It fails to explain how we can have short-term positive feedback and long-term negative feedback.

Complex system

Relationships contain feedback loops Both negative (damping) and positive (amplifying) feedback are always found in complex systems.

Ice age

Each glacial period is subject to positive feedback which makes it more severe, and negative feedback which mitigates and (in all cases so far) eventually ends it.

Operant conditioning

This provided immediate feedback and acted as positive reinforcement for a soldier's behavior.

Perceptual control theory

PCT demonstrates circular causation in a negative feedback loop closed through the environment.

Tipping points in the climate system

There are many positive and negative feedbacks to global temperatures and the carbon cycle that have been identified.


"...the largest of all the positive or temperature-amplifying feedbacks in  the UN’s arsenal is the water-vapor feedback.

Climate change feedback

Since water vapor is a greenhouse gas, the increase in water vapor content makes the atmosphere warm further; this warming causes the atmosphere to hold still more water vapor (a positive feedback), and so on until other processes stop the feedback loop.

Climate change feedback

The main positive feedback in global warming is the tendency of warming to increase the amount of water vapor in the atmosphere, which in turn leads to further warming.

Global warming

The main reinforcing feedbacks are the water vapour feedback, the ice–albedo feedback, and probably the net effect of clouds.

Greenhouse gas

Because water vapor is a greenhouse gas, this results in further warming and so is a "positive feedback" that amplifies the original warming.

Runaway greenhouse effect

An increase in temperature from greenhouse gases leading to increased water vapor (which is itself a greenhouse gas) causing further warming is a positive feedback, but not a runaway effect, on Earth.


(2009) have demonstrated recently  – the upper troposphere (the only place where adding CO2 to the  atmosphere could make any difference to temperature) is considerably  drier than the models are tuned to expect."

Atmosphere of Jupiter

In 2010, astronomers imaged the GRS in the far infrared (from 8.5 to 24 μm) with a spatial resolution higher than ever before and found that its central, reddest region is warmer than its surroundings by between 3–4 K. The warm airmass is located in the upper troposphere in the pressure range of 200–500 mbar.

Sea surface temperature

At the 500 hPa level, the air temperature averages −7 °C (18 °F) within the tropics, but air in the tropics is normally dry at this height, giving the air room to wet-bulb, or cool as it moistens, to a more favorable temperature that can then support convection.

Troposphere

If the upper air is warmer than predicted by the adiabatic lapse rate ( d S / d z > 0 {\displaystyle dS/dz>0} ), then when a parcel of air rises and expands, it will arrive at the new height at a lower temperature than its surroundings.

Troposphere

If, on the contrary, the upper air is cooler than predicted by the adiabatic lapse rate, then when the air parcel rises to its new height it will have a higher temperature and a lower density than its surroundings, and will continue to accelerate upward.

Uranus

The temperatures in the coldest upper region of the troposphere (the tropopause) actually vary in the range between 49 and 57 K (−224 and −216 °C; −371 and −357 °F) depending on planetary latitude.


Neptune's orbit is 164 years so observations (1950 to present day) span less than a third of a Neptunian year.

Neptune

The average distance between Neptune and the Sun is 4.5 billion km (about 30.1 astronomical units (AU)), and it completes an orbit on average every 164.79 years, subject to a variability of around ±0.1 years.

Neptune

Neptune's 164 year orbital period means that the planet takes an average of 13 years to move through each constellation of the zodiac.

Neptune

Neptune orbits the Sun once every 164.8 years at an average distance of 30.1 au (4.5 billion km; 2.8 billion mi).

Pluto

The semi-major axis of Pluto's orbit varies between about 39.3 and 39.6 au with a period of about 19,951 years, corresponding to an orbital period varying between 246 and 249 years.

Pluto

Pluto has yet to complete a full orbit of the Sun since its discovery, as one Plutonian year is 247.68 years long.


"A new storm and a new red spot on Jupiter hints at climate change, USA TODAY and dozens of other sources explained yesterday.

Atmosphere of Jupiter

The Great Red Spot (GRS) is a persistent anticyclonic storm, 22° south of Jupiter's equator; observations from Earth establish a minimum storm lifetime of 350 years.

Atmosphere of Jupiter

The new storm, previously a white spot in Hubble images, turned red in May 2008.

Jupiter

Jupiter

"New storm on Jupiter hints at climate changes".

Jupiter

The best known feature of Jupiter is the Great Red Spot, a persistent anticyclonic storm that is larger than Earth, located 22° south of the equator.


The temperatures are expected to change by as much as 10 Fahrenheit degrees at different places of the globe.

Earth

At the center, the temperature may be up to 6,000 °C (10,830 °F), and the pressure could reach 360 GPa (52 million psi).

Earth

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

Earth

This is predicted to produce changes such as the melting of glaciers and ice sheets, more extreme temperature ranges, significant changes in weather and a global rise in average sea levels.

Earth

About a billion years from now, all surface water will have disappeared and the mean global temperature will reach 70 °C (158 °F).

Fahrenheit

A temperature interval of 1 °F is equal to an interval of 5⁄9 degrees Celsius.


At least close to the new spot and to the equator, nothing less than global warming is expected"

Cloud

It is most prevalent in and along low pressure zones of surface tropospheric convergence which encircle the Earth close to the equator and near the 50th parallels of latitude in the northern and southern hemispheres.

Cloud

The water reacts by radiating, also in the infrared, both upward and downward, and the downward longwave radiation results in increased warming at the surface.

Global warming

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

Global warming

"A novel probabilistic forecast system predicting anomalously warm 2018–2022 reinforcing the long-term global warming trend".

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.


Jupiter's climate change is due to shifts in internal turbulence fueled from an internal heat source - the planet radiates twice as much energy as it receives from the sun.

Jupiter

Despite this, Jupiter still radiates more heat than it receives from the Sun; the amount of heat produced inside it is similar to the total solar radiation it receives.

Jupiter

The water clouds are assumed to generate thunderstorms in the same way as terrestrial thunderstorms, driven by the heat rising from the interior.

Jupiter

Jupiter's low axial tilt means that the poles constantly receive less solar radiation than at the planet's equatorial region.

Jupiter

Convection within the interior of the planet transports more energy to the poles, balancing out the temperatures at the cloud layer.

Neptune

As with Uranus, the source of this heating is unknown, but the discrepancy is larger: Uranus only radiates 1.1 times as much energy as it receives from the Sun; whereas Neptune radiates about 2.61 times as much energy as it receives from the Sun.


In a paper published online this week in the Journal of Geophysical Research-Atmosphere, economics professor Ross McKitrick says the resulting discrepancies may be leading to an overstatement of the role of greenhouse gases in the atmosphere.

Greenhouse gas

The 2007 Fourth Assessment Report compiled by the IPCC (AR4) noted that "changes in atmospheric concentrations of greenhouse gases and aerosols, land cover and solar radiation alter the energy balance of the climate system", and concluded that "increases in anthropogenic greenhouse gas concentrations is very likely to have caused most of the increases in global average temperatures since the mid-20th century".

Hockey stick controversy

On the day of publication, the ExxonMobil funded lobbying website Tech Central Station issued a press release headed "TCS Newsflash: Important Global Warming Study Audited – Numerous Errors Found; New Research Reveals the UN IPCC 'Hockey Stick' Theory of Climate Change is Flawed" announcing that "Canadian business executive Stephen McIntyre and economist Ross McKitrick have presented more evidence that the 20th century wasn't the warmest on record".

Ice age

At a meeting of the American Geophysical Union (December 17, 2008), scientists detailed evidence in support of the controversial idea that the introduction of large-scale rice agriculture in Asia, coupled with extensive deforestation in Europe began to alter world climate by pumping significant amounts of greenhouse gases into the atmosphere over the last 1,000 years.

Intergovernmental Panel on Climate Change:110

The executive summary of the WG I Summary for Policymakers report says they are certain that emissions resulting from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases, resulting on average in an additional warming of the Earth's surface.

Scientific consensus on climate change:59

Scientific consensus on climate change

A retired journalist for The New York Times, William K. Stevens wrote: "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.


The "decline" refers to a decline in northern tree-rings, not global temperature, and is openly discussed in papers and the IPCC reports.

Climatic Research Unit documents

The implications of the decline are discussed in Chapter 2 of the IPCC Third Assessment Report, and in Chapter 6 of the 2007 IPCC Fourth Assessment Report (AR4) which describes discussion of various possible reasons for the divergence which does not affect all the trees, and says that there is no consensus about the cause.

Climatic Research Unit documents

Several scientific sources state that the decline being referred to is a decline in tree ring climate proxy metrics, not temperature.

Climatic Research Unit documents

The issues with tree rings had not been hidden, but were extensively discussed in scientific literature and in IPCC reports.

Climatic Research Unit email controversy:44

This "decline" referred to the well-discussed tree-ring divergence problem, but these two phrases were taken out of context by global warming sceptics, including US Senator Jim Inhofe and former Governor of Alaska Sarah Palin, as though they referred to some decline in measured global temperatures, even though they were written when temperatures were at a record high.

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".


"Mike's Nature trick" has nothing to do with "hide the decline", instead refering to a technique by Michael Mann to plot instrumental temperature along with past reconstructions.

