of air pollution (specifically sulfur dioxide emissions) have generally cooled.

Global dimming

Global dimming is thought to have been caused by an increase in particulates or aerosols, such as sulfate aerosols in the atmosphere due to human action.

Global dimming

"Changes in mid-latitude variability due to increasing greenhouse gases and sulphate aerosols".

Global warming

From 1961 to 1990, a gradual reduction in the amount of sunlight reaching the Earth's surface was observed, a phenomenon popularly known as global dimming, typically attributed to aerosols from biofuel and fossil fuel burning.


"January 2008 capped a 12 month period of global temperature drops on all of the major well respected indicators.

Latvia

With average temperature +8.1 °C (47 °F).

Month

The Iranian / Persian calendar, currently used in Iran and Afghanistan, also has 12 months.

Year

All of these events can have wide variations of more than a month from year to year.

Year

Its average duration is 365.256363004 days (365 d 6 h 9 min 9.76 s) (at the epoch J2000.0 = January 1, 2000, 12:00:00 TT).

Year

It has a duration of approximately 354.37 days.


"The killer proof that CO2 does not drive climate is to be found during the Ordovician- Silurian and the Jurassic-Cretaceous periods when CO2 levels were greater than 4000 ppmv (parts per million by volume) and about 2000 ppmv respectively.

Devonian

The Devonian (/dɪˈvoʊn.i.ən, də-, dɛ-/ dih-VOH-nee-ən, də-, deh-) is a geologic period and system of the Paleozoic, spanning 60 million years from the end of the Silurian, 419.2 million years ago (Mya), to the beginning of the Carboniferous, 358.9 Mya.

Jurassic

The Jurassic (/dʒʊˈræs.ɪk/ juu-RASS-ik; from the Jura Mountains) is a geologic period and system that spanned 56 million years from the end of the Triassic Period 201.3 million years ago (Mya) to the beginning of the Cretaceous Period 145 Mya.

Ordovician

The Ordovician spans 41.6 million years from the end of the Cambrian Period 485.4 million years ago (Mya) to the start of the Silurian Period 443.8 Mya.

Silurian

The Silurian (/sɪˈljʊər.i.ən, saɪ-/ sih-LYOOR-ee-ən, sy-) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.8 million years ago (Mya), to the beginning of the Devonian Period, 419.2 Mya.

Triassic

The Triassic (/traɪˈæs.ɪk/ try-ASS-ik) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.9 million years ago (Mya), to the beginning of the Jurassic Period 201.3 Mya.


When CO2 levels were higher in the past, solar levels were also lower.

Anoxic event

These anoxic periods occurred at a time of low global temperatures (although CO 2 levels were high), in the midst of a glaciation.

Global warming

Less direct geological evidence indicates that CO2 values have not been this high for millions of years.

Greenhouse gas

For example, the mole fraction of carbon dioxide has increased from 280 ppm to 415 ppm, or 120 ppm over modern pre-industrial levels.

Greenhouse gas

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

Ice age

At times during the paleoclimate, carbon dioxide levels were two or three times greater than today.


"Of the rise in temperature during the 20th century, the bulk occurred from 1900 to 1940.

Moscow

The highest temperature ever recorded was 38.2 °C (100.8 °F) at the VVC weather station and 39.0 °C (102.2 °F) in the center of Moscow and Domodedovo airport on July 29, 2010 during the unusual 2010 Northern Hemisphere summer heat waves.

Moscow

The average July temperature from 1981 to 2010 is 19.2 °C (66.6 °F).

Moscow

The lowest ever recorded temperature was −42.1 °C (−43.8 °F) in January 1940.

Moscow

The annual temperature rose from 5.0 °C (41.0 °F)[citation needed] to 5.8 °C (42.4 °F) in the new 1981–2010 normals.

Rio de Janeiro

"Record lowest temperature since 7.3 °C (45.1 °F) in 2000".


That drop in temperature came after what was described in the National Geographic as 'six decades of abnormal warmth'."

Global warming

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

Global warming

The period from 1983 to 2012 was likely the warmest 30-year period of the last 1400 years in the Northern Hemisphere, where such assessment is possible (medium confidence).

Tropical cyclone

All these effects can combine to produce a dramatic drop in sea surface temperature over a large area in just a few days.

Tundra

During the winter it is very cold and dark, with the average temperature around −28 °C (−18 °F), sometimes dipping as low as −50 °C (−58 °F).

Tundra

Generally daytime temperatures during the summer rise to about 12 °C (54 °F) but can often drop to 3 °C (37 °F) or even below freezing.


Early 20th century warming was in large part due to rising solar activity and relatively quiet volcanic activity.

20th century

The average global temperature on Earth has increased by about 0.8° Celsius (1.4° Fahrenheit) since 1880; Two-thirds of the warming has occurred since 1975, at a rate of roughly 0.15-0.20 °C per decade.

20th century

One argument is that of global warming occurring due to human-caused emission of greenhouse gases, particularly carbon dioxide produced by the burning of fossil fuels.

Global warming

The slower pace of warming can be attributed to a combination of natural fluctuations, reduced solar activity, and increased volcanic activity.

Global warming

increased concentrations of greenhouse gases), solar luminosity, volcanic eruptions, and variations in the Earth's orbit around the Sun.

Huaynaputina

"Impact of powerful volcanic eruptions and solar activity on the climate above the Arctic Circle".


Volcanoes have been relatively frequent and if anything, have exerted a cooling effect.

Volcano

Large eruptions can affect temperature as ash and droplets of sulfuric acid obscure the sun and cool the Earth's lower atmosphere (or troposphere); however, they also absorb heat radiated from the Earth, thereby warming the upper atmosphere (or stratosphere).

Volcano

The aerosols increase the Earth's albedo—its reflection of radiation from the Sun back into space—and thus cool the Earth's lower atmosphere or troposphere; however, they also absorb heat radiated up from the Earth, thereby warming the stratosphere.

Volcano

Large injections may cause visual effects such as unusually colorful sunsets and affect global climate mainly by cooling it.

Volcano

This magma tends to be extremely viscous because of its high silica content, so it often does not attain the surface but cools and solidifies at depth.

Volcano

Such volcanoes are able to severely cool global temperatures for many years after the eruption due to the huge volumes of sulfur and ash released into the atmosphere.


While natural forcings can account for much of the early 20th Century warming, humans played a role as well.

Attribution of recent climate change:151

Attribution of recent climate change

(2012) stated that a combination of natural weather variability and human-induced global warming was responsible for the Moscow and Texas heat waves.

Intergovernmental Panel on Climate Change:127

Since the mid-20th century, most of the observed warming is "likely" (greater than 66% probability, based on expert judgement) due to human activities.

Intergovernmental Panel on Climate Change:158

Most of the global average warming over the past 50 years is "very likely" (greater than 90% probability, based on expert judgement) due to human activities.

Intergovernmental Panel on Climate Change:190

It is extremely likely (95-100% probability) that human influence was the dominant cause of global warming between 1951-2010.

Little Ice Age

Some researchers have proposed that human influences on climate began earlier than is normally supposed (see Early anthropocene for more details) and that major population declines in Eurasia and the Americas reduced this impact, leading to a cooling trend.


"Satellite measurements indicate an absence of significant global warming since 1979, the very period that human carbon dioxide emissions have been increasing rapidly.

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.

Carbon dioxide

Since the Industrial Revolution anthropogenic emissions – primarily from use of fossil fuels and deforestation – have rapidly increased its concentration in the atmosphere, leading to global warming.

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

In the scientific literature, there is an overwhelming consensus that global surface temperatures have increased in recent decades and that the trend is caused mainly by human-induced emissions of greenhouse gases.

Global warming

Human activity since the Industrial Revolution has increased the amount of greenhouse gases in the atmosphere, leading to increased radiative forcing from CO2, methane, tropospheric ozone, CFCs, and nitrous oxide.


Warming trends agree well with surface temperatures and model predictions except near the Poles.

Climate

These models predict an upward trend in the global mean surface temperature, with the most rapid increase in temperature being projected for the higher latitudes of the Northern Hemisphere.

General circulation model

These models project an upward trend in the surface temperature record, as well as a more rapid increase in temperature at higher altitudes.

Global warming

Sea level rise since 1990 was underestimated in older models, but now agrees well with observations.

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.

Global warming

In the tropics the net effect is to produce a significant warming, while at latitudes closer to the poles a loss of albedo leads to an overall cooling effect.


The global dimming trend reversed around 1990 - 15 years after the global warming trend began in the mid 1970's.

Global dimming

Global dimming

The brightening seen at sites in Antarctica during the 1990s, influenced by recovering from the Mount Pinatubo volcanic eruption in 1991, fades after 2000.

Global dimming

In China there is some indication for a renewed dimming, after the stabilization in the 1990s.

Global dimming

A 2007 NASA sponsored satellite-based study sheds light on the puzzling observations by other scientists that the amount of sunlight reaching Earth's surface had been steadily declining in recent decades, began to reverse around 1990.

