In the Arctic, the sea ice in the Arctic Ocean remained deficient in 2023, continuing a trend observed in the 44-year satellite records, with 2007 to 2022 being the 16 most down years in sea ice extent.

In July 2022, a significant ice-free area appeared near the North Pole, persisting for several weeks. In recent years, thinner and more loosely packed sea ice has replaced older and thicker ice formations in the Arctic.

The loss of Arctic sea ice is imminent – what is causing this situation?

The volume of Arctic glaciers reached its lowest point this year – two NASA scientists explain the overall reduction in Arctic glacier mass.

September marks the end of the Arctic summer, when Arctic ice stops melting and begins to refreeze, reaching its lowest point in ice content for the entire year. For captains seeking to traverse the Arctic, this is undoubtedly the most favourable time for navigation, especially in recent years.

Since the 1980s, human activities have led to a significant increase in carbon dioxide levels, resulting in higher temperatures and a drastic reduction in sea ice, approximately halving its extent in the Arctic region. This has facilitated navigation in the Arctic.

NASA scientists have studied the reasons for the changes in Arctic sea ice extent and their potential consequences. On September 16, 2021, the Arctic sea ice coverage reached its lowest level. Although not the lowest on record, a review of the changes in the minimum coverage over the years reveals a consistent downward trend in Arctic ice content due to climate change.

According to the latest climate assessment report from the Intergovernmental Panel on Climate Change, the average Arctic sea ice content has reached its lowest since 1850. The minimum ice content measured at the end of summer is also the weakest in at least a thousand years. Experts conclude, "By 2050, the Arctic may experience a September with almost no sea ice."

As Arctic ice melts, bright ice is replaced by dark and expansive open water. Dark surfaces absorb more sunlight, causing less solar radiation to reflect into space. This increases heat absorption in the Arctic, resulting in more ice loss. This positive feedback loop accelerates Arctic warming three times faster than the global average, though it is just one of the reasons for the rapid warming of the Arctic.

What has happened to Arctic sea ice since 2021?

The minimum ice volume in a given year is based on the previous year's climate changes. This year, the Arctic experienced unusually high-pressure systems and strong clockwise winds that pushed the thickest and oldest ice in the central Arctic to the Beaufort Sea north of Alaska, drawing the attention of ice scientists.

During the Arctic summer, snow and ice melt begins in May, coinciding with the entry of multiple cyclones into the Arctic. This increases sea ice outflow while maintaining relatively low temperatures around the Arctic. However, by June, the extent and speed of ice melt significantly increase as low-pressure systems dominate the Arctic, causing temperatures to rise several degrees above average.

Cyclones entering the Arctic from Siberia generate counterclockwise winds, leading to ice drift. This counterclockwise ice circulation pattern typically reduces the amount of sea ice moving out of the Arctic through the Fram Strait east of Greenland. This may contribute to the record-breaking summer sea ice conditions observed in the Greenland Sea.

This ice circulation pattern also increases ice outflow from the Laptev Sea near Siberia, setting a new historic low for early summer sea ice content in that region. Low-pressure systems also increase cloud cover over the Arctic. While clouds usually block solar radiation, reducing ice melt, they also capture heat lost from the ice surface, warming the atmosphere. Therefore, the impact of clouds on ice melt may be complex.

Despite these uncertainties, the Arctic appears not far from a summer ice-free state. The good news is that the future changes in Arctic ice volume depend on current emission levels, and there is still no evidence that the Earth has crossed the critical point of sea ice decline. This means that humans still have a significant degree of agency in determining the fate of Arctic sea ice.