|Part of a series on|
“”My suspicion is that in another four to five years you’re going to find people writing about climate change in the same way they wrote about the nuclear threat in the 50s. It’s just going to be in every story every time. People are going to come up with a set of climate-change tropes, like three-eyed mutants and giant two-headed whatevers, because this is the threat of our epoch and it just becomes blatantly obvious to everybody. Everybody’s going to pile on to the bandwagon and probably reduce the whole concept to kindling. That may be the actual solution to a genuine threat of Armageddon – to talk about it so much that it becomes banal.
|—Bruce Sterling, 2005|
Global warming, also known as anthropogenic (or human-caused) global warming, is the rising average temperature of Earth's atmosphere and oceans and its related effects. In the last 100 years, Earth's average surface temperature increased by about 0.8 °C (1.4 °F) with about two thirds of the increase occurring over just the last three decades. Anthropogenic global warming has recently become a major concern for humanity. Such concerns are supported worldwide by the wide majority of climatologists and scientists. Global warming is an increase in temperature in addition to the natural greenhouse effect.
The greenhouse effect interacts with other planet-wide influences such as the Milankovitch cycles in order to produce long term climate movements. Many gases contribute to the greenhouse effect, some of the most important being water vapor, methane and carbon dioxide.
Anthropogenic climate change
The phrase “global warming” by itself is often used to refer to the rapid rise in temperatures the planet has experienced since the start of the Industrial Revolution.
In its simplest form, the argument for anthropogenic climate change goes as follows.
- The Earth's atmosphere keeps the planet much warmer than it would be without an atmosphere.
- The main gases which contribute to this are carbon dioxide, methane and water vapor. Collectively these are called greenhouse gases.
- The ability of these gases to act as greenhouse gases can be shown in a laboratory.
- The quantity of these greenhouse gases in the atmosphere has increased sharply since the Industrial Revolution, and their concentration continues to increase.
- The concentration of these gases has increased as a consequence of human activity.
- The temperature of Earth's atmosphere has been increasing and continues to increase.
- The increase in global temperature correlates with the increases of greenhouse gases.
Up to this point virtually all scientists are in agreement - including those few global warming skeptics who understand the science and the data. Consequently the skeptics need to somehow attack the final leg of the argument:
The logical consequence of this blindingly obvious conclusion is that we should reduce the quantity of greenhouse gases which we pump into the atmosphere so as to reduce global warming.
Note that the statement that The increase in global temperature correlates with the increases of greenhouse gases is only true on a very broad timescale: GHGs have increased roughly exponentially but the temperature signal is far noisier, and displays almost no correlation with GHG changes on an annual basis, as expected. This is due to a variety of factors, from intrinsic noise in the climate system to the existence of other important forcing factors (most notably sulphate aerosols, which are a cooling factor).
Also note that while water vapour is correctly listed as a GHG, the human emissions of water vapor are not important in forcing climate change; water vapour is best thought of as a response to temperature change rather than a cause, because its atmospheric lifetime is very short (about 10 days), unlike other gases such as CO2..
What's so bad about global warming?
Global warming is "bad" for a number of reasons.
- A rise in sea level. Global warming will cause a continuing sea level rise of an uncertain amount, the IPCC reports a range of 9 – 88 cm (3.5 – 34.6 inches) up to 2100, but further contributions are possible from glacier and ice sheet discharge from Greenland and Antarctica. This small rise would cause significant disruption to coastal communities. If the whole Greenland ice sheet melted this would lead to a global rise of 7 m (23 ft).
- More active weather systems. More energy in the atmosphere will lead to more active weather systems, with more frequent and more violent storms.
- Disturbed rainfall patterns. Rainfall patterns will be significantly disrupted, with floods in some places and droughts in others.
- Acidification of the oceans. Carbon dioxide dissolves in water by reacting to make H2CO3 - carbonic acid, causing great damage to fish stocks and coral reefs. Note this is not a consequence of warming: it is a consequence of the forcing agent, CO2. To make matters worse, this acidification appears to have been an important factor in the Permian-Triassic Event, the most severe extinction Earth has ever known, and possibly every extinction other than the Cretaceous.
