Climate change making animals shrink

Many plant and animal species around the world are shrinking, thanks to climate change, National University of Singapore researchers say.

Increasing temperatures, they claim, have had far-reaching effects on the body size of organisms from plants to polar bears. Many organisms are already getting smaller and more are likely to follow suit as warming continues.

The researchers cite a number of studies to support their conclusion. Fossil evidence from the Palaeocene-Eocene Thermal Maximum, 55 million years ago, shows that invertebrates became up to 75 percent smaller as temperatures rose three to seven percent.

Over the last hundred years, animals from toads to deer have started to shrink, they say.

The shrinkage can be explained by metabolic changes, they say.

“Many studies are corroborating this general trend, and as more studies come out saying the same thing, we need to understand why this trend is happening and what it will mean for society,” says assistant professor David Bickford.

“This is a very different frame of reference, scientifically. It implies that we are changing the planet’s climate enough to have an effect on most species and we do not fully understand what will happen when species get smaller.”

The effects, he says, will be difficult to predict. It could, for example, mean crop harvests getting smaller, and with plant fodder declining, animal species too could be hit.

But the real problem isn’t likely to be the shrinkage itself, but rather the fact that some species will shrink more or faster than others, potentially destroying ecosystems.

The study appears in Nature Climate Change.