Lest you are worried that I have gone over to the darkside, here is some red blooded climate scepticism. I've been expecting some to balance all the pixels being spent on the Bali holiday junket.

First, more model criticism.

A new study comparing the composite output of 22 leading global climate models with actual climate data finds that the models do an unsatisfactory job of mimicking climate change in key portions of the atmosphere. . .

“The usual discussion is whether the climate model forecasts of Earth’s climate 100 years or so into the future are realistic,” said the lead author, Dr. David H. Douglass from the University of Rochester. “Here we have something more fundamental: Can the models accurately explain the climate from the recent past? “It seems that the answer is no.” . . .

“The last 25 years constitute a period of more complete and accurate observations, and more realistic modeling efforts,” said Dr. Fred Singer from the University of Virginia. “Nonetheless, the models are seen to disagree with the observations. We suggest, therefore, that projections of future climate based on these models should be viewed with much caution.”

The findings of this study contrast strongly with those of a recent study** that used 19 of the same climate models and similar climate datasets. That study concluded that any difference between model forecasts and atmospheric climate data is probably due to errors in the data.

“The question was, what would the models ‘forecast’ for upper air climate change over the past 25 years and how would that forecast compare to reality?” said Christy. “To answer that we needed climate model results that matched the actual surface temperature changes during that same time. If the models got the surface trend right but the tropospheric trend wrong, then we could pinpoint a potential problem in the models.

“As it turned out, the average of all of the climate models forecasts came out almost like the actual surface trend in the tropics. That meant we could do a very robust test of their reproduction of the lower atmosphere.

“Instead of averaging the model forecasts to get a result whose surface trends match reality, the earlier study looked at the widely scattered range of results from all of the model runs combined. Many of the models had surface trends that were quite different from the actual trend,” Christy said. “Nonetheless, that study concluded that since both the surface and upper atmosphere trends were somewhere in that broad range of model results, any disagreement between the climate data and the models was probably due to faulty data.

“We think our experiment is more robust and provides more meaningful results.”

This may seem like the usual suspects neeping about arcana. Perhaps it is so. This one is a bit harsher.

A paper I wrote, "I Was On the Global Warming Gravy Train," briefly describes the history of why we used to believe that carbon emissions caused global warming, and how we got to where we are now in the debate. . .

It was the early, low resolution ice core data first gathered in 1985 that convinced the world that CO2 was the culprit: CO2 levels and temperature rose and fell in lockstep over the last half a million years, to the resolution of the old ice core data (results from 1985–2000, data points over a thousand years apart). It was assumed (bad assumption #1) that CO2 levels controlled the world's temperature.

After further research, new high-resolution ice core results (data points only a few hundred years apart) in 2000–2003 allowed us to distinguish which came first, the temperature rises or the CO2 rises. We found that temperature changes preceded CO2 changes by an average of 800 years. So temperature caused the CO2 levels, and not the other way around as previously assumed. The world should have started backpedaling away from blaming carbon emissions in 2003. . .

Second crucial point, August 2007: There are several possible causes of global warming, and they each warm the atmosphere at different latitudes and altitudes — that is, each cause will produces a distinct pattern of hot spots in the atmosphere, or "signature." The greenhouse signature is very distinct from the others: warming due to greenhouse would cause most warming in the tropics at about 10 km up in the atmosphere:

As of August 2007, we've measured where the warming is occurring in a fair bit of detail, using satellites and balloons. The observed signature is nothing like the greenhouse signature. The distinct greenhouse signature is entirely missing:

There is no hotspot in the tropics at 10 km up, so now we know that greenhouse warming is not the (main) cause of global warming — so we know that carbon emissions are not the (main) cause of global warming.

Of course these observations need to be repeated by other researchers before we can be completely sure, but they are made by top-notch researchers and reported in top-of-the-line, peer-reviewed journals; so at this stage they look solid.

This dispute will be resolved in time, but I think not soon. It's way too politicized for honest discussion and analysis.