— Ch. 1 · Arctic Amplification And Warming Trends —
Climate change in the Arctic.
~6 min read · Ch. 1 of 6
On the 20th of June 2020, a temperature measurement inside the Arctic Circle reached 38 degrees Celsius. This heat was expected in the region only by the year 2100. The period from 1995 to 2005 marked the warmest decade since at least the 17th century. Temperatures during that time sat above the average recorded between 1951 and 1990. Alaska and western Canada saw their temperatures rise significantly during those years. Research published in October 2013 showed that current temperatures have not been seen for at least 44,000 years. Some studies suggest this warmth has not occurred for as long as 120,000 years. Since 2013, annual mean surface air temperature has remained warmer than the 1981-2010 mean. In January 2025, a study reported an abrupt transformation of lakes in Greenland from blue to brown states. This change followed record heat and rainfall events. Extreme anomalies appeared again from January to February 2016. During that month, the Arctic temperature exceeded levels seen between 1981 and 2010. By March, April, and May, average temperatures were higher than normal. An attribution study published in July 2020 stated such weather would happen once every 80,000 years without human-induced warming. The speed of this warming occurs three to four times faster than the global average. Natural life in the region is affected greatly by these rapid shifts.
Cryosphere Loss And Sea Ice Decline
The Arctic Ocean expects its first ice-free events before 2050. Some projections place this milestone in the late 2020s or early 2030s. No event like this has happened in the last 700,000 years. Sea ice regrows every winter but will occur more frequently as warming increases. A January 2025 study found lakes shifting from transparent blue to less transparent brown. This state change altered numerous physical, chemical, and biological features. Lakes became unprecedented in their transformation after a season of record heat. Climate change has lowered land ice thickness with every passing year. It also reduced sea ice cover extent over time. In 2020, mean surface air temperature was warmer than the 1981-2010 average. The reduction of sea ice brings more sunlight to phytoplankton. Annual marine primary production increased by over 30% between 1998 and 2020. By 2100, phytoplankton biomass is expected to rise by roughly 20% under low-emission scenarios. Under high-emission scenarios, that figure could reach 30 to 40%. Atlantic cod have moved deeper into the Arctic due to warming waters. Polar cod and local marine mammals are losing habitat. Many copepod species appear to be declining. This reduces numbers of fish such as walleye pollock or arrowtooth flounder. Around 9000 puffins and other shorebirds died of starvation in Alaska during 2016.