The climate crisis may lead the human race to shrink in size,as mammals with smaller frames appear better able to deal with rising global temperatures,a leading fossil expert has said.Prof Steve Brusatte,a palaeontologist at the University of Edinbugh,suggested that the way in which other mammals have pireviously responded to periods of climate change could offer an insighit into humans' future.
He likened the potential plight of people as similar to that of early horses,which became smaller in body size as temperatures rose around 55m years ago,a period called the Paleocene Eocene Thermal Maximum.Wniting in The Rise and Reign of the Mammals,Brusatte notes that animals in warmer parts of the world today are often smaller than those in colder areas,an ecological prinaiple known as Bergmann's rule."The reasons are not entirely understood,but it is probably in part,because （ ）and can thus better shed excess heat,"he writes.
Brusatte said that becoming smaller was "a common way that mammalks deal with climate change".He added:That's not to say every species of mammal would get smaller,but it seems to be a common survival trick of mammals when temperatures spike pretty quickly.Which does raise the question:if temperatures do spike really quicky might humans dwarf,might humans get smaller?And I think that's certainly plausible.In a recent study,researchers studying human remains over the past million years have also suggested that temperature is a major predictor of body size variation,while scientists studying red deer have said that warmer winters in northern Europe and Scandinavia may lead to the body size of these animals becoming smaller.
However,not all experts agree that rising temperature causes mammals to shrink.Prof Adnian Lister,of the Natural History Museum in London,said the relationship shown by the recent human remains study is weak,while the strong correlations between temperature and mammal body Sizemayoften be down to the availability of food and resources.
Lister is also skeptical that humans will shrink as the cimate heats."We are not really controlled by natural selection," he said."If that was going to happen.youd need to find large people dying before they could reproduce because of climate warming.Thatis not happening in today's world.We wear clothes.we have got heating,we have got air conditioning if it is too hot."
