Climate Change and Global Amphibian Declines

In 2006, Alan Pounds and colleagues published a paper in the journal, Nature, that claimed to show a link between global warming and the worldwide decline of amphibians. They argued that warming temperatures had allowed the emergence of chytridiomycosis, a disease caused by the amphibian chytrid fungus that has been wiping out amphibian species around the world. Despite providing only weak support for the role of climate change, the paper was splashed across the pages of hundreds of newspapers and magazines, all repeating the mantra that climate change was now a proven cause of amphibian declines.

This week, Karen Lips and colleagues published a paper in the journal, PLoS Biology, that challenges the conclusions of the Pounds paper. Although the media has portrayed the new paper as debunking the link between climate change and amphibian declines, the Lips et al. paper actually only refutes the analyses that Pounds et al. conducted and used to make their claim of a strong link between climate change and amphibian declines. This is an important distinction but one that as usual, is lost in the rush to create a catchy headline.

Both studies used similar data sets that describe the timing of amphibian declines in South America during the past several decades. However, the new paper reports that the link to climate change trumpeted by Pounds et al. is weakly supported at best. Lips et al. suggest that a more parsimonious explanation of the patterns of amphibian decline in South America is multiple introductions of the amphibian chytrid fungus into South America and subsequent spread across the continent. Lips et al. contend that there is no evidence for climate change driving this spread.

None of this detracts from the very real challenges posed by climate change to the conservation of amphibians around the world. It just highlights the important point that there is currently little support for the idea that global warming is responsible for amphibian declines.

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