April 10 – A growing number of intense wildfires across the globe is weakening the planet’s ability to absorb carbon dioxide, with more than 30% of the Arctic Boreal Zone now acting as a carbon source instead of a sink, according to a new study published in Nature Climate Change.
The findings come amid a wave of destructive wildfires in early 2025. In the United States, blazes in Texas and Oklahoma claimed at least 28 lives, destroyed over 14,000 structures, and scorched 16,000 hectares of land. In Japan, a fire near Ofunato city killed one person, damaged more than 200 buildings, and forced thousands to evacuate.
The fires also released vast amounts of carbon into the atmosphere. The European Union’s Copernicus Atmosphere Monitoring Service (CAMS) reported that wildfires emitted an estimated 800,000 tonnes of carbon in January alone — nearly four times the level recorded during the same period a decade ago. NASA satellite data showed that the fires’ radiative power significantly exceeded long-term averages between 2003 and 2024.
In India, forest fires remain a persistent threat. According to the India State of Forest Report 2024, Uttarakhand alone recorded over 5,000 incidents between November 2022 and June 2023. Though the number of fire hotspots in the country is slowly declining, climate researchers report that rising land temperatures and prolonged dry spells have made regions in the northwest and central parts of the country increasingly vulnerable to early and prolonged heatwaves — a key driver of wildfires.
Annual emissions from forest fires in India are estimated at 69 million tonnes of carbon dioxide, according to consulting firm Chase India. The Arctic Boreal Zone (ABZ), long regarded as a crucial carbon sink due to its permafrost, coniferous forests, and wetlands, is now showing signs of reversal. Researchers analyzing data from 200 monitoring sites between 1990 and 2020 found that nearly one-third of the region has begun releasing more carbon than it absorbs.
“While many northern ecosystems are still acting as carbon dioxide sinks, fires and thawing permafrost are cancelling out much of the net uptake,” said Anna Virkkala, a research scientist at the U.S.-based Woodwell Climate Research Center and co-author of the study.
Alaska accounted for 44% of the new emissions, with northern Europe and Siberia contributing 25% and 13% respectively. The researchers also observed that during non-summer months, the ABZ released more carbon than it absorbed during summer — a worrying seasonal shift.
The study traced the start of this transformation back to before 1990, accelerated by major fire events such as the 2003 Siberian wildfires and the 2012 Timmins fire in Canada. Thawing permafrost and shifting vegetation patterns, caused by rapid warming in Arctic regions, have led to increased decomposition of organic matter in the soil, further amplifying carbon emissions.
The findings echo warnings in the 2024 Arctic Report Card by the U.S. National Oceanic and Atmospheric Administration (NOAA), which said the Arctic is now absorbing record levels of pollution from fossil fuel combustion and frequent wildfires. “Many of the Arctic’s vital signs that we track are either setting or flirting with record-high or record-low values nearly every year,” said NOAA scientist Gerald Frost. “This is an indication that recent extreme years are the result of long-term, persistent changes, not natural variability.”
