Here, for example is an article that I wrote for Quadrant <a href="http://www.quadrant.org.au/blogs/doomed-planet/2009/12/diy-ocean-heating">http://www.quadrant.org.au/blogs/doomed-planet/2009/12/diy-ocean-heating</a> in which I use high school thermodynamic calculations to calculate the feasibility of the temperature shifts that are being quoted.