- Tipping points/feedback loops. There are many possible tipping points and feedback loops. As glaciers disappear, the planet will not be able to reflect as much solar radiation back into space. When northern permafrost melts, the organic material will decompose and release methane. As the oceans warm, their ability to dissolve carbon dioxide decreases, and if they ever reach a certain temperature, the methane stored under pressure on the seafloor will vaporize.
- Spread of tropical diseases. As northern latitudes become warmer, previously rare tropical diseases will gain a foothold there.
- Disruption of ocean currents. For example, the disruption of ocean currents could reduce the strength of the North Atlantic Drift that keeps Europe relatively warm for its latitude.
- Habitat loss or change faster than animals can adapt. Temperature zones will move north and south (depending on the hemisphere) too quickly for animals to follow or adapt to new habitats. The loss of polar habitats will leave animals such as polar bears with no place to go.
- Loss of mountain glaciers exacerbating summer droughts. Mountain glaciers act as natural reservoirs, releasing water which falls as snow in the winter during the summer. The loss of these glaciers will lead to floods in winter and droughts in the summer.
Not all of these consequences are certain, and some may be mitigated. For example, whilst GW might tend to lead to the spread of tropical diseases, advances in medicine or other activities (insect spraying, swamp draining) could well counteract this, as has already happened during the industrial era for a number of previously common diseases.
Equally though, there will probably be a large number of unanticipated additional - and probably negative - consequences.
A scientific consensus is reached when the vast majority of the scientists involved in a discipline broadly agree. When this occurs the case can be considered to have been demonstrated and the burden of proof then falls on those who would dispute the consensus. The following national and international organizations are part of the consensus:
- National Academy of Sciences (NAS)
- National Oceanic and Atmospheric Administration (NOAA)
- NASA’s Goddard Institute of Space Studies (GISS)
- Environmental Protection Agency (EPA)
- The Royal Society of the UK (RS)
- Canadian Meteorological and Oceanographic Society (CMOS)
- Intergovernmental Panel on Climate Change (IPCC)
- And many more.
Though some have taken non-committal stances, the vast majority of scientific bodies are convinced by the evidence. In addition, the Pentagon now ranks global warming as a "destabilizing force" (damn enviro-weenies).
National or international scientific bodies that reject anthropogenic global warming
Entrenched interests and global warming deniers
There are many entrenched interests who benefit from the current energy infrastructure of our modern civilisation. Commonly mentioned "villains" are oil companies and oil producing nations who would stand to lose a lot of money if action were taken to reduce the amount of carbon dioxide dumped into the atmosphere, as this would imply a reduction in the use of fossil fuels such as oil. But consumers are "the other half" of the same problem and (for example) US drivers have been very resistant to an increase in petrol (also known as "gas" in the colonies) taxation.
Consequently, interests have spent a vast amount of money in an effort to discredit the science behind man-made global warming, and encourage global warming denialism. ExxonMobil has been one of the prime movers and a recent Greenpeace report stated:
"ExxonMobil’s campaign to fund “think tanks” and organizations that spread misinformation about the science and policies of global warming is now widely known. The company’s multimillion dollar campaign has undoubtedly contributed to public confusion and government inaction on global warming over the past decade." 
Greenpeace is still monitoring ExxonMobil's attempts to distort public opinion in this area as can be seen in their website exxonsecrets dedicated to exposing the company's nefarious activities.
The disinformation campaign is similar to that embarked on by the tobacco companies who wished to persuade people that cigarettes were healthy, and the campaigns carried out by the oil companies when they wished to continue adding lead to petrol.
