Climate watch: Climate scientists are speaking more forcefully

Nine years have passed since the United Nations gathered climate scientists to produce a definitive report. A new report emerged this year, and it shows that we may be entering a new era for climate science. Knowledge of climate science increased greatly, but the scientists themselves have also changed.

A comparison of the very first assertions in the two reports is revealing. In 2014 the Intergovernmental Panel on Climate Change (IPCC) began by saying, “Human influence on the climate is clear.” The 2023 report asserts, “Human activities, principally through emission of greenhouse gases, have unequivocally caused global warming.” We have abandoned the vague realm of “influence” for the specificity and certitude of “unequivocal” causes.

To be sure the new tone is the result of the newly alarming scientific results, but the climate scientists are changing too. In this essentially scientific report they speak more forcefully, with a voice of conscience and concern for the climate justice movement, and with less reluctance to take on political controversy. We need to account for these important developments.

First, a more strident tone is associated not only with bad news but also with Greta Thunberg, whose youth movement is perhaps the most noticeable phenomenon to emerge in the debates over climate change since 2014. The scientists too are learning to be blunt and plain-spoken. For example, the new report largely abandons the term “anthropogenic” for the more user-friendly “human caused.”

Second, eloquent pleas have issued from those most seriously and disproportionately threatened by climate catastrophe, identified in the report as “Africa, Late Developing Countries, Small Island Developing States, Central and South America, Asia and the Arctic.” The message of the climate justice movement, awareness of which greatly increased in the last decade, has had its effect on the scientists.

Third, in step with science in general, the climate scientists feel compelled to consider political questions. The change is symbolized by the first-ever presidential endorsement by Scientific American in 2020 (Biden). Nature endorsed him too. The new IPCC report does not endorse a party or candidate, but there is a new-found willingness to embrace social and political (as opposed to purely scientific) subjects.

The new report devotes a whole section to “Equity and Inclusion.” Cost-benefit analysis (not specifically denounced in 2014) is now said to be “limited in its ability to represent all avoided changes from climate change.” The new report says repeatedly that emissions reductions must be “deep, rapid and sustained” or “immediate.” The website Carbon Brief noted that the 2023 document speaks for the first time boldly and plainly of “Losses and Damages,” loaded language meaning the necessity of transferring wealth from the developed to the less developed world to cope with climate change.

A complex and multicolored graph in the 2023 report illustrates a point that has been much quoted: “There is a rapidly narrowing window of opportunity to enable climate resilient development.” The graph, which has no exact counterpart in the 2014 report, abounds with socio-political concepts such as “poverty, inequity and injustice.” It visually echoes the previous graphs and charts explaining science, but this graph is really concerned with social and political issues.

Happily, the climate itself has not reached any drastic “tipping points,” one of the messages of the latest report, but the climate scientists seem on the brink of major changes.

To read for yourself, search for IPCC report 2023 or 2014 and select Summary for Policy Makers.