The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?

There are several claims that large numbers of scientists do not agree with the theory of climate change, the best known of which is a petition organised by the Oregon Institute of Science and Medicine (the OISM petition). This petition now appears to be signed by over 32,000 people with a BSc or higher qualification.

The signatories agree with these statements:

• The proposed limits on greenhouse gases would harm the environment, hinder the advance of science and technology, and damage the health and welfare of mankind.
• There is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gasses is causing or will, in the foreseeable future, cause catastrophic heating of the Earth’s atmosphere and disruption of the Earth’s climate.

No evidence has ever been offered to support the first statement, and the second statement is in flat contradiction with the scientists who study climate change. There are also valid issues regarding the methodology:

• The organisers have never revealed how many people they canvassed (so the response rate is unknown) nor have they revealed the sampling methodology, an ironic omission considering how much fuss is made about scientists being candid and making public their methods and data.
• The petition is, in terms of climate change science, rather out of date.

In the professional field of climate science, the consensus is unequivocal: human activities are causing climate change and additional anthropogenic CO2 may cause great disruption to the climate.

32,000 Sounds Like A Lot

In fact, OISM signatories represent a tiny fraction (~0.3%) of all US science graduates (petition cards were only sent to individuals within the U.S)

According to figures from the US Department of Education Digest of Education Statistics: 2008, 10.6 million science graduates have gained qualifications consistent with the OISM polling criteria since the 1970-71 school year. 32,000 out of 10 million is not a very compelling figure, but a tiny minority – approximately 0.3 per cent.

There are many issues casting doubt on the validity of this petition. On investigation, attempts to undermine the scientific consensus on climate change often appear to have ideological roots, vested business interests or political sponsors. The claims made for the OISM petition do not withstand objective scrutiny, and the assertions made in the petition are not supported by evidence, data or scientific research.

Several independent studies have shown that 97% of climate scientists agree that humans are causing the climate to change, that CO2 is causing global changes to the climate, and that the consequences could be catastrophic. These views form the scientific consensus on climate change.

*****

Correction: on 26th June 2013 I corrected the original post at Skeptical Science after it was pointed out to me that no surveys asked respondents to comment on the consequences of climate change. I regret that in this re-post, the error was not corrected until now (4th October 2013). Thanks to Guardian blogger Portentious for pointing this out, and apologies for the omission.

Footnote: this post was written for SkepticalScience as part of an ongoing project to add ‘basic’ rebuttals of common climate change denial arguments. References for all statements can be found in the intermediate discussion “Over 31,000 scientists signed the OISM petition“