Global warming and the 2008 American elections
Although global warming deniers are probably more common in the United States than in the rest of the world, it is possible that the global warming argument has been won even there. None of the main 2008 presidential candidates was a global warming denialist (although Sarah Palin, the fundamentalist Republican candidate for Vice-President, was a denialist, buying into Climategate and implying there is no consensus among scientists) and all of them had some commitment to renewable energy sources. While this may have been partly because of the threat of peak oil, it suggests that the time of political interference in the science of global warming may be coming to an end.
Hierarchy of global warming denial
Global warming deniers form a sliding scale of denial which is outlined below - in general these beliefs are designed to prevent action being taken.
- Not only deny global warming, but insist the opposite is occurring  (taken from the Conservapedia homepage). This probably goes beyond denialism and verges on the psychotic.
- Simply deny global warming is happening - and maintain that no action is necessary - an increasingly uncommon position.
- Global warming is happening, but it’s not caused by humanity - so we don’t have to do anything.
- Global warming is happening, and it is in part caused by humanity, but mostly it's caused by solar activity. So we don't have to do anything.
- Global warming is happening, it is caused by humanity, but it may be a good thing - so we don’t have to do anything.
- Global warming is happening, it is caused by humanity, it is a bad thing, but China isn’t doing anything - so we don’t have to do anything.
- Global warming is happening, it is caused by humanity, it is a bad thing, but even if China does something it’s too late for us to do anything and it would cost us money - so we don’t have to do anything.
- (There is an hypothesized eighth step, "Global warming was happening, it was caused by humanity, it is a very bad thing and previous governments should have done something, but it's too late now")
When debating global warming, it is wise to establish beforehand which of the opinions each debater holds, referring to the list above - otherwise you can waste a lot of time proving the wrong point. It may be similar to arguing with someone about the New World Order as you need to find out exactly where they stand before engaging with them.
Global warming skeptics have raised a number of slightly more scientific arguments which are covered below.
Claims by global warming denialists
“”What I’m suggesting is we have a sort of an eco-evangelical hysteria going on and it leads me to almost wonder if we are becoming a nation of environmental hypochondriacs that are willing to use the power of the state to impose enormous restrictions on the rights and the comforts of, and incomes of individuals who serve essentially a paranoia, a phobia, that has very little fact evidence in fact. Now these are observations that are popular to make because right now it's almost taken as an article of faith that this crisis is real. Let me say I take it as an article of faith if the lord God almighty made the heavens and the Earth, and He made them to His satisfaction and it is quite pretentious of we little weaklings here on earth to think that, that we are going to destroy God’s creation.
|—Dick Armey (R-TX), on global warming|
NASA and the Y2K bug
Steve McIntyre deduced, and NASA recently admitted, that NASA programmers had a Y2K bug in their source code that processes temperature data. This bug introduced a 0.02 percent change in the temperature data that has been corrected. Before this correction 1998 was the listed as the hottest year recorded but this difference was statistically non-significant with the second place year 1934. With the correction 1934 becomes the hottest year but it is still statistically non-significant. 1934 was a period of intense drought in the United States, as it was during the Dust Bowl years in the Great Depression. The change does not affect the global temperature; it only changes the temperature data for the United States.
The old temperature series data for the U.S. was as follows:
With the correction it changes to:
Denialists jumped on the bandwagon in regards to this shift making many grandiose claims that it invalidates all of the data that proves this has been the hottest decade in recorded history. This is not the case; it makes a minor change that does not change the decade averages or the global averages. It takes one year during an intense drought in the United States and moves it up non-significantly.
Glacier retreat calculations
Scientists have found DNA from ancient animals in an ice layer of Greenland, 1.9 km (1.2 miles) beneath the surface. Since this study indicates that the ice layer survived the last interglacial, it has led to speculation that the ice caps may be able to also withstand global warming. However, the main author of the study dismissed suggestions that his team's data indicated that sea levels would not rise to predicated levels, saying that "during the last interglacial, sea levels rose by 5-6m, but this must have come from other sources additional to the Greenland ice cap, such as Antarctic ice. I would anticipate that as the Earth warms from man-made climate change, these sources would still contribute to a rise in sea levels." Another scientist pointed out that it may not be reasonable to extrapolate the study's results to our current situation, because the temperature changes in previous interglacials occurred at a much slower pace. Coincidentally, this article provides evidence that the world is at least 120,000 years old, which flies in the face of creationists who claim the earth is 6000 years old.
