The critical point would be the loss of the Arctic ice cover, not the rise in sea level it produces. But still, I think every little bit hurts, so that's useful information.
Absolutely. More insolation means more thermal expansion, and fewer thermal niches for polar poikilotherms and many other megafauna in the Arctic.
Somewhat off topic, I read an interesting article in the Chronicle Herald that was talking about 2012. Not some abstract numerology or Mayan mythology, but related to storm surge. The Saros cycle produces a half meter higher tide in the Bay of Fundy every 18 years, when the Sun, Moon, and Earth are aligned. Where I type right now, is on a flood plain...Truro would be underwater in 2013 (actual peak of the cycle) were a storm like that which hit Saint John in 1976-the Groundhog Day Gale- to ride up the Bay.