Global warming

From 1961 to 1990, a gradual reduction in the amount of sunlight reaching the Earth's surface was observed, a phenomenon popularly known as global dimming, typically attributed to aerosols from biofuel and fossil fuel burning.


(Kerr 2007) points out that the sunlight-reflecting haze that cools much of the planet seems to have thinned over the past decade or so.

Pale Blue Dot

Pale Blue Dot is a photograph of planet Earth taken on February 14, 1990, by the Voyager 1 space probe from a record distance of about 6 billion kilometers (3.7 billion miles, 40.5 AU), as part of that day's Family Portrait series of images of the Solar System.

Pale Blue Dot

In the photograph, Earth's apparent size is less than a pixel; the planet appears as a tiny dot against the vastness of space, among bands of sunlight reflected by the camera.

Pale Blue Dot

Earth appears as a blue dot primarily because of Rayleigh scattering of sunlight in its atmosphere.

Titan (moon)

Before the arrival of Voyager 1 in 1980, Titan was thought to be slightly larger than Ganymede (diameter 5,262 kilometers (3,270 mi)) and thus the largest moon in the Solar System; this was an overestimation caused by Titan's dense, opaque atmosphere, with a haze layer 100-200 kilometres above its surface.

Titan (moon)

Conversely, haze in Titan's atmosphere contributes to an anti-greenhouse effect by reflecting sunlight back into space, cancelling a portion of the greenhouse effect and making its surface significantly colder than its upper atmosphere.


The warm and cool regions roughly balance each other out with little impact on global temperature.

Global warming

The main balancing feedback to global temperature change is radiative cooling to space as infrared radiation, which increases strongly with increasing temperature.

Global warming

This could trigger cooling in the North Atlantic, Europe, and North America.

Global warming

Globally, these effects are estimated to have led to a slight cooling, dominated by an increase in surface albedo.

Global warming

Terraforming of Venus

This in turn would raise planetary albedo and act to cool the global temperature to Earth-like levels, despite the greater proximity to the Sun.


"Britain's big freeze is the start of a worldwide trend towards colder weather that seriously challenges global warming theories, eminent scientists claimed yesterday.

Climate change (general concept)

As a consequence of humans emitting greenhouse gases, global surface temperatures have started rising.

Climate change denial

Climate change denialism is the prime example, where a handful of scientists, allied with an effective PR machine, are publicly challenging the scientific consensus that global warming is real and is due primarily to human consumption of fossil fuels.

Global cooling

The current scientific consensus on climate change is that the Earth underwent global warming throughout the 20th century and continues to warm.

Global dimming

His findings appeared to contradict global warming — the global temperature had been generally rising since the 70s.

Ice age

The consensus theory of the scientific community is that the resulting greenhouse effect is a principal cause of the increase in global warming which has occurred over the same period, and a chief contributor to the accelerated melting of the remaining glaciers and polar ice.


The world has entered a 'cold mode' which is likely to bring a global dip in temperatures which will last for 20 to 30 years, they say.

Climate change mitigation

One of the targets that has been suggested is to limit the future increase in global mean temperature (global warming) to below 2 °C, relative to the pre-industrial level.

Climate change mitigation

They say that even if all the current pledges will be accomplished there is a chance for a 4.5 degree temperature rise in decades.

Climate

Increases in greenhouse gases, such as by volcanic activity, can increase the global temperature and produce an interglacial period.

Climate

These models predict an upward trend in the global mean surface temperature, with the most rapid increase in temperature being projected for the higher latitudes of the Northern Hemisphere.

Sea surface temperature

At heights near the tropopause, the 30-year average temperature (as measured in the period encompassing 1961 through 1990) was −77 °C (−132 °F).


A natural cycle requires a forcing, and no known forcing exists that fits the fingerprints of observed warming - except anthropogenic greenhouse gases.

Global warming

Attributing detected temperature changes and extreme events to human-caused increases in greenhouse gases requires scientists to rule out known internal climate variability and natural external forcings.

Global warming

Increased concentrations of gases such as CO 2 (~20%), ozone and N 2O are external forcing on the other hand.

Global warming

Human activity since the Industrial Revolution has increased the amount of greenhouse gases in the atmosphere, leading to increased radiative forcing from CO2, methane, tropospheric ozone, CFCs, and nitrous oxide.

Scientific consensus on climate change:115

Scientific consensus on climate change

Scientific consensus on climate change:511

Scientific consensus on climate change

The spatial and temporal fingerprint of warming can be traced to increasing greenhouse gas concentrations in the atmosphere, which are a direct result of burning fossil fuels, broad-scale deforestation and other human activity."


The minute increase of anthropogenic CO2 in the atmosphere (0.008%) was not the cause of the warming—it was a continuation of natural cycles that occurred over the past 500 years."

Carbon dioxide in Earth's atmosphere

Following the start of the Industrial Revolution, atmospheric CO 2 concentration increased to over 400 parts per million and continues to increase, causing the phenomenon of global warming.

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.

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.

Scientific consensus on climate change:130

Scientific consensus on climate change

The introduction includes this statement: There is strong evidence that the warming of the Earth over the last half-century has been caused largely by human activity, such as the burning of fossil fuels and changes in land use, including agriculture and deforestation.

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.


The El Nino Southern Oscillation shows close correlation to global temperatures over the short term.

El Niño–Southern Oscillation

El Niño events cause short-term (approximately 1 year in length) spikes in global average surface temperature while La Niña events cause short term cooling.

El Niño–Southern Oscillation

Therefore, the relative frequency of El Niño compared to La Niña events can affect global temperature trends on decadal timescales.

El Niño–Southern Oscillation

The studies of historical data show the recent El Niño variation is most likely linked to global warming.

El Niño–Southern Oscillation

For example, an increase in the frequency and magnitude of El Niño events have triggered warmer than usual temperatures over the Indian Ocean, by modulating the Walker circulation.

El Niño–Southern Oscillation

Changes in the Walker circulation with time occur in conjunction with changes in surface temperature.


However, it is unable to explain the long term warming trend over the past few decades.

Attribution of recent climate change

Over the past five decades there has been a global warming of approximately 0.65 °C (1.17 °F) at the Earth's surface (see historical temperature record).

Global warming

In the scientific literature, there is an overwhelming consensus that global surface temperatures have increased in recent decades and that the trend is caused mainly by human-induced emissions of greenhouse gases.

Hockey stick controversy

The New York Times highlighted their finding that the 20th century had been the warmest century in 600 years, quoting Mann saying that "Our conclusion was that the warming of the past few decades appears to be closely tied to emission of greenhouse gases by humans and not any of the natural factors".

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."

Phenology

Between 1850 and 1950 a long-term trend of gradual climate warming is observable, and during this same period the Marsham record of oak-leafing dates tended to become earlier.


"Three Australasian researchers have shown that natural forces are the dominant influence on climate, in a study just published in the highly-regarded Journal of Geophysical Research.

Antarctica

Some scientific studies suggest that ozone depletion may have a dominant role in governing climatic change in Antarctica (and a wider area of the Southern Hemisphere).

Attribution of recent climate change:110

Attribution of recent climate change

As noted, clear and compelling scientific evidence supports the case for a pronounced human influence on global climate.

Attribution of recent climate change

According to the Intergovernmental Panel on Climate Change (IPCC), it is "extremely likely" that human influence was the dominant cause of global warming between 1951 and 2010.

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".

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".


Mount Kilimanjaro's shrinking glacier is complicated and not due to just global warming.

Mount Kenya

There are currently 11 small glaciers, which are shrinking rapidly, and will likely be gone forever by 2050, due to global warming[citation needed].

Mount Kilimanjaro

It appears that decreasing specific humidity instead of temperature changes has caused the shrinkage of the slope glaciers since the late 19th century.

Mount Kilimanjaro

Loss of glacier mass is caused by both melting and sublimation.

Mount Kilimanjaro

While the current shrinking and thinning of Kilimanjaro's ice fields appears to be unique within its almost twelve millennium history, it is contemporaneous with widespread glacier retreat in mid-to-low latitudes across the globe.

Mount Kilimanjaro

Because of its shrinking glaciers and disappearing ice fields, the mountain has been the subject of many scientific studies.


There is ample evidence that Earth's average temperature has increased in the past 100 years and the decline of mid- and high-latitude glaciers is a major piece of evidence.

Global warming

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

There is considerable evidence that over the very recent period of the last 100–1000 years, the sharp increases in human activity, especially the burning of fossil fuels, has caused the parallel sharp and accelerating increase in atmospheric greenhouse gases which trap the sun's heat.

Ice age

The history of the Himalayas broadly fits the long-term decrease in Earth's average temperature since the mid-Eocene, 40 million years ago.

Retreat of glaciers since 1850

The Altai region has also experienced an overall temperature increase of 1.2 degrees Celsius in the last 120 years according to a report from 2006, with most of that increase occurring since the late 20th century.


