The Southern Ocean around Antarctica is warming at an alarming rate—twice that of the rest of the world’s oceans. Now, researchers have developed more powerful evidence pointing to the human causes.
Though warming had been observed in the past, there was little historical data to allow scientists to pinpoint the causes with much certainty.
In a new study, researchers used climate models, the past observations that did exist and data flowing in from new ocean-going sensors to show how greenhouse gas emissions and the depletion of ozone in the atmosphere have led to both a warming of the Southern Ocean and an increase in its freshwater content. The findings also rule out natural variability as a major source of those changes.
“The observed warming is due to human influence,” said oceanographer Neil Swart, a research scientist with Environment and Climate Change Canada who led the study, published Monday in the journal Nature Geoscience. “That may have been suspected or proposed before, but this is the evidence that really proves it.”