This whole blog-to-blog comment conversation thing can get a bit maddening. What we really need is to all sit down in a room together. I think a lot of the misunderstandings that turn into arguments would instead play out as useful conversations. Plus we could drink beer*.
Today’s disjointed conversation has Mark Hadfield raising good questions in the comments here on Inkstain:
There’s no doubt that this metric (globally averaged surface temperature) doesn’t tell the whole story, but it’s quite another thing to suggest that it tells us nothing, or very little. Now I’m not suggesting that Roger (Senior) is suggesting such a thing, but the trouble is that on this issue, as on many others, I find it hard to work out what Roger *is* suggesting.
Over on his blog, Roger responds:
Here is what I am “suggesting”. For the assessment of global heat content changes (”global warming”) over the last 50 years, we focus on the assessment of ocean heat content changes, as the primary metric to assess the radiative imbalance of the climate system (http://blue.atmos.colostate.edu/publications/pdf/R-247.pdf). We avoid using the trends in the globally-averaged surface temperatures, since this diagnostic is fraught with a wide range of problems, including the most recent one that we identified in our GRL paper (http://blue.atmos.colostate.edu/publications/pdf/R-302.pdf). For earlier time periods, we have no choice but to use an estimate of global averaged temperature trends, but we need to recognize the very large uncertainty that exists with such a climate metric.
I don’t think globally averaged surface temperature tells us nothing. In fact, I think it answers a question the general public has, which is “how much warmer is it getting.” People live in air at the surface, so by “warmer,” it’s surface temperature they want to understand. That’s why I defended Juliet Eilperin last month against Roger’s criticism, and why I’ll probably do an end-of-the-year story for the paper that includes a discussion of the fact that 2005 is the warmest year ever. But I also am increasingly persuaded that an overemphasis on that one s
* I don’t really like beer. It’s metaphor.