Scientists found that the Arctic is warming four times faster than the rest of the planet in a recent paper published in Geophysical Research Letters.

By reducing the typical 30-year period used in Arctic amplification index calculations to 21 years, the researchers claim to have picked up on what previous research had missed.

Due to the loss of snow and ice in the Arctic, dark areas of land and water are created, which absorb heat instead of reflecting it into the atmosphere, resulting in more ice loss and darker areas. Arctic amplification index is a ratio between the Arctic and global mean static air temperature.

“Thirty years is considered the minimum to represent climate change,” Petr Chylek, a physicist and climate researcher at Los Alamos National Laboratory, said. 

'We shortened the time interval to 21 years. We observed two distinct steps in the Arctic amplification index after 1986, in contrast with previous investigations that found a smooth increase.

The Coupled Model Intercomparison Project (CIMP) consists of a set of climate models with shared parameters that were used to produce the recent Intergovernmental Panel on Climate Change Assessment Report.

Four of the 39 climate change models in CIMP reproduced the 1986 step, but none reproduced the 1999 step that the researchers detected.

We attributed the first step to increased concentrations of carbon dioxide and other pollutants in the atmosphere because several models did it correctly, but the second step to climate variability since none of the models reproduced it.

As far as predicting future Arctic warming is concerned, Chylek said their findings could be a valuable guidepost.

“We assume the four models are slightly better at predicting future climates because they correctly reproduce at least the first step,” he said.

It is common for people to average all models and assume that an ensemble of models is more reliable than any single model. In this case, the average does not work.'