NOTE: This material was originally posted in a VERY LONG stand-alone blog. I have extracted it and placed it in its own blog to improve readability.
So far we have seen that the IPCC AR4 is the standard in the current state of climatology. Furthermore, at least 41 or 43 scientific societies have endorsed its conslusions, 2 have expressed some doubt about certain aspects of it, but NONE have rejected it. One might expect that to be very strong evidence that there is a scientific consensus. I would.
But I suppose that if one has a strong enough desire to disbelieve it. They can argue that the IPCC misrepresents the science and that these scientific organizations are political branches of the field and do not necessarily represent the science in the field (although the fact that the American Association of Petroleum Geologists changed its negative statement after member protests and no organization expressing support of the IPCC have reported any significant protest coming from its membership strongly suggest otherwise). Is there anything that does unequivocally represent the science in a field? YES!! ... peer-reviewed journals that publish papers pertaining to that field! One can talk consensus or lack of it until they are blue in the face, but it is what is published that counts. That is where new information is presented, tested and (if it survives the testing) eventually becomes a part of the scientific body of that field. If the information is not there ... then it isn't science. What does the actual literature say?
Naomi Oreskes, an historian of science and a geologist, surveyed the literature. She looked at 928 papers published in pertinent journals between the years of 1993 and 2003. She found that 75% presented data that agreed with the consensus view that anthropogenic global warming is real, 25% dealt with techniques in paleoclimatology (in other words they were testing the confidence that one can have in those techniques and thus were not directly concerned with the question of whether or not anthropogenic global warming was real), and 0% contradicted the consensus view. I believe that is the most important finding. It says that anybody, scientists or not, who denies global warming has no data capable of withstanding scientific scrutiny against it. That is the ULTIMATE in scientific consensus.
It should come as no surprise that global-warming denialists have attacked this too. But at some point even to them it must become apparent that if you are calling all of science liars, then there IS a consensus within that science. OK, that is my case that there is a scientifc consensus. My personal opinion is that is good enough to stand on its own. But so far I have not looked very closely at jackbenimble's case for there not being one. I will do that in the final blog of this series.
Update: Shortly after posting this blog a major survey of earth scientists was done concerning whether or not there is a scientific consensus on global warming. The survey was done by University of Illinois - Chicago researcher Peter Doran and his graduate student Maggie Kendall Zimmerman. They invited 10,257 earth scientists to participate, of which 3,146 accepted. The preliminary report focuses on just two of the questions:
(1) When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?
(2) Do you think human activity is a significant contributing factor in changing mean global temperatures?
Over 90% answered "risen" to question 1 and 82% "yes" to question 2. Doran and Zimmerman broke that response down by subdisipline. 79 people who labelled their area of expertise as climatology and had published more than 50% of their recent peer-reviewed papers on climate change answered question 1. 76 or those said that in their opinion global temperatures have risen since the pre-1800s (96.2%). 77 of these answered question 2. 75 said that human activity is a significant contributing factor (97.4%).
Among the general public only 58% would agree that humans play a significant role in global warming (question 2) Among earth scientists only Petroleum Geologists were less likely than the general public to agree. Only 48 of 103 agreed that human activity is a significant contributing factor (47%). Petroleum Geologists have close ties with oil companies and would be the most adversely effected should we actually decide to cut our carbon emissions. Given this economic incentive their disagreement makes sense to me.
Somewhat surprisingly the group next most likely to disagree were meteorologists. 23 or 36 (64%) answered "yes" to whether or not human activity contributed significantly to climate change. While this is still higher than the general public, it is higher than I would have predicted. However, the main concern of meteorologists is to predict the weather. Short-term weather is notoriously unpredictable. Perhaps this explains their resistance to climatological data. However, the climate (weather averaged over time) is not nearly as unpredictable as is weather. I cannot tell you whether or not it will be colder or warmer a week from now, but this being January, I can tell you with a great deal of certainty that come July it will be warmer where I live (Houston, Texas).
But in any case, what this survey clearly demonstrates is that among those people who are most familiar with climatological research -- the climatologists actually publishing the research -- there is no significant dissention from either (1) Global warming is happening (96.2% agreement) and (2) Human activity plays a significant role (97.4% agreement).