Nature generates more CO2 than humans
While it is true that natural sources of CO2 release represent a much higher percentage of CO2 output, natural carbon "sinks" that take up that CO2 balance it out. The amount of CO2 in the atmosphere has been relatively constant for hundreds of thousands of years due to output and input being equal. What humans are doing is burning and releasing sources of CO2 without adding additional carbon sinks. We are actually removing carbon sinks. This means the net amount of CO2 is increasing over time due to our involvement even though our total output is less than natural sources.
One of the interesting things is that the natural outputs of CO2 and the human-made outputs contain different isotopes. Fossil fuel burning outputs CO2 that has less 14C and 13C than do natural sources. Using tree ring dating it can be shown that the proportion of 14C-containing CO2 in the atmosphere decreased substantially prior to the 1940s, when the largely defensive weapon of atomic bomb negated our ability to use that test. But 13C testing confirmed the 14C testing and showed that fossil fuel burning is the number one contributor to the increase in the CO2 in the atmosphere. 
Volcanic activity, specifically underwater volcanic activity, is often cited (usually drawing on the writings of Ian Plimer) as producing more CO2 than humans. This, however, is demonstrably false.
Oddly enough, some denialists also point out the significant amounts of CO2 created by livestock, and somehow totally ignore that these animals are bred and kept by humans, ergo making it human-made emissions.
Clearly it is human-caused (anthropogenic) burning of fossil fuels that is responsible.
CO2 levels lag behind temperature increases
There have been several major changes in the Earth's climate over its 4.5 billion year history. These have included spectacular effects such as the snowball earth and periods of intense global warming. These periods of warming and cooling all have a range of causes mostly involving positive feedback loops, such as ice reflecting the sun back to space causing more ice, reflecting more sun, and Milankovitch cycles, variations in Earth's orbit that have an effect on climate. The warming had similar positive feedback loops, which initially could have been caused by one of many factors but eventually the warming increased the levels of CO2 which then caused even more warming. The fact that CO2 level increases have not been responsible for the start of a 100 percent of all global warming events on the planet does not negate the fact that CO2 in the atmosphere does cause warming.
Water vapour is a more important greenhouse gas
Water vapour is one of the most potent greenhouse gases in the Earth's atmosphere and accounts for a substantial portion of the greenhouse effect that raises the Earth's temperature from an inhospitable 19 degrees below zero to a more temperate 16 degrees above zero. Global warming denialists have used this to claim that carbon dioxide is an unimportant gas in the greenhouse effect - and this can be coupled with the fact that burning fossil fuels (oxidation) results in the release of water vapour in addition to carbon dioxide.
However, this argument that CO2 is not the cause of global warming misses (possibly intentionally) several key facts. Firstly, water vapour is often saturated in the atmosphere, and this leads to rain. Adding water to the atmosphere may alter weather patterns but its concentration does not differ on the scales considered by climate scientists. As it is removed from the atmosphere on a fast time scale, it can cause short lived but extreme changes in temperature, and so is the cause of much freak, but short-term, weather. Carbon dioxide on the other hand has a much longer life-time in the atmosphere and its concentration is not capped by saturation in the atmosphere. This makes the effect that CO2 has on the Earth's climate a considerable force.
It has been hotter in the past so it is just cyclical
While it is true that there have been cyclical patterns of temperature changes throughout our planet's history, this does not mean that causes are unknown, unknowable, or all the same. Science and the application of the scientific method is a great method for working out cause/effect relationships. Scientists have managed to link several warming and cooling cycles in the geologic history to specific causes. They have also shown that the modern warming is due to an increase in the levels of CO2 and other greenhouse gasses in the atmosphere, which is itself caused by the added output of humans burning fossil fuels and destroying carbon sinks.
