Thursday, September 19, 2013

Rising waters

Climate science: Rising tide 

This is quite a good article on the complexities in calculating likely sea level rise under global warming.

The unevenness of the rise is something not often highlighted:
Adding to the complexity, the oceans do not rise evenly all over the world as water is poured in. Air pressure, winds and currents can shove water in a given ocean to one side: since 1950, for example, a 1,000-kilometre stretch of the US Atlantic coast north of Cape Hatteras in North Carolina has seen the sea rise at 3–4 times the global average rate5. In large part, this is because the Gulf Stream and the North Atlantic current, which normally push waters away from that coast, have been weakening, allowing water to slop back onto US shores.

Finally, waters near big chunks of land and ice are literally pulled up onto shores by gravity. As ice sheets melt, the gravitational field weakens and alters the sea level. If Greenland melted enough to raise global seas by an average of 1 metre, for example, the gravitational effect would lower water levels near Greenland by 2.5 metres and raise them by as much as 1.3 metres far away.

1 comment:

Anonymous said...

Great to see Homer Paxton commenting on your blog, Steve. He gives the site the air or authority that's needed in order to raise it's profile.