The folks at the Real Climate blog have offered up some comments on my letter to Nature Geosciences (PDF) which appeared last week. In the condescending tone that we have come to expect from Real Climate, they helpfully frame their comments in terms of teaching me some lessons. I encourage you to read the whole post, but here is my response (submitted for their posting approval) to their three main points, which I’ve highlighted in bold:

Thanks for this discussion. Full text of the letter can be found here:

http://sciencepolicy.colorado.edu/admin/publication_files/resource-2592-2008.07.pdf

1. IPCC already showed a very similar comparison as Pielke does, but including uncertainty ranges.

RESPONSE: Indeed, and including the uncertainty ranges would not change my conclusion that:

“Temperature observations fall at
the low end of the 1990 IPCC forecast range
and the high end of the 2001 range. Similarly,
the 1990 best estimate sea level rise projection
overstated the resulting increase, whereas the
2001 projection understated that rise.”

2. If a model-data comparison is done, it has to account for the uncertainty ranges – both in the data (that was Lesson 1 re noisy data) and in the model (that’s Lesson 2).

RESPONSE: I did not do a “model-data comparison”. One should be done, though, I agree.

3. One should not mix up a scenario with a forecast – I cannot easily compare a scenario for the effects of greenhouse gases alone with observed data, because I cannot easily isolate the effect of the greenhouse gases in these data, given that other forcings are also at play in the real world.

RESPONSE: Indeed. However, I made no claims about attribution, so this is not really relevant to my letter.

Thanks again, and I’ll be happy to follow the discussion.