The existence of previous warming cycles does not negate the seriousness of the current one. These previous cycles destroyed a great deal of life on the planet, and if similar effects occurred today they would probably destroy all of human civilization, along with the humanity that created it. This does mean that the earth itself will survive, but that no denialist would be around to gloat.
Global warming has more to do with the sun than the earth
Changes in the sun have not been shown to provide a significant change to the Earth's climate. There has not been any significant change in the total energy output of the sun since we have started measuring it, and no changes in the sun or sun phenomenon correlate with increased temperatures. One thing that can change is small perturbations in the orbit of the earth that draw the planet closer or further from the sun. These perturbations might be linked to the start of several of the major climate changes in the geologic history of the earth. However, the actual change in temperature due to these orbital changes is small and the large scale changes are due to feed back loops localized to earth pushing things in one direction or another.
There is no evidence that such an orbital shift is happening now, but even if it has, it can only explain a very small percentage of the increase in global temperature. The main cause is an increase in atmospheric CO2 levels, which are increasing due to humans burning fossil fuel and destroying carbon sinks. This issue was also a point of contention in the Soon and Baliunas controversy.
It must be the sun because Mars and Pluto are warming too
Many of the planets and moons in our solar system are big enough and geologically active enough to have both an atmosphere and a climate. In any given system there will be some planets increasing in temperature and some decreasing in temperature. This is due to changes in the localized climate, just as it is with earth. The causes are different for each planet and have little to no bearing on each other. The localized cause of climate warming on the planet earth is the increase levels of CO2 in the atmosphere being caused by humans burning fossil fuels and destroying carbon sinks.
Even if the sun does have a role, it is not likely that our own activities are helping the situation. It would actually be even more incentive to temper our works, because anthropogenic activity combined with solar activity obviously equals even higher rates of warming.
Urban heat sinks
This point contends that weather station readings are affected by their proximity to cities, or "urban heat sinks." See the article on Patrick Michaels, a notable proponent of this argument, for a treatment of this point.
Hey look! There's been no global warming since 1998
One of the most popular claims made against climate science is that there has been "no global warming since 1998," or even that there has been a pattern of "global cooling" since that year. Skeptics who have made this argument include Tim Ball, Nigel Lawson, Fred Singer and Christopher Monckton. The origins of this argument are unclear; perhaps it might have originated in an article by Bob Carter which appeared the Daily Telegragh in 2006.
This argument fails for several reasons: it only takes into account surface temperatures, and does not deal with oceanic temperatures; it fails to do any sort of trend analysis, and it does not take into account cyclical oscillations or variation. Most importantly, it is the finest example of cherry picking. Classic climate denialism demands that average global temperature measurements must be taken from the peak of the hottest year and measured to the point trough of the coolest year. If the denialists ever picked years either side of 1998 as their start point, the argument would sink faster than the Titanic. This is because globally, 1998 was a record breaking hot year due to a very strong El Nino. 
Using anecdotal evidence
Using arguments such as "Wow, it's really cold today! Global warming, my ass!" or "See! It's snowing in Atlanta for the first time in years!" to argue that "global warming" misuses numerical data, since even without global warming, there are fluctuations in local temperatures. Global warming refers to an overall average increase in temperatures of air and water. Additionally, global warming will result in some local areas that are cooler, despite the global average increasing. Strangely enough, this is a common argument used by Fox News and other right-wing organizations who often claim scientists are only using anecdotes of hot weather as proof of global warming when the opposite is true.
Claiming there is no consensus in respect of global warming
Global warming denialists often try to claim that there is no scientific consensus, despite the fact that the Intergovernmental Panel on Climate Change (IPCC)---the main international body associated with investigating the phenomenon---says: 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.....There is very high confidence that the net effect of human activities since 1750 has been one of warming.  Despite this assertion, denialists have attempted to use such methods as the discredited Oregon Petition in an effort to prove their case.
