However, James Hansen was also the lead author on a previous study from the NASA Goddard Institute for Space Studies (GISS) projecting global warming in 1981, which readers may have surmised from my SkS ID, is as old as I am. This ancient projection was made back when climate science and global climate models were still in their relative infancy, and before global warming had really begun to kick in.
As Hansen et al. described it,
"The global temperature rose by 0.2°C between the middle 1960's and 1980, yielding a warming of 0.4°C in the past century.
This temperature increase is consistent with the calculated greenhouse effect due to measured increases of atmospheric carbon dioxide.
Variations of volcanic aerosols and possibly solar luminosity appear to be primary causes of observed fluctuations about the mean trend of increasing temperature.
It is shown that the anthropogenic carbon dioxide warming should emerge from the noise level of natural climate variability by the end of the century, and there is a high probability of warming in the 1980's."
This analysis from Hansen et al. (1981) shows a good understanding of the major climate drivers, even 31 years ago. The study was also correct in predicting warming during the remainder of the 1980s. The Skeptical Science Temperature Trend Calculator reveals that the trend from 1981 to 1990 was 0.09 +/- 0.35°C per decade - not statistically significant because this is such a short timeframe, but most likely a global warming trend nonetheless.
Global Warming Skeptics Stuck in 1981?
Hansen et al. noted that the human-caused global warming theory had difficulty gaining traction because of the mid-century cooling, which ironically is an argument still used three decades later to dispute the theory:
"The major difficulty in accepting this theory has been the absence of observed warming coincident with the historic CO2 increase. In fact, the temperature in the Northern Hemisphere decreased by about 0.5°C between 1940 and 1970, a time of rapid CO2 buildup."
However, as we will see in this post, despite these doubts, the global warming projections in Hansen et al. (1981), based on the human-caused global warming theory, were uncannily accurate.