7 . What will the weather be like tomorrow?

8 . 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.

Professor Steve Brusatte, a palaeontologist at the University of Edinburgh, suggested that the way in which other mammals have previously responded to periods of climate change could offer an insight into humans’ future. He compared the potential problem of people as similar to that of early horses, which became smaller in body size as temperatures rose around 55 million years ago.

Writing 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 principle known as Bergmann’s rule. “The reasons are not entirely understood, but it is probably, in part, because smaller animals have a higher surface area relative to their volume than bigger animals and can thus improve the dissipation of the extra heat,” he writes.

Brusatte said that becoming smaller was “a common way that mammals 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 rise pretty quickly. That does raise the question: If temperatures do rise really quickly, might humans get smaller? And I think that’s certainly reasonable.”

However, not all experts agree that rising temperature causes mammals to shrink. Professor Adrian Lister, of the Natural History Museum in London, said the relationship shown by the recent human remains study is weak. “We are not really controlled by natural selection,” he said. “If that was going to happen, you’d need to find large people dying before they could reproduce because of climate warming. That is not happening in today’s world. We wear clothes, we have got heating, we have got air conditioning if it is too hot.”