U. of Ariz. Contradicts Its Own Study’s Conclusion that “the Pace of Climate-Driven Extinction Is Accelerating’

Craig Bannister | September 19, 2023
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In the same press release, the University of Arizona announced both that its new study proves “the pace of climate-driven extinction is accelerating” – and that it “hasn't seen any showing that this acceleration of extinction has already happened.”

Its conclusion that climate-caused extinction is currently accelerating is based on its study of the Yarrow’s spiny lizard, the release explains:

“Climate change is causing extinctions at an increasing rate, a new study by the University of Arizona researchers shows. They surveyed populations of the Yarrow's spiny lizard in 18 mountain ranges in southeastern Arizona and analyzed the rate of climate-related extinction over time.

“’The magnitude of extinction we found over the past seven years was similar to that seen in other studies that spanned almost 70 years,’ said John J. Wiens, a professor in the Department of Ecology and Evolutionary Biology at UArizona, and the senior author of the study.”

However, later in the release, Professor Wiens contradicts his study’s accelerating-climate-caused-extinction conclusion:

“Although previous studies have predicted that climate-related extinctions will increase with the rising pace of global warming, Wiens said he hasn't seen any showing that this acceleration of extinction has already happened.”

What’s more, not all Yarrow spiny lizards are succumbing to warm, low-elevations, Wiens concedes:

“However, not all low-elevation populations went extinct between the surveys, Wiens said. For example, two populations that occurred at very low elevations survived.”

Thus, spiny lizards who could stand the heat survived and those who couldn’t didn’t, the University of Arizona analysis concluded:

“[P]opulations that were less genetically variable and were exposed to greater climate change effects were the ones that tended to go extinct. This suggests that the populations with less genetic variation had less ability to adapt to climate change.”

In addition to projecting the experience of select groups of spiny lizards onto all species, the release also makes no mention of whether or not the doomed lizard populations made any effort to migrate to cooler locations.