Figure 1:
Temperature prognosis by the Hansen Group from 1988. The different scenarios assume 1.5% CO2 increase (blue), fixed CO2 emissions (green) and stopped CO2 emissions (red). In reality CO2 emissions have increased about 2.5% per year, which would be more than depicted the the blue curve scenario. The black curve is the actual temperature (smoothed 5-year mean). The Hansen-Model overestimated the temperature by 1,9°C and is thus a full 150% off. Graph supplemented as to Hansen et al. (1988).
At their Die kalte Sonne website, Professor Fritz Vahrenholt and Dr. Sebastian Lüning present a guest post by Prof. Jan-Erik Solheim, who comments on the huge divergence between Hansen’s 1988 forecast and actual observations. I’ve translated his guest post in English:
What ever became of James Hansen’s 1988 temperature forecast? Time for an evaluation by Prof. Jan-Erik Solheim
One of the most important publications on “dangerous man-made climate change” is one by James Hansen and his colleagues in the year 1988 which appeared in the Journal of Geophysical Research. The title of the publication: Global Climate Changes as Forecast by Goddard Institute for Space Studies Three-Dimensional Model.
Click source to read FULL report from P. Gosselin