A new study reveals that falling water levels in Mediterranean reservoirs can cause a surge in methane emissions, potentially compounding climate change. Researchers found that as water levels drop, exposed sediments release stored greenhouse gases.
Continental aquatic ecosystems like lakes and reservoirs account for over 40% of global methane emissions, according to the study. However, most emission estimates rely on one-off measurements, leaving considerable uncertainty about the true scale of the problem.
The research highlights that these ecosystems play an outsized role in the global carbon cycle despite covering a small fraction of Earth's surface. The study focused specifically on Mediterranean reservoirs, where cyclical droughts and water management practices cause water levels to fluctuate.
These findings suggest that climate-driven water scarcity could create a feedback loop, accelerating methane release and further warming the planet. The study underscores the need for more continuous, long-term monitoring of reservoirs to accurately assess and mitigate emissions.
While the findings are drawn from regional data, the study's authors note that the underlying mechanism of sediment exposure likely applies to reservoirs globally.