Antarctic circulation could slow by more than 40 per cent over the next three decades, with significant implications for oceans and the climate.<\/p>\n\n\n\n
he deep ocean circulation that forms around Antarctica could be headed for collapse, say scientists.<\/p>\n\n\n\n
Such a decline would stagnate the bottom of the oceans and affect climate and marine ecosystems for centuries to come.<\/p>\n\n\n\n
The results are detailed in a new study<\/a> coordinated by Scientia Professor Matthew England<\/a>, Deputy Director of the ARC Centre for Excellence in Antarctic Science (ACEAS)<\/a> at UNSW Sydney. The work, published today in Nature<\/em>, includes lead author Dr Qian Li \u2013 formerly from UNSW and now at the Massachusetts Institute of Technology (MIT) \u2013 as well as co-authors from the Australian National University (ANU) and CSIRO.<\/p>\n\n\n\n Cold water that sinks near Antarctica drives the deepest flow of the overturning circulation \u2013 a network of currents that spans the world\u2019s oceans. The overturning carries heat, carbon, oxygen and nutrients around the globe. This influences climate, sea level and the productivity of marine ecosystems. <\/p>\n\n\n\n \u201cOur modelling shows that if global carbon emissions continue at the current rate, then the Antarctic overturning will slow by more than 40 per cent in the next 30 years \u2013 and on a trajectory that looks headed towards collapse,\u201d says Prof England. <\/p>\n\n\n\n Read more: State of the climate: what Australians need to know about major new report<\/a> <\/p>\n<\/blockquote>\n\n\n\n About 250 trillion tonnes of cold, salty, oxygen-rich water sinks near Antarctica each year. This water then spreads northwards and carries oxygen into the deep Indian, Pacific and Atlantic Oceans. <\/p>\n\n\n\n \u201cIf the oceans had lungs, this would be one of them,\u201d Prof England says.<\/p>\n\n\n\n The international team of scientists modelled the amount of Antarctic deep water produced under the IPCC \u2018high emissions scenario\u2019<\/a>, until 2050. <\/p>\n\n\n\n The model captures detail of ocean processes that previous models haven\u2019t been able to, including how predictions for meltwater from ice might influence the circulation. <\/p>\n\n\n\n This deep ocean current has remained in a relatively stable state for thousands of years, but with increasing greenhouse gas emissions, Antarctic overturning is predicted to slow down significantly over the next few decades.<\/p>\n\n\n\n\n
Modelling the deep ocean<\/h5>\n\n\n\n