A quick thread about melting glaciers, which I've written about in today's #climatewire: eenews.net/stories/106007…
Research increasingly shows that a major factor in glacier retreat, in both Antarctica and Greenland, is the intrusion of warm ocean water -- it seeps beneath ice shelves and helps melt the ice from the bottom up. /2
(This new Antarctic mapping project shows the extent of glacier retreat around the continent the last few years and points to warm water intrusion as a likely culprit.) /3 eenews.net/stories/106007…
But where is all this warm water coming from? We know it's there, and we know it's affecting the ice -- but what's driving it? This is a super interesting question with a lot of answers. /4
The obvious solution would be that the oceans are simply warming up, thanks to climate change. They generally are, but that's actually not what's behind most of the warm water intrusion we're seeing at the ice edge. /5
Rather, complex ocean/atmospheric circulation systems are driving *natural* warm water masses to the edge of the ice sheets. So next question is -- why does there seem to be a recent increase in warm water intrusion in some places? Is climate change playing a role? /6
Another complicated question! Scientists I've spoken to say it's likely -- but in really complex ways we're still parsing out. E.g. warming in tropics may alter Antarctic wind patterns, which affect upwelling of warm water. (In Greenland, entirely different processes at play.) /7
Need both more data taken directly from the ice front (not easy to do consistently in Greenland and esp. remote Antarctica!) & continued improvement of ocean models to figure out what's been going on and how climate change may affect these physical processes in the future. /8
(All this doesn't even get into complicated ? of what happens once the water actually reaches the ice sheet -- e.g. how does seafloor topography affect water's access to glaciers, or glaciers' behavior as they melt. Some big projects working to address these ?s as well.) /9
In summary: understanding ice-ocean interactions is now a critical component of our ability to accurately predict behavior of the ice sheets and future sea-level rise. But there are so many moving parts we're just starting to figure out. Truly fascinating stuff. /end