'Gore claims the snowcap atop Africa's Mt. Kilimanjaro is shrinking and that global warming is to blame.

Mount Kenya

Mount Kilimanjaro

Kibo's diminishing ice cap exists because Kilimanjaro is a little-dissected, massive mountain that rises above the snow line.

Mount Kilimanjaro

Mount Kilimanjaro

Retreat of glaciers since 1850

"The Shrinking Glaciers of Kilimanjaro: Can Global Warming Be Blamed?".


Without the forests' humidity, previously moisture-laden winds blew dry.

Aralam Wildlife Sanctuary

Strong winds of dry nature blow from September to April, causing dryness in the locality with the result there is a fire hazard, especially in the deciduous forests.

Cloud forest

An important feature of cloud forests is the tree crowns can intercept the wind-driven cloud moisture, part of which drips to the ground.

Dwarf forest

Throughout the year, wind speed, temperature and humidity are fairly consistent, with humidity usually greater than 90%.

Neotropical realm

Laurel forest and other cloud forest are subtropical and mild temperate forest, found in areas with high humidity and relatively stable and mild temperatures.

Sierra Madre Occidental

This causes east winds bringing moisture from the Gulf of Mexico.


First, they concur with the believers that the Earth has been warming since the end of a Little Ice Age around 1850.

Earth

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

Ice age

Ice age

The consensus theory of the scientific community is that the resulting greenhouse effect is a principal cause of the increase in global warming which has occurred over the same period, and a chief contributor to the accelerated melting of the remaining glaciers and polar ice.

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 result is a picture of relatively cool conditions in the seventeenth and early nineteenth centuries and warmth in the eleventh and early fifteenth centuries, but the warmest conditions are apparent in the twentieth century.


Believers think the warming is man-made, while the skeptics believe the warming is natural and contributions from man are minimal and certainly not potentially catastrophic à la Al Gore.'

An Inconvenient Truth

The film's thesis is that global warming is real, potentially catastrophic, and human-caused.

Climate change denial

Attribution sceptics or deniers (who accept the global warming trend but see natural causes for this), [and] doubt that human activities are responsible for the observed trends.

Climate change denial

There is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gases is causing or will, in the foreseeable future, cause catastrophic heating of the Earth's atmosphere and disruption of the Earth's climate.

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".

Global warming

The disputed issues include the causes of increased global average air temperature, especially since the mid-20th century, whether this warming trend is unprecedented or within normal climatic variations, whether humankind has contributed significantly to it, and whether the increase is completely or partially an artifact of poor measurements.


The human fingerprint in global warming is evident in multiple lines of empirical evidence - in satellite measurements of outgoing infrared radiation, in surface measurements of downward infrared radiation, in the cooling stratosphere and other metrics.

Global warming

It is a major aspect of climate change and has been demonstrated by direct temperature measurements and by measurements of various effects of the warming.

Global warming

Solar irradiance has been measured directly by satellites, and indirect measurements are available beginning in the early 1600s.

Scientific consensus on climate change

Scientific consensus on climate change

The spatial and temporal fingerprint of warming can be traced to increasing greenhouse gas concentrations in the atmosphere, which are a direct result of burning fossil fuels, broad-scale deforestation and other human activity."

Sea surface temperature

The satellite measurement is made by sensing the ocean radiation in two or more wavelengths within the infrared part of the electromagnetic spectrum or other parts of the spectrum which can then be empirically related to SST.


Fundamental physics and global climate models both make testable predictions as to how the global climate should change in response to anthropogenic warming.

Science

This new explanation is used to make falsifiable predictions that are testable by experiment or observation.

Scientific theory

Scientific theories are testable and make falsifiable predictions.

Scientific theory

This may be as simple as observing that the theory makes accurate predictions, which is evidence that any assumptions made at the outset are correct or approximately correct under the conditions tested.

Scientific theory

The defining characteristic of all scientific knowledge, including theories, is the ability to make falsifiable or testable predictions.

Theory

These predictions can be tested at a later time, and if they are incorrect, this may lead to revision, invalidation, or rejection of the theory.


The IPCC confirms that computer modeling predicts the existence of a tropical, mid-troposphere “hot spot” about 10km above the Earth’s surface.

General circulation model

These models are the basis for model predictions of future climate, such as are discussed by the IPCC.

Global warming

Computer models are run on supercomputers to reproduce and predict the circulation of the oceans, the annual cycle of the seasons, and the flows of carbon between the land surface and the atmosphere.

IPCC Third Assessment Report

Such models cannot yet simulate all aspects of climate (e.g., they still cannot account fully for the observed trend in the surface-troposphere temperature difference since 1979) and there are particular uncertainties associated with clouds and their interaction with radiation and aerosols.

Intergovernmental Panel on Climate Change:113

They judge that global mean surface air temperature has increased by 0.3 to 0.6 °C over the last 100 years, broadly consistent with prediction of climate models, but also of the same magnitude as natural climate variability.

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.


"The Pacific Decadal Oscillation (PDO) is a temperature pattern in the Pacific Ocean that spends roughly 20-30 years in the cool phase or the warm phase.

Climate variability

The PDO is a pattern of Pacific climate variability that shifts phases on at least inter-decadal time scale, usually about 20 to 30 years.

Pacific decadal oscillation

The Pacific Decadal Oscillation (PDO) is a robust, recurring pattern of ocean-atmosphere climate variability centered over the mid-latitude Pacific basin.

Pacific decadal oscillation

The PDO is detected as warm or cool surface waters in the Pacific Ocean, north of 20°N.

Pacific decadal oscillation

During a "warm", or "positive", phase, the west Pacific becomes cooler and part of the eastern ocean warms; during a "cool" or "negative" phase, the opposite pattern occurs.

Pacific decadal oscillation

The 2014 flip from the cool PDO phase to the warm phase, which vaguely resembles a long and drawn out El Niño event, contributed to record-breaking surface temperatures across the planet in 2014.


Pacific decadal oscillation

During El Nino events, deep convection and heat transfer to the troposphere is enhanced over the anomalously warm sea surface temperature, this ENSO-related tropical forcing generates Rossby waves that propagate poleward and eastward and are subsequently refracted back from the pole to the tropics.

Pacific decadal oscillation

During the positive phase the wintertime Aleutian low is deepened and shifted southward, warm/humid air is advected along the North American west coast and temperatures are higher than usual from the Pacific Northwest to Alaska but below normal in Mexico and the Southeastern United States.

Pacific decadal oscillation

1924/1925: PDO changed to a "warm" phase.

Pacific decadal oscillation

Pacific decadal oscillation

1976/1977: PDO changed to a "warm" phase.


Pacific decadal oscillation

There is evidence of reversals in the prevailing polarity (meaning changes in cool surface waters versus warm surface waters within the region) of the oscillation occurring around 1925, 1947, and 1977; the last two reversals corresponded with dramatic shifts in salmon production regimes in the North Pacific Ocean.

Pacific decadal oscillation

Pacific decadal oscillation

1945/1946: The PDO changed to a "cool" phase, the pattern of this regime shift is similar to the 1970s episode with maximum amplitude in the subarctic and subtropical front but with a greater signature near the Japan while the 1970s shift was stronger near the American west coast.

Pacific decadal oscillation

Pacific decadal oscillation


Pacific decadal oscillation

Pacific decadal oscillation

Pacific decadal oscillation

Pacific decadal oscillation

Pacific decadal oscillation


When the PDO last switched to a cool phase, global temperatures were about 0.4C cooler than currently.

Climate variability

The temperature changes occurred somewhat suddenly, at carbon dioxide concentrations of about 600–760 ppm and temperatures approximately 4 °C warmer than today.

Pacific decadal oscillation

Pacific decadal oscillation

Pacific decadal oscillation

Pacific decadal oscillation


The long term warming trend indicates the total energy in the Earth's climate system is increasing due to an energy imbalance.

Earth's energy budget

Earth's energy budget

An imbalance in the Earth radiation budget requires components of the climate system to change temperature over time.

Earth's energy budget

Earth is very close to being in radiative equilibrium, the situation where the incoming solar energy is balanced by an equal flow of heat to space; under that condition, global temperatures will be relatively stable.

Earth's energy budget

Climate forcings are changes that cause temperatures to rise or fall, disrupting the energy balance.

Global warming

Global warming is the long-term rise in the average temperature of the Earth's climate system.


According to the second law of  thermodynamics such a planetary machine can never exist."

Black hole

This result, now known as the second law of black hole mechanics, is remarkably similar to the second law of thermodynamics, which states that the total entropy of an isolated system can never decrease.

Second law of thermodynamics

It refers to a cycle of a Carnot heat engine, fictively operated in the limiting mode of extreme slowness known as quasi-static, so that the heat and work transfers are between subsystems that are always in their own internal states of thermodynamic equilibrium.

Second law of thermodynamics

Such a machine is called a "perpetual motion machine of the second kind".

