Since the 1970s, Arctic surface air temperature has likely increased by more than double the global average, and Arctic sea ice has undergone tremendous mass loss. The sustained decrease of sea ice facilitates the accessibility of Arctic sea passages. 

Compared with the customary route through the Straits of Malacca and the Suez Canal, the Northeast Passage (NEP) can shorten the distance from Europe to northwestern Asia by about one-third, which would help to reduce the expense of transport and environmental pollution. 

Recently, a research group led by Prof. KANG Shichang from the Northwest Institute of Eco-Environment and Resources of the Chinese Academy of Sciences, together with collaborators, reviewed the past changes in sea ice in September from 1988 to 2016 and assessed the future accessibility along the NEP 4. 

According to the researchers, significant warming was presented in the deep layer in the Arctic seas along the NEP in recent decades (1988-2016). The positive anomaly of seawater temperature moved westward and increased notably in coastal areas. 

The NEP is projected to be navigable for open water ships in September from 2021 to 2025, which would extend to August to October during 2026 to 2050 under both socioeconomic pathway (SSP) 2-4.5 and SSP5-8.5. Polar Class 6 ships would be capable of crossing the NEP from August to December during 2021 to 2025 and from July to December during 2026 to 2050.  

In addition, the Vilkitsky Strait and Dmitrii Laptev Strait have higher accessibility than the Shokalskiy Strait and Sannikov Strait, especially in the next five years. 

The above findings provide important references for the route planning and navigation of ships with different abilities to break the ice in the future.

This study has been published in the Global and Planetary Change entitled "Changes in sea ice and future accessibility along the Arctic Northeast Passage".  

 Northeast Passage and surrounding water depth in the Arctic (Image by CHEN Jinlei)