Global Warming refers to the idea that the Earth's average temperature could significantly increase to the point where it will have noticeable effects on how people live.
The following points of debate have pretty much been resolved (see #News for details regarding the answers):
- whether or not the Earth is currently on a general warmining trend – yes
- whether or not this will have significant effects on anyone – yes
- whether or not those effects will be bad – in the short term, yes; beyond that depends on a lot of unknown factors
There continues to be debate on the following points:
- whether or not this trend, if it is real, will continue
- whether or not the warming is being caused by humanity (strong circumstantial evidence that it is)
- Could be caused by random climatic drift
- Could be caused by changes in any of countless variables, e.g. the sun's energy output
- whether it is in humanity's best interest to attempt countermeasures (as opposed to "letting nature take its course")
- what sorts of countermeasures should be taken (e.g. should we try to counteract the warming trend itself, or just be prepared to deal with the changing climate and rising sea levels as they happen?)
There appears to be some considerable political pressure to deny that there is a dangerous warming trend.
Difficulty of Resolution
Part of the problem is that the issue has become heavily politicized, largely because direct countermeasures (attempts to counteract the warming trend) tend to be unpopular amongst those who would need to implement them, and those who would need to implement them are generally large businesses with significant amounts of political clout and ability to drive the discussion in directions favorable to them.
Another part of the problem is that determining whether or not the phenomenon is of genuine concern requires the integration of large amounts of data – over long timespans and a large number of different geographical locations – in order to notice subtle real effects without raising false alarms due to temporary or local effects.
Although the majority of scientists agree that global warming is occurring and is caused by humanity, a few disagree; each of these few generally express one of the following positions:
- The Earth is not warming: surface records seem to show a warming trend, but satellite and weather balloon records do not.
- The Earth is warming but the cause is unknown
- The Earth is warming but mostly due to natural processes
- Global warming is occurring but not as much as feared
Another counterargument which seems to come up frequently is the idea that the Earth is self-correcting (generally referred to as Gaia theory) and any warming trend will surely be followed by an eventual cooling trend. Although this may be true in general, there is also strong evidence that Earth has been significantly warmer or colder than at present for quite long stretches of time — apparently even freezing over completely on at least one occasion (Snowball Earth), remaining that way for many millions of years and only unfreezing when the accumulation of geothermally-released carbon dioxide in the atmosphere became sufficient to create a counteracting greenhouse effect.
At least one group has argued that the Earth is actually cooling:
- New Research Indicates the Earth May Be Cooling by Amy Ridenour of the conservative National Center for Public Policy Research
- Conflicting Claims on Global Warming and Why It's All Moot at LiveScience
- Friends Committee on National Legislation
- Al Gore at the TED 2006 conference has some good overviews on the Global Warming situation: "There's no real disagreement about global warming – a survery of peer reviewed papers showed 928 supporting a theory of global warming and 0 opposing it. But there's a powerful lobby that is producing doubt, and suceeding – a survey ... reveals that 53% of popular press articles have some doubt about global warming."
- 2005-05-04 ExxonMobil Spends Millions Funding Global Warming Skeptics: doesn't automatically invalidate global warming skepticism, but any argument which starts with "many authorities seem to agree that it's not happening" should be aware that the balance may have been tilted a bit.
- "stabilization wedges": No single solution will be efficient enough fast enough, but in combination they may be enough
- 2006-04-02 Cooler Heads Needed on Warming By George Will
- 2006-03-17 Statistical Analysis Bolsters Theory Linking Warmer Oceans to Stronger Hurricanes (slashdot)
- 2006-03-02 NASA Mission Detects Significant Antarctic Ice Mass Loss
- 2006-02-16 Greenland Ice-Loss Doubles in Past Decade, Raising Sea Level Faster
- Greenland's glaciers are speeding to the ocean: different article on same study; glaciers moving faster than expected
- 2006-02-13 Snows of Kilimanjaro disappearing, glacial ice loss increasing
- 2006-01-30 Top climatologist accuses US of trying to gag him: James Hansen, NASA's top climate scientist, has accused the Bush administration of trying to stop him from speaking out after he called for swift cuts in emissions of the greenhouse gases linked to global warming...
- 2006-01-25 2005 was the warmest year on record
- 2006-01-18 the blame is not with the plants (in case anyone was confused about that)
- 2006-01-09 Tiny Ocean Creatures Tell of Global Warming
- 2006-01 Decoder: "How the White House edits out global warming" by Paul Rauber
- 2005-12-19 Most of Arctic's near-surface permafrost to thaw by 2100
- 2005-12-07 Global Warming Could Halt Ocean Circulation, With Harmful Results: "[This] has been characterized as a high-consequence, low-probability event. Our analysis [...] indicates it is a high-consequence, high-probability event."
- 2005-12-02 Atlantic currents show signs of weakening
- 2005-11-28 Close Coupling Of Climate With Green House Gases In The Past
- New ice cores expand view of climate history: climate of the past 200 years clearly an anomaly; "There is now no question this is due to human influence."
- Global Warming Doubles Rate Of Ocean Rise (alt): improved historical data show increase since Industrial Revolution started
- Ice cores and climate change: more links and analysis
- 2005-11-24 New evidence; Today's atmospheric carbon dioxide levels are highest in 650,000 years
- 2005-11-11 Impact of regional climate change on human health (news brief)
- 2005-11-03 Study Shows Escalating Climate Change Impacts...
- 2005-11-02 Modeling Of Long-term Fossil Fuel Consumption Shows 14.5 Degree Hike In Temperature
- 2005-10-13 World Temperatures Keep Rising With a Hot 2005 By Juliet Eilperin, Washington Post Staff Writer
- 2005-09-23 CNN: New era of hurricanes "But don't rush to blame it on global warming, experts warn."
- 2005-09-16 Global warming 'past the point of no return'
- 2005-05-10 The (UK) Guardian: "David Bellamy's inaccurate and selective figures on glacier shrinkage are a boon to climate change deniers"