Not everything you read on the internet is true.
If you were ill would you trust a fellow blogger, a wingnut on the internet or someone who studied medicine for many years? If one maverick doctor disagrees with the consensus would you trust your life to them or the majority opinion? Global warming is highly complex, and it takes a while to fully understand what it is, why it's happening and why it's a threat. This is a potential minefield to anyone who's not an expert on the subject. To illustrate the point try this: Google geocentric theory (the idea that the sun goes round the earth) and you'll find arguments that you won't be able to counter without resorting to some form of "But everyone knows most scientists say otherwise!"
It's understandable that people want to come to their own conclusions, but by far the best way to start doing that is to look not so much at what's being said, but at WHO is saying it. These are just some of the most significant people warning us of the global warming threat:
First, the scientists:
The Intergovernmental Panel on Climate Change (IPCC). 2500+ scientific expert reviewers, 800+ contributing authors and 450+ lead authors from 130+ counties, working more than 6 years to review thousands of peer-reviewed papers. They published their first report on climate change in 1990 and have published an updated one every 5 years since then
The National Scientific Academies of the following countries issued this statement in support of the IPCC:
"The work of the Intergovernmental Panel on Climate Change (IPCC) represents the consensus of the international scientific community on climate change science. We recognise IPCC as the world's most reliable source of information on climate change and its causes, and we endorse its method of achieving this consensus. Despite increasing consensus on the science underpinning predictions of global climate change, doubts have been expressed recently about the need to mitigate the risks posed by global climate change. We do not consider such doubts justified."
The National Academy of Sciences (US), (founded in 1863 by Abraham Lincoln, 1 in 10 of its members is a nobel prize winner!)
American Association for the Advancement of Science (around since before the US Civil War. It's the largest scientific society in the world, with 144,000 members!)
Royal Society (United Kingdom),
Chinese Academy of Sciences,
Science Council of Japan,
Russian Academy of Sciences,
Academia Brasiliera de Ciências (Brazil),
Royal Society of Canada,
Académie des Sciences (France),
Deutsche Akademie der Naturforscher Leopoldina (Germany),
Indian National Science Academy,
Accademia Nazionale dei Lincei (Italy),
Australian Academy of Sciences,
Royal Flemish Academy of Belgium for Sciences and the Arts,
Caribbean Academy of Sciences,
Indonesian Academy of Sciences,
Royal Irish Academy,
Academy of Sciences Malaysia,
Academy Council of the Royal Society of New Zealand,
Royal Swedish Academy of Sciences.
See the full statement here: http://royalsociety.org/displaypagedoc.asp?id=13619
Government sources:
In 2008 (i.e. still during the George W. Bush era), all 16 US intelligence agencies (who aren't normally known for being green), including the CIA, FBI and National Security Agency jointly produced a report known as the National Intelligence Assessment. The report warned of a wide of a wide range of national security threats if global warming isn't properly addressed.
The Pentagon, in 2003 (i.e. also in the George W. Bush era) released a study which warned: "There is substantial evidence to indicate that significant global warming will occur during the 21st century. ...With inadequate preparation, the result could be a significant drop in the human carrying capacity of the Earth’s environment" http://www.guardian.co.uk/environment/2004/feb/22/usnews.theobserver
Governments from all around the world are meeting in Copenhagen to discuss what action to take against climate change.
John McCain promised to take action against climate change http://www.nrdc.org/onearth/04spr/mccain1.asp?r=n (again, this would suggest that it's NOT in fact a liberal plot)
Also in Britain where I live, all the major political parties, including the conservative party agree that global warming is man-made and a threat.
China has declared that it will take action on climate change http://climateprogress.org/2009/08/13/china-signals-plans-curb-greenhouse-gases-beijing-renewable/ and has recently closed coal power plants with a total of 7,467 generating units.
The president of the Maldives made the following remarkable short speech: http://vimeo.com/3661273
Corporations:
One would have thought that big corporations would be the last people to accept that global warming is real, given that many of them, particularly oil companies, may stand to lose out of consumption of their products is necessarily reduced:
Exxonmobil is an oil giant, and the largest company in the world. For a long time they have funded those who deny global warming http://www.greenpeace.org/usa/campaigns/global-warming-and-energy/exxon-secrets. However, in 2007 they finally stated that global warming is a serious risk and must be addressed by governments.
80 global corporations including Shell, BP, Duke Energy, Michelin and British Airways wrote a document to G8 leaders calling for stronger action against climate change.
Wanna see even more sources? The list just goes on and on! Click the following link:
http://logicalscience.com/consensus/consensus.htm#organizations
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So who are the skeptics?
At this date, there is only 1 professional scientific organization which does not concur that the science clearly points to man-made global warming being a serious threat. That's the American Association of Petroleum Geologists, who state that the globe is warming but that their membership is divided on the degree of human influence. However, this is not all that surprising when you consider that they may feel that their jobs will be threated by action taken against to prevent global warming.
The Oregon Petition/petition project etc:
An online petition which anyone can sign. The number of signers is now up to 31,000, although you may hear it quoted as a lower number if someone isn't up to date. To sign you're supposed to hold a science degree, although it can be in ANY area of science, the names are not disclosed and nobody actually checks to see if the signers really do have degrees. http://www.petitionproject.org
A compiled list of 400 scientists against global warming:
Amazingly, some people on this list are counted multiple times, and many are not scientists but engineers, inventors, economists etc.
A few think tanks and advocacy organizations (i.e. people with agendas to push, NOT scientists!):
e.g. The Heartland Institute, The Marshall Institute, The Competitive Enterprise Institute...
A small number of oft-quoted individual scientists.
Robert M. Carter, Richard Lindzen, S. Fred Singer, Roy Spencer etc.
Most of these skeptics are qualified in fields other than CLIMATE science, which is the relevant field.
A slew of journalists, writers, bloggers and documentary makers who present different versions of events, where global warming is portrayed as shambles/conspiricy/liberal plot. They are pretty successful at convincing people, because your average member of the public doesn't know any better.
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It's easy to think that you've found a serious hole in the global warming argument, when in fact you simply haven't properly understood it. In particular, if you go searching for holes in the argument you will surely think you've found some. However, look deeper and there are solid answers to every single one of those holes. To assume instead that ALL these scientists are lying or incompetant is paranoid to say the least! If you're curious about how certain parts of the picture add up, this website does a good job of answering the most popular skeptical concerns:
http://www.skepticalscience.com/argument.php