Gadget by The Blog Doctor.

Sunday, July 18, 2010

Who Should You Believe


To fully understand the climate problem we face it is necessary to have some expertise in a range of scientific disciplines including: physics (particularly radiation physics), chemistry, oceanography, glaciology, geology and Mathematics (particularly statistics and calculus). For most people this is not a practical task.

One method of making sense of the claims of climate science instead of indulging in a serious scientific study, is to check on the opinions of those who are qualified to make a judgement.

There are two methods of surveying informed opinion on the topic of Anthropogenic (human caused) Global Warming (AGW).

The first is to survey individual scientists. In the next section of this post I investigate three surveys, one of which claims that a very large number of scientists doubt AGW and the other two claim that the vast majority of qualified scientists support the AGW hypothesis. My conclusion is that the pro AGW survery are more convincing.

The second method is to investigate the policies of sceince organisations, which seems a more effective approach. As I show later in the post, the vast majority of organisations that represent scientists, have policy statements that support the view that the world is warming and that the major cause is human caused (anthropogenic) carbon dioxide. There is a small group of organizations of scientists that have noncommital policy positions, but none that directly oppose the conventional global warming view.

It is clear from an analysis of the policy statements of scientific organisations that the vast majority of people qualified to make a judgenent are of the view that the world is warming and the major cause is human caused carbon dioxide.

Surveys of Individuals

This section discusses three approaches to determining the opinions of individual scientists.

The Oregon Petition

The Global Warming Petition Project, usually referred to as the Oregon Petition has a website that can be found Here. A wikipedia article on the petition can be found Here

Below is the statements that petitioners signed (taken from the website:

The video below also discusses the petition. Note that it gives a long biography of one of the leading lights of the petition, and does not start to discuss the petition until the 4 minute 20 second mark.

It is clear from the evidence that the Oregon Petition is not a reliable indicator of scientific opinion on climate change. There is no attempt to check the qualifications of those participating in the petition, a fact which is admitted by Robinson who runs the petition: "When we're getting thousands of signatures there's no way of filtering out a fake" - source Wikipedia article above and video.

The Doran and Zimmerman Survey

The chart below is taken from this location.

This link is to a news release on the survey.

To here Professor Doran discuss the survey click on this link.

Geoscience faculty members at Universities, and US Federal Research Facilities were contacted for this survey, totalling 10,257 Earth scientists. Replies were received form 3146 people.

Two questions were asked:

  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?

According to those conducting the survey:
Results show that overall, 90% of participants answered “risen” to question 1 and 82% answered yes to question 2.

This is a more convincing survey than the Oregon Petition as Doran and Zimmerman were careful to validate the identities of those who responded. Only members of Earth Science faculties were contacted and only those contacted could respond to the survey. There is little doubt that those who responded have expertise in the relevant area of science.

The major problem with this survey is the relatively small number of people who responded. This is particularly an issue with the sub groups, for instance, the "Climatologists who are active publishers on climate change" group only numbered 79 people.

UPDATE: 11/01/2011
Dennis Ambler has written a critique of this survey. Ambler's essay can be found here. That Ambler's arguments are absurd and statistically illiterate can be seen at this link and this link. Andrew Bolt uncritically linked to Ambler's nonsense here, which raises serious questions about Mr Bolt, which are discussed in the comments here. This all raises the question, How Can Denialists Get the Maths So Wrong?

PNAS Expert Credibility in Climate Science article

In June 2010, the Proceedings of the National Academy of Sciences of the United States, published an article titled Expert Credibility in Climate Science.

The research in this article strongly supports the survey results of Doran and Zimmerman. The paper can be found at this link.

The results of the reserch are summarised below. (ACC is the initials for Anthropogenic Climate Change, ie Climate Change caused by human activities.)

... we use an extensive dataset of 1,372 climate
researchers and their publication and citation data to show that (i)
97–98% of the climate researchers most actively publishing in the
field support the tenets of ACC outlined by the Intergovernmental
Panel on Climate Change, and (ii) the relative climate expertise and
scientific prominence of the researchers unconvinced of ACC are
substantially below that of the convinced researchers.

