How Might Climate Change Affect Asian Elephants?

elephantsThis morning’s news brought word of a study in Nature Climate Change that predicts devastating global species losses as a result of climate change. The analysis found that some 57 percent of plants and 34 percent of animals would lose more than half of their range by the 2080s if nothing is done to stem the tide of rising greenhouse gases.

“This broader issue of potential range loss in widespread species is a serious concern as even small declines in these species can significantly disrupt ecosystems,” the study’s lead author, Rachel Warren of the University of East Anglia in England, said in a statement.

But it might be easy for many people to ignore something as nebulous as “plants” or “animals” or “ecosystems.” After all, maybe your favorite one won’t be affected. So lets look at another recent study, one of Asian elephants in Myanmar (Burma) that was just published online in Ecology.

Researchers from the United Kingdom and Germany analyzed longevity data from 1,024 semi-captive elephants that were born between 1948 and 1999. These elephants are used in places like the timber industry in Myanmar. They work during the day but forage for food on their own at night, and they breed at will. They have many similarities to fully wild elephants but are easier to study.

This dataset included not just information on how long each elephant lived and how they died, but also about the environmental conditions during their lifespans — specifically, temperatures and rainfall. That let the scientists see how the elephants survived during hot versus cold spells, or during rainy seasons and droughts.

Both temperature and rainfall influenced the survival of elephants over the time of the study. Heat was especially bad — most deaths occurred when temperatures were above 24 degrees Celsius (75 degrees Fahrenheit). Very cold times also weren’t good for the elephants, nor was drought.

That is not good news for Asian elephants, which are already dwindling in numbers. Southeast Asia is expected to warm by up to 3 degrees C over the next 30 to 40 years, accompanied by changes to the yearly monsoon season. “Increased extremes in temperature and rainfall (both within a year and between years) may therefore lead to significant increases in mortality of Myanmar elephants in the near future,” the researchers write.

There has been some debate in the scientific community about whether long-lived creatures will be affected all that much by climate change, and whether species in tropical regions, already adapted for heat, will do as badly under warming conditions. This study, of long-lived elephants living in tropical Myanmar, puts holes in both those theories. “Despite living in a highly seasonal environment, our results indicate that modest deviations from optimal conditions have effects on Asian elephant survival,” the researchers write. Elephant survival under even modest climate changes, therefore, will be a challenge.

Image of elephants in Myanmar courtesy of flickr user Mandala Travel