Thermodynamic equilibrium

Then, according to the second law of thermodynamics, the whole undergoes changes and eventually reaches a new and final equilibrium with the surroundings.

Thermodynamics

The second law defines the existence of a quantity called entropy, that describes the direction, thermodynamically, that a system can evolve and quantifies the state of order of a system and that can be used to quantify the useful work that can be extracted from the system.


The atmosphere of the Earth is less able to absorb shortwave radiation from the Sun than thermal radiation coming from the surface.

Atmosphere of Earth

Solar radiation (or sunlight) is the energy Earth receives from the Sun.

Atmosphere of Earth

For example, O2 and O3 absorb almost all wavelengths shorter than 300 nanometers.

Atmosphere of Earth

This rise in temperature is caused by the absorption of ultraviolet radiation (UV) radiation from the Sun by the ozone layer, which restricts turbulence and mixing.

Earth

This last phenomenon is known as the greenhouse effect: trace molecules within the atmosphere serve to capture thermal energy emitted from the ground, thereby raising the average temperature.

Sun

Sunlight on the surface of Earth is attenuated by Earth's atmosphere, so that less power arrives at the surface (closer to 1,000 W/m2) in clear conditions when the Sun is near the zenith.


The effect of this disparity is that thermal radiation escaping to space comes mostly from the cold upper atmosphere, while the surface is maintained at a substantially warmer temperature.

Atmosphere of Earth

The geological record however shows a continuous relatively warm surface during the complete early temperature record of Earth – with the exception of one cold glacial phase about 2.4 billion years ago.

Atmosphere of Earth

Although the temperature may be −60 °C (−76 °F; 210 K) at the tropopause, the top of the stratosphere is much warmer, and may be near 0 °C.

Earth

The climate is colder at high altitudes than at sea level because of the decreased air density.

Global warming

This is much colder than the conditions that actually exist at the Earth's surface (the global mean surface temperature is about 14 °C).

Global warming

Before the Industrial Revolution, naturally occurring amounts of greenhouse gases caused the air near the surface to be warmer by about 33 °C (59 °F) than it would be in their absence.


This is called the "atmospheric greenhouse effect", and without it the Earth's surface would be much colder.

Earth

Global warming

Without the Earth's atmosphere, the Earth's average temperature would be well below the freezing temperature of water.

Greenhouse effect

The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without this atmosphere.

Greenhouse effect

Because the Earth's surface is colder than the Sun, it radiates at wavelengths that are much longer than the wavelengths that were absorbed.

Greenhouse effect

Because the Earth is much colder than the Sun, it radiates at much longer wavelengths, primarily in the infrared part of the spectrum (see Figure 1).


Glaciers are in rapid retreat worldwide, despite 1 error in 1 paragraph in a 3000 page IPCC report.

Global warming

Surface temperature increases are greatest in the Arctic, which has contributed to the retreat of glaciers, permafrost, and sea ice.

Physical impacts of climate change

Glaciers have been retreating worldwide for at least the last century; the rate of retreat has increased in the past decade.

Retreat of glaciers since 1850

"Widespread, rapid grounding line retreat of Pine Island, Thwaites, Smith, and Kohler glaciers, West Antarctica, from 1992 to 2011".

Retreat of glaciers since 1850

"Fast-flow advance and parallel rapid retreat of non-surging tidewater glaciers in Icy Bay and Yakutat Bay, Alaska 1888–2003".

West Antarctic Ice Sheet

"Widespread, rapid grounding line retreat of Pine Island, Thwaites, Smith and Kohler glaciers, West Antarctica from 1992 to 2011".


"In 1999 New Scientist reported a comment by the leading Indian glaciologist Syed Hasnain, who said in an email interview with this author that all the glaciers in the central and eastern Himalayas could disappear by 2035.

Criticism of the IPCC Fourth Assessment Report:34

This was a March 2005 World Wildlife Fund Nepal Program report, page 29: In 1999, a report by the Working Group on Himalayan Glaciology (WGHG) of the International Commission for Snow and Ice (ICSI) stated: “glaciers in the Himalayas are receding faster than in any other part of the world and, if the present rate continues, the livelihood [sic] of them disappearing by the year 2035 is very high”.

Criticism of the IPCC Fourth Assessment Report:35

— WWF p. 29 On page 2, the WWF report cited an article in the 5 June 1999 issue of New Scientist which quoted Syed Hasnain, Chairman of the International Commission for Snow and Ice (ICSI), saying that most of the glaciers in the Himalayan region "will vanish within 40 years as a result of global warming".

Criticism of the IPCC Fourth Assessment Report:36

That article was based on an email interview, and says that "Hasnain's four-year study indicates that all the glaciers in the central and eastern Himalayas could disappear by 2035 at their present rate of decline."

Criticism of the IPCC Fourth Assessment Report:48

New Scientist has drawn attention to Hasnain's claim about the timing of glaciers disappearing: "Glaciers in the Himalaya are receding faster than in any other part of the world and, if the present rate continues, the likelihood of them disappearing by the year 2035 is very high," says the International Commission for Snow and Ice (ICSI) in its recent study on Asian glaciers.

Ganges

They, in turn, drew their information from an interview conducted by New Scientist with Dr. Hasnain, an Indian glaciologist, who admitted that the view was speculative.


But the central message of the IPCC AR4, is confirmed by the peer reviewed literature.

Global warming controversy

Scientific consensus is normally achieved through communication at conferences, publication in the scientific literature, replication (reproducible results by others), and peer review.

Hockey stick controversy

Global Change Research Program, over the scientific consensus shown by the IPCC report and about the peer reviewed status of the papers it cited.

IPCC Fourth Assessment Report

It is designed to be a powerful, scientifically authoritative document of high policy relevance, which will be a major contribution to the discussions at the 13th Conference of the Parties in Bali during December 2007.

Intergovernmental Panel on Climate Change:27

The IPCC was tasked with reviewing peer-reviewed scientific literature and other relevant publications to provide information on the state of knowledge about climate change.

Scientific consensus on climate change:32

Scientific consensus on climate change

Synthesis reports are assessments of scientific literature that compile the results of a range of stand-alone studies in order to achieve a broad level of understanding, or to describe the state of knowledge of a given subject.


Satellites and on-site measurements are observing that Himalayan glaciers are disappearing at an accelerating rate.

Himalayas

An acceleration of ice loss across the Himalayas over the past 40 years has been proved with satellite photos.

Himalayas

In recent years, scientists have monitored a notable increase in the rate of glacier retreat across the region as a result of climate change.

Retreat of glaciers since 1850

Overall, glaciers in the Greater Himalayan region that have been studied are retreating an average of between 18 and 20 m (59 and 66 ft) annually.

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

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


"[T]he influence of  so-called greenhouse gases on near-surface temperature - is not yet  absolutely proven.

Global warming

"The artificial production of carbon dioxide and its influence on temperature".

Global warming

In the scientific literature, there is an overwhelming consensus that global surface temperatures have increased in recent decades and that the trend is caused mainly by human-induced emissions of greenhouse gases.

Global warming

Before the Industrial Revolution, naturally occurring amounts of greenhouse gases caused the air near the surface to be warmer by about 33 °C (59 °F) than it would be in their absence.

Greenhouse effect

The presence of N2, CH4, and H2 in the atmosphere contribute to a greenhouse effect, increasing the surface temperature by 21K over the expected temperature of the body with no atmosphere.

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.


In other words, there is as yet no incontrovertible  proof either of the greenhouse effect, or its connection with alleged  global warming.

Climate change denial

Play media Climate change denial, or global warming denial is denial, dismissal, or unwarranted doubt that contradicts the scientific consensus on climate change, including the extent to which it is caused by humans, its effects on nature and human society, or the potential of adaptation to global warming by human actions.

Climate change denial

There is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gases is causing or will, in the foreseeable future, cause catastrophic heating of the Earth's atmosphere and disruption of the Earth's climate.

Intergovernmental Panel on Climate Change:157

"Robust findings" of the Synthesis report include: "Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global average sea level".

James Hansen

He argued that if the temperature rose 0.4 °C above the 1950–1980 mean for a few years, it would be the "smoking gun" pointing to human-caused global warming.

James Hansen

Hansen testified that "Global warming has reached a level such that we can ascribe with a high degree of confidence a cause and effect relationship between the greenhouse effect and observed warming...It is already happening now" and "The greenhouse effect has been detected and it is changing our climate now...We already reached the point where the greenhouse effect is important."


The statement that so-called greenhouse gases,  especially CO2, contribute to near-surface atmospheric warming is in  glaring contradiction to well-known physical laws relating to gas and  vapour, as well as to general caloric theory.'

James Hansen

In 2000, Hansen advanced an alternative view of global warming over the last 100 years, arguing that during that time frame the negative forcing via aerosols and the positive forcing via carbon dioxide (CO 2) largely balanced each other out, and that the 0.74±0.18 °C net rise in average global temperatures could mostly be explained by greenhouse gases other than carbon dioxide, such as methane and chlorofluorocarbons.

