Since the beginning of time, human beings and other living creatures have evolved to adapt to their ever-changing environments. One of the main drivers of changes in body size for the past million years is the temperature. Colder, harsher climates were linked to larger bodies, while warmer climates were linked to smaller bodies. With carbon dioxide levels off the charts and climate change becoming more dire, some experts are predicting humans will once again evolve to withstand the warming planet.

Professor of paleontology at the University of Edinburgh, Steve Brusatte, believes humans will shrink in size to better withstand the effects of climate change. His theory is based on an early species of horses, which evolved to have a smaller body size as temperatures warmed during the Paleocene Eocene Thermal Maximum, about 55 million years ago. Brusatte believes the plight of horses then and humans now are very similar and could provide insights into how humans might evolve in the future. He also said becoming smaller was a “common way that mammals deal with climate change” and acknowledged “that’s not to say every species of mammal would get smaller … [but it] does raise the question: If temperatures do spike really quickly might humans dwarf, might humans get smaller? And I think that’s certainly plausible.” (EcoWatch, Buzz)