Climatic Research Unit documents

"Mike's Nature trick" referred to Michael E. Mann's paper on temperature trends published by Michael Mann in Nature in 1998, which combined various proxy records and related them to actual temperature records: it included a figure later dubbed the ""hockey stick" graph, which clearly distinguished between the proxy and instrumental data.

Climatic Research Unit email controversy:43

Many commentators quoted one email in which Phil Jones said that he had used "Mike's Nature trick" in a 1999 graph for the World Meteorological Organization "to hide the decline" in proxy temperatures derived from tree-ring analyses when measured temperatures were actually rising.

Hockey stick graph

As part of his Phd research, Michael E. Mann worked with seismologist Jeffrey Park on developing statistical techniques for find long term oscillations of natural variability in the instrumental temperature record of global surface temperatures over the last 140 years; Mann & Park 1993 showed patterns relating to the El Niño–Southern Oscillation, and Mann & Park 1994 found what was later termed the Atlantic multidecadal oscillation.

Michael E. Mann

The same procedure was also used to represent key information in the instrumental temperature record for comparison with the proxy series, enabling validation of the reconstruction.

Michael E. Mann

In it, "Spatially resolved global reconstructions of annual surface temperature patterns" were related to "changes in greenhouse-gas concentrations, solar irradiance, and volcanic aerosols" leading to the conclusion that "each of these factors has contributed to the climate variability of the past 400 years, with greenhouse gases emerging as the dominant forcing during the twentieth century.


The decline in tree-ring growth is openly discussed in papers and IPCC reports.

Climatic Research Unit documents

Both of the papers referred to were in fact cited and discussed in the IPCC."

Climatic Research Unit documents

Climatic Research Unit documents

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.

Intergovernmental Panel on Climate Change:201

The Special Report on Emissions Scenarios (SRES) is a report by the IPCC which was published in 2000.


The divergence of tree-ring proxies from temperatures after 1960 is openly discussed in the peer-reviewed literature and the last two IPCC assessment reports.

Climatic Research Unit documents

Climatic Research Unit documents

Global warming

Hockey stick controversy

Dendroclimatologist Keith Briffa's February 1998 study reporting a divergence problem affecting some tree ring proxies after 1960 warned that this problem had to be taken into account to avoid overestimating past temperatures.

Scientific consensus on climate change:171

Scientific consensus on climate change

The Geological Society of America (GSA) concurs with assessments by the National Academies of Science (2005), the National Research Council (2006), and the Intergovernmental Panel on Climate Change (IPCC, 2007) that global climate has warmed and that human activities (mainly greenhouse‐gas emissions) account for most of the warming since the middle 1900s.


Currently, humans are emitting around 29 billion tonnes of carbon dioxide into the atmosphere per year.

Carbon dioxide

Human activities emit about 29 billion tons of carbon dioxide per year, while volcanoes emit between 0.2 and 0.3 billion tons.

Fossil fuel

The burning of fossil fuels produces around 21.3 billion tonnes (21.3 gigatonnes) of carbon dioxide (CO2) per year.

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

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

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


Current CO2 levels are the highest in 15 million years.

Carbon dioxide in Earth's atmosphere

The current concentration may be the highest in the last 20 million years.

Carbon dioxide in Earth's atmosphere

The present concentration is the highest for 14 million years.

Greenhouse gas

However, various proxies and modeling suggests larger variations in past epochs; 500 million years ago CO 2 levels were likely 10 times higher than now.

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.


"...there is the contention by Wolfgang Knorr of the Department of Earth Sciences at the University of Bristol in England that carbon dioxide levels in the atmosphere are about where they were 160 years ago." (as quoted by Ken Ward Jr.)

Botany

The concentration of carbon dioxide in the atmosphere today is much lower than it was when plants emerged onto land during the Ordovician and Silurian periods.

Eocene

For example, diverse geochemical and paleontological proxies indicate that at the maximum of global warmth the atmospheric carbon dioxide values were at 700–900 ppm while other proxies such as pedogenic (soil building) carbonate and marine boron isotopes indicate large changes of carbon dioxide of over 2,000 ppm over periods of time of less than 1 million years.

Eocene

"Paleobotanical Evidence for Near Present-Day Levels of Atmospheric CO2 During Part of the Tertiary".

Eocene

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

Ice age

At a meeting of the American Geophysical Union (December 17, 2008), scientists detailed evidence in support of the controversial idea that the introduction of large-scale rice agriculture in Asia, coupled with extensive deforestation in Europe began to alter world climate by pumping significant amounts of greenhouse gases into the atmosphere over the last 1,000 years.


Warming causes more moisture in the air which leads to more extreme precipitation events.

Effects of global warming

Over most of the mid-latitude land masses and wet tropical regions, extreme precipitation events will very likely become more intense and frequent.

Global warming

As air gets warmer, it can hold more moisture.

Global warming

Overall, higher temperatures bring more rain and snowfall, but for some regions droughts and wildfires increase instead.

Global warming

Further examples include sea level rise, widespread melting of snow and land ice, increased heat content of the oceans, increased humidity, and the earlier timing of spring events, such as the flowering of plants.

Global warming

The effects of global warming include rising sea levels, regional changes in precipitation, more frequent extreme weather events such as heat waves, and expansion of deserts.


Far from contradicting global warming, record snowfall is predicted by climate models and consistent with our expectation of more extreme precipitation events.

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.

Global warming

The warming evident in the instrumental temperature record is consistent with a wide range of observations, documented by many independent scientific groups; for example, in most continental regions the frequency and intensity of heavy precipitation has increased.

Sea level rise

Simultaneously, the capacity of the atmosphere to carry precipitation increases with temperature so that precipitation, in the form of snowfall, increases in global and regional models.

Snow

Snow science often leads to predictive models that include snow deposition, snow melt, and snow hydrology—elements of the Earth's water cycle—which help describe global climate change.

Weather

Climate change caused by human activities that emit greenhouse gases into the air is expected to affect the frequency of extreme weather events such as drought, extreme temperatures, flooding, high winds, and severe storms.


Meanwhile, it will likely to continue to snow in Chicago in the coming days.

Chicago

Winters are cold and snowy, although the city typically sees less snow and rain in winter than that experienced on the East Coast; blizzards do occur, as in 2011.

Chicago

Northeast winds from wintertime cyclones departing south of the region sometimes bring the city lake-effect snow.

Hurricane Sandy

Up to 2 to 3 feet (0.6–0.9 m) of snow was forecast for mountainous areas of the state.

Hurricane Sandy

On October 29, snow was falling in parts of the state.

Hurricane Sandy

Snow was reported in some parts of eastern Ohio and south of Cleveland.


There have long been claims that some unspecificed "they" has "changed the name from 'global warming' to 'climate change'".

Climate change (general concept)

The term "climate change" is often used to refer specifically to anthropogenic climate change (also known as global warming).

Climate change (general concept)

In this sense, especially in the context of environmental policy, the term climate change has become synonymous with anthropogenic global warming.

Climate change (general concept)

Shaftel 2016: "'Climate change' and 'global warming' are often used interchangeably but have distinct meanings.

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".

Scientific consensus on climate change:212

Scientific consensus on climate change

In addition to referring to the IPCC as "[the] world's best climate scientists", they stated that climate change is happening as "the result of emissions since industrialization and we have already set in motion the next 50 years of global warming – what we do from now on will determine how worse it will get."


They changed the name from “global warming” to “climate change” after the term global warming just wasn’t working (it was too cold)!

Climate change (general concept)

Global warming

Research in the 1950s suggested that temperatures were increasing, and a 1952 newspaper used the term "climate change".

Global warming

Both the terms global warming and climate change were used only occasionally until 1975, when Wallace Smith Broecker published a scientific paper on the topic, "Climatic Change: Are We on the Brink of a Pronounced Global Warming?".

Global warming

Oxford Dictionary chose climate emergency as the word of the year 2019 and defines the term as "a situation in which urgent action is required to reduce or halt climate change and avoid potentially irreversible environmental damage resulting from it".

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).


Measurements of carbon isotopes and falling oxygen in the atmosphere show that rising carbon dioxide is due to the burning of fossil fuels and cannot be coming from the ocean.

Carbon dioxide

Currently, about half of the carbon dioxide released from the burning of fossil fuels remains in the atmosphere and is not absorbed by vegetation and the oceans.

Carbon dioxide

As the concentration of carbon dioxide increases in the atmosphere, the increased uptake of carbon dioxide into the oceans is causing a measurable decrease in the pH of the oceans, which is referred to as ocean acidification.

Carbon dioxide

Gas solubility decreases as the temperature of water increases (except when both pressure exceeds 300 bar and temperature exceeds 393 K, only found near deep geothermal vents) and therefore the rate of uptake from the atmosphere decreases as ocean temperatures rise.

Global warming

CO2 emissions are continuing to rise due to the burning of fossil fuels and land-use change.

Ocean acidification

Ocean acidification is the ongoing decrease in the pH of the Earth's oceans, caused by the uptake of carbon dioxide (CO 2) from the atmosphere.


"The solubility of carbon dioxide in water is listed in the Handbook of Chemistry and Physics as a declining function of temperature. ...

