At the end of winter, Arctic sea ice reaches its annual maximum. This year, that occurred on March 22. Satellites measured an area of 14.3 million square kilometers of ice, the lowest value since measurements began in 1978. Is such a low value a sign that the Arctic region has already entered a new climate? Or might we see more sea ice again in the coming years? In a recently published study in Nature Scientific Reports, we show that it greatly depends on the season and which climate variable and area you look at in the Arctic region when the new climate makes its entrance.

Climate Change in the Arctic Region 

Due to the increase of greenhouse gases in the atmosphere, the entire Earth is warming. Due to locally reinforcing processes, the Arctic region is warming three to four times faster than the rest of the world. This is accompanied by a rapid retreat and thinning of sea ice, melting of permafrost, and an increase in precipitation (especially rainfall). This has led to a multitude of ecological changes, making it crucial to determine whether the Arctic region has already entered a new, previously unexperienced climate. 

Trends and Year-to-Year Variations 

The long-term changes in Arctic temperature, precipitation (upward), and sea ice area and thickness (downward) are strong and also depend on the precise location and season. However, the Arctic region also harbors enormous year-to-year fluctuations in all the aforementioned climate variables. The question now is whether, and if so when, the trends will rise above the variability, so that we can determine where and when the Arctic region has entered (or will enter) a new climate, a climate that, because it lies outside the previous variations, has not occurred before.