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.

Scientific consensus on climate change:459

Scientific consensus on climate change

The Intergovernmental Panel on Climate Change said the likelihood was 90 percent to 99 percent that emissions of heat-trapping greenhouse gases like carbon dioxide, spewed from tailpipes and smokestacks, were the dominant cause of the observed warming of the last 50 years.

Scientific consensus on climate change

The spatial and temporal fingerprint of warming can be traced to increasing greenhouse gas concentrations in the atmosphere, which are a direct result of burning fossil fuels, broad-scale deforestation and other human activity."

Scientific consensus on climate change:672

Scientific consensus on climate change

The changes in temperature have been associated with increasing concentrations of atmospheric carbon dioxide (CO 2) and other GHGs in the atmosphere."


The modelers confused cause and effect, thereby getting the feedback in the wrong direction."

Correlation does not imply causation

Example 2 In other cases it may simply be unclear which is the cause and which is the effect.

Hawthorne effect

[vague] Possible explanations for the Hawthorne effect include the impact of feedback and motivation towards the experimenter.

Network effect

[citation needed] Because of the positive feedback often associated with the network effect, system dynamics can be used as a modelling method to describe the phenomena.

Network effect

Just as positive network externalities (network effects) cause positive feedback and exponential growth, negative network externalities create negative feedback and exponential decay.

Positive feedback

When a change occurs in a system, positive feedback causes further change, in the same direction.


"Many people think the science of climate change is settled.

Climate change (general concept)

The scientific consensus on climate change is "that climate is changing and that these changes are in large part caused by human activities", and it "is largely irreversible".

Climate change denial

Regrettably, this creates the impression that scientific opinion is evenly divided or completely unsettled" Begley 2007: "polls found that 64 percent of Americans thought there was 'a lot' of scientific disagreement on climate change; only one third thought planetary warming was "mainly caused by things people do."

Global warming controversy

Many of the issues that are settled within the scientific community, such as human responsibility for global warming, remain the subject of politically or economically motivated attempts to downplay, dismiss or deny them—an ideological phenomenon categorised by academics and scientists as climate change denial.

Intergovernmental Panel on Climate Change:345

"The work of the Intergovernmental Panel on Climate Change (IPCC) represents the consensus of the international scientific community on climate change science.

Scientific consensus on climate change:297

Scientific consensus on climate change

A question that frequently arises in popular discussion is whether there is a scientific consensus on climate change.


The geologic record provides us with abundant evidence for such perpetual natural climate variability, from icecaps reaching almost to the equator to none at all, even at the poles.

Mesozoic

Even with the overall warmth, temperature fluctuations should have been sufficient for the presence of polar ice caps and glaciers, but there is no evidence of either.

Paleocene

Based on this and estimated plant-gas exchange rates and global surface temperatures, the climate sensitivity was calculated to be +3 °C when CO2 levels doubled, compared to 7° following the formation of ice at the poles.

Paleocene

About 60.5 mya at the Danian/Selandian boundary, there is evidence of anoxia spreading out into coastal waters, and a drop in sea levels which is most likely explained as an increase in temperature and evaporation, as there was no ice at the poles to lock up water.

Paleocene

Warm coastal upwellings at the poles would have inhibited permanent ice cover.

Triassic

There is no evidence of glaciation at or near either pole; in fact, the polar regions were apparently moist and temperate, providing a climate suitable for forests and vertebrates, including reptiles.


The climate debate is, in reality, about a 1.6 watts per square metre or 0.5 per cent discrepancy in the poorly known planetary energy balance."

Emissions trading

There is no consensus over the magnitude of long-term carbon leakage.

London

On average the price per square metre in central London is €24,252 (April 2014).

Percentage

In mathematics, a percentage (from Latin per centum "by a hundred") is a number or ratio expressed as a fraction of 100.

Percentage

Watts Up With That?

Watts Up With That features material disputing the scientific consensus on climate change, including claims the human role in global warming is insignificant and carbon dioxide is not a driving force of warming.


Different areas of science are understood with varying degrees of certainty.

Science

Natural science is concerned with the description, prediction, and understanding of natural phenomena based on empirical evidence from observation and experimentation.

Science

Theories vary in the extent to which they have been tested and verified, as well as their acceptance in the scientific community.

Science

For example, knowing the details of only a person's genetics, or their history and upbringing, or the current situation may not explain a behavior, but a deep understanding of all these variables combined can be very predictive.

Science

This realization is the topic of intersubjective verifiability, as recounted, for example, by Max Born (1949, 1965) Natural Philosophy of Cause and Chance, who points out that all knowledge, including natural or social science, is also subjective.

Science

Aristotle maintained that man knows a thing scientifically "when he possesses a conviction arrived at in a certain way, and when the first principles on which that conviction rests are known to him with certainty".


For example, we have a lower understanding of the effect of aerosols while we have a high understanding of the warming effect of carbon dioxide.

Carbon dioxide

Absorption of infrared light at the vibrational frequencies of atmospheric carbon dioxide traps energy near the surface, warming the surface and the lower atmosphere.

Carbon dioxide

Carbon dioxide is of greatest concern because it exerts a larger overall warming influence than all of these other gases combined and because it has a long atmospheric lifetime (hundreds to thousands of years).

Global cooling

The paper suggested that the global warming due to greenhouse gases would tend to have less effect with greater densities, and while aerosol pollution could cause warming, it was likely that it would tend to have a cooling effect which increased with density.

James Hansen

In 2000, Hansen advanced an alternative view of global warming over the last 100 years, arguing that during that time frame the negative forcing via aerosols and the positive forcing via carbon dioxide (CO 2) largely balanced each other out, and that the 0.74±0.18 °C net rise in average global temperatures could mostly be explained by greenhouse gases other than carbon dioxide, such as methane and chlorofluorocarbons.

James Hansen

He described this as a Faustian bargain because atmospheric aerosols had health risks, and should be reduced, but doing so would effectively increase the warming effects from CO 2.


Poorly understood aspects of climate change do not change the fact that a great deal of climate science is well understood.

Climate change (general concept)

The scientific consensus on climate change is "that climate is changing and that these changes are in large part caused by human activities", and it "is largely irreversible".

Intergovernmental Panel on Climate Change:319

In principle, this means that any significant new evidence or events that change our understanding of climate science between this deadline and publication of an IPCC report cannot be included.

Scientific consensus on climate change:192

Scientific consensus on climate change

To inform decisions on adaptation and mitigation, it is critical that we improve our understanding of the global climate system and our ability to project future climate through continued and improved monitoring and research.

Scientific consensus on climate change:306

Scientific consensus on climate change

They provide an analysis of what is known and not known, the degree of consensus, and some indication of the degree of confidence that can be placed on the various statements and conclusions."

Scientific consensus on climate change:94

Scientific consensus on climate change

The statement stresses that the scientific understanding of climate change is now sufficiently clear to justify nations taking prompt action, and explicitly endorsed the IPCC consensus.


In the 11,400 years since the end of the last Ice Age, sea  level has risen at an average of 4 feet/century, though it is now rising  much more slowly because very nearly all of the land-based ice that is  at low enough latitudes and altitudes to melt has long since gone."

Ice age

This low precipitation allows high-latitude snowfalls to melt during the summer.

Ice age

During the last glacial period the sea-level has fluctuated 20–30 m as water was sequestered, primarily in the Northern Hemisphere ice sheets.

Ice age

During the most recent North American glaciation, during the latter part of the Last Glacial Maximum (26,000 to 13,300 years ago), ice sheets extended to about 45th parallel north.

Last Glacial Period

As a result of melting ice, the land has continued to rise yearly in Scandinavia, mostly in northern Sweden and Finland where the land is rising at a rate of as much as 8–9 mm per year, or 1 meter in 100 years.

Sea level

For at least the last 100 years, sea level has been rising at an average rate of about 1.8 mm (0.07 in) per year.


Observed sea levels are actually tracking at the upper range of the IPCC projections.

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.

James Hansen

Rahmstorf and coauthors showed concern that sea levels are rising at the high range of the IPCC projections, and that this was due to thermal expansion and not from melting of the Greenland or Antarctic ice sheets.

Sea level rise

In its fifth assessment report (2013) the Intergovernmental Panel on Climate Change (IPCC) estimated how much sea level is likely to rise in the 21st century based on different levels of greenhouse gas emissions.

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

For example, in 2007 the Intergovernmental Panel on Climate Change (IPCC) projected a high end estimate of 60 cm (2 ft) through 2099, but their 2014 report raised the high-end estimate to about 90 cm (3 ft).


When accelerating ice loss from Greenland and Antarctica are factored into sea level projections, the estimated sea level rise by 2100 is between 75cm to 2 metres.

Sea level rise

Estimates on future contribution to sea level rise from Greenland range from 0.3 to 3 metres (1 to 10 ft), for the year 2100.