A 2004 study by Naomi Oreskes reviewed over 900 peer-reviewed papers and found none that dissented from the consensus. Criticism of the study has been withdrawn but continues to be repeated in denialist circles.
Many of these claims are thrown into one big denialist soup. However, the problem is that many of them are also contradictory in nature. For example, the common talking points about it being warmer during the Medieval Warm Period and low climate sensitivity ("it's not that bad") contradict each other because a warmer Medieval Warm Period would imply high climate sensitivity. Another common assertion is that certain temperature records and proxies are inaccurate, though these supposedly inaccurate measurements are often used to argue that "it happened in the past, so it's natural" or "it's not that bad."
Anyone who, even after the occurrence of extreme weather events that seem to intensify yearly, does not see the validity of decades of scientific documentation that catalogues the existence of global warming, is a lost cause. Time is of the essence. Instead of spending resources trying to convince people (anyone who still doesn't get it, will never get it) that global warming is in fact real, the people in this world who have a clue should put the focus on action and moving forward by championing the solutions to this crisis that threatens the entire planet. These solutions involve fostering the use of hybrid vehicles, wind power, solar power, hydro power and perhaps even a containable form of nuclear power.
In the event that such things are a dead end (and there is the opinion that it's too late to reverse climate change by merely reducing or stopping what we're doing) there is geo-engineering. This involves trying to force climate change back in the opposite direction intentionally. Among these options is lacing the atmosphere with particulate matter in order to seed clouds and artificial carbon sequestration technology to actively remove the carbon dioxide from the atmosphere at a rate faster than natural sinks such as photosynthesis as ocean carbonates. These carry additional risks as we've already fucked the environment accidentally because we didn't understand it well enough, and any more messing about is liable to make things far worse and far sooner.
Note on abbreviations
Global warming is often abbreviated as "AGW" for anthropogenic global warming or "ACC" for anthropogenic climate change. Some deniers add a C to these (to make CAGW or CACC) to stand for "catastrophic." This is a bullshitting tactic whereby the denier can say "I'm not a denier, I do not deny that human-produced emissions can have an effect on climate. I am merely asking questions about whether the impact will be as catastrophic as CAGW proponents say it will." Needless to say, it's a staple among the "not that bad/CO2 is plant food" crowd.
So, we can do this two ways: suck it up and take the necessary steps now to mitigate the expected damage to human civilization, or wait another few decades debating PRATTs while millions (possibly billions) of people die around us. At this time, the following video would be more than appropriate:
- Greenhouse effect
- The global warming wager
- Global Warming Denial Bingo
- The Great Global Warming Swindle, denialist propaganda film
- American Government: Institutions and Policies - a textbook heavily criticised for its stance on global warming.
- Freeman Dyson
- Steve McIntyre
- Patrick Michaels
- Steve Milloy
- Christopher Monckton
- Lubos Motl
- Ian Plimer
- Frederick Seitz
- S. Fred Singer
- Roy Spencer
- Anthony Watts
- NASA Data
- National Academies of Science reports
- NOAA data
- The Discovery of Global Warming
- Pew Center on Global Climate Change
- Royal Society's Summary of the Science and Policy Reports and Statements
- Blue Man Group on Global Warming (YouTube)
- Antarctica warming (BBC/Nature)
- An excellent post at the science blog ill-considered about "how to talk to a global warming denialist"
- Other ScienceBlogs with regular AGW coverage: Deltoid, Stoat
- BBC News - Tackling climate change with technology (a very brief overview of the pros and cons of technology that could be used to tackle climate change)
- Realclimate, its wiki, and its denialist PRATT list
- Interesting infographic comparison of debate points by both sides of the argument.
- Skeptical Science, another guide to denialist PRATTs handily organized by "difficulty level" of the science.
- Logical Science, very thorough coverage of both the science and politics of global warming.
