These "Concerned Scientists" posts address a recent viewpoint article in the journal BioScience, World Scientists’ Warning to Humanity: A Second Notice (2017). Specifically, I'm looking at the chances climate change skeptics would be swayed by the evidence and arguments the article presents. 

Some basic points so far:

  1. Obvious "persuasive intent" backfires when the audience doesn't trust the source of information.
  2. If a piece is mostly accurate but includes exaggerations or misleading claims, you've lost the skeptical audience.
  3. If the piece is accurate and persuasive to an already converted mind but leaves out relevant and well-known information,  you've lost the skeptical audience.

The 2017 Second Notice clearly violated the second point with its "over 15,000" scientist signatories. Judging from the homepage of the main authors' website, the individuals who signed off on the article do not appear to have been vetted but were self-identified "scientists" whose credentials were not checked and who were not required to submit contact information. The authors clearly lost Round One with the skeptic crowd.

Round Two comes in the first sentence of the piece:

Twenty-five years ago, the Union of Concerned Scientists and more than 1700 independent scientists, including the majority of living Nobel laureates in the sciences, penned the 1992 “World Scientists’ Warning to Humanity”.

Here the 2017 authors continue with the status-mongering, presenting themselves as carrying the torch of esteemed predecessors. They are also inviting scrutiny of the 1992 document, summarized as follows:

The environment is suffering critical stress: stratospheric ozone depletion, shrinking ground water supplies, toxic river runoff, collapsing fisheries, loss of soil productivity, decreasing food production, destruction of tropical rain forests, irreversible loss of species, unrestrained population growth, and global warming.

Fundamental change is urgent. We must move away from fossil fuels; halt deforestation; loss of species and agricultural land; prioritize efficient use of energy, water, and other materials; stabilize population through voluntary family planning and improved social/economic conditions; reduce and eventually eliminate poverty; greatly reduce violence and war; ensure sexual equality; and ensure women’s control over their reproductive decisions.

Not a bad list of environmental ills, many of which we’ve made a lot of progress on, including: ozone depletion; reforestation in Russia, China, the US and Europe; population growth except for Africa; and recovery of fisheries in US and Europe. Rain forest destruction, especially in the Amazon and Indonesia, remain a major concern, as does the ever-growing list of endangered species. Many of the recommendations are common sense but the authors' imperious tone can be a real turn-off, especially to a skeptical audience. I counted 19 instances of "must" in this rather short document. And then the authors of the 1992 piece make a claim that strains credibility:

“No more than one or a few decades remain before the chance to avert the threats we now confront will be lost and the prospects for humanity immeasurably diminished.”

While this picture of impending doom may have mobilized sympathetic readers in 1992, it probably would have reinforced doubts in others.  Ask a climate change skeptic why they don't trust climate change claims and you may get a history of false alarms in the environmental movement - false alarms endorsed by prominent scientists. Remember the population explosion, peak oil? So when scientists confidently predict global disaster in the very near future, a skeptic would likely file that one away as another case of alarmist rhetoric coming from the usual suspects.

Back to 2017's World Scientists’ Warning to Humanity: A Second Notice. The 2017 authors have just lost Round Two. Insofar as their intention is to convert the unconverted, I would say they haven't gotten over the lack of trust hurdle. In fact, the hurdle keeps getting higher.