The earth’s sunscreen is interacting with climate change and is affecting marine and terrestrial systems in the Southern Hemisphere according to new research published in the journal Nature.
Increased solar radiation penetrating through the damaged ozone layer is interacting with the changing climate, and the consequences are rippling through the Earth’s natural systems, effecting everything from weather to the health and abundance of sea mammals like seals and penguins. These findings were detailed in a review article published today in Nature Sustainability by members of the United Nations Environment Programme’s Environmental Effects Assessment Panel, which informs parties to the Montreal Protocol.
“What we’re seeing is that ozone changes have shifted temperature and precipitation patterns in the southern hemisphere, and that’s altering where the algae in the ocean are, which is altering where the fish are, and where the walruses and seals are, so we’re seeing many changes in the food web,” said Kevin Rose, a researcher at Rensselaer Polytechnic Institute who serves on the panel and is a co-author of the review article.
The 1987 Montreal Protocol on Substances that Deplete the Ozone Layer — the first multilateral environmental agreement to be ratified by all member nations of the United Nations — was designed to protect Earth’s main filter for solar ultraviolet radiation by phasing out production of harmful manmade substances, such as the chlorofluorocarbons class of refrigerants. The treaty has largely been considered a success, with global mean total ozone projected to recover to pre-1980 levels by the middle of the 21st century. Earlier this year, however, researchers reported detecting new emissions of ozone-depleting substances emanating from East Asia, which could threaten ozone recovery.
While ozone depletion has long been known to increase harmful UV radiation at the Earth’s surface, its effect on climate has only recently become evident. The report points to the Southern Hemisphere, where a hole in the ozone layer above Antarctica has pushed the Antarctic Oscillation — the north-south movement of a wind belt that circles the Southern Hemisphere — further south than it has been in roughly a thousand years. The movement of the Antarctic Oscillation is in turn directly contributing to climate change in the Southern Hemisphere.
As climate zones have shifted southward, rainfall patterns, sea-surface temperatures, and ocean currents across large areas of the southern hemisphere have also shifted, impacting terrestrial and aquatic ecosystems. The effects can be seen in Australia, New Zealand, Antarctica, South America, Africa, and the Southern Ocean.
From the study abstract (paywall):
Changes in stratospheric ozone and climate over the past 40-plus years have altered the solar ultraviolet (UV) radiation conditions at the Earth’s surface. Ozone depletion has also contributed to climate change across the Southern Hemisphere. These changes are interacting in complex ways to affect human health, food and water security, and ecosystem services. Many adverse effects of high UV exposure have been avoided thanks to the Montreal Protocol with its Amendments and Adjustments, which have effectively controlled the production and use of ozone-depleting substances. This international treaty has also played an important role in mitigating climate change. Climate change is modifying UV exposure and affecting how people and ecosystems respond to UV; these effects will become more pronounced in the future. The interactions between stratospheric ozone, climate and UV radiation will therefore shift over time; however, the Montreal Protocol will continue to have far-reaching benefits for human well-being and environmental sustainability.
We know what to do. We have leaders who refuse to act.