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

In high emission scenario, it will be 34 cm by 2050 and 111 cm by 2100.

Sea level rise


This small warming is  likely a result of the natural alterations in global ocean currents  which are driven by ocean salinity variations.

Sea level rise

Thus, a small change in the mean temperature of the ocean represents a very large change in the total heat content of the climate system.

Sea

This movement is slow and is driven by differences in density of the water caused by variations in salinity and temperature.

Shutdown of thermohaline circulation

However, the Atlantic Meridional Overturning Circulation (AMOC) is driven by ocean temperature and salinity differences.

Thermohaline circulation

In the deep ocean, the predominant driving force is differences in density, caused by salinity and temperature variations (increasing salinity and lowering the temperature of a fluid both increase its density).

Thermohaline circulation

The thermohaline circulation is mainly driven by the formation of deep water masses in the North Atlantic and the Southern Ocean caused by differences in temperature and salinity of the water.


Human kind has little or nothing to do with the recent temperature changes.

An Inconvenient Truth

White House deputy press secretary Dana Perino stated that "The president noted in 2001 the increase in temperatures over the past 100 years and that the increase in greenhouse gases was due to a certain extent to human activity".

Climate change denial

According to these groups, there is natural variability that will abate over time, and human influences have little to do with it.

Climate change denial

There is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gases is causing or will, in the foreseeable future, cause catastrophic heating of the Earth's atmosphere and disruption of the Earth's climate.

Ecology

Human-driven modifications to the planet's ecosystems (e.g., disturbance, biodiversity loss, agriculture) contributes to rising atmospheric greenhouse gas levels.

The Great Global Warming Swindle

Atmospheric carbon dioxide levels and temperature change since 1940.


"The IPCC also made false predictions on the Amazon rain forests, referenced to a non peer-reviewed paper produced by an advocacy group working with the WWF.

Criticism of the IPCC Fourth Assessment Report:65

The source cited in the report for this claim is a non-peer reviewed policy paper published by International Institute for Sustainable Development, a Canadian think tank.

Criticism of the IPCC Fourth Assessment Report:67

Former IPCC chairman Robert Watson said "Any such projection should be based on peer-reviewed literature from computer modelling of how agricultural yields would respond to climate change.

Rather, it assesses published literature, including peer-reviewed and non-peer-reviewed sources.

Intergovernmental Panel on Climate Change:80

According to IPCC guidelines, authors should give priority to peer-reviewed sources.

Intergovernmental Panel on Climate Change:82

Examples of non-peer-reviewed sources include model results, reports from government agencies and non-governmental organizations, and industry journals.


The IPCC statement on Amazon rain forests is correct.

Intergovernmental Panel on Climate Change:170

"Likely" means greater than 66% probability of being correct, based on expert judgement.

Intergovernmental Panel on Climate Change:261

The IPCC has since acknowledged that the date is incorrect, while reaffirming that the conclusion in the final summary was robust.

Intergovernmental Panel on Climate Change:263

The date of 2035 has been correctly quoted by the IPCC from the WWF report, which has misquoted its own source, an ICSI report "Variations of Snow and Ice in the past and at present on a Global and Regional Scale".

Intergovernmental Panel on Climate Change:284

The National Research Council's report agreed that there were some statistical failings, but these had little effect on the graph, which was generally correct.

Intergovernmental Panel on Climate Change:329

In May 2010, Pachauri noted that the IPCC currently had no process for responding to errors or flaws once it issued a report.


The error was incorrect citation, failing to mention the peer-reviewed papers where the data came from.

Google Scholar

Released in beta in November 2004, the Google Scholar index includes most peer-reviewed online academic journals and books, conference papers, theses and dissertations, preprints, abstracts, technical reports, and other scholarly literature, including court opinions and patents.

Hockey stick controversy

He stated that MBH had given out their full data and descriptions of methods, and were not the only evidence in the IPCC TAR that recent temperatures were likely the warmest in 1,000 years; "a variety of independent lines of evidence, summarized in a number of peer-reviewed publications, were cited in support".

Intergovernmental Panel on Climate Change:81

Authors may refer to non-peer-reviewed sources (the "grey literature"), provided that they are of sufficient quality.

Retractions in academic publishing

In academic publishing, a retraction is a statement published in an academic journal stating that a peer-reviewed article previously published in the journal should be considered invalid as a source of knowledge.

Scientific journal

Scientific journals contain articles that have been peer reviewed, in an attempt to ensure that articles meet the journal's standards of quality, and scientific validity.


On a world scale coral reefs are in decline.

Conservation biology

Global assessments of coral reefs of the world continue to report drastic and rapid rates of decline.

Coral reef

"From despair to repair: Dramatic decline of Caribbean corals can be reversed".

Coral reef

According to the Caribbean Coral Reefs - Status Report 19702-2012, states that; stop overfishing especially fishes key to coral reef like parrotfish, coastal zone management that reduce human pressure on reef, (for example restricting coastal settlement, development and tourism) and control pollution specially sewage, may reduce coral decline or even reverse it.

Coral

In 1998, 16% of the world's reefs died as a result of increased water temperature.

Marine protected area

Coral reef systems have been in decline worldwide.


Over the last 30-40 years 80% of coral in the Caribbean have been destroyed and 50% in Indonesia and the Pacific.

2004 Indian Ocean earthquake and tsunami:144

The tsunami devastated the northwestern coastlines of Sumatra, especially in Aceh Province, Indonesia, about 20 minutes after the initial earthquake.

Coral bleaching

During this time, over 70 percent of the coral reefs around the world have become damaged.

Coral bleaching

The Indian Ocean in 1998 reported 20% of its coral had died and 80% was bleached.

Coral

Coral

Over 50% of the world's coral reefs may be destroyed by 2030; as a result, most nations protect them through environmental laws.


"Three recent articles give us reason to question the alarmists’ claims  that coral reefs are in deep trouble due to the buildup of greenhouse  gases." (World Climate Report)

Coral reef

Greenhouse gas emissions present a broader threat through sea temperature rise and sea level rise, though corals adapt their calcifying fluids to changes in seawater pH and carbonate levels and are not directly threatened by ocean acidification.

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".

Global warming

The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased "Myths vs. Facts: Denial of Petitions for Reconsideration of the Endangerment and Cause or Contribute Findings for Greenhouse Gases under Section 202(a) of the Clean Air Act".

Scientific consensus on climate change:11

Scientific consensus on climate change

It is "extremely likely" that this warming arises from "human activities, especially emissions of greenhouse gases" in the atmosphere.

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.


Over the past 250 years, humans have added just one part of CO2 in 10,000 to the atmosphere.

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.

Greenhouse gas

In the modern era, emissions to the atmosphere from volcanoes are approximately 0.645 billion tonnes of CO 2 per year, whereas humans contribute 29 billion tonnes of CO 2 each year.

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

As a result of this balance, the atmospheric mole fraction of carbon dioxide remained between 260 and 280 parts per million for the 10,000 years between the end of the last glacial maximum and the start of the industrial era.

Scientific consensus on climate change:718

Scientific consensus on climate change

Since the time of the Industrial Revolution about 200 years ago, the concentration of carbon dioxide in the atmosphere has increased from about 280 parts per million to 370 parts per million, an increase of around 30%.


Volcanoes emit around 0.3 billion tonnes of CO2 per year.

Greenhouse gas

Greenhouse gas

In current trend, annual emissions will grow to 1.34 billion tonnes by 2030.

Hekla

In total 24,000 tonnes of CO2 was emitted.

NW Rota-1

The volcano produces about 400,000 ± 100,000 tonnes per year (400,000 ± 100,000 t/a) of CO 2, which is about 0.2–0.6% of the worldwide CO 2 flux at subaerial volcanoes.

Volcano

Volcanic activity releases about 130 to 230 teragrams (145 million to 255 million short tons) of carbon dioxide each year.


"Each unit of CO2 you put into the atmosphere has less and less of a warming impact.

Emissions trading

The international community began the long process towards building effective international and domestic measures to tackle GHG emissions (carbon dioxide, methane, nitrous oxide, hydroflurocarbons, perfluorocarbons, sulphur hexafluoride) in response to the increasing assertions that global warming is happening due to man-made emissions and the uncertainty over its likely consequences.

Human impact on the environment

This creates air pollution, including nitrous oxides and particulates, and is a significant contributor to global warming through emission of carbon dioxide, for which transport is the fastest-growing emission sector.

Incineration

Still the global warming potential of the landfill gas emitted to atmosphere is significant.

Kyoto Protocol

The Kyoto Protocol is an international treaty which extends the 1992 United Nations Framework Convention on Climate Change (UNFCCC) that commits state parties to reduce greenhouse gas emissions, based on the scientific consensus that (part one) global warming is occurring and (part two) it is extremely likely that human-made CO2 emissions have predominantly caused it.

Physical impacts of climate change

This additional CO2 led to a projected increase in warming of between 0.1 and 1.5 °C.


