weight of evidence

Jul. 13, 2019

Whether it is temperature or precipitation or fire damage, each year that passes brings more weather records. This week it is 90 degree temperatures in Alaska- shattering the previous record of 85 degrees. Although most Americans have come to the reality of climate change, there are still deniers and we still lack the political will to legislate or build policy based on the preponderance and convergence of the evidence. There is a denial industry funded by the fossil fuel and petro-chemical companies that literally denies the science, and seeks to confuse the public. There is denial within governments, where spin-doctors pretend that regulations are bad and offer a false binary choice of reducing carbon versus destroying our economy. When our politicians resist the science in favor of their big donors, denial prospers.

Back in 2016, Peabody Energy faced a court case in Minnesota to determine whether the State of Minnesota should continue using its exceptionally low established estimates of the ‘social cost of carbon’, or whether it should adopt higher federal estimates. On nearly every key point the judge ruled that the preponderance of evidence was on the side of the environmental groups and recommended that the State of Minnesota use the federal social cost of carbon estimates. Coal’s climate deniers took their best shot at climate science, and they lost because, in the courts, facts and evidence have power over opinion and speculation.

What do I mean by preponderance of evidence? I mean an overwhelming body of scientific, peer-reviewed research. For example,  James L. Powell, a former member of the National Science Board and current executive director of the National Physical Science Consortium, analyzed published research on global warming and climate change between 1991 and 2012 and found that of the 13,950 articles in peer-reviewed journals, only 24 rejected anthropogenic global warming. Again in 2017, James Powell published a meta-analysis of 54,195 peer-reviewed papers, finding a 99.94% consensus about human-caused climate change. Cook analyzed 11,944 peer-reviewed papers published between 1991-2011. Out of them, about a third (4,013) expressed a position on man-made climate change, and 3,894 (or 97%) supported the position that humans are causing climate change. 

There are thousands and thousands of studies documenting climate change and its effects and among scientists, there’s essentially a consensus regarding climate change. While the details and the exact specifics of how it is happening are still very much an area of active research, there’s not much denying that it is happening and that we are causing it. Add to this the fact that 9 of 10 top climate change deniers are linked to the petrol-chemical and fossil fuel industries and one can see where the confusion and misinformation is coming from.

Here are some links to studies and websites so you can examine some of the preponderance of evidence for yourself instead of being conned by moneyed interests.

Link to a study: Quantifying the consensus on anthropogenic global warming in the scientific literature: https://iopscience.iop.org/article/10.1088/1748-9326/8/2/024024

There is a significant gap between public perception and reality, with 57% of the US public either disagreeing or unaware that scientists overwhelmingly agree that the earth is warming due to human activity. Contributing to this 'consensus gap' are campaigns designed to confuse the public about the level of agreement among climate scientists. In 1991, Western Fuels Association conducted a $510 000 campaign whose primary goal was to 'reposition global warming as theory (not fact)'. A key strategy involved constructing the impression of active scientific debate using dissenting scientists as spokesmen (Oreskes 2010). The situation is exacerbated by media treatment of the climate issue, where the normative practice of providing opposing sides with equal attention has allowed a vocal minority to have their views amplified (Boykoff and Boykoff 2004). A systematic, comprehensive review of the literature provides quantitative evidence countering this assertion. The number of papers rejecting AGW is a miniscule proportion of the published research, with the percentage slightly decreasing over time. Among papers expressing a position on AGW, an overwhelming percentage (97.2% based on self-ratings, 97.1% based on abstract ratings) endorses the scientific consensus on AGW.

Link to a study: Consensus on consensus: a synthesis of consensus estimates on human-caused global warming: https://iopscience.iop.org/article/10.1088/1748-9326/11/4/048002

The consensus that humans are causing recent global warming is shared by 90%–100% of publishing climate scientists according to six independent studies by co-authors of this paper. Those results are consistent with the 97% consensus reported by Cook et al based on 11,944 abstracts of research papers, of which 4,014 took a position on the cause of recent global warming. A survey of authors of those papers (N = 2412 papers) also supported a 97% consensus. Tol (2016 Environ. Res. Lett.) comes to a different conclusion using results from surveys of non-experts such as economic geologists and a self-selected group of those who reject the consensus. Tol's erroneous conclusions stem from conflating the opinions of non-experts with experts and assuming that lack of affirmation equals dissent. 

Link to a study: The Scientific Consensus on Climate Change: How Do We Know We’re Not Wrong? Naomi Oreskes: http://www.lpl.arizona.edu/sites/default/files/resources/globalwarming/oreskes-chapter-4.pdf

https://en.wikipedia.org/wiki/Surveys_of_scientists%27_views_on_climate_change

https://skepticalscience.com/

https://skepticalscience.com/fixednum.php   This link has rebuttals for most of the climate deniers’ myths and fallacies.