Animals and plants all over the planet are shrinking because of climate change, scientists warned.
The trend could have a major impact on the burgeoning human population, making it harder to feed everyone.
It could also lead to extinctions as ecosystems are thrown into disarray, robbing living things of the resources they need to survive, experts say.
Organisms become smaller as warmer and drier conditions affect early development and growth, according to the researchers. They point to a century of evidence of plants and animals reducing in size as a result of climate change.
Examples include grasses and trees, toads, tortoises, goshawks, gulls, woodrats, Soay sheep and red deer. Even polar bears are starting to get smaller in response to the loss of sea ice, it is claimed.
Cold blooded animals, which make up the majority of life on Earth, were said to be especially vulnerable. Size reduction made creatures such as amphibians more susceptible to desiccation – or extreme dryness – from evaporative heat loss.
Experimental research had also shown that for every degree Celsius of warming, plants of various types shrank by between 3 per cent and 17 per cent.
Each degree rise in temperature was also known to decrease the body size of marine invertebrates by 0.5 per cent to 4 per cent, of fish by 6 per cent to 22 per cent, of beetles by 1 per cent to 3 per cent, and of salamanders by 14 per cent.
Studies had also shown that corals, oysters, scallops and other calcifying ocean dwellers suffer stunted growth as a result of climate change acidifying the sea. The research, led by Dr David Bickford from the National University of Singapore, is reported in the journal Nature Climate Change.
The scientists pointed out that by 2100 average temperatures could rise by as much as 7C. This mirrors the dramatic changes seen during the Palaeocene-Eocene Thermal Maximum 55 million years ago, when temperatures rose and precipitation levels fell by about 40 per cent.
The consequences of species getting smaller were “not yet fully understood, but could be far-reaching for biodiversity and humans alike”, said the scientists. They warned that shrinking fish and crustaceans could adversely affect the nearly one billion people who get their main sources of protein from the sea.
There would also be an impact on crops. “Feeding the billions of additional people expected by 2050 will become increasingly difficult as many areas become drier and crop plants are unable to grow as large,” the researchers wrote.