I will post my comments when they are done, but suffice it to say that this is yet another report written backwards, with the guts of the report written by politicians trying to push an agenda. This is an incredibly shallow document, more shallow even than the IPCC report and possibly even than the IPCC summary for policy makers. Call it the NASA summary for the mentally retarded.
The report is a full-force sales piece for catastrophic global warming. Not once in the entire chapter I read was there a hint of doubt or uncertainty. Topics for which scientists have but the flimsiest of understandings, for example feedback effects, are treated with the certainty of Newtonian mechanics. Any bit of conflicting evidence — whether it be the fact that oceans were rising before the industrial era, or that tropospheric temperatures are not higher than surface temperatures as predicted, or that large parts of Antarctica are gaining ice — are blissfully omitted.
Many of the most important propositions in the report are stated without proof or citation. Bill Kovacs wrote the other day that of the 21 papers that were cited, only 8 are available to the public prior to the August 14 deadline for public comment. Just like with the IPCC, the summary is written months ahead of the science. Much of the report seems to be cut-and-pasted from other sources (you can tell, be graphs are reproduced exactly as they appear in other reports, such as the IPCC fourth assessment). In many cases, the data between these various charts do not agree (for example, their charts have three or four different versions of 20th century global temperatures, none of which are either sourced or consistent).
And, of course, the hockey stick, the Freddy Krueger of scientific analysis, is brought back yet again from the dead.
Let me give you just one taste of the quality science here. Here is a precipitation chart they put in on page 28:
This is like those before-and-after photo games. Can you see the sleight of hand? Look at the legend for the green historic line. It says that it is based on "Simulations." This means that someone has hypothesized a relationship between temperature and precipitation (the precipitation line in this chart is tellingly nearly identical in pattern and slope to the "human + natural" temperature model output as shown at the top of page 26) and built that relationship into a model. So the green line is a result of a) a model projecting temperature backward and b) the model taking that temperature and, based on a series of assumptions that temperature drives heavy precipitation events, generating this graph of heavy precipitation events.
Now, look at the caption. It calls the green line "observed…changes in the heaviest 5 percent of precipitation events." I am sorry, but model output and observations are not the same thing. Further, note the circularity of the argument. Models built on the assumption that temperature increases cause an increase in these events is used as proof that temperature increases these events.
By the way, look at the error band on the green line. For some reason, we have near perfect knowledge for worldwide precipitation events in the 1960’s, but are less certain about the 1990’s.