The Arctic Tundra Has Switched From “Carbon Sink To Carbon Source”

PICTURE COURTESY : FACTUAL AMERICA

The Arctic tundra has transformed into a net emitter of greenhouse gases instead of a “carbon sink”, for the first time, according to the Arctic Report Card issued this week by the US National Oceanic and Atmospheric Administration (NOAA). The 2024 Arctic Report Card highlights record-breaking and near-record-breaking observations that demonstrate dramatic change. For millennia, the tundra regions of the Arctic drew in carbon from the atmosphere and locked it in permafrost.That is the case no more, according to an annual report issued by the NOAA.

• 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 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.
• 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.

The Arctic continues to warm at a faster rate than the global average and has turned into a carbon source with declines of previously large inland caribou herds, and increasing winter precipitation. The sink-to-source switch means that carbon-based plant and animal matter that has been stored in permafrost for thousands of years now streams into the air because of warmth-induced decomposition, said Brendan Rogers, a scientist with the Woodwell Climate Research Center and one of the Arctic Report Card’s co-authors.

Adaptation is increasingly necessary and Indigenous Knowledge and community-led research programs are essential to understand and respond to rapid Arctic changes.

The writer of this article is Dr. Seema Javed, an environmentalist & a communications professional in the field of climate and energy