There was another thread around here somewhere yesterday about Mars heating up as well -indicating increased solar activity instead of manmade catastrophe.
http://www.space.com/scienceastronomy/pluto_warming_021009.html
http://www.channel4.com/science/microsites/U/ukweather2080/guides/planets.html
http://science.slashdot.org/article.pl?sid=07/03/03/2310250
http://www.scienceagogo.com/news/19980526052143data_trunc_sys.shtml