Carbon dioxide

Also, the Intergovernmental Panel on Climate Change (IPCC) writes in their Climate Change 2007: Synthesis Report: "The uptake of anthropogenic carbon since 1750 has led to the ocean becoming more acidic with an average decrease in pH of 0.1 units.

Henry's law

The following table lists some temperature dependencies: Solubility of permanent gases usually decreases with increasing temperature at around room temperature.

Henry's law

Often, the smaller the gas molecule (and the lower the gas solubility in water), the lower the temperature of the maximum of the Henry's law constant.

Solubility

In liquid water at high temperatures, (e.g.

Solubility

that approaching the critical temperature), the solubility of ionic solutes tends to decrease due to the change of properties and structure of liquid water; the lower dielectric constant results in a less polar solvent.


The IPCC’s predicted equilibrium warming path bears no relation to the far lesser rate of “global warming” that has been observed in the 21st century to date.

Intergovernmental Panel on Climate Change:112

They predict that under a "business as usual" (BAU) scenario, global mean temperature will increase by about 0.3 °C per decade during the [21st] century.

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.

Scientific consensus on climate change:23

Scientific consensus on climate change

The current trajectory of global greenhouse gas emissions is not consistent with limiting global warming to below 1.5 or 2 °C, relative to pre-industrial levels.

Scientific consensus on climate change:507

Scientific consensus on climate change

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


It seems scientists have noticed recently that quite a few planets in our solar system seem to be heating up a bit, including Pluto."

Comet

A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process called outgassing.

Exoplanet

This could be caused by the interaction between the stellar wind and the planet's magnetosphere creating an electric current through the planet that heats it up causing it to expand.

Pluto

The presence of methane, a powerful greenhouse gas, in Pluto's atmosphere creates a temperature inversion, with the average temperature of its atmosphere tens of degrees warmer than its surface, though observations by New Horizons have revealed Pluto's upper atmosphere to be far colder than expected (70 K, as opposed to about 100 K).

Solar System

It is the hottest planet, with surface temperatures over 400 °C (752 °F), most likely due to the amount of greenhouse gases in the atmosphere.

Solar System

The four largest, Ganymede, Callisto, Io, and Europa, show similarities to the terrestrial planets, such as volcanism and internal heating.


Pluto's climate change over the last 14 years is likely a seasonal event.

Neptune

The long orbital period of Neptune results in seasons lasting forty years.

Neptune

As a result, Neptune experiences similar seasonal changes to Earth.

Neptune

"Evidence for methane escape and strong seasonal and dynamical perturbations of Neptune's atmospheric temperatures".

Planet

Each planet therefore has seasons, changes to the climate over the course of its year.

Uranus

Observations from Earth have shown seasonal change and increased weather activity as Uranus approached its equinox in 2007.


Pluto experiences drastic season changes due to an elliptical orbit (that takes 250 Earth years).

Pluto

It has a moderately eccentric and inclined orbit during which it ranges from 30 to 49 astronomical units or AU (4.4–7.4 billion km) from the Sun.

Pluto

Pluto's orbital period is currently about 248 years.

Pluto

The semi-major axis of Pluto's orbit varies between about 39.3 and 39.6 au with a period of about 19,951 years, corresponding to an orbital period varying between 246 and 249 years.

Pluto

Like Uranus, Pluto rotates on its "side" in its orbital plane, with an axial tilt of 120°, and so its seasonal variation is extreme; at its solstices, one-fourth of its surface is in continuous daylight, whereas another fourth is in continuous darkness.

Pluto

Pluto has yet to complete a full orbit of the Sun since its discovery, as one Plutonian year is 247.68 years long.


There are a myriad of other radiative forcings that affect the planet's energy imbalance.

Attribution of recent climate change

Radiative forcing is a measure of how various factors alter the energy balance of the Earth's atmosphere.

Earth's energy budget

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

Radiative forcing

Radiative forcing or climate forcing is the difference between insolation (sunlight) absorbed by the Earth and energy radiated back to space.

Radiative forcing

Changes to Earth's radiative equilibrium, that cause temperatures to rise or fall over decadal periods, are called climate forcings.

Radiative forcing

The radiation balance is altered by such factors as the intensity of solar energy, reflectivity of clouds or gases, absorption by various greenhouse gases or surfaces and heat emission by various materials.


Volcanoes, solar variations, clouds, methane, aerosols - these all change the way energy enters and/or leaves our climate.

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

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

Global cooling

Human activity — mostly as a by-product of fossil fuel combustion, partly by land use changes — increases the number of tiny particles (aerosols) in the atmosphere.

Global warming

Solid and liquid particles known as aerosols – from volcanoes, plankton, and human-made pollutants – reflect incoming sunlight, cooling the climate.

Greenhouse gas

If this energy balance is shifted, Earth's surface becomes warmer or cooler, leading to a variety of changes in global climate.


While there are many drivers of climate, CO2 is the most dominant radiative forcing and is increasing faster than any other forcing.

Carbon dioxide in Earth's atmosphere

The increased radiative forcing due to increased CO2 in the Earth's atmosphere is based on the physical properties of CO2 and the non-saturated absorption windows where CO2 absorbs outgoing long-wave energy.

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.

Greenhouse gas

Recent data also shows that the concentration is increasing at a higher rate.

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

Positive radiative forcing leads to warming by increasing the net incoming energy, whereas negative radiative forcing leads to cooling.


The Independent Climate Change Email Review investigated the CRU scientists' actions relating to peer review.

Climatic Research Unit email controversy:135

Scientific integrity demands robust, independent peer review, however, and AAAS therefore emphasised that investigations are appropriate whenever significant questions are raised regarding the transparency and rigour of the scientific method, the peer-review process, or the responsibility of individual scientists.

Climatic Research Unit email controversy:239

The report, issued on 18 February 2011, cleared the researchers and "did not find any evidence that NOAA inappropriately manipulated data or failed to adhere to appropriate peer review procedures".

Climatic Research Unit email controversy:82

The review would also scrutinise the CRU's policies and practices for "acquiring, assembling, subjecting to peer review, and disseminating data and research findings" and "their compliance or otherwise with best scientific practice".

Climatic Research Unit email controversy:85

On 22 March 2010 the university announced the composition of an independent Science Assessment Panel to reassess key CRU papers that have already been peer-reviewed and published in journals.

Soon and Baliunas controversy

The Independent Climate Change Email Review, an independent review funded by the University of East Anglia and chaired by Sir Muir Russell, examined allegations that the emails showed attempts to undermine normal procedures of publication.


The Review concluded that CRU's actions were normal and did not threaten the integrity of peer review.

Climatic Research Unit email controversy:174

It found that the CRU's work had been "carried out with integrity" and had used "fair and satisfactory" methods.

Climatic Research Unit email controversy:192

Describing its report as "hugely positive", he stated that "it is especially important that, despite a deluge of allegations and smears against the CRU, this independent group of utterly reputable scientists have concluded that there was no evidence of any scientific malpractice."


While it's true that any single country's CO2 emissions reductions will make little difference, only if every nation agrees to limit CO2 emissions can we achieve significant cuts on a global scale.

Climate change mitigation

Cost-effective 2 °C scenarios project annual global greenhouse gas emissions to peak before the year 2020, with deep cuts in emissions thereafter, leading to a reduction in 2050 of 41% compared to 1990 levels.

Climate change mitigation

"Cut Global Emissions by 7.6 Percent Every Year for Next Decade to Meet 1.5°C Paris Target - UN Report".

Emissions trading

It is one of the ways countries can meet their obligations under the Kyoto Protocol to reduce carbon emissions and thereby mitigate global warming.

Global warming

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

Kyoto Protocol

The 36 countries that were committed to emission reductions only accounted for 24% of the global greenhouse gas emissions in 2010.


Australia accounts for 1.5 per cent of global carbon emissions.

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.

Australia

"Australia's carbon dioxide emissions twice world rate".

Australia

Australia's carbon dioxide emissions per capita are among the highest in the world, lower than those of only a few other industrialised nations.

Climate change and agriculture

Agriculture, forestry and land-use change contributed around 20 to 25% of global annual emissions in 2010.

Kyoto Protocol

In 2008, countries with a Kyoto cap made up less than one-third of annual global carbon dioxide emissions from fuel combustion.


Monckton appears to have cherry-picked temperature data from a few stations.

British Columbia

Canadian Climate Normals 1981–2010 Station Data.

Christopher Monckton, 3rd Viscount Monckton of Brenchley:72

He says a greenhouse effect exists, and that carbon dioxide contributes to it, but claims there is no "causative link" from CO2-concentration to global average temperature.

Christopher Monckton, 3rd Viscount Monckton of Brenchley:74

Monckton's opinions contradict the scientific opinion on climate change, where there is consensus for anthropogenic global warming, and show a decisive link between carbon dioxide concentration and global average temperatures.

Terra Nova Expedition

Gear, clothes, and sleeping bags were constantly iced up; on 5 July, the temperature fell below −77 °F (−61 °C)—"109 degrees of frost—as cold as anyone would want to endure in darkness and iced up clothes", wrote Cherry-Garrard.

Terra Nova Expedition

The meteorological data collected was the longest unbroken weather record in the early twentieth century, providing baselines for current assessments of climate change.


