Guest essay by Eric Worrall
Recycled climate wisdom from Seth Borenstein…
Global warming shrank animals in the past. Scientists say it could happen again.
Seth Borenstein, Associated Press
WASHINGTON — Global warming shrank certain animals in the ancient past, and scientists worry it could happen again.
Warm-blooded animals got smaller at least twice in Earth’s history when carbon dioxide levels soared and temperatures spiked as part of a natural warming, a new study says.
University of New Hampshire researcher Abigail D’Ambrosia warned that mammals — but not people — could shrivel in the future under even faster man-made warming.
“It’s something we need to keep an eye out for,” said D’Ambrosia, who led the new work. “The question is how fast are we going to see these changes.”
Read more: https://amp.usatoday.com/story/99345782/
The abstract of the study;
Repetitive mammalian dwarfing during ancient greenhouse warming events
Abigail R. D’Ambrosia1, William C. Clyde, Henry C. Fricke, Philip D. Gingerich and Hemmo A. Abels
Abrupt perturbations of the global carbon cycle during the early Eocene are associated with rapid global warming events, which are analogous in many ways to present greenhouse warming. Mammal dwarfing has been observed, along with other changes in community structure, during the largest of these ancient global warming events, known as the Paleocene-Eocene Thermal Maximum [PETM; ~56 million years ago (Ma)]. We show that mammalian dwarfing accompanied the subsequent, smaller-magnitude warming event known as Eocene Thermal Maximum 2 [ETM2 (~53 Ma)]. Statistically significant decrease in body size during ETM2 is observed in two of four taxonomic groups analyzed in this study and is most clearly observed in early equids (horses). During ETM2, the best-sampled lineage of equids decreased in size by ~14%, as opposed to ~30% during the PETM. Thus, dwarfing appears to be a common evolutionary response of some mammals during past global warming events, and the extent of dwarfing seems related to the magnitude of the event.
Shrinking animals is one of my favourite climate scare stories. The fear of climate shrinking animals has such a camp 1980s science fiction feel, but what they are actually talking about is a very gradual process which took place over a prolonged period – certainly not something a person could “keep an eye on” over any reasonable timeframe.