Here are some good websites for what the climate change could possibly do to currents and coastal zones. I'm still writing up the summary and will post it when I'm done.
How the currents will change:
http://www.whoi.edu/page.do?pid=12455&tid=282&cid=9986
Affect on the Gulf coast:
http://www.usgcrp.gov/usgcrp/nacc/gulfcoastworkshop.htm#chapter5\\