Antarctic wind vortex is strongest for 1000 years

http://www.newscientist.com/article/mg22229693.200-antarctic-wind-vortex-is-strongest-for-1000-years.html#.U4DfrXJdWQA

New Scientist magazine
14 May 2014
Magazine issue 2969

OUR greenhouse gas emissions are boosting a vortex of winds around Antarctica. As this maelstrom accelerates, it shrinks, dragging rain away from Western Australia.

Earlier studies suggested that the hole in the ozone layer above Antarctica was boosting the winds. Now Nerilie Abram of the Australian National University in Canberra and her colleagues have shown that global warming is just as important.

The team reconstructed Antarctic temperatures over the past 1000 years using an ice core. The temperatures correlate with wind strength, and the team found that the winds are now the strongest they have been in the past millennium. But the gain in strength began in the 1940s, decades before the ozone hole. So the team simulated weather patterns in the last 1000 years using climate models and greenhouse gas levels from ice cores. All the models predicted that the winds would pick up by the 1940s, suggesting that greenhouse gases were playing a role (Nature Climate Change, doi.org/sqv).

As the ozone hole heals, its effect on the winds will weaken. But rising temperatures will counteract this. The two factors may balance until 2045, says Wenju Cai from the CSIRO, Australia's national research agency, in Melbourne. After that, unless we reduce emissions, greenhouse gases will boost the winds further, and Western Australia will lose even more of its rain.