The full data for latitudes 64-90°N reveal the Arctic is warmer today than in 1940.

Arctic fox

Globally, the Pliocene was about 2–3 °C warmer than today, and the Arctic during the summer in the mid-Pliocene was 8 °C warmer.

Arctic

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

Arctic

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

Arctic

The Arctic is affected by current global warming, leading to Arctic sea ice shrinkage, diminished ice in the Greenland ice sheet, and Arctic methane release as the permafrost thaws.

Arctic

Due to the poleward migration of the planet's isotherms (about 56 km (35 mi) per decade during the past 30 years as a consequence of global warming), the Arctic region (as defined by tree line and temperature) is currently shrinking.


When you account for the effects which are not reflected in the market price of fossil fuels, like air pollution and health impacts, the true cost of coal and other fossil fuels is higher than the cost of most renewable energy technologies.

Energy industry

The large-scale use of renewable energy technologies would "greatly mitigate or eliminate a wide range of environmental and human health impacts of energy use".

Fossil fuel

Fossil fuel prices generally are below their actual costs, or their "efficient prices," when economic externalities, such as the costs of air pollution and global climate destruction, are taken into account.

Fossil fuel

Oil refineries also have negative environmental impacts, including air and water pollution.

Fossil fuel

Moreover, these environmental pollutions impacts on the human beings because its particles of the fossil fuel on the air cause negative health effects when inhaled by people.

Human impact on the environment

The health impact of transport emissions is also of concern.


[Wind energy] is a more expensive way of producing energy than the alternative.

Alternative fuel

However, U.S. civilian nuclear power is considerably more expensive than wind power.

Wind power

The modeling also shows that "even without a carbon price (the most efficient way to reduce economy-wide emissions) wind energy is 14% cheaper than new coal and 18% cheaper than new gas."

Wind power

Costs of production from coal fired plants built in "the 1970s and 1980s" are cheaper than renewable energy sources because of depreciation.

Wind power

"Wind power is cheapest energy, EU analysis finds".

Wind power

"Renewable energy now cheaper than new fossil fuels in Australia".


'Antarctic sea ice set a new record in October 2007, as photographs distributed by the National Oceanic and Atmospheric Administration showed penguins and other cold-weather creatures able to stand farther north on Southern Hemisphere sea ice than has ever been recorded.

Antarctica

"A 40-y record reveals gradual Antarctic sea ice increases followed by decreases at rates far exceeding the rates seen in the Arctic".

Antarctica

The extent of sea ice around Antarctica (in terms of square kilometers of coverage) has remained roughly constant in recent decades, although the amount of variation it has experienced in its thickness is unclear.

Antarctica

B. C. "Antarctica appears to have broken a heat record".

Cryosphere

The overall trend indicated in the passive microwave record from 1978 through mid-1995 shows that the extent of Arctic sea ice is decreasing 2.7% per decade.

Sea

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


The news of expanding Antarctic sea ice stole headlines from global warming alarmists who asserted Arctic sea ice had reached its lowest extent since 1979.'

Antarctic sea ice

The net change is a slight increase in the area of sea ice in the Antarctic seas (unlike the Arctic Ocean, which is showing a much stronger decrease in the area of sea ice).

Antarctic sea ice

Sea ice coverage in the Arctic has shrunk at a much faster rate than it has expanded in the Southern Ocean.

Antarctica

Arctic sea ice decline

For January 2016, the satellite based data showed the lowest overall Arctic sea ice extent of any January since records begun in 1979.

Climate change in the Arctic

The effects of global warming in the Arctic, or climate change in the Arctic include rising air and water temperatures, loss of sea ice, and melting of the Greenland ice sheet with a related cold temperature anomaly, observed since the 1970s.


The result did suggest the sea level  was increasing in the western Pacific, but this was offset by a drop in  the level near the Alaskan coast.

2004 Indian Ocean earthquake and tsunami:287

Sea level rise

Five of the Solomon Islands have disappeared due to the combined effects of sea level rise and stronger trade winds that were pushing water into the Western Pacific.

Sea level rise

Satellites are useful for measuring regional variations in sea level, such as the substantial rise between 1993 and 2012 in the western tropical Pacific.

Sea level rise

"Multidecadal sea level anomalies and trends in the western tropical Pacific".

Settlement of the Americas

A drop of eustatic sea level by about 60 m to 120 m lower than present-day levels, commencing around 30,000 years BP, created Beringia, a durable and extensive geographic feature connecting Siberia with Alaska.


“Our analyses do not indicate  acceleration in sea level in U.S. tide gauge records during the 20th  century,” the study’s authors concluded.

Past sea level

This compares to an average rate of 1.7 ± 0.5 mm per year for the 20th century.

Past sea level

Based on tide gauge data, the rate of global average sea level rise during the 20th century lies in the range 0.8 to 3.3 mm/yr, with an average rate of 1.8 mm/yr.

Sea level rise

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

Sea level rise

For instance, a 2016 study led by Jim Hansen concluded that based on past climate change data, sea level rise could accelerate exponentially in the coming decades, with a doubling time of 10, 20 or 40 years, respectively, raising the ocean by several meters in 50, 100 or 200 years.

Sea level rise

More importantly, the GMSL curve shows a net acceleration, estimated to be at 0.08mm/yr2.


Humans are emitting 26 gigatonnes of CO2 into the atmosphere.

Carbon dioxide

Human activities emit about 29 billion tons of carbon dioxide per year, while volcanoes emit between 0.2 and 0.3 billion tons.

Fossil fuel

The burning of fossil fuels produces around 21.3 billion tonnes (21.3 gigatonnes) of carbon dioxide (CO2) per year.

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

The pharmaceutical industry emitted 52 megatonnes of Carbon dioxide into the atmosphere in 2015.

Greenhouse gas

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


89 percent of the stations fail to meet the National Weather Service’s own siting requirements that stations must be 30 metres away from an artificial heating or radiating/reflecting heat source.

International Space Station

From the heat exchangers, ammonia is pumped into external radiators that emit heat as infrared radiation, then back to the station.

Passive solar building design

This is done using good siting and window positioning, small amounts of thermal mass, with good-but-conventional insulation, weatherization, and an occasional supplementary heat source, such as a central radiator connected to a (solar) water heater.

Renewable energy

Low Temperature Geothermal refers to the use of the outer crust of the earth as a Thermal Battery to facilitate Renewable thermal energy for heating and cooling buildings, and other refrigeration and industrial uses.

Solar energy

In low geographical latitudes (below 40 degrees) from 60 to 70% of the domestic hot water use with temperatures up to 60 °C can be provided by solar heating systems.

Solar energy

Historically they have been used in arid climates or warm temperate regions to keep buildings cool by absorbing solar energy during the day and radiating stored heat to the cooler atmosphere at night.


A number of independent studies using near-global satellite data find positive feedback and high climate sensitivity.

Climate change feedback

Climate change feedback is important in the understanding of global warming because feedback processes may amplify or diminish the effect of each climate forcing, and so play an important part in determining the climate sensitivity and future climate state.

Climate change feedback

Observations and modelling studies indicate that there is a net positive feedback to warming.

Climate change feedback

"High sensitivity of peat decomposition to climate change through water-table feedback".

Global warming controversy

Other analyses have found that the iris effect is a positive feedback rather than the negative feedback proposed by Lindzen.

Global warming

Models not only project different future temperature with different emissions of greenhouse gases, but also do not fully agree on the strength of different feedbacks on climate sensitivity and the amount of inertia of the system.


It appears, for the entire tropics, the observed outgoing radiation fluxes increase with the increase in sea surface temperatures (SSTs).

El Niño

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

El Niño

However, during the duration of a single event, the area with the greatest sea surface temperature anomalies can change.

Eocene

Using isotope proxies to determine ocean temperatures indicates sea surface temperatures in the tropics as high as 35 °C (95 °F) and, relative to present-day values, bottom water temperatures that are 10 °C (18 °F) higher.

Mediterranean tropical-like cyclone

In tropical and subtropical areas, sea surface temperatures (SSTs) rose 0.2 °C (0.36 °F) within a 50-year period, and in the North Atlantic and Northwestern Pacific tropical cyclone basins, the potential destructiveness and energy of storms nearly doubled within the same duration, evidencing a clear correlation between global warming and tropical cyclone intensities.

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.


The observed behavior of radiation fluxes implies negative feedback processes associated with relatively low climate sensitivity.

Climate change feedback

Climate change feedback

Climate change feedback

The main negative feedback comes from the Stefan–Boltzmann law, the amount of heat radiated from the Earth into space changes with the fourth power of the temperature of Earth's surface and atmosphere.

Global warming

Reinforcement

Negative reinforcement occurs when the rate of a behavior increases because an aversive event or stimulus is removed or prevented from happening.


When you read Phil Jones' actual words, you see he's saying there is a warming trend

Global warming controversy

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

Hockey stick controversy

They concluded that although the 20th century was almost certainly the warmest of the millennium, the amount of anthropogenic warming remains uncertain."

Hockey stick controversy

He said there had probably been no global warming since the 1940s, and "Satellite data show no appreciable warming of the global atmosphere since 1979.

