Climate Change Linked to Rapid Species Fluctuations

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Climate change is making the world "bluer," according to new study that finds that weather and animal populations are fluctuating more rapidly than in years past.

The blue shift is not literal; rather, the color blue is used to represent rapid fluctuations in a system called "spectral color," which ecologists use to describe environmental change. The increasing blueness of the environment may be altering species extinction risks, said study author Bernardo Garcia-Carreras, a graduate student at Imperial College London.

"From simple models, it appears that if the spectral color of the population becomes bluer, as our results seem to suggest, then extinction risk is reduced," Garcia-Carreras told LiveScience. "It is good news in that sense."

But there is a large caveat to the good news, Garcia-Carreras said. Environmental fluctuations are just one influence on species survival. Other factors — such as overall temperature change and habitat loss — put pressure on species that could offset any benefits from a bluer world. [Read: With Climate Change, Expect More Monster Winter Storms]

"We've only looked at change in spectral colors," Garcia-Carreras said. "We're not trying to say that climate change is great for populations."

To assign a color to the environment, Garcia-Carreras and his colleagues used temperature data from the Climatic Research Unit and the Global Historical Climatology Network, which gave them a picture of daily weather throughout the 20th century. To gauge fluctuations in animal populations, they used the Global Population Dynamics Database, which tracks population changes for 147 species, ranging from insects to mammals, over the past 30 years.

Overall, global temperatures showed a small but significant shift from "red" (or slow fluctuations) to rapid, "blue" fluctuations in the last half of the century, Garcia-Carreras said. The change wasn't identical for the entire world, he said. Asia saw shifts toward slower fluctuations. But on the whole, the "bluer" world also correlated with faster shifts in animal populations, Garcia-Carreras said.

The "blue"-ing of the environment may ease extinction risk because a swing toward unwelcoming conditions is usually followed by a fast return to more salutary surroundings. Understanding what these changes mean for individual species will require more work, Garcia-Carreras said.

"With this information in hand, we can try to look more specifically at what mechanisms underlie the effect the changing spectral color of the environment might be having on populations," he said. 

You can follow LiveScience senior writer Stephanie Pappas on Twitter @sipappas.