北极海冰多年连续下降至近记录低位

National Snow & Ice Data Center, September 22

Although media tend to focus on the Arctic sea ice extent (or area) minimum each September, sea ice volume and thickness – especially, surviving multi-year sea ice – is at least as important. Although this year’s minimum was only the 12th lowest on record, the amount of multi-year ice set a record or near-record low.

The Arctic has lost over 95% of its thick multi-year sea ice since 1985. This multi-year ice plays a crucial role in stabilizing the Arctic region. Having persisted through at least one summer melt season, it provides a layer of insulation that protects keystone Arctic Ocean species that have evolved to always have a ceiling of thick ice above; and without which they cannot survive. Multi-year ice also slows the warming of the Arctic Ocean and of the region as a whole, by maintaining a cover of snow and ice on the surface of the water that reflects sunlight.

In 1985, multiyear ice made up 16% of the total sea ice cover. Today, it has dropped to just 1%. The loss of this thick, resilient ice cover threatens the stability of the Arctic region, and illustrates the importance of lowering emissions to preserve as much sea ice for as long as possible.

https://nsidc.org/arcticseaicenews/