Hockey stick controversy

In fact, if one ignores the unusual El Nino year of 1998, one sees a cooling trend."

Hockey stick controversy

From this, he concluded that "The post-1980 global warming trend from surface thermometers is not credible.


'Phil Jones said that for the past 15 years there has been no "statistically significant" warming.

Hockey stick controversy

Hockey stick controversy

Hockey stick controversy

The authors concluded that "Northern Hemisphere mean annual temperatures for three of the past eight years are warmer than any other year since (at least) AD1400", and estimated empirically that greenhouse gases had become the dominant climate forcing during the 20th century.

Hockey stick graph

He said 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".

Hockey stick graph

The reconstruction found significant variability around a long-term cooling trend of –0.02 °C per century, as expected from orbital forcing, interrupted in the 20th century by rapid warming which stood out from the whole period, with the 1990s "the warmest decade, and 1998 the warmest year, at moderately high levels of confidence."


"a [cloudcover] change in the Tropics could lead to a negative feedback in the global climate, with a feedback factor of about –1.1, which if correct, would more than cancel all the positive feedbacks in the more sensitive current climate models" (Lindzen et al.

Climate change feedback

Observations and modelling studies indicate that there is a net positive feedback to warming.

Climate change feedback

The impact of this negative feedback effect is included in global climate models summarized by the IPCC.

Global warming

The main reinforcing feedbacks are the water vapour feedback, the ice–albedo feedback, and probably the net effect of clouds.

Richard Lindzen

This hypothesis suggests a negative feedback which would counter the effects of CO 2 warming by lowering the climate sensitivity.

Richard Lindzen

The feedback due to water vapor is a major factor in determining how much warming would be expected to occur with increased atmospheric concentrations of carbon dioxide, and all existing computer models assume positive feedback — that is, that as the climate warms, the amount of water vapour held in the atmosphere will increase, leading to further warming.


Dropped stations show more warming than kept stations.

Environmental impact of wind power

Compared with other low-carbon power sources, wind turbines have one of the lowest global warming potentials per unit of electrical energy generated out of any power source.

Environmental impact of wind power

Overall, wind farms lead to a slight warming at night and a slight cooling during the day time.

Environmental impact of wind power

Another peer-reviewed study suggested that using wind turbines to meet 10 percent of global energy demand in 2100 could actually have a warming effect, causing temperatures to rise by 1 °C (1.8 °F) in the regions on land where the wind farms are installed, including a smaller increase in areas beyond those regions.

Urban heat island

In fact, the lower-tropospheric temperatures warm at a slightly greater rate over North America (about 0.28°C/decade using satellite data) than do the surface temperatures (0.27°C/decade), although again the difference is not statistically significant.

Urban heat island

Throughout the daytime, particularly when the skies are cloudless, urban surfaces are warmed by the absorption of solar radiation.


Two American researchers allege that U.S. government scientists have  skewed global temperature trends by ignoring readings from thousands of  local weather stations around the world, particularly those in colder  altitudes and more northerly latitudes, such as Canada.

Global warming controversy

There were a small number of weather stations in the 1850s, and the number didn't reach the current 3000+ until the 1951 to 1990 period The 2001 IPCC Third Assessment Report (TAR) acknowledged that the urban heat island is an important local effect, but cited analyses of historical data indicating that the effect of the urban heat island on the global temperature trend is no more than 0.05 °C (0.09 °F) degrees through 1990.

Global warming controversy

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

Global warming controversy

In a NASA report published in January 2013, Hansen and Sato noted "the 5-year mean global temperature has been flat for a decade, which we interpret as a combination of natural variability and a slowdown in the growth rate of the net climate forcing."

Global warming controversy

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

Global warming controversy

U.S. officials, such as Philip Cooney, have repeatedly edited scientific reports from US government scientists, many of whom, such as Thomas Knutson, have been ordered to refrain from discussing climate change and related topics.


Dropped weather stations actually show a slightly warmer trend compared to kept stations.

New York City

Winters are chilly and damp, and prevailing wind patterns that blow sea breezes offshore temper the moderating effects of the Atlantic Ocean; yet the Atlantic and the partial shielding from colder air by the Appalachian Mountains keep the city warmer in the winter than inland North American cities at similar or lesser latitudes such as Pittsburgh, Cincinnati, and Indianapolis.

Photovoltaics

Another benefit of a floating solar system is that the panels are kept at a lower temperature than they would be on land, leading to a higher efficiency of solar energy conversion.

Sweden

However, Sweden is much warmer and drier than other places at a similar latitude, and even somewhat farther south, mainly because of the combination of the Gulf Stream and the general west wind drift, caused by the direction of planet Earth's rotation.

Sweden

Continental west-coasts (to which all of Scandinavia belongs, as the westernmost part of the Eurasian continent), are notably warmer than continental east-coasts; this can also be seen by comparing e.g.

WSEE-TV

The Newswatch branding was dropped after 28 years to coincide with the switch.


There is no way for us to prevent the world’s CO2 emissions    from doubling by 2100"

Climate change mitigation

For example, the emissions reductions proposed by Nordhaus (2010) might lead to global warming (in the year 2100) of around 3 °C, relative to pre-industrial levels.

Greenhouse gas

Projected annual energy-related CO 2 emissions in 2030 were 40–110% higher than in 2000, with two-thirds of the increase originating in developing countries.

Greenhouse gas

Projections consistently showed increase in annual world emissions of "Kyoto" gases, measured in CO 2-equivalent) of 25–90% by 2030, compared to 2000.

Greenhouse gas

"Global CO 2 emissions: annual increase halves in 2008".

Ocean acidification

Members of the InterAcademy Panel recommended that by 2050, global anthropogenic CO 2 emissions be reduced less than 50% of the 1990 level.


The argument that solving the global warming problem by reducing human greenhouse gas emissions is "too hard" generally stems from the belief that (i) our technology is not sufficiently advanced to achieve significant emissions reductions,

Climate change mitigation

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

Global warming

Successful adaptation is easier if there are substantial emission reductions.

Global warming

For example, bicycling reduces greenhouse gas emissions while reducing the effects of a sedentary lifestyle at the same time.

Global warming

The development and scaling-up of clean technology, such as cement that produces less CO2, is critical to achieve sufficient emission reductions for the Paris agreement goals.

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.


However, studies have determined that current technology is sufficient to reduce greenhouse gas emissions the necessary amount, and that we can do so without significant impact on the economy.

Carbon tax

Economists generally argue that carbon taxes are the most efficient and effective way to curb climate change, with the least adverse effects on the economy.

Carbon tax

There is overwhelming agreement among economists that carbon taxes are the most efficient and effective way to curb climate change, with the least adverse effects on the economy.

Carbon tax

A 2015 study of carbon taxes in British Columbia found that the taxes reduced greenhouse gas emissions by 5–15% while having negligible overall economic effects.

Climate change mitigation

As is stated in Article 2 of the Convention, this requires that greenhouse gas (GHG) concentrations are stabilized in the atmosphere at a level where ecosystems can adapt naturally to climate change, food production is not threatened, and economic development can proceed in a sustainable fashion.

Scientific consensus on climate change:510

Scientific consensus on climate change

To reduce the global net economic, environmental and social losses in the face of these impacts, the policy objective must remain squarely focused on returning greenhouse gas concentrations to near pre-industrial levels through the reduction of emissions.


"There are many urgent priorities that need the attention of Congress, and it is not for me as an invited guest in your country to say what they are.

Hillary Clinton

She responded to General David Petraeus's September 2007 Report to Congress on the Situation in Iraq by saying, "I think that the reports that you provide to us really require a willing suspension of disbelief."

Nancy Pelosi

Pelosi said Congress had "a moral duty to the brave women and men coming forward to seize this moment and demonstrate real, effective leadership to foster a climate of respect and dignity in the workplace".

Nancy Pelosi

In November, when asked about Democrats beginning the impeachment process against Trump in the event they won a majority of seats in the 2018 elections, Pelosi said it would not be one of their legislative priorities but that the option could be considered if credible evidence appeared during the ongoing investigations into Russian interference in the 2016 election.

Ronald Reagan

In a September 1985 press conference, Reagan said: "this is a top priority with us ... there's no question about the seriousness of this and the need to find an answer."

Triage

identify the priority of the patient's need for medical treatment and transport from the emergency scene.


Global warming is an increasingly urgent problem.

Global warming

"Climate Change and Financial Instability Seen as Top Global Threats".

Global warming

In 2019, the British Parliament became the first national government in the world to officially declare a climate emergency.

Global warming

Public reactions to global warming and concern about its effects have been increasing, with many perceiving it as the worst global threat.

Global warming

People who regard climate change as catastrophic, irreversible, or rapid might label climate change as a climate crisis or a climate emergency.

Global warming

Oxford Dictionary chose climate emergency as the word of the year 2019 and defines the term as "a situation in which urgent action is required to reduce or halt climate change and avoid potentially irreversible environmental damage resulting from it".


One more decade of business as usual will make this impossible.

Google

And we hit $50 billion in revenues for the first time last year – not a bad achievement in just a decade and a half."

Mad (magazine)

DC Comics) and Warner Bros. by the end of that decade.