Stephen Schneider, who died recently, discusses the findings in the video below:

This is much more convincing than the two other surveys discussed above. It might be objected that only 1,372 people were investigated, but these are genuine experts who publish in the technical literature on Climate Change. This is a much larger number of experts than in the Doran and Zimmerman Survey, and of cause we have no idea of the expertise of those who responded to the Oregon Petition.

STATS Survey

Further confirmation of the strength of expert opinion can be found in a survey by STATS at the George Mason University. See this link for details.

Surveys of Science Organizations

There are many organisations that represent the interests of working scientists, and many of them have working scientists as members.

These organisations are sensitive to the views of their memberships. The American Association of Petroleum Geologists is an interesting case in point. It had a policy statement, before July 2007, that denied the science on glabal warming. The Association was forced to change that view because as stated by the then President the "current policy statement is not supported by a significant number of our members and prospective members", (the quote can be found towards the bottom of this link). The current policy is noncommital, which is probably as far as an organization representing geologists employed by the fossil fuel industry could be expected to go.

It is clear that the vast majority of organizations of scientists support the IPCC view summrised as follows:

An increasing body of observations gives a collective picture of a warming world and other changes in the climate system... There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.

There is now no organization representing scientists that actively denies anthopogenic (human caused) global warming. A small group are noncommital on the issue. Here is an article describing the opinions of many scientific organizations.

The following list of science organisations is taken from the document at this location.

Note that all of the organizations mentioned support the IPCC view with the exception of the 5 noncommital groups at the bottom.

As no organization of national or international repute, that represents scientists, denies anthropogenic global warming, clearly the vast majority of those most qualified to make a judgement support the consensus (IPCC) view.

Details of the views of the individual organizations listed below can be found at either of the two links above.

Synthesis reports
Intergovernmental Panel on Climate Change (IPCC) 2007
U.S. Global Change Research Program
Arctic Climate Impact Assessment
Statements by concurring organizations
o Academies of Science
European Academy of Sciences and Arts
InterAcademy Council
International Council of Academies of Engineering and Technological
Joint science academies' statements
Network of African Science Academies
Royal Society of New Zealand
Polish Academy of Sciences
National Research Council (US)
o General science
American Association for the Advancement of Science
European Science Foundation
Federation of Australian Scientific and Technological Societies
o Earth sciences
American Geophysical Union
European Federation of Geologists
European Geosciences Union
Geological Society of America
Geological Society of Australia
International Union of Geodesy and Geophysics
National Association of Geoscience Teachers
Stratigraphy Commission of the Geological Society of London
o Meteorology and oceanography
American Meteorological Society
Australian Meteorological and Oceanographic Society
Canadian Foundation for Climate and Atmospheric Sciences
Canadian Meteorological and Oceanographic Society
Royal Meteorological Society (UK)
World Meteorological Organization
o Paleoclimatology
American Quaternary Association
International Union for Quaternary Research
o Biology and life sciences
American Association of Wildlife Veterinarians
American Society for Microbiology
Australian Coral Reef Society
Institute of Biology (UK)
Society of American Foresters
The Wildlife Society (international)
o Human health
American Academy of Paediatrics
American College of Preventive Medicine
American Medical Association
American Public Health Association
Australian Medical Association
World Federation of Public Health Associations
World Health Organization
o Miscellaneous
American Astronomical Society
American Chemical Society
American Institute of Physics
American Physical Society
American Statistical Association
Engineers Australia (The Institution of Engineers Australia)
International Association for Great Lakes Research
Noncommittal statements
American Association of State Climatologists
American Association of Petroleum Geologists
American Geological Institute
American Institute of Professional Geologists
UPDATE 17/08/2021

The evidence keeps mounting.

Here is a link to a post on the Vision Prize that gives further evidence of the strength of the consensus view.

1 comment:

Anonymous said...

great post dad, really interesting and challenging...love Cath