Arctic Climate Impact Assessment
The Arctic Climate Impact Assessment (ACIA) (in German: Climate Impact Assessment for the Arctic) is a study commissioned by the Arctic Council and published in 2004 on the consequences of global warming in the Arctic . More than 300 scientists describe in detail which climatic changes have been observed in the Arctic so far and which are to be expected in the future.
The ACIA found that global warming has a particular impact on the Arctic . Because of the polar amplification, the air temperatures rise almost twice as much as the global average, the vast majority of all glaciers north of the Arctic Circle are retreating, and the area of the Arctic sea ice has been decreasing significantly for several decades. Animal and plant species migrate from more southern regions and come into contact with the flora and fauna of the Arctic.
From the middle of the 20th century to the beginning of the 21st century, the average summer temperatures in Alaska and Siberia had risen by two to three degrees Celsius. In winter it was around three to four degrees Celsius. The researchers expect average temperatures in the Arctic to rise by around four to seven degrees Celsius on average over the next hundred years. An increase of seven to ten degrees Celsius is expected above the sea. If this proves to be true, the ice shelf in Greenland will probably melt completely and the water level will rise by almost seven meters.
Scientists expect the North Pole to be ice-free by the end of the 21st century . An area of around 990,000 square kilometers of ice has already melted in the last 30 years. The melting of the ice sets a feedback mechanism in motion, since the sun's rays are reflected less and less and therefore the warming progresses faster and faster.
According to the report, climate change poses a particular challenge for people living in the Arctic. Traditional ways of life, some of which had been continued uninterrupted for several centuries, should no longer prove to be suitable. The number of cases in which Eskimo hunters break in and drown on sea ice that has become too thin is already increasing. Entire villages have to be relocated from coastal regions because houses are at risk of collapse due to the erosion caused by the thawing permafrost . Similar risks also lurk in the rest of the infrastructure in the Arctic, including oil pipelines in particular .
The scientists base their calculations on the assumption that there will be no radical change in global carbon dioxide emissions. Some damage is irreversible, as it takes at least decades to get a grip on the warming caused by greenhouse gases . According to the study, other damage could be significantly reduced.