I've heard the global warming trend expressed in degrees per decade, but about how much energy per unit time (i.e. power) does this represent? Ideally I'd like to include atmospheric heating, ocean heating, and the heat of fusion for ice melt.
As you might guess, googling this question leads mostly to a blog that won't answer this question, so please link a reference. Thanks!
Baccheus
Favorite Answer
The net effect of human activities is a strong warming influence of more than 1.6 Watts per square meter.
-- National Academy of Science
You can download their booklet (pdf) from this page.
http://nas-sites.org/americasclimatechoices/more-resources-on-climate-change/climate-change-lines-of-evidence-booklet/
Once you've opened the booklet you can either read the whole thing for a good understanding of global warming or just search for "watts" to answer your specific question.
The Royal Society (the national academy of science in the U.K.) published a guide in 2010. That guide can be downloaded from here.
http://royalsociety.org/policy/publications/2010/climate-change-summary-science/
They provide more breakouts that might be more helpful. For example, that 1.6 quoted above is net of all human activity including the cooling effects of pollution. The effect of just the enhanced greenhouse effect is about 2.9 watts per square meter.