- Deep Climate, great coverage of climate issues and often features original research by noted denialist debunker John Mashey
- Policy Lass
- Clearing Up the Climate Debate, 14-part series at The Conversation
- The rules for providing evidence of AGW
- DenialDepot (Yes, this is a parody blog)
- Open Climate Science 101
Global warming deniers
- Climate Audit.org, Steve McIntyre
- CEI. org Competitive Enterprise Institute
- "Carbon: We call it life"
- Winnipeg bred global warming denier Tim Ball avoids embarrassment at Peoples Court
- ↑ http://www.ballardian.com/sterling-on-ballard
- ↑ The Greenhouse Effect - University of California
- ↑ Greenhouse Gases - Frequently Asked Questions - NOAA Satellite and Information Centre
- ↑ Greenhouse Effect and Global Warming
- ↑ Greenhouse Gases, Climate Change, and Energy - Energy Information Administration
- ↑ Global warming - Nodvin, Stephen C. in The Encyclopedia of Earth
- ↑ http://www.ipcc.ch/SPM2feb07.pdf (dead link)
- ↑ NRC Exonerates "Hockey Stick" Graph, Ending "Mann-Hunt" by Two Canadian Skeptics - DeSmog Blog
- ↑ Temperature Variations in Past Centuries and the so-called "Hockey Stick" - Real Climate
- ↑ The debate's over: Globe is warming - USA Today
- ↑ There's no question that the Earth is getting hotter—and fast. The real questions are: How much of the warming is our fault, and are we willing to slow the meltdown by curbing our insatiable appetite for fossil fuels? - National Geographic
- ↑ Global Warming Myths and Facts - Environmental Defense Fund
- ↑ http://mustelid.blogspot.com/2005/01/water-vapour-is-not-dominant.html
- ↑ Ward, Peter F. Under a Green Sky
- ↑ For a thorough run-down, see the treatment of the scientific consensus by Logical Science and Wikipedia.
- ↑ Pentagon to rank global warming as a destabilizing force
- ↑ Global Warming Skeptics: A Primer - Environmental Defense Fund
- ↑ Al Gore and the Attack of the Global Warming Cranks - Denialism
- ↑ ExxonMobil’s Continued Funding of Global Warming Denial Industry - Greenpeace
- ↑ Smoke Signals - Grist
- ↑ 
- ↑ Don’t Wreck the Economy in the Name of the Environment, Says Bob Barr - Barr '08
- ↑ http://rfdamerica.com/?p=991
- ↑ The Global Warming Myth? - ABC News
- ↑ Global Warming, New Ice Age / Extreme Weather - Conspiracy Café
- ↑ http://thinkprogress.org/2009/07/31/armey-pollution-gospel/
- ↑ Ancient Biomolecules from Deep Ice Cores Reveal a Forested Southern Greenland - Willerslev, Eske et al. Science 6 July 2007: Vol. 317. no. 5834, pp. 111-4 DOI: 10.1126/science.1141758
- ↑ 28.0 28.1 Greenland ice yields hope on climate - The Boston Globe
- ↑ Greenland's ancient forests shed light on stability of ice sheet - Natural Environment Research Council
- ↑ Photographic evidence of glacial retreat.
- ↑ http://www.newscientist.com/article/dn11638
- ↑ James Frank. Explaining how the water vapor greenhouse effect works (Skepticalscience.com, 2nd September 2010)
- ↑ There IS a problem with global warming... it stopped in 1998 By Bob Carter
- ↑ [http://www.skepticalscience.com/global-warming-stopped-in-1998-basic.htm What has global warming done since 1998? from Skepticalscience
- ↑ NASA Research Finds 2010 Tied for Warmest Year on Record
- ↑ IPCC report
- ↑ Oreskes, Naomi. The Scientific Consensus on Climate Change. Science 3 December 2004: Vol. 306 no. 5702 p. 1686.
- ↑ What does Naomi Oreskes' study on consensus show?, Skeptical Science
- ↑ See here for a full list of contradictory claims.