By Abdullahi Lukman
Southwestern Europe’s ecosystems lost 27% of their carbon sink capacity during the 2022 heatwave, revealing growing vulnerability to climate change
A dramatic rise in extreme weather events, driven by climate change, is increasingly disrupting Earth’s carbon cycle and threatening the ability of natural ecosystems to help offset global warming.
According to a recent study published in *Global Biogeochemical Cycles*, the record-breaking heatwave of 2022 reduced vegetation’s ability to absorb carbon dioxide (CO₂) by 27% in parts of southwestern Europe—a region that includes Portugal, Spain, southern France, and Italy.
This drop in carbon uptake was so severe that vegetation in the affected areas failed to absorb more CO₂ than Spain emitted in the same year, according to data from the Spanish National Institute of Statistics.
The findings reveal a growing imbalance in the global carbon budget and raise concerns about the future of natural carbon sinks in a warming world.
Carbon sinks are vital components of the planet’s climate regulation system. Forests, soils, and oceans naturally absorb large amounts of CO₂, helping to mitigate climate change by keeping greenhouse gas concentrations in check.
However, the new research suggests that their ability to perform this role is being significantly undermined by more frequent and intense heatwaves and droughts.
The study, led by Ricard Segura Barrero of the Institute of Environmental Science and Technology at the Autonomous University of Barcelona (ICTA-UAB), analyzed two decades of carbon flux data—from 2001 to 2022—across 10 biogeographic regions in southwestern Europe.
The research found that ecosystems in continental and humid climates were particularly affected by extreme heat and dry spells, while Mediterranean regions, which are historically more accustomed to such conditions, showed greater resilience.
Related Posts
“We’re seeing that ecosystems are not adapting quickly enough to the accelerating pace of climate extremes,” Segura Barrero said. “The carbon balance is tipping, and that has serious implications not just for Europe, but for the entire global carbon cycle.”
Although rising temperatures have extended the plant growing season in some areas, theoretically increasing the period of carbon uptake, the research found that these gains are being offset by a simultaneous rise in CO₂ emissions caused by increased plant respiration and faster decomposition of organic material.
Water availability—specifically soil moisture—emerged as a key variable. Ecosystems hit by heatwaves during periods of low moisture were especially vulnerable, as plants reduce photosynthesis and CO₂ uptake under stress.
To validate their models, researchers used satellite data that measured sun-induced fluorescence—an accurate indicator of photosynthetic activity.
These measurements confirmed a substantial decrease in plant productivity during the 2022 heatwave, providing a clearer picture of how sensitive carbon exchange is to climate extremes.
The implications of these findings are far-reaching. As the planet continues to warm, extreme weather events are projected to become more frequent and intense.
If ecosystems continue to lose their capacity to act as carbon sinks, more CO₂ will remain in the atmosphere, accelerating the pace of global warming.
Researchers emphasize the urgent need to improve monitoring of carbon fluxes in vulnerable regions and to invest in policies that protect and adapt ecosystems to a rapidly changing climate.
This includes better land management practices, reforestation efforts, and climate-resilient agricultural techniques.
“Our ability to meet global climate targets depends not only on reducing emissions but also on preserving and strengthening the natural systems that absorb them,” Segura Barrero concluded.
“This study is a clear signal that we must act now to safeguard these ecosystems before their ability to help us is lost.”
