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Survey says: 97% of climate scientists agree that humans cause global warming

By: Dr. Jeff Masters, 4:14 PM GMT on May 07, 2013

Two studies done in 2009 and 2010 found that 97% of actively publishing climate scientists agree that humans cause global warming. But what would a larger sample of the scientific literature show, extended all the way up to 2011? You're invited to help find out, by participating in an anonymous 10-minute survey where you will be reading the abstracts (summaries) of ten randomly selected technical papers on Earth's climate published between 1991 and 2011. The survey was created by physicist John Cook of The Global Change Institute at Australia's University of Queensland. Mr. Cook is the creator of one of my favorite climate change websites, skepticalscience.com. He authored one of our special Earth Day 2013 essays, Closing the Consensus Gap on Climate Change, from which I have pulled Figure 1 below. Mr. Cook is lead author on a new paper called "Quantifying the consensus on anthropogenic global warming in the scientific literature," to be published in the next month or so in Environmental Research Letters. The paper analyzes the same papers included in the survey you're asked to participate in, and the researchers plan to compare the results. Each of these 11,944 papers written by 29,083 authors and published in 1,980 journals included the keywords "global warming" or "global climate change" in their listing in the ISI Web of Science database. After reading each abstract, you will be asked to rate the level of endorsement within the abstract for the proposition that human activity (i.e., anthropogenic greenhouse gases) is causing global warming. There will be these choices available on a drop-down menu for you to choose from:

1. Explicit Endorsement with Quantification: abstract explicitly states that humans are causing more than half of global warming.
2. Explicit Endorsement without Quantification: abstract explicitly states humans are causing global warming or refers to anthropogenic global warming/climate change as a given fact.
3. Implicit Endorsement: abstract implies humans are causing global warming. E.g., research assumes greenhouse gases cause warming without explicitly stating humans are the cause.
4. Neutral: abstract doesn't address or mention issue of what's causing global warming.
5. Implicit Rejection: abstract implies humans have had a minimal impact on global warming without saying so explicitly. E.g., proposing a natural mechanism is the main cause of global warming.
6. Explicit Rejection without Quantification: abstract explicitly minimizes or rejects that humans are causing global warming.
7. Explicit Rejection with Quantification: abstract explicitly states that humans are causing less than half of global warming.
8. Don't know.

When you are all done, the survey will let you know how your average score for the ten papers compares to the rating given by the authors. The survey took me about 8 minutes to complete, and it was interesting to see the tremendous diversity of research being done on global warming in my random sample. I'll post about Mr. Cook's results when his paper is published in the next few months.


Figure 1. Two recent studies have sought to measure the level of agreement in the scientific community in different ways and arrived at strikingly consistent results. A 2009 study led by Peter Doran surveyed over 3,000 Earth scientists and found that as the scientists' expertise in climate change grew, so did the level of agreement about human-caused global warming. For the most qualified experts, climate scientists actively publishing peer-reviewed research, there was 97% agreement. Alternatively, a 2010 analysis led by William Anderegg compiled a database of scientists from public declarations on climate change, both supporting and rejecting the consensus. Among scientists who had published peer-reviewed climate research, there was 97% agreement. However, it is worth pointing out that science is not decided by majority vote. This is articulated concisely by John Reisman who says: "Science is not a democracy. It is a dictatorship. It is evidence that does the dictating." Figure and text taken from Mr. John Cook's special Earth Day essay, Closing the Consensus Gap on Climate Change.

Thanks for participating!

Jeff Masters

Climate Change

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.