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Abstract: Global temperatures measured since 2005 are incompatible with the IPCC model predictions made in 2007 by WG1 in AR4. All subsequent temperature data from 2006 to 2011 lies between 1 and 6 standard deviations below the model predictions. The data show with > 90%  confidence level that the models have over-exaggerated global warming.

Background: In 2000 an IPCC special report proposed several future economic scenarios each with a different CO2 emission profile. For the 2007 assessment report these scenarios were used to model predictions for future global temperatures. The results for each of the scenarios were then used to lobby governments. It would appear that as a result of these predictions, there is  one favoured scenario – namely B1 which alone is capable of limiting temperature rises to 2 degrees.

The Scenarios: These descriptions are taken from the SRES special report.

The A1 scenario is a case of rapid and successful economic development, in which regional average income per capita converge – current distinctions between “poor” and “rich” countries eventually dissolve. The transition to economic convergence results from advances in transport and communication technology, shifts in national policies on immigration and education, and international cooperation in the development of national and international institutions that enhance productivity growth and technology diffusion.

The A2 world has less international cooperation than the A1 or B1 worlds. People, ideas, and capital are less mobile so that technology diffuses more slowly than in the other scenario families. International disparities in productivity, and hence income per capita, are largely maintained or increased in absolute terms. People, ideas, and capital are less mobile so that technology diffuses more slowly than in the other scenario families. International disparities in productivity, and hence income per capita, are largely maintained or increased in absolute terms.

The central elements of the B1 future are a high level of environmental and social consciousness combined with a globally coherent approach to a more sustainable development (favoured by IPCC?).  Heightened environmental consciousness might be brought about by clear evidence that impacts of natural resource use, such as deforestation, soil depletion, over-fishing, and global and regional pollution, pose a serious threat to the continuation of human life on Earth. A strong welfare net prevents social exclusion on the basis of poverty.”

The consequent CO2 emission trends  which have been  simulated  for each scenario are shown  below.

Fig 1: CO2 levels for different scenarios

IPCC approved models were run on these scenarios using these predicted CO2 levels. As discussed before all IPCC models assume a strong positive feedback of water leading to amplifications of 100-200%. The resultant predictions over a 300 year period are shown below. These graphs undoubtedly helped influence political opinion to limit future warming to 2 degrees which implicitly supports scenario B1. Note also how scenario A2 explodes exponentially, presumably leading to the extinction of all life on Earth. This is the only scenario without some  world eco-governance body  and seemingly ends in disaster !

Figure 2: AR4 figure for long term predictions for each scenario

Basics: The main focus of this post is on  the technical summary of WG1 which contained specific short term  predictions using the same models  for warming up to 2030. This is important because good science makes testable predictions over realistic timescales. Otherwise it is not science at all but just dogma. The data used in  the original 2007 report was available only up to 2005. Since then we have had 6 more years of data which we can now confront with the model predictions. Meanwhile  CO2 levels have continued to rise in line with all scenarios (except that fixing levels at  2000).

The figure below shows the new data points plotted over the original figure that appeared in the WG1 report ( see here). The new black trend curve is a smoothed FFT fit through the data points. The results are startling.

Figure 3: TS figure from WP1 updated with the latest temperature data from HADCRUT3. The black curve is an FFT smooth through all points. Curves are (quoting TS): Multi-model means of surface warming (compared to the 1980–1999 base period) for the SRES scenarios A2 (red), A1B (green) and B1 (blue), shown as continuations of the 20th-century simulation. The latter two scenarios are continued beyond the year 2100 with forcing kept constant (committed climate change as it is defined in Box TS.9). An additional experiment, in which the forcing is kept at the year 2000 level is also shown (orange).

The trend speaks for itself. Predicted warming has not occurred and the actual temperatures are all more than one standard deviation below even the fixed 2000 CO2 levels (orange curve). All 6 annual temperatures lie below all scenario curves. The quoted error on a single measurement is 0.05 deg.C so we can now calculate the probability of these measurements  being a statistical fluctuation.

year sigma     probability
2006   1        0.32
2007   3        0.001
2008   4        0.0001
2009   2        0.04
2010   2        0.04
2011   6        <0.00001

The total probability that IPCC predictions are correct but the data points are just a fluctuation is vanishingly small ~ 10^-14 ! It is therefore possible to state with over 90% confidence that the IPCC 2007 model predictions are incorrect and exaggerate any warming. Will we have to wait another year for the 2012 data to be published before the IPCC admit that they have simply got it wrong?