New Deal

Historians generally agree that during Roosevelt's 12 years in office there was a dramatic increase in the power of the federal government as a whole.

New Deal

In Roosevelt's 12 years in office, the economy had an 8.5% compound annual growth of GDP, the highest growth rate in the history of any industrial country, but recovery was slow and by 1939 the gross domestic product (GDP) per adult was still 27% below trend.

Self-publishing

The growth in new titles has been strong, particularly in the past decade.


The long term trend from albedo is of cooling.

Albedo

The scattering of radiation causes atmospheric cooling, whereas absorption can cause atmospheric warming.

Albedo

[citation needed] Arctic regions notably release more heat back into space than what they absorb, effectively cooling the Earth.

Albedo

A layer of snowfall increases local albedo, reflecting away sunlight, leading to local cooling.

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

Orbital forcing from cycles in the earth's orbit around the sun has, for the past 2,000 years, caused a long-term northern hemisphere cooling trend that continued through the Middle Ages and the Little Ice Age.


"Earth’s Albedo has risen in the past few years, and by doing reconstructions of the past albedo, it appears that there was a significant reduction in Earth’s albedo leading up to a lull in 1997.

Climate sensitivity

Climate sensitivity can be estimated by using reconstructions of Earth's past temperatures and CO 2 levels.

Global warming

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

Ice age

Ice age

Ice and snow increase Earth's albedo, i.e.

Quaternary glaciation

The ice sheets themselves, by raising the albedo (the extent to which the radiant energy of the Sun is reflected from Earth) created significant feedback to further cool the climate.


The most interesting thing here is that the albedo forcings, in watts/sq meter seem to be fairly large.

Earth's energy budget

Called the albedo of Earth, around 35 units are reflected back to space: 27 from the top of clouds, 2 from snow and ice-covered areas, and 6 by other parts of the atmosphere.

Earth's energy budget

This comes to 0.087 watt/square metre, which represents only 0.027% of Earth's total energy budget at the surface, which is dominated by 173,000 terawatts of incoming solar radiation.

Radiative forcing

In this report radiative forcing values are for changes relative to preindustrial conditions defined at 1750 and are expressed in Watts per square meter (W/m2)."

Radiative forcing

Radiative forcing (measured in watts per square meter) can be estimated in different ways for different components.

Radiative forcing

"solar forcing"), the radiative forcing is simply the change in the average amount of solar energy absorbed per square meter of the Earth's area.


The long term trend from albedo is that of cooling.

Albedo

Albedo

Albedo

Albedo

The water vapor causes cooling on the land surface, causes heating where it condenses, acts a strong greenhouse gas, and can increase albedo when it condenses into clouds.

Little Ice Age


Tree-ring proxy reconstructions are reliable before 1960, tracking closely with the instrumental record and other independent proxies.

Divergence problem

The deviation of some tree ring proxy measurements from the instrumental record since the 1950s raises the question of the reliability of tree ring proxies in the period before the instrumental temperature record.

Michael E. Mann

In August 2003 Mann with Phil Jones published reconstructions using various high-resolution proxies including tree rings, ice cores and sediments.

Temperature record of the past 1000 years:0

The temperature record of the past 1,000 years or longer is reconstructed using data from climate proxy records in conjunction with the modern instrumental temperature record which only covers the last 150 years at a global scale.

Temperature record of the past 1000 years:19

As there are few instrumental records before 1850, temperatures before then must be reconstructed based on proxy methods.

Temperature record of the past 1000 years:5

Individual proxy records, such as tree ring widths and densities used in dendroclimatology, are calibrated against the instrumental record for the period of overlap.


Actual reconstructions "diverge" from the instrumental series in the last part of 20th century.

20th century

The Marshall Plan—which spent $13 billion ($100 billion in 2018 US dollars) to rebuild the economies of post-war nations—launched "Pax Americana".

Hockey stick controversy

Early quantitative reconstructions were published in the 1980s.

Hockey stick controversy

They were followed in April by a third reconstruction led by Gabriele C. Hegerl.

Hockey stick controversy

2009 which reconstructed the climate of the Arctic over the last 2,000 years, and a new method of analysis using Bayesian statistics developed by Martin Tingley and Peter Huybers.

Hockey stick controversy

The resulting reconstruction went back to 1400, and was published in November as Mann, Park & Bradley 1995.


For instance, in the original hockey stick (ending 1980) the last 30-40 years of data points slightly downwards.

Field hockey

Each player carries a "stick" that normally measures between 80–95 cm (31–38"); shorter or longer sticks are available.

Temperature record of the past 1000 years:18

Since the direct temperature record is more accurate than the proxies (indeed, it is needed to calibrate them) it is used when available: i.e., from 1850 onwards.

Temperature record of the past 1000 years:2

The curve shown in graphs of these reconstructions is widely known as the hockey stick graph because of the sharp increase in temperatures during the last century.

Temperature record of the past 1000 years:35

The 2007 IPCC Fourth Assessment Report cited 14 reconstructions, 10 of which covered 1,000 years or longer, to support its conclusion that "Average Northern Hemisphere temperatures during the second half of the 20th century were very likely higher than during any other 50-year period in the last 500 years and likely the highest in at least the past 1,300 years".

Temperature record of the past 1000 years:55

The term hockey stick was coined by the climatologist Jerry Mahlman, to describe the pattern this showed, envisaging a graph that is relatively flat to 1900 as forming an Ice hockey stick's "shaft", followed by a sharp increase corresponding to the "blade".


Europe and Asia  emit most of the soot from burning coal, wood, dung, and diesel in open  fires or without particulate filters in stoves, chimneys, smokestacks,  and exhaust pipes.

Air pollution

Most of these fine particles are a by-product of... burning... coal, gasoline, diesel, wood, trash...

Air pollution

It is a product of combustion of fuel such as natural gas, coal or wood.

Diesel exhaust

Modern car engines use a diesel particulate filter (DPF) to capture carbon particles and then intermittently burn them using extra fuel injected directly into the filter.

Diesel particulate filter

A diesel particulate filter (DPF) is a device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine.

Soot

They include soot from coal burning, internal-combustion engines, power-plant boilers, hog-fuel boilers, ship boilers, central steam-heat boilers, waste incineration, local field burning, house fires, forest fires, fireplaces, and furnaces.


The United States has been restricting soot emissions  in Draconian fashion since the Clean Air Act of 1963.

Clean Air Act (United States)

§ 7401) is a United States federal law designed to control air pollution on a national level.

Clean Air Act (United States)

The Clean Air Act of 1963 was the first federal legislation regarding air pollution control.

Clean Air Act (United States)

The Clean Air Act of 1970 (1970 CAA) authorized the development of comprehensive federal and state regulations to limit emissions from both stationary (industrial) sources and mobile sources.

Clean Air Act (United States)

In 1997 EPA tightened the NAAQS regarding permissible levels of the ground-level ozone that make up smog and the fine airborne particulate matter that makes up soot.

Clean Air Act (United States)

The first federal legislation to actually pertain to "controlling" air pollution was the Clean Air Act of 1963.


"NASA satellite data from the years 2000 through 2011 show the Earth's atmosphere is allowing far more heat to be released into space than alarmist computer models have predicted, reports a new study in the peer-reviewed science journal Remote Sensing.

Cassini–Huygens

Visible and Infrared Mapping Spectrometer (VIMS) The VIMS was a remote sensing instrument that captured images using visible and infrared light to learn more about the composition of moon surfaces, the rings, and the atmospheres of Saturn and Titan.

Global warming controversy

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

Global warming controversy

This premature announcement came from a preliminary news release about a study which had not yet been peer reviewed.

Global warming controversy

In a NASA report published in January 2013, Hansen and Sato noted "the 5-year mean global temperature has been flat for a decade, which we interpret as a combination of natural variability and a slowdown in the growth rate of the net climate forcing."

Global warming

Another line of evidence for the warming not being due to the Sun is how temperature changes differ at different levels in the Earth's atmosphere.


The study indicates far less future global warming will occur than United Nations computer models have predicted, and supports prior studies indicating increases in atmospheric carbon dioxide trap far less heat than alarmists have claimed.

Climate change in the Arctic

The authors conclude that "anthropogenic increases in greenhouse gases have led to unprecedented regional warmth."

Global warming controversy

A 2007 study by David Douglass and coworkers, concluded that the 22 most commonly used global climate models used by the IPCC were unable to accurately predict accelerated warming in the troposphere although they did match actual surface warming, concluding "projections of future climate based on these models should be viewed with much caution".

Global warming

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

IPCC Fourth Assessment Report

Confidence in these near-term projections is strengthened because of the agreement between past model projections and actual observed temperature increases.

Richard Lindzen

The feedback due to water vapor is a major factor in determining how much warming would be expected to occur with increased atmospheric concentrations of carbon dioxide, and all existing computer models assume positive feedback — that is, that as the climate warms, the amount of water vapour held in the atmosphere will increase, leading to further warming.


A subsequent study by Dessler (2011) found that Spencer's paper was not a test of climate sensitivity or feedbacks, and his assumptions do not match empirical observational data.

Evolution as fact and theory

Phylogenetic theory is used to test the independent distributions of traits and their various forms to provide explanations of observed patterns in relation to their evolutionary history and biology.

