The authors of this article misunderstood the basis of the ‘projections’ for 1990-2000 in the IPCC’s Third Assessment Report (2000). As explained in the Special Report on Emissions Scenarios (2000), ‘the 1990 and 2000 emissions scenarios were standardized in all the SRES scenarios, with emissions diverging after the year 2000′ (Box 5.1, p. 243).

The SRES went on to explain that ‘The standardized scenarios share the same values for emissions in both 1990 and 2000′, and that ‘The 1990 and 2000 emissions estimates for all gases, except SO2, were set to be equal to the initial values in the unadjusted four marker scenarios.’ So, for example, the projections for emissions AND FOR TEMPERATURE for the A1FI scenario, which was not a marker, were set BY ASSUMPTION as equal to those of the average of the four markers.

As an indication of the possible scale of the effect of this procedure, the A1FI scenario assumed that the global energy supply from coal would increase by 30% between 1990 and 2000, compared with an increase of about 5% for the A1B and B1 scenarios.
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So when Rahmstorf et al concluded that ALL OF the IPCC projections underestimated the temperature rise, they were not in fact evaluating the performance of models against observations – at least as far as the 1990-2000 period was concerned (the greater part of the comparison). For this period, the outputs of the individual models were discarded in favour of an average of a subset of the models.

Contrary to the claims in Rahmstorf et al (2007), the analysis does not in fact represent an evaluation of the IPCC models for the 1990-2000 decade. For the period 2000-2020, the IPCC models projected an increase of about 0.2 C per decade, as shown in Lucia’s graphic above.

The main one is that the IPCC scenario with the highest projections of growth in output and rapidity of industrialisation – the A1 scenario – predicted the LOWEST increase in temperatures, and vice versa: see Table II.4 in Appendix II to ‘Climate Change 2001: The Scientific Basis’.

The main one is that the IPCC scenario with the highest projections of growth in output and rapidity of industrialisation – the A1 scenario – predicted the LOWEST increase in temperatures, and vice versa: see Table II.4 in Appendix II to ‘Climate Change 2001: The Scientific Basis’.

Just like in any other religion, one cannot doubt or even question anything from the sacred book, one must accept everything for the better or the worst. After all the bible wasn’t written by men it was written the messengers of god.

Only the real climate scientists, speaking the thruth of the AR4, have the luxury to call another scientist works heresy and do so by the sole will of his words. After all his words are his commands.

Which occurred, I opine, because IPCC didn’t really see the rapid industrialization of India and especially China coming…

Lucia is saying that recent trends are inconsistent with the IPCC prediction. You are saying that they are in fact consistent. She has showed her work. You have showed a little blog attitude and nothing more.

If you want to teach us something, then please just show the quantitative basis behind your claims that recent trends are consistent with IPCC predictions, rather than just asserting that claim without evidence. I’d guess you won’t, but if you do we’ll highlight your work here.

http://www.skepticalscience.com/Comparing-IPCC-projections-to-observations.html

commentary on a paper in “Science” last May. The conclusion, for temperature, is that IPCC TAR was on the low side of the actual temperature trend.