The Arctic is one of the most sensitive areas of the planet to global warming, and the retreat of its icy mantle has consequences at the global level. Now, a study published in the magazine Geophysical Research Letters analyses the results of 40 different climate models to attempt to make predictions about the medium-term situation of the ice that covers the North Pole.
Every summer, the ice sheet that covers much of the Arctic recedes as a result of rising temperatures, and in winter this icy blanket grows again. As a result of global warming, the Arctic ice sheet has shrunk dramatically in recent decades. In the coming years, the trend of this decline will largely depend on the pace of greenhouse gas emissions.
Scenario of low emissions
One of the most striking conclusions of this study is that, even if greenhouse gas emissions are reduced significantly, the Arctic will probably be ice-free during the summer.
"If we are able to reduce global emissions quickly and substantially, keeping global warming below two degrees’ Celsius relative to pre-industrial levels, Arctic sea ice will probably also disappear occasionally in summer,” explains Dirk Notz, who leads a research group on sea ice at the University of Hamburg, Germany. This will happen even prior to 2050, and it is one of the results that has surprised us the most.
In a more pessimistic scenario, with higher levels of emissions, the Arctic Ocean will be ice-free most of the time, resulting in consequences for the entire planet.
Consequences of ice loss in the Arctic
Last year, the average monthly extension of the ice surface at the North Pole in September, the month in which it normally records its minimum extent, was the third lowest recorded.
One of the most well-known effects of the melting of the poles is the evident rise in sea level, which would bring numerous problems such as floods in some of the world’s most populous cities and trigger significant migratory flows.
There is a known relationship between ice loss at the poles and atmospheric and ocean circulation patterns. Its consequences, as well as the feedback mechanisms that are activated, cannot be accurately predicted, but it has been observed, for example, that persistent and anomalous weather patterns have been observed in the particularly hot years in the Arctic.
Additionally, a smaller ice surface implies less reflection or albedo of the sun’s rays. This in turn causes the Earth’s surface to retain more heat and thus generates a feedback loop that leads to a further increase in global temperatures.
On the other hand, sediments deposited in the marine permafrost contain large amounts of methane, a greenhouse gas that will be released into the atmosphere in large quantities as a result of thawing and will continue to contribute to climate change.
Reference: SIMIP Community (2020): Arctic Sea Ice in CMIP6, Geophysical Research Letters https://doi.org/10.1029/2019GL086749