Regression analysis

A properly conducted regression analysis will include an assessment of how well the assumed form is matched by the observed data, but it can only do so within the range of values of the independent variables actually available.

Richard Lindzen

Andrew Dessler published a paper which found errors in Lindzen and Choi 2011, and concluded that the observations it had presented "are not in fundamental disagreement with mainstream climate models, nor do they provide evidence that clouds are causing climate change.

Roy Spencer (scientist)

In 2008, Spencer and William Braswell published a paper in the Journal of Climate which suggests that natural variations in how clouds form could actually be causing temperature changes, rather than the other way around, and could also lead to overestimates of how sensitive the Earth's climate is to greenhouse gas emissions.

Science

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


Hansen's 1988 results are evidence that the actual climate sensitivity is about 3°C for a doubling of atmospheric CO2.

Climate sensitivity

Without feedbacks the radiative forcing of approximately 3.7 W/m2, due to doubling CO 2 from the pre-industrial 280 ppm, would eventually result in roughly 1 °C global warming.

Climate sensitivity

The equilibrium climate sensitivity (ECS) refers to the equilibrium change in global mean near-surface air temperature that would result from a sustained doubling of the atmospheric equivalent CO 2 concentration (ΔT2×).

Climate sensitivity

In his first paper on the matter, he estimated that global temperature would rise by around 5 to 6 °C (9.0 to 10.8 °F) if the quantity of CO 2 was doubled.

Climate sensitivity

For constant humidity they computed a climate sensitivity of 2.3 °C per doubling of CO2 (which they rounded to 2, the value most often quoted from their work, in the abstract of the paper).

James Hansen

An alternate scenario would keep the warming to below this if climate sensitivity were below 3 °C for doubled CO 2.


'On June 23, 1988, NASA scientist James Hansen testified before the House of Representatives that there was a strong "cause and effect relationship" between observed temperatures and human emissions into the atmosphere.

James Hansen

Hansen was invited by Rafe Pomerance to testify before the United States Senate Committee on Energy and Natural Resources on June 23, 1988.

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."

James Hansen

Hansen said that NASA was 99% confident that the warming was caused by the accumulation of greenhouse gases in the atmosphere and not a random fluctuation.

James Hansen

During a senate meeting on June 23, 1988, Hansen reported that he was ninety-nine percent certain the earth was warmer then than it had ever been measured to be, there was a clear cause and effect relationship with the greenhouse effect and lastly that due to global warming, the likelihood of freak weather was steadily increasing.

James Hansen

...Dr. James E. Hansen of the National Aeronautics and Space Administration told a Congressional committee that it was 99 percent certain that the warming trend was not a natural variation but was caused by a buildup of carbon dioxide and other artificial gases in the atmosphere.


At that time, Hansen also produced a model of the future behavior of the globe’s temperature, which he had turned into a video movie that was heavily shopped in Congress.

James Hansen

The first climate prediction computed from a general circulation model that was published by Hansen was in 1988, the same year as his well-known Senate testimony.

James Hansen

The second generation of the GISS model was used to estimate the change in mean surface temperature based on a variety of scenarios of future greenhouse gas emissions.

James Hansen

Hansen concluded that global warming would be evident within the next few decades, and that it would result in temperatures at least as high as during the Eemian.

James Hansen

Hansen compared the corrected troposphere temperatures with the results of the published GISS model, and concluded that the model is in good agreement with the observations, noting that the satellite temperature data had been the last holdout of global warming denialists, and that the correction of the data would result in a change from discussing whether global warming is occurring to what is the rate of global warming, and what should be done about it.

James Hansen


That model predicted that global temperature between 1988 and 1997 would rise by 0.45°C (Figure 1).

General circulation model

Over the same time period, the "likely" range (greater than 66% probability, based on expert judgement) for these scenarios was for a global mean temperature increase of 1.1 to 6.4 °C.

General circulation model

In a scenario where global emissions start to decrease by 2010 and then declined at a sustained rate of 3% per year, the likely global average temperature increase was predicted to be 1.7 °C above pre-industrial levels by 2050, rising to around 2 °C by 2100.

General circulation model

In a projection designed to simulate a future where no efforts are made to reduce global emissions, the likely rise in global average temperature was predicted to be 5.5 °C by 2100.

General circulation model

Under the same emissions scenario but with a different model, the predicted median warming was 4.1 °C.

Global warming

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


But his results are evidence that the actual climate sensitivity is about 3°C for a doubling of atmospheric CO2.

Global warming

Arrhenius calculated the temperature increase expected from doubling CO 2 to be around 5-6 °C.

Richard Lindzen

Lindzen has stated that due to the non-linear effects of carbon dioxide in the atmosphere, CO2 levels are now around 30% higher than pre-industrial levels but temperatures have responded by about 75% 0.6 °C (1.08 °F) of the expected value for a doubling of CO2.

Richard Lindzen

The IPCC (2007) estimates that the expected rise in temperature due to a doubling of CO2 to be about 3 °C (5.4 °F), ± 1.5°.

Richard Lindzen

Lindzen has given estimates of the Earth's climate sensitivity to be 0.5 °C based on ERBE data.

Svante Arrhenius

On the other hand, any doubling of the percentage of carbon dioxide in the air would raise the temperature of the earth's surface by 4°; and if the carbon dioxide were increased fourfold, the temperature would rise by 8°."


Had he used the currently accepted value of approximately 3°C warming for a doubling of atmospheric CO2, Hansen would have correctly projected the ensuing global warming.

Greenhouse effect

The effect was more fully quantified by Svante Arrhenius in 1896, who made the first quantitative prediction of global warming due to a hypothetical doubling of atmospheric carbon dioxide.

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

Decades ago, they correctly predicted how much Earth's temperature would rise due to increasing atmospheric CO2.

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

An alternate scenario would keep the warming to below this if climate sensitivity were below 3 °C for doubled CO 2.


Global brightening is caused by changes in cloud cover, reflective aerosols and absorbing aerosols.

Black carbon

In addition to black carbon, fossil fuel and biofuel soot contain aerosols and particulate matter that cool the planet by reflecting the sun's radiation away from the Earth.

Black carbon

A purely scattering aerosol will reflect energy that would normally be absorbed by the earth-atmosphere system back to space and leads to a cooling effect.

Global dimming

Aerosols and other particulates absorb solar energy and reflect sunlight back into space.

Global dimming

The particles reflect and absorb sunlight, less sun rays reach Earth surface layers, thus resulting in cooler water and land surface temperatures, and also less cloud formation, subsequently dampening the development of hurricanes.

Global warming

Solid and liquid particles known as aerosols – from volcanoes, plankton, and human-made pollutants – reflect incoming sunlight, cooling the climate.


While changes in cloud cover & aerosols lead to more sunlight hitting the surface, this can be compensated by the cooling effect on the atmosphere due to fewer clouds trapping less warmth and fewer absorbing aerosols absorbing less sunlight.

Climate system

Some primarily scatter sunlight and thereby cool the planet, while others absorb sunlight and warm the atmosphere.

Global dimming

Global warming

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

Global warming

For instance, the change from a dark forest to grassland makes the surface lighter, causing it to reflect more sunlight.

Particulates

For instance, if absorbing aerosols are present in a layer aloft in the atmosphere, they can heat surrounding air which inhibits the condensation of water vapour, resulting in less cloud formation.


satellites confirmed measurements from ground stations show a considerable, and naturally-occurring, global brightening from 1983-2001 (Pinker et al., 2005).

Global dimming

There was solar brightening beyond 2000 at numerous stations in Europe, the United States, and Korea.

Global dimming

Wild et al., using measurements over land, report brightening since 1990, and Pinker et al.

Global warming

"A Revisit of Global Dimming and Brightening Based on the Sunshine Duration".

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.

Wilkinson Microwave Anisotropy Probe

The Wilkinson Microwave Anisotropy Probe (WMAP), originally known as the Microwave Anisotropy Probe (MAP), was a spacecraft operating from 2001 to 2010 which measured temperature differences across the sky in the cosmic microwave background (CMB) – the radiant heat remaining from the Big Bang.


Elementary radiative-transfer calculations demonstrate that a natural surface global brightening amounting to ~1.9 Wm–2 over the 18-year period of study would be expected – using the IPCC’s own methodology – to have caused a transient warming of 1 K (1.8 F°).

Climate sensitivity

The global temperature increase since the beginning of the industrial period (taken as 1750) is about 0.8 °C (1.4 °F), and the radiative forcing due to CO 2 and other long-lived greenhouse gases – mainly methane, nitrous oxide, and chlorofluorocarbons – emitted since that time is about 2.6 W/m2.

Climate sensitivity

Taking planetary heat uptake rate as the rate of ocean heat uptake estimated by the IPCC AR4 as 0.2 W/m2, yields a value for S of 2.1 °C (3.8 °F).

Climate sensitivity

Solar irradiance is about 0.9 W/m2 brighter during solar maximum than during solar minimum, which correlated in measured average global temperature over the period 1959-2004.

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.

Paleocene

The Paleocene–Eocene thermal maximum was an approximate 200,000 year long event where the global average temperature rose by some 5 to 8 °C (9 to 14 °F), and mid-latitude and polar areas may have exceeded modern tropical temperatures of 24–29 °C (75–84 °F).


