Research shows that the Arctic is warming twice as fast as the rest of the world
We are approximately 1.1 degrees Celsius warmer now than we were at the start of the industrial revolution. The pace of warming has been uneven, with some regions experiencing a much greater degree of warming than others.
There are many such regions, including the Arctic. According to a new study, the Arctic has warmed nearly four times faster than the rest of the world over the past 43 years. Consequently, the Arctic is 3 degrees Celsius warmer on average than in 1980.
As a result, this is alarming, since the Arctic contains delicate and sensitive climate components that can have global repercussions if over-pushed. Is there a reason why the Arctic is warming so fast? There is a large part of the explanation that has to do with sea ice. Winters see this layer of seawater freeze and partly melt, but summers see it partially melt.
In the summer, the sea ice is covered in bright snow that reflects around 85 percent of the sun's incoming radiation back to space. On the other hand, the open ocean has the opposite effect. Due to its dark color, the ocean absorbs 90 percent of solar energy.
With sea ice covering the Arctic Ocean, solar radiation is less likely to be absorbed. A positive feedback loop results from sea ice melt amplifying ocean warming as absorption rates increase, resulting in even faster ocean warming as sea ice melt accelerates. Arctic amplification is largely due to this feedback loop, which explains why the Arctic is warming so much more than the rest of the planet.
What is the extent of Arctic amplification? In order to quantify the magnitude of Arctic amplification, numerical climate models have been used. According to them, the Arctic is warming 2.5 times faster than the global average, indicating an amplification ratio of 2.5. Based on observations over the last 43 years, the Arctic is warming four times faster than the global average.
It is rare for climate models to obtain values that high. Models may not fully capture the feedback loops responsible for Arctic amplification, thus underestimating the potential consequences of future Arctic warming. Is there a need for concern? Sea ice is not the only aspect of the Arctic climate that is sensitive to warming.
In the event that they are pushed too far, they will have global consequences as well. The (now not so) permanently frozen layer of the Earth's surface is permafrost. Active layers, the topmost layer of soil that thaws in the summer, deepen as temperatures rise across the Arctic. As a consequence, the active layer becomes more active, releasing carbon into the atmosphere.
There is enough carbon in Arctic permafrost to raise global temperatures by more than 3 degrees Celsius. There is the potential for runaway positive feedback if permafrost thawing accelerates, often referred to as the permafrost carbon time bomb.
Permafrost thaw will be further accelerated by the release of previously stored carbon dioxide and methane. Ice sheets on Greenland are also susceptible to temperature rise in the Arctic. The largest ice mass in the northern hemisphere would raise global sea levels by 7.4 meters if it melted completely.