Alaska is now ice-free and the Arctic is melting at an unprecedented rate. What next?

For centuries this area of the world was impenetrable due to extensive polar ice

Year on year the Arctic is losing an area of ice greater than the size of Scotland (file photo) (Getty)

The Northwest Passage was first navigated by Norwegian explorer Roald Amundsen between 1903 and 1906. For centuries this area of the world had been impenetrable due to its extensive polar ice.

However, had these early 20th-century explorers attempted the crossing just 100 hundred years later, they would have found it plain sailing.

Year on year the Arctic is losing an area of ice greater than the size of Scotland. The news that Alaska is ice-free at the moment is the latest indication that our climate is now moving into unchartered territory.

At the start of this month the Arctic sea ice stretched over an area of six million square kilometres, which is two million square kilometres below the long-term average between 1981 and 2010.

When sea ice melts, sea levels do not change. However, warming temperatures in the Arctic are also causing land-based ice on Greenland to melt too. If all the ice on Greenland melted, sea levels could rise by as much as 6 metres (20 feet).

There is a much more immediate worry for communities living in the northern parts of Alaska as Arctic animals they hunt move further north.

Historically, the sea ice protected coastal towns from destructive waves. However, according to Dr Rick Thoman, a climate specialist at the Alaska Center for Climate Assessment and Policy, some coastal settlements are “imminently” threatened by increased erosion and flooding.

Further afield, vanishing Arctic ice is causing weather systems all over the world to change in unpredictable ways.

Extreme weather events such as heatwaves, floods and droughts is linked to unusual weather patterns in the upper atmosphere which are influenced by warmer Arctic temperatures.

The steepness of the cold-hot gradient of air coming from the Arctic to the equator can also affect the speed and pattern of high altitude winds such as the jetstream.

This is not the first time Alaska has been ice-free but it is the earliest this has ever happened.

The ice will grow when temperatures drop in the autumn but it’s an extremely worrying sign of things to come as the likelihood of an ice-free Arctic draws closer.