When we do the calculations and include all radiative forcings and the amount of heat being absorbed by the oceans, it shows that the Earth has warmed almost exactly as much as we would expect.

Earth's energy budget

The net heat flux is buffered primarily by becoming part of the ocean's heat content, until a new equilibrium state is established between radiative forcings and the climate response.

Earth

This effect is much less significant than the total energy change due to the axial tilt, and most of the excess energy is absorbed by the higher proportion of water in the Southern Hemisphere.

Global warming

Although the most common measure of global warming is the increase in the near-surface atmospheric temperature, over 90% of the additional energy stored in the climate system over the last 50 years has warmed ocean water.

Greenhouse effect

Most of this thermal radiation is absorbed by the atmosphere and warms it.

Greenhouse effect

Earth's surface, warmed to an "effective temperature" around −18 °C (0 °F), radiates long-wavelength, infrared heat in the range of 4–100 μm.


Arctic sea ice loss is three times greater than Antarctic sea ice gain, and the amount of solar energy absorbed by the Earth is increasing as a result.

Earth

The amount of solar energy reaching Earth's surface decreases with increasing latitude.

Earth

Global warming

More of the Sun's energy is now absorbed in these regions, contributing to Arctic amplification, which has caused Arctic temperatures to increase at more than twice the rate of the rest of the world.

SUPPORTS SUPPORTS SUPPORTS SUPPORTS SUPPORTS

Sea ice

As the sea ice melts, its surface area shrinks, diminishing the size of the reflective surface and therefore causing the earth to absorb more of the sun's heat.

Sea ice

As the ice melts it lowers the albedo thus causing more heat to be absorbed by the Earth and further increase the amount of melting ice.

SUPPORTS SUPPORTS SUPPORTS SUPPORTS NOT_ENOUGH_INFO


When the internal variability is removed from the temperature record, what we find is nearly monotonic, accelerating warming throughout the 20th Century.

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.

Instrumental temperature record

The global average and combined land and ocean surface temperature, show a warming of 0.85 [0.65 to 1.06] °C, in the period 1880 to 2012, based on multiple independently produced datasets.

Instrumental temperature record

This view ignores the presence of internal climate variability.

Paleoclimatology

The geological record, however, shows a continually 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.

Temperature

For a body that is not in its own state of internal thermodynamic equilibrium, different thermometers can record different temperatures, depending respectively on the mechanisms of operation of the thermometers.


The motions of the massive oceans where heat is moved between deep layers and the surface provides variability on time scales from years to centuries.

Atlantic Ocean

Surface water temperatures, which vary with latitude, current systems, and season and reflect the latitudinal distribution of solar energy, range from below −2 °C (28 °F) to over 30 °C (86 °F).

Climate variability

These fluctuations in atmospheric temperature, sea surface temperature, precipitation or other parameters can be quasi-periodic, often occurring on inter-annual, multi-annual, decadal, multidecadal, century-wide, millennial or longer timescales.

Climate variability

El Niño and La Niña are important temperature fluctuations in surface waters of the tropical Eastern Pacific Ocean.

Global warming

By itself, the climate system experiences various cycles which can last for years (such as the El Niño–Southern Oscillation) to decades or centuries.

Meteorology

Significant movement of heat, matter, or momentum on time scales of less than a day are caused by turbulent motions.


In fact, the authors go on to estimate climate sensitivity from their findings, calculate a value between 2.3 to 4.1°C.

Climate sensitivity

The IPCC literature assessment estimates that TCR likely lies between 1 °C and 2.5 °C.

Climate sensitivity

For constant humidity they computed a climate sensitivity of 2.3 °C per doubling of CO2 (which they rounded to 2, the value most often quoted from their work, in the abstract of the paper).

Climate sensitivity

The 1990 IPCC First Assessment Report estimated that equilibrium climate sensitivity to a doubling of CO 2 lay between 1.5 and 4.5 °C (2.7 and 8.1 °F), with a "best guess in the light of current knowledge" of 2.5 °C (4.5 °F).

Climate sensitivity

IPCC authors concluded ECS is very likely to be greater than 1.5 °C (2.7 °F) and likely to lie in the range 2 to 4.5 °C (4 to 8.1 °F), with a most likely value of about 3 °C (5 °F).

Climate sensitivity

The IPCC Fifth Assessment Report reverted to the earlier range of 1.5 to 4.5 °C (2.7 to 8.1 °F) (high confidence) because some estimates using industrial-age data came out low.


A new peer-reviewed study on Surface Warming and the Solar Cycle found that times of high solar activity are on average 0.2°C warmer than times of low solar activity, and that there is a polar amplification of the warming.

Climate change in the Arctic

According to a 2015 study, reductions in black carbon emissions and other minor greenhouse gases, by roughly 60 percent, could cool the Arctic up to 0.2 °C by 2050.

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).

IPCC Fourth Assessment Report

Warming in the last 100 years has caused about a 0.74 °C increase in global average temperature.

IPCC Fourth Assessment Report

Climate sensitivity is defined as the amount of global average surface warming following a doubling of carbon dioxide concentrations.

Solar cycle

Also, average solar activity in the 2010s was no higher than in the 1950s (see above), whereas average global temperatures had risen markedly over that period.


The Petition Project features over 31,000 scientists signing the petition stating "there is no convincing scientific evidence that human release of carbon dioxide will, in the forseeable future, cause catastrophic heating of the Earth's atmosphere".

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".

Scientific consensus on climate change:175

Scientific consensus on climate change

Evidence from the geological record is consistent with the physics that shows that adding large amounts of carbon dioxide to the atmosphere warms the world and may lead to: higher sea levels and flooding of low-lying coasts; greatly changed patterns of rainfall; increased acidity of the oceans; and decreased oxygen levels in seawater.

Scientific consensus on climate change:543

Scientific consensus on climate change

7–10 "There is now convincing evidence that since the industrial revolution, human activities, resulting in increasing concentrations of greenhouse gases have become a major agent of climate change.

Scientific consensus on climate change:77

Scientific consensus on climate change

Human activities, primarily the burning of fossil fuels (coal, oil, and natural gas), and secondarily the clearing of land, have increased the concentration of carbon dioxide, methane, and other heat-trapping ("greenhouse") gases in the atmosphere...There is international scientific consensus that most of the warming observed over the last 50 years is attributable to human activities.


The 30,000 scientists and science graduates listed on the OISM petition represent a tiny fraction (0.3%) of all science graduates.

Art Robinson

The OISM website states that "several members of the Institute's staff are also well known for their work on the Petition Project", and that the petition has "more than 31,000" signatures by scientists.

Art Robinson

Robinson asserted in 2008 that the petition has over 31,000 signatories, with 9,000 of these holding a PhD degree.

Doctor of Philosophy

The number of PhD graduates has grown substantially in many countries since 2000, PhD Graduates still represent a relatively small, elite group within most countries — around 1.1% of adults among OECD countries.

Oregon Petition

As of 2013, the petition's website states, "The current list of 31,487 petition signers includes 9,029 PhD; 7,157 MS; 2,586 MD and DVM; and 12,715 BS or equivalent academic degrees.

Science, technology, engineering, and mathematics:53

The total fresh STEM graduates were 2.6 million in 2016.


More importantly, the OISM list only contains 39 scientists who specialise in climate science.

Antarctica

Ongoing experiments are conducted by more than 4,000 scientists from many nations.

Botany

A botanist, plant scientist or phytologist is a scientist who specialises in this field.

List of climate scientists

The list includes scientists from several specialities or disciplines.

Oregon Petition

In 2001, Scientific American took a random sample "of 30 of the 1,400 signatories claiming to hold a Ph.D. in a climate-related science."

Oregon Petition

Crudely extrapolating, the petition supporters include a core of about 200 climate researchers – a respectable number, though rather a small fraction of the climatological community.


The fact that so many studies on climate change don't bother to endorse the consensus position is significant because scientists have largely moved from what's causing global warming onto discussing details of the problem (eg - how fast, how soon, impacts, etc).

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".

Scientific consensus on climate change

This consensus is supported by various studies of scientists' opinions and by position statements of scientific organizations, many of which explicitly agree with the Intergovernmental Panel on Climate Change (IPCC) synthesis reports.

Scientific consensus on climate change:144

Scientific consensus on climate change

International Council of Academies of Engineering and Technological Sciences (CAETS) in 2007, issued a Statement on Environment and Sustainable Growth: As reported by the Intergovernmental Panel on Climate Change (IPCC), most of the observed global warming since the mid-20th century is very likely due to human-produced emission of greenhouse gases and this warming will continue unabated if present anthropogenic emissions continue or, worse, expand without control.

Scientific consensus on climate change:650

Scientific consensus on climate change

AAWV Position Statement on Climate Change, Wildlife Diseases, and Wildlife Health "There is widespread scientific agreement that the world's climate is changing and that the weight of evidence demonstrates that anthropogenic factors have and will continue to contribute significantly to global warming and climate change.

Scientific consensus on climate change:78

Scientific consensus on climate change

There is an extensive discussion in the scientific literature on what policies might be effective in responding to climate change.