Thanks John for the follow up. You are correct that T (and thus T^4) are going up using the global average surface temperature trends analyzed by GISS and others. However, as we show in our JGR paper, there are quite a few issues with the quantitative assessment of the trend including a warm bias.
Moreover, since neither lower tropospheric temperature trends or upper ocean heat content have been increasing in the last several years, it raises questions on the accuracy of using T' (the global average surface temperature) to diagnose global warming (or cooling).
The question of whether the more accurate T^4, weighted spatially, should be used is one of the issues that needs to be included in the discussion. You were the key person who wrote and edited the text with me in our JGR paper on this topic.
Regardless of our views on policy implications regarding the role of humans in the climate system, we need objective assessments of the data. This did not occurr in the 2007 IPCC assessment as I have documented on Climate Science, with the evaluation of the spatial distribution of [T+T']^4 being one example.