Arctic summers could soon see no sea ice, scientists warn

The transformation in the Arctic is happening at an unprecedented rate. The sea ice is getting thinner and scarcer with each passing year, driven by the rising global temperatures. The temperature increase in polar regions is outpacing the global average, and the situation could worsen still.

A recent study by scientists from the University of Colorado in Boulder has found that within the next ten years, the Arctic could see days without sea ice during the summer. The findings, published in "Nature Reviews Earth & Environment," indicate that the disappearance of sea ice could occur much earlier than earlier predictions suggested.

September is when the Arctic's ice cover is at its smallest. New projections suggest that by mid-century, there might be a September completely devoid of ice. By the century's end, the period without ice could extend for several months each year, depending on greenhouse gas emissions. In the most severe scenario, some winter months in the Arctic could also become ice-free.

When scientists talk about an "ice-free" Arctic, they mean that the ice cover is less than 622,000 square kilometres. This figure is approximately 20% of the minimum seasonal ice extent observed in the Arctic during the 1980s. In recent years, the September sea ice extent in the Arctic Ocean has been around 3.258 million square kilometres.

The researchers analyzed existing literature and climate models to understand how the Arctic's ice extent might change. Their analysis suggests that the first ice-free day could happen in the next few years, significantly influenced by the level of greenhouse gas emissions. Continual absence of ice in September is predicted between 2035 and 2067. Under the worst scenario studied, by the century's end, the Arctic would be free of ice from May to January. In less severe scenarios for the period assessed, ice-free conditions would persist from August to October.

"Predicting the first ice-free conditions in the Arctic, observable in daily satellite data, is of immense importance," said Alexandra Jahn, the study's lead author.

Jahn acknowledged that greenhouse gas emissions are a fundamental cause of global warming and the subsequent loss of sea ice. The diminishing ice cover lets the ocean absorb more heat, accelerating both ice melt and Arctic warming.

The vanishing sea ice profoundly affects the region's wildlife, which relies on the ice for survival. There's also concern about warming waters inviting invasive species, which could disrupt local ecosystems.

The disappearance of sea ice presents a danger to Arctic communities, especially those along the coast. Sea ice acts as a natural buffer against waves, helping to protect these areas.

While an ice-free Arctic seems inevitable, Jahn stresses that future emission levels will dictate the frequency of these conditions. In the bleakest scenario, with the Arctic free of ice for nine months a year, the region would undergo a dramatic transformation. "Turning from a white to a blue Arctic marks a complete environmental overhaul. Hence, keeping our emissions as low as possible remains critical," Jahn stated.

Encouragingly, Arctic sea ice can regenerate relatively quickly under favourable conditions. "Unlike Greenland's ice, which formed over millennia, the Arctic sea ice could reappear within a decade if we find effective ways to remove CO2 from the atmosphere," Jahn said.

Source: University of Colorado at Boulder