Next time you’re at the beach take a deep, long sniff: That special coastal scent might not last forever. While you’re at it, put on some extra sunscreen: As that smell dwindles, cloud cover could, too.
The unique oceanside smell that flows over your olfactory organs is loaded with sulfur — dimethylsulfide, to be exact, or DMS. It’s produced when phytoplankton decompose. And it’s a fragrant compound that’s as special as it smells: In the atmosphere it reacts to produce sulfuric acid, which aids in the formation of clouds.
But it’s a smell that’s endangered by climate change. Experiments have linked the rising acidity of the world’s oceans to falling levels of DMS. A paper published online Sunday in the journal Nature Climate Change warns that ocean acidification could reduce DMS emissions by about one-sixth in 2100 compared with pre-industrial levels.
Clouds do more for us than just dispense quenching rain and snow: They also reflect light and heat away from the earth, helping to keep temperatures down.
Scientists at the Max Planck Institute for Meteorology found that the knock-on effects of rising ocean acidity threaten to rob the world of so much of its cloud cover that global temperatures could noticeably rise.
“Marine DMS emissions are the largest natural source of atmospheric sulphur and changes in their strength have the potential to alter the Earth’s radiation budget,” the scientists wrote. From an explainer article in Nature:
On a global scale, a fall in DMS emissions due to acidification could have a major effect on climate, creating a positive-feedback loop and enhancing warming. …
In a ‘moderate’ scenario described by the Intergovernmental Panel on Climate Change, which assumes no reductions in emissions of heat-trapping gases, global average temperatures will increase by 2.1 to 4.4 °C by the year 2100.
The model [used for the new research] projected that the effects of acidification on DMS could cause enough additional warming for a 0.23 to 0.48 °C increase if atmospheric CO2 concentrations double. The moderate scenario projects CO2 doubling long before 2100.
Diminished cloud cover and rising temperatures are bad enough, but the real horror might be raising kids in a world where the only place you can smell the ocean is Bath & Bodyworks.