Rising heat<\/p>\n
The Southern Ocean’s layers – with cold, relatively fresh water sitting on top of warmer, saltier water below – act as a lid, trapping heat at depth.<\/p>\n
But the new research shows this barrier has weakened.<\/p>\n
As the feedback loop locked in the change, the ocean’s surface became saltier and less layered.<\/p>\n
By analysing ocean data and using a high-resolution model, the research team found that warm ‘Circumpolar Deep Water’ has been rising closer to the surface, where it can directly melt sea ice.<\/p>\n
They say loss of sea ice destabilises the world’s ocean current systems – warming the planet far quicker than expected.<\/p>\n
“This is not just about warmer air temperatures,” says Professor Matthew England, an oceanographer at UNSW and co-author of the study.<\/p>\n
“We’re seeing heat that has been stored in the ocean for decades now breaking through to the surface,” Prof. England says.<\/p>\n
“Once that happens, it becomes very difficult for the system to return to its previous state.”<\/p>\n
While the surface warming can fluctuate from year to year, the heat stored in the ocean represents a deeper, longer-term shift in the climate system.<\/p>\n
A tale of two Antarcticas<\/p>\n
The research also reveals a split across the continent.<\/p>\n
While sea ice loss was driven mostly by this upward surge of deep ocean heat in East Antarctica, the story is different in West Antarctica.<\/p>\n
Increased cloud cover, which is linked to warm air moving down from the subtropics, has trapped heat in the ocean – melting ice from above, most significantly during the summers of 2016 and 2019.<\/p>\n
Together, these processes have reshaped the entire Antarctic sea ice system.<\/p>\n
“This is a coupled atmosphere-ocean-ice event,” Prof. England says. “You’ve got changes in winds, clouds, sea-ice and ocean circulation all reinforcing each other.<\/p>\n
“That’s why the response has been so abrupt.”<\/p>\n","protected":false},"excerpt":{"rendered":"Rising heat The Southern Ocean’s layers – with cold, relatively fresh water sitting on top of warmer, saltier…\n","protected":false},"author":2,"featured_media":133311,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[49,48,66],"class_list":["post-661243","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ca","tag-canada","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/661243","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=661243"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/661243\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/133311"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=661243"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=661243"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=661243"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}