England [UK], May 18 (ANI): A new study led by the University of East Anglia (UEA) reveals that the damaging effects of the ozone hole on the Southern Ocean’s carbon uptake can be reversed—provided greenhouse gas emissions decrease rapidly.
The Southern Ocean, surrounding Antarctica, absorbs a disproportionately large amount of atmospheric carbon relative to its size. This carbon uptake helps reduce the greenhouse effect, significantly mitigating human-caused climate change. Understanding the factors controlling this carbon absorption is therefore critical.
Researchers from UEA and the UK’s National Centre for Atmospheric Science (NCAS) examined how ozone depletion and greenhouse gas (GHG) emissions influence Southern Ocean circulation and its capacity to absorb carbon. They analyzed changes during the 20th century and projected shifts through the 21st century. Their findings appear in Science Advances.
Lead author Dr. Tereza Jarnikova of UEA’s Tyndall Centre for Climate Change Research said, “An interesting, and hopeful, highlight of this work is that the effects of human-caused ozone hole damage on the winds, circulation, and carbon uptake of the Southern Ocean are reversible, but only under a lower scenario of greenhouse gas emissions.”
The Southern Ocean’s unique circulation and properties enable it to absorb large amounts of atmospheric carbon. However, intensified winds in recent decades—driven by stratospheric ozone loss—have reduced this carbon uptake. The stronger winds bring carbon-rich deep waters to the surface, decreasing the ocean’s ability to absorb more atmospheric carbon.
The study indicates this trend could reverse as the ozone hole recovers. Yet, rising GHG emissions may also strengthen winds, creating uncertainty about future Southern Ocean circulation and carbon uptake.
“We found that in the past decades, ozone depletion led to a relative reduction of the carbon sink because stronger winds brought higher-carbon water from the depths to the surface,” explained Dr. Jarnikova. “This isn’t true in the future: the influence of ozone on winds diminishes as the ozone hole heals, replaced by the increasing influence of greenhouse gas emissions, which also lead to strong winds.”
The researchers also found that future changes in ocean circulation will have less impact on carbon uptake than in the past, due to changing carbon distribution between surface and deep ocean layers.
Using the Earth system model UKESM1, the team simulated three ozone scenarios for 1950–2100: one with no ozone hole, one with a realistic ozone hole that begins healing after the 1987 Montreal Protocol, and one where the ozone hole remains at its 1987 size throughout the 21st century. They combined these with two greenhouse gas scenarios—low and high emissions—to assess physical ocean changes and corresponding carbon uptake over 150 years.
This study underscores the critical interplay between ozone recovery and greenhouse gas emissions in shaping the Southern Ocean’s role in climate regulation. (ANI)
About The Author
