Technical Report: Arctic Heatwave

• Main Authors: Cotti, Davide, Sebesvari, Zita
• Language: unknown
• Published: United Nations University - Institute for Environment and Human Security (UNU-EHS) 2021
• Subjects: albedo; Arctic; Sea ice
• Online Access: http://collections.unu.edu/view/UNU:9189

In 2020, the Arctic had the second-highest air temperatures and second-lowest area of sea ice coverage on record. 2020 was one of the three warmest years on record, with the most notable warmth being observed in the Siberian Arctic, where temperatures reached 38.0°C in Verkhoyansk, provisionally the highest known temperature anywhere north of the Arctic Circle. This fueled the most active wildfire season in an 18-year-long data record, as estimated in terms of carbon dioxide emissions released from fires. In the past decade, Arctic temperatures have increased by nearly 1°C. If greenhouse gas emissions stay on the same trajectory, the North will have warmed by 4°C year-round by 2050. Projections point to an ice-free Arctic in the summer in the next 10-15 years, meaning that the once ice-covered white ocean will turn into a blue ocean. An important regulating mechanism in the Arctic is the albedo effect: when sunlight hits a white surface such as snow and ice, more of it is reflected back into space without warming its surroundings than when light hits a darker surface. When ice melts and uncovers darker land and water, more solar energy is absorbed, which warms the Arctic even further. This technical background report for the 2020/2021 edition of the Interconnected Disaster Risks report analyses the root causes, drivers, impacts and potential solutions for the Arctic heatwave through a forensic analysis of academic literature, media articles and expert interviews.