Uncategorized

Steve McIntyre’s recent Ohio State University presentation is now available online. This is an excellent summary of the ‘Hockey Stick’ debate and the climate debate in general, which extends to 45 pages (including references).

The presentation concludes:

So where does that leave us?

In my opinion, there are serious and probably fatal problems with the main proxies used as supposed evidence against a warm MWP – the Graybill strip bark chronologies, Briffa’s adjustment to the Tornetrask series, the inconsistency between Briffa’s Yamal substitution and the updated Polar Urals series and so on. For every proxy that supposedly shows a MWP cooler than the present, there seems to be one that is just as good or better evidencing the opposite. For the California and Urals proxies so fundamental to the Hockey Stick, the ecological evidence is further evidence against the Graybill and Briffa chronologies being interpretable as temperature proxies.

The selection of proxies in studies displayed by IPCC seems to me to be biased against proxies with a warm MWP. IPCC itself does not carry out any independent due diligence of the type that might be expected in a prospectus. Further, in 2007, as in 2001, the authors involved in preparing the paleoclimate section were active parties in controversies and, in the end, IPCC Fourth Assessment Report strongly reflects their partisan point of view.

Is there a wider lesson here for engineers? We are often told that the “Science is settled”. But engineers, of all people, know that, even if the “science is settled”, the engineering work may have just begun. One would hardly derive the parameters for a chemical process from an article in Nature without an engineering feasibility study.

The most critical question in climate is the estimation of a parameter – is the sensitivity of climate to doubled CO2 1.5, 2.5 or 3.5 deg C? Or could it be 6 deg C or 0.6 deg C?

In some ways, the estimation of such parameters through the development of complicated computer models is reminiscent of activities carried out by engineers. One important difference is that climate scientists typically report their results in highly summary form in journals like Nature, rather than in the 1000-page or 2000-page engineering studies that an aerospace engineering enterprise would produce.

Viewed from this perspective, a remarkable aspect of the climate debate has been the seeming inability of the climate science community to narrow confidence intervals on this estimate. In 1979, the Charney Report (National Research Council 1979) estimated the impact at 3 deg C with a 1.5 degree range either way. In 2007, IPCC AR4 estimates are virtually unchanged. With all the improvements in scientific knowledge and all the efforts of climate scientists over the years, why has the improvement of these confidence intervals proved so resistant? I don’t know, but it’s worth thinking about.

According to Roger Pielke Sr, the answer is YES. He concludes: Thus the value of global warming of the last 4 years fails to agree with the IPCC projections (the values are not even close!). The agrument that this is too short of a time is spurious unless the modellers can account for where else in their model results the missing Joules went.

Moreover, this is not too short of a time period to compare with the models. Heat, unlike temperature at a single level as used to construct a global average surface temperature trend, is a variable in physics that can be assessed at any time period (i.e. a snapshot) to diagnose the climate system heat content. Temperature not only has a time lag, but a single level represents an insignificant amount of mass within the climate system.

The answer to the question on this weblog “Can the IPCC model projections of global warming be evaluated from just several years of observed data” is YES. The conclusion for the past four years is that the model projections are not skillful on this time period.

Roger Pielke Sr’s Climate Science Weblog: Can The IPCC Model Projections Of Global Warming Be Evaluated From Just Several Years Of Data?

“POLITICIANS seem to think that the science is a done deal,” says Tim Palmer. “I don’t want to undermine the IPCC, but the forecasts, especially for regional climate change, are immensely uncertain.”

Palmer is a leading climate modeller at the European Centre for Medium-Range Weather Forecasts in Reading, UK, and he does not doubt that the Intergovernmental Panel on Climate Change (IPCC) has done a good job alerting the world to the problem of global climate change. But he and his fellow climate scientists are acutely aware that the IPCC’s predictions of how the global change will affect local climates are little more than guesswork. They fear that if the IPCC’s predictions turn out to be wrong, it will provoke a crisis in confidence that undermines the whole climate change debate.

On top of this, some climate scientists believe that even the IPCC’s global forecasts leave much to be desired. …

A subscription is required to read the full New Scientist article: Poor forecasting undermines climate debate