Quietly bubbling from the ocean, iodine has garnered little attention from climate change researchers – until now.
Each year seafaring bacteria produce about 500,000 tonnes of iodine, which enters the atmosphere in molecules called iodocarbons. These form aerosols that shade the planet but also form ozone, a greenhouse gas.
Lucy Carpenter and Charlotte Jones at the University of York, UK, say that as the oceans warm, chlorine in the water will react more readily with iodocarbons, destroying them before they hit the atmosphere (Geophysical Research Letters, vol 34, p L13804).
This may result in fewer cooling aerosols, but the reduced ozone production may nevertheless help to slow warming slightly.