In a series of posts, we've been scrutinizing a recent viewpoint article in the journal BioScience, World Scientists’ Warning to Humanity: A Second Notice (2017) - specifically looking at the chances climate change skeptics would be swayed by the evidence and arguments the article presents. The "Alliance of World Scientists" (AWS) was behind this article, which boasts "15,364 scientist signatories from 184 countries". If the authors want to change minds about climate change, they're already off to a bad start. Talk to just about any skeptic and you'll find a deep resistance to arguments from authority. And what is this business about having so many signatories if not an attempt to overwhelm resistance by signaling authority? It didn't work with "the consensus" and it won't work with 15,364 scientists.
Who are these "scientists" anyway? Basically, just about any graduate student, PhD, or professor, as long as they're not in the humanities. For example, the List of Signatories includes psychologists, sociologists, anthropologists, economists, engineers, neuroscientists, medical doctors, and many, many professors and PhDs without any mention of discipline. Visiting the AWS homepage, one learns that there was no vetting of signatories, no checking their credentials, no need for them to have expertise related to the content of the article, and no required contact information. They just had to self-identify as "scientists" and be at least a graduate student in something science-y.
Now to the meat of the AWS article, which is about the failure of humanity to make sufficient progress in solving numerous environmental challenges. These include climate change, deforestation, ocean dead zones, mass extinctions, loss of biodiversity, overpopulation, declining fish stocks and the spread of ruminant farming. I've focused on how climate change skeptics might react to the piece, because the authors say its purpose is to help overcome "dogged opposition" so political leaders can "do the right thing" and save our "imperiled biosphere". Perhaps there is dogged opposition to revitalizing marine life, saving endangered species or having fewer children, but I don't think that's what they're talking about. I think they're talking about climate change skeptics who might oppose aggressive or controversial measures to counteract global warming. Weaken doubt within that constituency, and politicians will get a spine (or be converted themselves). At least that's the theory.
To this end, the AWS article is presented as a follow-up to a 1992 document from the Union of Concerned Scientists (USC), which catalogues many of the same environmental challenges and calls for immediate action to avert global catastrophe. The AWS authors support their case with a series of alarming charts that appear to confirm the UCS was right, both about the environmental challenges and the need for immediate action. With the exception of ozone depletion, everything's gotten much worse. The charts all have steep slopes, like this:
Source: Ripple et al (2017) World Scientists’ Warning to Humanity: A Second Notice. https://academic.oup.com/bioscience/article/67/12/1026/4605229
I left out the captions, because the charts are meaningless in themselves. As the authors note (in small print), the "y-axes do not start at zero, and it is important to inspect the data range when interpreting each graph.” They do provide a link - File S1 - for additional information, but clearly these charts are meant to scare more than inform. Another Red Flag to those so inclined.
To my mind, the AWS authors are saying: "earlier scientists were right but their calls for serious action went unheeded. We are thus on the verge of disaster. We are also scientists - in fact, we are legions of scientists - so we are also right. Ignore us at your peril!" But scientists aren't right about everything and they are known to change their minds anyway. There are plenty of debatable assumptions, predictions, and proposals in both the 1992 and 2017 articles. Unfortunately, the AWS authors mix well-documented facts (say, the spreading of ocean dead zones) with less widely supported claims (say, the unmitigated threat of "alien species"), blurring the line between the known and the hypothetical.
When it comes to anthropogenic climate change, there may be a scientific consensus about its existence but that's about it. Climate change skeptics know this. You're not going to change their minds or voting patterns by pretending otherwise.