Once the atmosphere reaches a saturation point, additional input of CO2 will not really have any major impact.

Atmosphere of Earth

Both exceed 100% because their CO2 values were increased to 345 ppmv, without changing their other constituents to compensate.

Carbon dioxide

This approach can increase original oil recovery by reducing residual oil saturation by between 7% to 23% additional to primary extraction.

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

Other scientists were initially sceptical and believed the greenhouse effect to be saturated so that adding more CO 2 would make no difference.

Global warming

Increased concentrations of gases such as CO 2 (~20%), ozone and N 2O are external forcing on the other hand.


If the CO2 effect was saturated, adding more CO2 should add no additional greenhouse effect.

Carbon dioxide in Earth's atmosphere

This increase of CO 2 and other long-lived greenhouse gases in Earth's atmosphere has produced the current episode of global warming.

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.

Carbon dioxide

While transparent to visible light, carbon dioxide is a greenhouse gas, absorbing and emitting infrared radiation at its two infrared-active vibrational frequencies (see the section "Structure and bonding" above).

Carbon dioxide

Global warming


However, satellite and surface measurements observe an enhanced greenhouse effect at the wavelengths that CO2 absorb energy.

Carbon dioxide in Earth's atmosphere

CO 2 absorbs and emits infrared radiation at wavelengths of 4.26 µm (asymmetric stretching vibrational mode) and 14.99 µm (bending vibrational mode) and consequently is a greenhouse gas that plays a significant role in influencing Earth's surface temperature through the greenhouse effect.

Carbon dioxide

Carbon dioxide

Absorption of infrared light at the vibrational frequencies of atmospheric carbon dioxide traps energy near the surface, warming the surface and the lower atmosphere.

Carbon dioxide

Less energy reaches the upper atmosphere, which is therefore cooler because of this absorption.

Carbon dioxide


This argument originates from Angstrom's work in 1901.

Anders Jonas Ångström

Anders Jonas Ångström (Swedish: [ˈânːdɛʂ ˈjûːnas ˈɔ̂ŋːstrœm]; 13 August 1814 – 21 June 1874) was a Swedish physicist and one of the founders of the science of spectroscopy.

Angstrom

In 1852, Ångström formulated in Optiska undersökningar (Optical researches), a law of absorption, later modified somewhat and known as Kirchhoff's law of thermal radiation.

Angstrom

This use is evident in Bragg's paper on the structure of ice, which gives the c- and a-axis lattice constants as 4.52 A.U.

Argument

This classic was originally published in French in 1958.

Rabbit, Run (film)

Rabbit, Run is a 1970 American independent film directed by Jack Smight.


We now know that the planetary energy balance is determined by the upper levels of the troposphere and that the saturation of the absorption at the central frequency does not preclude the possibility to absorb more energy.

Carbon dioxide

Heat transfer

In the case of the Earth-atmosphere system, it refers to the process by which long-wave (infrared) radiation is emitted to balance the absorption of short-wave (visible) energy from the Sun.

Ionosphere

This is the main reason for absorption of HF radio waves, particularly at 10 MHz and below, with progressively less absorption at higher frequencies.

Troposphere

The reason for this temperature difference is that the ground absorbs most of the sun's energy, which then heats the lower levels of the atmosphere with which it is in contact.

Troposphere

Its fundamental principle is that of balance – the energy that the Earth absorbs from the sun each year is equal to that which it loses to space by radiation.


"A July 6, 2007 study published in the journal Science about Greenland by an international team of scientists found DNA “evidence that suggests the frozen shield covering the immense island survived the Earth’s last period of global warming,” according to a Boston Globe Article.  ...

2012 in science

(MSNBC) (New York Times) (Nature) 28 June – An international team of astronomers discovers evidence that our Milky Way had an encounter with a small galaxy or massive dark matter structure perhaps as recently as 100 million years ago, and as a result of that encounter it is still ringing like a bell.

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.

Greenland

Ben Keene, the atlas's editor, commented: "In the last two or three decades, global warming has reduced the size of glaciers throughout the Arctic and earlier this year, news sources confirmed what climate scientists already knew: water, not rock, lay beneath this ice bridge on the east coast of Greenland.

Lake Vostok

However, microbiologist David Pearce of the University of Northumbria in Newcastle, UK, stated that the DNA could simply be contamination from the drilling process, and not representative of Lake Vostok itself.

Snowball Earth

Life may have survived 'snowball Earth' in ocean pockets BBC News online (2010-12-14) report on research presented in the journal Geology by Dr Dan Le Heron (et al.)


[T]he study indicates “Greenland’s ice may be less susceptible to the massive meltdown predicted by computer models of climate change, the main author ... said in an interview. ...

Attribution of recent climate change:217

Attribution of recent climate change

In an e-mail interview with Than (2007), Peiser stated that: "I think it is an intriguing coincidence that warming trends have been observed on a number of very diverse planetary bodies in our solar system, (...) Perhaps this is just a fluke."

Climate change feedback

"Arctic Permafrost Is Going Through a Rapid Meltdown — 70 Years Early".

Climate change in the Arctic

It is also predicted that Greenland will become warm enough by 2100 to begin an almost complete melt during the next 1,000 years or more.

Greenland ice sheet

Greenland ice sheet

An ice sheet response time of centuries seems probable, and we cannot rule out large changes on decadal time-scales once wide-scale surface melt is underway."


Small amounts of very active substances can cause large effects.

Alcohol (drug)

Specifically, ethanol is a very low molecular weight compound and is of exceptionally low potency in its actions, causing effects only at very high (millimolar (mM)) concentrations.

Alcohol (drug)

Slightly higher levels of 5 to 10 mM, which are associated with light social drinking, produce measurable effects including changes in visual acuity, decreased anxiety, and modest behavioral disinhibition.

Alcohol (drug)

In the upper range of recreational ethanol concentrations of 20 to 50 mM, depression of the central nervous system is more marked, with effects including complete drunkenness, profound sedation, amnesia, emesis, hypnosis, and eventually unconsciousness.

Caffeine

Doses as low as 100 mg/day, such as a 6 oz cup of coffee or two to three 12 oz servings of caffeinated soft-drink, may continue to cause sleep disruption, among other intolerances.

Lysergic acid diethylamide

For example, an active dose of mescaline, roughly 0.2 to 0.5 g, has effects comparable to 100 µg or less of LSD.


"We have been grossly misled to think there is tens of thousands of times as much CO2 as there is!

Greenhouse gas

In the modern era, emissions to the atmosphere from volcanoes are approximately 0.645 billion tonnes of CO 2 per year, whereas humans contribute 29 billion tonnes of CO 2 each year.

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

As of 2006 the annual airborne fraction for CO 2 was about 0.45.

Greenhouse gas

Total anthropogenic emissions at the end of 2009 were estimated at 49.5 gigatonnes CO 2-equivalent.

Greenhouse gas

"CO2 in the atmosphere just exceeded 415 parts per million for the first time in human history".


If the public were aware that man-made CO2 is so incredibly small there would be very little belief in a climate disaster ..."

An Inconvenient Truth

Steven Quiring, climatologist from Texas A&M University added that "whether scientists like it or not, An Inconvenient Truth has had a much greater impact on public opinion and public awareness of global climate change than any scientific paper or report."

Bread

CO2 generation, on its own, is too small to account for the rise.

Climate change denial

In Britain, only 43% believe man-made global warming is a fact, down from… 55% in July.

Climate change denial

Gelbspan 1998 p. 3 "But some individuals do not want the public to know about the immediacy and extent of the climate threat.

Climate change denial

Rennie 2009: "Claim 1: Anthropogenic CO2 can't be changing climate, because CO2 is only a trace gas in the atmosphere and the amount produced by humans is dwarfed by the amount from volcanoes and other natural sources.


While methane is a more potent greenhouse gas than CO2, there is over 200 times more CO2 in the atmosphere.

Atmospheric methane

Methane in the Earth's atmosphere is a strong greenhouse gas with a global warming potential (GWP) 104 times greater than CO2 in a 20-year time frame; methane is not as persistent a gas as CO2 (assuming no change in carbon sequestration rates) and tails off to about GWP of 28 for a 100-year time frame.

Atmospheric methane

Methane is a strong GHG with a global warming potential 84 times greater than CO2 in a 20-year time frame.

Atmospheric methane

That is, over a 20-year period, it traps 84 times more heat per mass unit than carbon dioxide (CO2) and 32 times the effect when accounting for aerosol interactions.

Atmospheric methane

Since methane gas is twenty-five times stronger (for a given weight, averaged over 100 years) than CO 2 as a greenhouse gas; this would immensely magnify the greenhouse effect.

Natural gas

Natural gas is thus a more potent greenhouse gas than carbon dioxide due to the greater global-warming potential of methane.


"A United Nations report has identified the world's  rapidly growing herds of cattle as the greatest threat to the climate,  forests and wildlife. ...

