Animals Are 'Shrinking' Due To Climate Change

Animals and plants across the world are shrinking from the effects of climate change on their habitats, scientists warn.

Rising temperatures and changes in weather patterns seem to be changing development and growth for many species.

Nearly 45 per cent of the creatures for which data was reviewed found that they grew smaller over multiple generations due to climate change. Researchers cited the example of polar bears shrinking in response to the loss of sea ice.

The change could also have a major affect on the human population, with major food sources such as fish and crops likely to grow smaller and less reliably than today, with ecosystems dramatically changing too.

"Consequences of this shrinking are not yet fully understood, but could have far-reaching consequences for biodiversity and humans alike," said Dr David Bickord from the National University of Singapore, who conducted the report published in the Nature Climate Change journal.

"Because recent climate change may be faster than past historical changes in climate, many organisms may not respond or adapt quickly enough... the species that can adapt are the species that will be affected by potential declines in body size."

Over the past century animals such as Soay sheep, blue tits, red deer and tortoises have all reduced in size, according to the research. Cold-blooded animals were said to be more vulnerable, with the reduced size making the creatures more susceptible to drying out.

One major issue is that not all plants and animals will shrink at the same rate, leading to reduced food chains and throwing finely balanced ecosystems off kilter. This could ultimately lead to animals at the top of the food chain - including humans - will also grow to smaller sizes and be more vulnerable to diseases.

"We do not yet know the exact mechanisms involved, or why some organisms are getting smaller while others are unaffected," Bickford added.

"Until we understand more, we could be risking negative consequences that we can't yet quantify."

These findings mirror those what happened around 55 million years ago, when some species of insects and squirrels we were wiped out when temperatures rose between 3 and 7 degrees.

During the past century global average temperatures have risen by almost 1C, with experts predicting the temperatures could rise by a further 7C by 2100.