Arctic Warming: The Arctic is warming four times faster than the rest of the world, new research reveals

Arctic Warming: The Earth has warmed by about 1.1 °C since the start of the Industrial Revolution. That warming has not been uniform, with some regions warming at a far greater rate. One such region is the Arctic. A new study shows that the Arctic has warmed nearly four times faster than the rest of the world over the past 43 years. This means that the Arctic is on average about 3 °C warmer than in 1980. This is worrying, as the Arctic contains sensitive and delicately balanced climate components, which, if exposed to extreme pressure, will react with global consequences.

Why is Arctic warming so fast?

A large part of the Arctic is covered by sea ice. It is a thin layer of sea water (usually one meter to five meters thick) that freezes in winter and partially melts in summer. The sea ice is covered in a luminous layer of snow that reflects back about 85% of the incoming solar radiation from space. The opposite happens in the open sea. As the deepest natural surface on the planet, the ocean absorbs 90% of solar radiation.

The Arctic Ocean, when covered with sea ice, acts as a large reflective blanket, reducing the absorption of solar radiation. As sea ice melts, absorption rates increase, resulting in a positive feedback loop, where sea ice melts at a faster rate than ocean warming, which also accelerates ocean warming. This feedback loop is largely known as Arctic amplification, and is the explanation for why the Arctic is warming so much more than the rest of the planet.

Is Arctic amplification underestimated?

Numerical climate models have been used to measure the magnitude of Arctic amplification. They typically estimate the amplification ratio to be around 2.5, meaning the Arctic is warming 2.5 times faster than the global average. Based on observational records of surface temperatures over the past 43 years, the new study estimates the Arctic amplification rate to be about four times that.

How worried should we be?

In addition to sea ice, the Arctic contains other climate components, which are extremely sensitive to warming. If there were too many pressures, they would have global consequences. One of those elements is permafrost, which is the permanently frozen layer of the Earth’s surface. As temperatures rise in the Arctic, the active layer, the top layer of soil that melts each summer, deepens. This, in turn, increases biological activity in the active layer resulting in carbon release into the atmosphere.

Arctic permafrost contains enough carbon to raise the global average temperature by more than 3 °C. Should permafrost thawing be accelerated, this is likely to happen in a positive feedback process, often referred to as the permafrost carbon time bomb. Already stored carbon dioxide and methane gases will contribute to further Arctic warming, subsequently accelerating future permafrost melting.

The second Arctic component sensitive to temperature rise is the Greenland ice sheet. As the largest ice mass in the Northern Hemisphere, it contains enough frozen ice to raise global sea levels by 7.4 meters when completely melted.

When the amount of ice melting exceeds the rate at which snow accumulates in winter, it will rapidly lose mass. When this limit is exceeded, its surface decreases. This will speed up melting, as the temperature is higher at lower altitudes.

Prior research has put the required temperature increase around Greenland at about 4.5 °C above pre-industrial levels. Given the extraordinary pace of Arctic warming, the possibility of exceeding this critical threshold is increasing rapidly.

Although there are some regional differences in the magnitude of Arctic amplification, the observed pace of Arctic warming is far greater than the implied models. This brings us dangerously close to critical climate limits that if this happens will have global consequences. As anyone who has worked on these problems knows, what happens in the Arctic is not limited to the Arctic.

Latest World News