Madagascar

The island's diverse ecosystems and unique wildlife are threatened by the encroachment of the rapidly growing human population and other environmental threats.

United Nations Development Programme

Major programmes underway are: ART Global Initiative World Alliance of Cities Against Poverty Territorial Approach to Climate Change Africa–Kazakhstan Partnership for the SDGs Since 1991, the UNDP has annually published the Human Development Report, which includes topics on Human Development and the annual Human Development Index.

United Nations Environment Programme

UNEP in 2005, 15 years ago, predicted "50 million people could become environmental refugees by 2010, fleeing the effects of climate change."'

United Nations

Also in 2005, the Human Security Report documented a decline in the number of wars, genocides, and human rights abuses since the end of the Cold War, and presented evidence, albeit circumstantial, that international activism—mostly spearheaded by the UN—has been the main cause of the decline in armed conflict in that period.

Wildlife

Destroying the nesting habitats of these birds would cause a decrease in the cattle population because of the spread of insect-borne diseases.


...Livestock are responsible for 18 per cent of the  greenhouse gases that cause global warming, more than cars, planes and  all other forms of transport put together.

Agriculture

It is one of the largest sources of greenhouse gases, responsible for 18% of the world's greenhouse gas emissions as measured in CO2 equivalents.

Agriculture

Animal husbandry is also responsible for greenhouse gas production of CO 2 and a percentage of the world's methane, and future land infertility, and the displacement of wildlife.

Greenhouse gas

Cumulative anthropogenic (i.e., human-emitted) emissions of CO 2 from fossil fuel use are a major cause of global warming, and give some indication of which countries have contributed most to human-induced climate change.

Livestock

The IPCC (Intergovernmental Panel on Climate Change) has estimated that agriculture (including not only livestock, but also food crop, biofuel and other production) accounted for about 10 to 12 percent of global anthropogenic greenhouse gas emissions (expressed as 100-year carbon dioxide equivalents) in 2005 and in 2010.Cows produce some 570 million cubic metres of methane per day, that accounts for from 35 to 40% of the overall methane emissions of the planet.

Methane

A 2013 study estimated that livestock accounted for 44% of human-induced methane and ~15% of human-induced greenhouse gas emissions.


Burning fuel to produce fertiliser to grow feed, to  produce meat and to transport it - and clearing vegetation for grazing -  produces 9 per cent of all emissions of carbon dioxide, the most common  greenhouse gas.

Agriculture

Agriculture

Agriculture contributes to climate change by anthropogenic emissions of greenhouse gases, and by the conversion of non-agricultural land such as forest for agricultural use.

Carbon dioxide

It is produced by combustion of wood and other organic materials and fossil fuels such as coal, peat, petroleum and natural gas.

Greenhouse gas

One liter of gasoline, when used as a fuel, produces 2.32 kg (about 1300 liters or 1.3 cubic meters) of carbon dioxide, a greenhouse gas.

Greenhouse gas

The vast majority of anthropogenic carbon dioxide emissions come from combustion of fossil fuels, principally coal, oil, and natural gas, with additional contributions coming from deforestation, changes in land use, soil erosion and agriculture (including livestock).


And their wind and manure emit more than one third of  emissions of another, methane, which warms the world 20 times faster  than carbon dioxide.

Atmospheric methane

Methane is a strong GHG with a global warming potential 84 times greater than CO2 in a 20-year time frame.

Biogas

The methane in biogas is 28 times more potent a greenhouse gas than carbon dioxide.

Methane

Methane is an important greenhouse gas with a global warming potential of 34 compared to CO2 (potential of 1) over a 100-year period, and 72 over a 20-year period.

Methane

Compared to other hydrocarbon fuels, methane produces less carbon dioxide for each unit of heat released.

Natural gas

While the lifetime of atmospheric methane is relatively short when compared to carbon dioxide, with a half-life of about 7 years, it is more efficient at trapping heat in the atmosphere, so that a given quantity of methane has 84 times the global-warming potential of carbon dioxide over a 20-year period and 28 times over a 100-year period.


Individual carbon dioxide molecules have a short life time of around 5 years in the atmosphere.

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

Carbon dioxide is of greatest concern because it exerts a larger overall warming influence than all of these other gases combined and because it has a long atmospheric lifetime (hundreds to thousands of years).

Global warming

This is due to carbon dioxide's very long lifetime in the atmosphere.

Greenhouse gas

The atmospheric lifetime of a species therefore measures the time required to restore equilibrium following a sudden increase or decrease in its concentration in the atmosphere.

Greenhouse gas

The atmospheric lifetime of CO 2 is estimated of the order of 30–95 years.


The final amount of extra CO2 that remains in the atmosphere stays there on a time scale of centuries.

Carbon price

the CO2 concentration already released into the atmosphere since the beginning of industrialization, which has risen from well below 300 PPM to more than 415 PPM (2019).

Global warming

Long-term effects of global warming: On the timescale of centuries to millennia, the magnitude of global warming will be determined primarily by anthropogenic CO2 emissions.

Global warming

Eventually, the land and oceans will take up most of the extra carbon dioxide, but as much as 20 percent may remain in the atmosphere for many thousands of years."

Global warming

Less direct geological evidence indicates that CO2 values have not been this high for millions of years.

Petroleum

Atmospheric CO2 has risen over the last 150 years to current levels of over 390 ppmv, from the 180 – 300 ppmv of the prior 800 thousand years This rise in temperature has reduced the Arctic ice cap to 1,100,000 sq mi (2,800,000 km2),[citation needed] smaller than ever recorded.


[T]he overwhelming majority of peer-reviewed studies  [find] that CO2 in the atmosphere remained there a short time.

Climate change denial

Some climate change denial groups say that because CO 2 is only a trace gas in the atmosphere (roughly 400ppm, or 0.04%, 4 parts per 10,000) it can only have a minor effect on the climate.

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.

Global warming

In 2013, CO2 readings taken at the world's primary benchmark site in Mauna Loa surpassing 400 ppm for the first time.

Peer review

Peer review is the evaluation of work by one or more people with similar competences as the producers of the work (peers).

Three Mile Island accident

A peer-reviewed research article by Dr. Steven Wing found a significant increase in cancers from 1979–1985 among people who lived within ten miles of TMI; in 2009 Dr. Wing stated that radiation releases during the accident were probably "thousands of times greater" than the NRC's estimates.


CO2 levels are measured by hundreds of stations scattered across 66 countries which all report the same rising trend.

Carbon dioxide in Earth's atmosphere:153

Carbon dioxide in Earth's atmosphere

The Integrated Carbon Observation System (ICOS) continuously releases data about CO 2 emissions, budget and concentration at individual observation stations.

Carbon dioxide in Earth's atmosphere:163

Carbon dioxide in Earth's atmosphere

Now measurements are made at many sites globally.

Carbon dioxide in Earth's atmosphere:167

Carbon dioxide in Earth's atmosphere

There are several surface measurement (including flasks and continuous in situ) networks including NOAA/ERSL, WDCGG, and RAMCES.

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

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


"The Keeling curve, which is widely used to show the increase in CO2 emissions, is based on data from the top of Mount Mauna Loa in Hawaii.

Keeling Curve

The Keeling Curve is a graph of the accumulation of carbon dioxide in the Earth's atmosphere based on continuous measurements taken at the Mauna Loa Observatory on the island of Hawaii from 1958 to the present day.

Keeling Curve

"Carbon dioxide tops 400 ppm at Mauna Loa, Hawaii".

Keeling Curve

Keeling’s Tellus article of 1960 presented the first monthly CO 2 records from Mauna Loa and Antarctica (1957 to 1960), finding a “distinct seasonal cycle…and possibly, a worldwide rise in CO2 from year to year.” By the 1970s, it was well established that the increase of atmospheric carbon dioxide was ongoing and due to anthropogenic emissions.

Keeling Curve

Carbon dioxide measurements at the Mauna Loa Observatory in Hawaii are made with a type of infrared spectrophotometer, now known as a nondispersive infrared sensor, that is calibrated using World Meteorological Organization standards.

Keeling Curve

Charles David Keeling, of Scripps Institution of Oceanography at UC San Diego, was the first person to make frequent regular measurements of atmospheric CO 2 concentrations at the South Pole, and on Mauna Loa, Hawaii from March 1958 onwards.


To claim that humidity is decreasing requires you ignore a multitude of independent reanalyses that all show increasing humidity.

Dew point

When the moisture content remains constant and temperature increases, relative humidity decreases, but the dew point remains constant.

Humidity

Heating cold outdoor air can decrease relative humidity levels indoors to below 30%, leading to ailments such as dry skin, cracked lips, dry eyes and excessive thirst.

Humidity

As temperature decreases, the amount of water vapor needed to reach saturation also decreases.

Humidity

As the temperature of a parcel of air decreases it will eventually reach the saturation point without adding or losing water mass.

Humidity

Under conditions of high humidity, the rate of evaporation of sweat from the skin decreases.