CO2 Uptake By Amazon Forests Falters; Atmospheric CO2 Content Spikes, Satellite Providing These Data May Be Shut Down
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Our new satellite analysis shows that the Amazon rainforest, which has long been a huge absorber of carbon, is struggling to keep up. And worryingly, the satellite that made this discovery could soon be switched off.
Systematic measurements of CO₂ in the atmosphere began in the late 1950s, when the Mauna Loa observatory in Hawaii (chosen for its remoteness and untainted air) registered about 315 parts per million (ppm). Today, it's more than 420 ppm. But just as important is the rate of change. The annual rise in global CO₂ has gone from below 1ppm in the 1960s to more than 2 ppm a year in the 2010s. Every extra ppm represents about 2 billion tons of carbon—roughly four times the combined mass of every human alive today.
Across six decades of measurements, atmospheric CO₂ has gradually increased. There have been some large but temporary departures, typically associated with unusual weather caused by an El Niño in the Pacific. But the long-term trend is clear. In 2023, CO₂ in the atmosphere grew by about 2.70ppm. That's a large step up, but not too unusual. Yet in 2024, it was an unprecedented 3.73 ppm.
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From the satellite data, we infer that the largest changes in CO₂ emissions and absorption during 2023 and 2024, compared with the baseline year of 2022, were over tropical land. The largest change was over the Amazon, where much less CO₂ is being absorbed. Similar slowdowns also appeared over southern Africa and southeast Asia, parts of Australia, the eastern US, Alaska and western Russia.
Conversely, we detected more carbon being absorbed over western Europe, the US and central Canada. Other data backs this up. For instance, plants emit a faint glow as they photosynthesize—remarkably, we can see this glow from space. Measurements of this glow along with vegetation greenness both show that tropical ecosystems were less active in 2023 and 2024.
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https://phys.org/news/2025-10-carbon-dioxide-amazon-faltering-satellite.html