Southern Ocean key to slowing warming

·2-min read

The Southern Ocean surrounding Antarctica is earth's best maritime hope of slowing down the pace of climate change by absorbing most of the excess heat trapped in the planet's atmosphere.

Scientists at the UNSW's Centre for Excellence in Antarctic Science say oceans have absorbed more than 90 per cent of the excess heat caused by carbon emissions in the last 50 years.

The Southern Ocean has done most of the heavy lifting in the last century.

"The Southern Ocean dominates this ocean heat uptake, due in part to the geographic set-up of the region," said UNSW PhD candidate Maurice Huguenin.

The lead author of a new study published this week in the journal Nature Communications said strong westerly winds surrounding the ice continent help in the absorption process.

"These winds influence how the waters absorb heat and around Antarctica they can exert this influence while remaining uninterrupted by land masses," he said.

Mr Huguenin explained waters are pushed northward, absorbing vast quantities of heat from the atmosphere, before the excess heat is pumped into the ocean's interior.

The researchers ran a model with atmospheric conditions fixed in the 1960s, prior to any significant human-caused climate change, and then compared it with all the environmental man-made damage sustained in the last 50 years.

But while ocean warming helps slow the pace of climate change, it is not without cost.

Co-author and UNSW professor Matthew England says sea levels will continue to rise because of extra heat emitted from the planet, which will adversely affect weather events even more.

"Sea levels are rising because heat causes water to expand and ice to melt," he said.

"Ecosystems are experiencing unprecedented heat stress and the frequency and intensity of extreme weather events is changing."

Dr England noted this trend will also affect food supply chains.

The authors ultimately stressed the urgent need to tackle climate change and reduce greenhouse gas emissions.

"The less carbon dioxide we emit into the atmosphere, the less ocean change and sea-level rise we will lock in," they said.

"This can help limit the level of adaptation required by the billions of people living near the ocean by minimising the detrimental impacts of ocean warming on both sea-level and their primary food source".