杏MAP导航

By Federico Citterich

As climate change continues to impact our everyday lives, Arctic regions are silently being devastated as well. The Arctic sea ice extent is shrinking by 13% per decade, and it is becoming significantly thinner. Consequently, Arctic sea levels are rising worryingly, now accounting for 35% of the global increase in ocean levels. This negatively affects Arctic wildlife, directly threatening ice-dependent species but indirectly menacing ice-independent organisms as well.

鈥淎nd this is happening because the Arctic is warming almost four times faster than the rest of the world鈥�, said Maurizio Azzaro, Head of the Institute of Polar Sciences in the section of Messina (Italy). The phenomenon, known as Arctic Amplification, is now well-recorded and acknowledged amongst the scientific community. 

鈥淧art of the reason why Arctic Amplification is happening is that the Arctic is very white, as it contains great amounts of ice and snow. As climate change melts away that white expanse, a darker surface is produced and exposed, and darker surfaces absorb more sunlight鈥�, explained Azzaro. 鈥淭his is known as the ice-albedo feedback鈥�.

鈥淥ther positive feedbacks play a significant role in promoting Arctic Amplification as well, including the cloud feedback and the ocean feedback鈥�, added Azzaro.

Due to Arctic Amplification, the warming-induced changes that affect the rest of the world are happening three to four times faster in Arctic regions. Expressing deep concern, he said, 鈥淭he Arctic as we know it is disappearing very quickly鈥�.

Wildflowers on a hill overlooking a fjord filled with icebergs in Greenland

The impact of Arctic Amplification on global temperature

However, the effects of Arctic Amplification may not be restricted to Arctic regions. According to a new study carried out by researchers from University College London, Arctic Amplification will be responsible for the breaching of the Paris Agreement鈥檚 2°C threshold eight years earlier than if the area was warming at the average global rate.

The Paris Agreement is a 2015 international treaty on climate change that aims at keeping the increase in the global average temperature to well below 2°C above pre-industrial levels, while also pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels.

鈥淔or many people, the Paris Agreement temperature thresholds are the primary means of understanding and quantifying climate change鈥�, said Alistair Duffey, a PhD candidate at University College London鈥檚 Earth Sciences Department and lead author of the study. 鈥淥ur research aims at translating climate change in the Arctic in more familiar terms for people鈥�.

To carry out the study, the researchers compared future climate change projections with and without Arctic Amplification. 鈥淭his enables us to quantify the direct impact of Arctic Amplification鈥�, explained Duffey.

According to the scientists, the extra warming in the Arctic translates to a five- and eight-year difference when the models reach the 1.5°C and 2°C thresholds, respectively. 鈥淎ccording to the models, Arctic Amplification pulls the time the world would breach the Paris Agreement thresholds forward鈥�, highlighted Duffey.

A melting iceberg due to unusually high temperatures in Scoresby Fjord, Greenland   (AFP or licensors)

Less ice, altered ocean circulation, and extreme weather

Arctic Amplification has other important effects as well. 鈥淎s we warm the Arctic, we melt significant portions of the permanently frozen ground that extends in the northern hemisphere of the world, known as permafrost鈥�, said Duffey. 鈥淭his can in turn increase methane and carbon dioxide emissions, adding greenhouse gases to the global warming engine鈥�.

鈥淭he melting of permafrost can also lead to the release of dormant ancient viruses and bacteria, as well as promoting landslides and other geological accidents鈥�, explained Azzaro. 鈥淭he consequences for life and the environment can be catastrophic鈥�.

Studies also suggest that the addition of large quantities of fresh water from the melting of glaciers can disrupt ocean circulation, hence directly affecting marine organisms.

鈥淎dditionally, there is evidence that the extra warming in the Arctic and its associated loss of sea ice is directly linked to extreme weather in the northern hemisphere of the Earth鈥�, Azzaro added.

Prospects

鈥淎rctic warming adds substantial uncertainty to climate forecasts鈥�, said Duffey. 鈥淭his is because there is some variability in quantifications of Arctic Amplification within the scientific community, which hence affects different future climate predictions鈥�.

鈥淢ore studies are needed to further understand Arctic Amplification and all its causes. This might improve our future climatic models鈥�, he added.

鈥淲e will certainly have to think more about integrating data from different disciplines鈥�, Azzaro concluded. 鈥淭hat of global warming is now an ever-evolving landscape in which long-term, natural variations collide and coevolve with man-driven changes鈥�.

Icebergs in the Arctic Ocean   (AFP or licensors)