The Arctic tundra is now emitting more CO2 than it stores

REPORT CARD HEADLINES

In the air

• Arctic annual surface air temperatures ranked second warmest since 1900.
• Autumn 2023 and summer 2024 were especially warm across the Arctic with temperatures ranking 2nd and 3rd warmest, respectively.
• An early August 2024 heatwave set all-time record daily temperatures in several northern Alaska and Canada communities.
• The last nine years are the nine warmest on record in the Arctic.
• Summer 2024 across the Arctic was the wettest on record.
• Arctic precipitation has shown an increasing trend from 1950 through 2024, with the most pronounced increases occurring in winter.

In the ocean

• In September 2024, the extent of sea ice, which has a profound influence on the Arctic environment, was the sixth-lowest in the 45-year satellite record.
• All 18 of the lowest September minimum ice extents have occurred in the last 18 years.
• Arctic Ocean regions that are ice-free in August have been warming at a rate of 0.5°F (0.3°C) per decade since 1982.
• In most of the shallow seas that ring the Arctic Ocean, August mean sea surface temperatures were 3.6-7.2°F (2-4°C) warmer than 1991-2020 averages, though the Chukchi Sea was 1.8-7.2°F (1-4°C) cooler than average.
• Long-term ocean primary productivity—plankton blooms—continue to increase in all Arctic regions, except for the Pacific Arctic, throughout the observational record of 2003-24. However, in 2024, lower-than-average values were dominant across much of the Arctic.
• Ice seal populations remain healthy in the Pacific Arctic, though the ringed seal diet is shifting from Arctic cod to saffron cod with warming waters.

On land

• When including the impact of increased wildfire activity, the Arctic tundra region has shifted from storing carbon in the soil to becoming a carbon dioxide source. Circumpolar wildfire emissions have averaged 207 million tons of carbon per year since 2003.
• The Arctic remains a consistent methane source.
• Alaskan permafrost temperatures were the second warmest on record.
• Warmer temperatures impact caribou movements and survival through direct summer heat and changes in winter snow and ice conditions, with regional variations in population declines and recoveries.
• Arctic migratory tundra caribou populations have declined by 65% over the last 2-3 decades. While the generally smaller coastal herds of the western Arctic have seen some recovery over roughly the last decade, previously large inland herds are continuing a long-term decline or remain at the lowest populations noted by Indigenous elders.
• Summer heat impacts on caribou herds are projected to increase over the next 25-75 years, requiring shared knowledge between scientists and northern communities for management strategies.
• Snow accumulation during the 2023/24 winter was above average across both the Eurasian and North American Arctic.
• Despite above-average snow accumulation, the snow season was the shortest in 26 years over portions of central and eastern Arctic Canada. Arctic snow melt is occurring 1-2 weeks earlier than historical conditions throughout May and June.
• Greenland Ice Sheet mass loss lowest since 2013.
• Tundra greenness, a measure of expanding shrub cover due to warming temperatures, ranked second highest in the 25-year satellite record.

Indigenous Knowledge and partnerships

• Indigenous hunters are the original researchers of their homelands, with observation and monitoring skills integral to traditional practices.
• The Ittaq Heritage and Research Centre in Kangiqtugaapik (Clyde River), Nunavut, Canada operates the Angunasuktiit program, teaching traditional hunting and harvesting to new generations.
• Supporting Indigenous leadership in Arctic research requires sustained support of Indigenous ways of life and knowledge generation.