With regards to the evaporation, surely while it does lower the temperature of the water it can not raise the temperature of the air above that of the ocean. (skepticalscience.com)
And second, we've heard: «most scientists agree» that CO2 will raise temperatures by x amount? (wattsupwiththat.com)
An ice cap which is rejecting heat all winter can absorb the same amount of heat during summer without raising its temperature to the melting point. (skepticalscience.com)