Greenland Ice Melting Due to Natural Climate Variation: It's Not Just Global Warming

How fast is Greenland melting? That's a good question, and now scientists may have an answer. They've taken a closer look at the phenomenon, and have found that up to half of recent warming in Greenland and surrounding areas may be due to climate variations that original in the tropical Pacific and might not be connected with the overall warming of the planet.

That's not to say that unnatural warming doesn't play a role, though. About half of the warming can be attributed to the global warming caused by rising carbon dioxide emissions. The problem is that the two causes in tandem are causing Greenland to melt at an unprecedented rate.

In fact, Greenland and parts of neighboring Canada have experienced some of the most extreme warming since 1979 at a rate of about 1 degree Celsius per decade. That's about twice the global average.

In order to understand this warming a bit better, the researchers employed observations and advanced computer models. They found that a warmer western tropical Pacific Ocean had caused atmospheric changes over the North Atlantic that have warmed the surface by about a half-degree per decade since 1979.

"The pattern of the changes in the tropical Pacific that are responsible for remarkable atmospheric circulation changes and warming in Greenland and the Canadian Arctic are consistent with what we could call natural variability," said David Battisti, one of the researchers in a news release.

It's not all that surprising to find this natural variability in an area where warming is so rapid. In many of the fastest-warming areas on Earth, natural variations and global warming combine to create a "perfect storm" for warming. The work reveals that it's not only unnatural warming, but that natural variation is to blame. That said, global warming remains a major issue.

"Nothing we have found challenges the idea that globally, glaciers are retreating," said Battisti in a news release. "We looked at this place because the warming there is really remarkable. Our findings help us to understand on a regional scale how much of what you see is human-induced by the buildup of CO2, and how much of it is natural variability."

The findings are published in the journal Nature.