Nearly 50% of planet’s insects and plants could lose habitat at 3.2 degree C : Climatologists

A recent study published in the prestigious journal Science has found that if the Earth warms by 3.2 degrees Celsius, or about 5.8 degrees Fahrenheit, then 49 percent of the planet’s insects, 44 percent of plants and 26 percent of vertebrates will lose more than half of their geographic habitat. This is the level of warming predicted by the year 2100 if countries honour their pledge under the Paris Agreement to reduce emissions.

The authors arrived at this conclusion analyzing the information on a database they had prepared about temperatures and spatial needs of more than 100,000 plants, insects and other animals. They compared it to various climate scenarios and found that insects in particular would lose ground. Other recent researches have also found insects are already in serious decline worldwide.

“Within North America species, say a bird, will have a preferred climate that it likes,” says Rachel Warren, a co-author of the study and professor of global change and environmental biology at the University of East Anglia. “It wouldn’t be found north of that range because it’s too cold, and wouldn’t be found south of that range because it’s too hot,” he was quoted as telling the New York Times’ Climate Forward publication.

But as the climate warms, the species will have to move if we let the planet warm by 3.2 degrees Celsius, most species will find fewer places that hit their thermal sweet spot and many will dies off.

The researchers also looked at what would happen if we limited warming to two degrees Celsius, the formal target under the Paris Agreement.

At that level of warming, 18 percent of insects, 16 percent of plants and 8 percent of vertebrates would lose more than half their range.

While the difference between two degrees and 3.2 degress of warming may seem insignificant. But it is not. During the last ice age, Dr Warren said, the planet was only six degrees cooler than its preindustrial average.

“Three degrees is a half ice-age. In fact, the Earth would be almost unrecognizable if the Earth warmed by three degrees. Once that happens, really big impacts kick in,” said Dr warren.