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The oceans have absorbed 90% of the excess heat produced by carbon pollution from human activities since the beginning of the industrial era. Photo/Down Earth
LISBON – The oceans have absorbed 90% of the excess heat produced by carbon pollution from human activities since the beginning of the industrial era. As a result, marine heat waves, extremely high water temperatures, become more intense.
These conditions can have a particularly severe impact on species that are unable to migrate to escape too warm waters. For example, corals on the Great Barrier Reef and kelp forests in southern Australia and the northeastern Pacific.
In a new study published in the journal Nature Climate Change, researchers looked at the impact of temperature spikes in deeper waters. “Heat waves in the deep sea don’t know much about their characteristics,” Eliza Fragkopoulou of the Center for Marine Sciences at Portugal’s University of the Algarve told AFP.
Using on-site observations and modeling, the researchers examined global marine heat waves from 1993 to 2019. Including data from up to 2,000 meters below sea level.
They found the highest intensity occurred at a depth of 50 to 200 meters below the surface. Sometimes up to 19% stronger than heat waves at the surface.
Its duration also increases with depth, with warming lasting up to two years after surface temperatures return to normal. These high stress conditions occur in 22% of the global ocean.
The regional variability of marine heat waves makes measuring biodiversity exposure complicated, and their duration varies by location due to different ocean conditions. In general, Fragkopoulou, said impacts on biodiversity occur from the surface to a depth of 250 meters.
The largest parts of the ocean categorized as highly exposed are found in the North Atlantic and Indian Oceans, at depths between 1,000 and 2,000 meters. This condition has the potential to threaten sensitive species as climate change makes extreme events more frequent.
(wib)
