Claim: There is no consensus among climate scientists that global warming is caused by human activities.

Why this Claim is Wrong: In fact, scientists today are in near unanimous agreement that today's global warming is caused by humans. In wider polls, the greater a person's understanding of climate science, the greater is his conviction that global warming is human-caused (Doran 2009, see blue graph below). Only among non-scientists in the lay public is there significant controversy and disagreement, and that’s a result of efforts by supporters of the fossil fuel industry to sow misinformation. The major scientific organizations of all the industrialized countries, including the highest ranking (the National Academy of Sciences) agree that climate change is real and human-caused. The most ignorant, or agenda-biased group of scientists siding against human-caused global warming (~54%) were economic geologists (nice video summarizing this issue). Anderegg, et al. (2010) in the journal The Proceedings of the National Academy of Sciences finds ~98% of active, publishing climate scientists agree that global warming is caused by humans. Here is an interview discussing this study on YouTube. The 2010 Anderegg paper explicitly acknowledges that there is an honored place for honest, genuine searches for alternative explanations, and that ultimately it is evidence that decides. But climate science is not a young field, and there is no significant disagreement about basic facts.


Response to the survey question "Do you think human activity is a significant contributing factor in changing mean global temperatures?" (Doran 2009) General public data come from a 2008 Gallup poll.

The leader of the "no consensus" argument is Richard Lindzen, who has made this false claim before Congress. This piece by Lindzen on the Cato Institute website cites not a single piece of evidence or reference to support his opinions. You can read more about Richard Lindzen at the bottom of the main page.

Other investigators into this question find the same conclusion... Cook et al. (2012) studied 12,000 climate research papers in peer-reviewed journals and of those taking a position on human-caused global warming, they find over 97% in agreement - "Our analysis indicates that the number of papers rejecting the consensus on AGW is a vanishingly small proportion of the published research." . An even more one-sided result is revealed in a newer study by J. L. Powell (2013), showing that of 13,950 peer-reviewed papers in scientific journals on climate change published between 1991 and 2012, only 24 (far less than 1%) reject the notion of human-caused global warming.

Scientific agreement that climate change is human-caused is essentially unanimous.

Update Jan 2014
And finally, a newer study finds only a single author (in an obscure Russian journal) who does not agree that climate change is human-caused. This is the conclusion of a study of 2,258 journal papers by a total of 9,136 different authors publishing in late 2013, discussed here. You will have to click on the thumbnail image at left to see the full size image in order to notice that microscopic razor-thin slice of the pie.

Even more important, there are essentialy no popular media stories reporting this "97%" figure which ask the obvious questions: First... "So, does that mean 3% reject human-caused global warming?" That's the unstated implication that the casual reader will take-away. NO. Virtually all of the 3% are staying cautious and not wanting to make a statement (Powell 2014). So the consensus is much stronger... “Look at it this way: If someone says that 97 percent of publishing climate scientists accept anthropogenic [human-caused] global warming, your natural inference is that 3 percent reject it. But I found only 0.006 percent who reject it. That is a difference of 500 times.” - Powell . Here's another very obvious question not asked and not reported in popular media - How many of the supposed 3% (or 0.006%) are directly or significantly funded by Big Oil or right-wing think tanks? I'm thinking of names like Fred Singer, Roy Spencer, John Christy, Richard Lindzen (bottom of link page) , and Willie Soon...


Update 2015
With new record high global average temperatures in 2014 and again in 2015, the go-to lie of "Global Warming has Stopped" is being replaced by a re-play of the "There's no Consensus", by the Republicans campaigning for the '16 election. Rick Santorum simply bullies and lies his way through this interview on national TV. repeating the false meme that the 97% is based on only 77 scientists, and numerous other outright fabrications and distortions. The link shows the actual authors of the studies and their response. And another Republican presidential candidate Chris Christy attempts to humiliate an innocent (and very correct) questioner at a news conference, on his ridiculous statements about human breathing and climate change - essentially calling the questioner a liar in no uncertain terms. It's Christy who's the liar here - check for yourself. Isn't it amazing how, even in the internet age, politicians feel safe in just flat-out lying to the very public that is going to elect them? As if there will be no fact-checking to call them out?


In Short: Numerous studies show strong consensus among active climate scientists (essentially unanimous) supporting AGW, and this conviction is growing with time (i.e. later studies show the consensus even more lop-sided). Those with the greatest experience and expertise in climate science show the strongest conviction. Richard Lindzen's claim there is "no consensus" is simply out of touch with reality, or a deliberate lie, or both.




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