Global warming

From RationalWiki

Global warming is the atmospheric consequence of the greenhouse effect resulting in the increase in the average temperature of the Earth. This atmospheric warming is vital to all life on earth; without it the planet would be 33 °C colder than today's average of 14 °C.

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. The greenhouse effect theory is supported worldwide by many climatologists and scientists in general.

[edit] Anthropogenic Climate Change

The phrase “global warming” is also 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.

1. The Earth's atmosphere keeps the planet much warmer than it would be without an atmosphere.^[1]
2. The main gases which contribute to this are carbon dioxide, methane and water vapor.^[2]
3. The ability of these gases to act as greenhouse gases can be shown in a laboratory.^[3]
4. The quantity of these greenhouse gases in the atmosphere has increased sharply since the Industrial Revolution, and their concentration continues to increase.^[4]
5. The concentration of these gases has increased as a consequence of human activity.^[5]
6. The temperature of Earth's atmosphere has been increasing and continues to increase.^[6]
7. The increase in global temperature correlates with the increases of greenhouse gases.^[7][8]
   
   Up to this point virtually all scientists are in agreement - including global warming skeptics who understand the science and the data^[9]. Consequently the skeptics need to somehow attack the final leg of the argument:
   
   
8. As humanity has been increasing the quantity of global warming gases in the atmosphere, and as the temperature of the atmosphere has increased in line with these gases, then human activity is responsible for global warming.^[10][11]

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.

[edit] What's so bad about global warming?

Main article Effects of global warming Global warming is "bad" for a number of reasons.

• A rise in sea level. Global warming will cause a sea level rise of 9 - 88 cm (3.5 – 34.6 inches). 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. The ocean has a limited capacity to dissolve carbon dioxide before it ceases to absorb any more, thus leading to further warming. This would also cause great damage to fish stocks.
• Tipping points/feedback loops. There are many possible tipping points and feedback loops. For instance, if global warming causes the northern permafrost to melt this will release vast amounts of methane, which would make the problem much worse.
• Spread of tropical diseases. As northern latitudes become warmer, previously rare tropical diseases will gain a foothold there.
• Disruption of ocean currents. The disruption of ocean currents could shut down the Gulf Steam with unpredictable consequences.
• 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.

[edit] Entrenched Interests and Global Warming Deniers

There are many entrenched interests - such as 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. Consequently, they have spent a vast amount of money^[12] in an effort to discredit the science behind man-made global warming, and encourage global warming denialism ^[13]. 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." ^[14]

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^[15], and the campaigns carried out by the oil companies when they wished to continue adding lead to petrol.

As a result of the actions of Exxon and others, many wacky global warming conspiracy theories have been invented. These conspiracy theories vary from the weird to the humorous.

[edit] 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 is a global warming sceptic (though Sarah Palin, Republican candidate for Vice-President, believes that global warming is not caused by mankind^[16]) and all of them have some commitment to renewable energy sources. While this may be 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.

The only candidate who has expressed doubt about Global warming is no-hope, third-party Libertarian Party candidate Bob Barr, ^[17]

Some people believe that where political candidates stand on the issue lends credence to one side or the other, others believe that their views aren't relevant unless they are also climate scientists - and this is exactly why the Bush administration's attempts to distort the clear evidence of climate change was such a bad idea.

[edit] Hierarchy of Global Warming Opinions

Global warming deniers form a sliding scale of denial which is outlined below - in general these beliefs are designed to prevent action being taken.

1. Global warming isn’t happening^[18] - so we don’t have to do anything, since there is no evidence of a problem.
2. Apparently unconvinced by the clear evidence of global warming and unwilling to accept that human behavior has a significant effect on climate change - would not support spending taxpayers' money without even more convincing evidence. So we don't have to do anything.
3. Global warming is happening, but it’s not caused by humanity - so we don’t have to do anything.
4. Global warming is happening, it is caused by humanity, but it may be a good thing^[19] - so we don’t have to do anything.
5. 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.
6. 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.
7. (There is an hypothesized sixth 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.

[edit] Claims by global warming denialists

[edit] 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 effect the global temperature only 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.

[edit] 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.^[20] 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. ^[21] 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."^[22] 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.^[21] 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.

[edit] Nature generates more CO₂ than man

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 man is 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 man made outputs are chemically different. Fossil fuel burning outputs CO₂ that has more C14 and C13 than do natural sources. Using tree ring dating it can be shown that C14 containing CO₂ has been responsible for most of the CO₂ increase up until the 1940s, when the largely defensive weapon of atomic bomb negated our ability to use that test. But C13 testing confirmed the C14 testing and showed that fossil fuel burning is the number one contributor to the increase in the CO₂ in the atmosphere.

Clearly it is human-caused (anthopogenic) burning of fossil fuels that is responsible.

[edit] 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 includes spectacular effects such as the snowball earth, and have also included periods of intense global warming. These periods of warming and cooling all have a range of causes mostly involving positive feed back loops, such as ice reflecting the sun back to space causing more ice, reflecting more sun. The warming had similar positive feed back loops, initially it could be 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.

[edit] 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 through out 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.

[edit] 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.

[edit] 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.

[edit] Using anecdotal evidence

The argument "Wow, it's really fucking cold today! Global warming, my ass!" 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.

[edit] Claiming there is no consensus in respect of global warming

Global warming denialists often try to claim that ther is no scientific consensus, despite the fact that the 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 emperatures, 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. ^[23]. Notwithstanding this denialists have attempted to use such methods as the discredited Oregon Petition in an effort to prove their case.

[edit] Conservapedia

[edit] Consensus

[edit] Are the Himalayan glaciers retreating?

[edit] Two additional articles on Conservapedia deserve mention:

Global sea level measured by surface gauges between 1807 and 2002 and by satellite between 1993 and 2006 Sea level increase in the last few centuries is the result of natural factors and is unrelated to anthropogenic global warming[citation needed]. The trend of 7 inches per century began in the 1850s, long before the use of fossil fuels; see Hydrocarbon use. (The "citation needed" tag is on the original!) (no commentary)

CP's graph with population overlay The two graphs (for sea level rise and glacier shrinkage) do show an inversion of cause and effect between hydrocarbon use and the effect. However they also omit the major early "hydrocarbon" used - timber, whether as wood or charcoal. The use (combustion) of timber was the prime mover of the Industrial Revolution and of the deforestation of much of the industrialising western world, and began anywhere between 1600 and 1750, depending on location. The rapidly increasing population after the "dark ages" also increased timber consumption both for building, where the major effect would be of deforestation, and for heating with the additional production of greenhouse gasses. Data for timber usage is not easy to find but population growth can be superimposed on either graph and shows a different picture. At first the effect lags behind but, as "hydrocarbon" usage increases, storms ahead. Incidentally, if the scales are manipulated (stretching hydrocarbon use "taller") the difference is much less apparent.

[edit] Rational arguments against global warming

[edit] See also

• The global warming wager‎

[edit] External links

• Climate Audit.org.
• NASA Data

[edit] Global Warming Deniers

• Competitive Enterprise Institute
• "Carbon: We call it life"
• Winnipeg bred global warming denier Tim Ball avoids embarrassment at Peoples Court

[edit] Footnotes