A scientific hypothesis is tested by its predictive powers. Scientists reason: if this theory is correct, then X should be the case. They test for X; if they find X to be true, it tends to confirm the theory. If X is not the case, the theory is disproved. Some of a theory’s implications may relate to the future, and thus can only be tested over time. The anthropogenic global warming theory has been with us for quite a while now–I first learned about it circa 1970–so how have its predictions fared over time?
We have written a number of times about James Hansen, one of the leading global warming alarmists. In 1988, he authored one of the most influential alarmist papers, titled “Global climate change, according to the prediction of the Goddard Institute for Space Studies.” Hansen and his colleagues modeled the global temperature impact of varying levels of future CO2 emissions. This chart, from Watts Up With That, summarizes Hansen’s 1988 predictions, compared with actually observed temperatures. Briefly, Hansen’s prediction was off by 150%.
This is the explanation of the lines on the chart:
Figure 1: Temperature forecast Hansen’s group from the year 1988. The various scenarios are 1.5% CO 2 increase (blue), constant increase in CO 2 emissions (green) and stagnant CO 2 emissions (red). In reality, the increase in CO 2 emissions by as much as 2.5%, which would correspond to the scenario above the blue curve. The black curve is the ultimate real-measured temperature (rolling 5-year average). Hansen’s model overestimates the temperature by 1.9 ° C, which is a whopping 150% wrong.
While global warming alarmists cloak themselves in the mantle of science, the truth is that there is nothing scientific about their enterprise. The models that are the sole basis for global warming alarmism have been proved conclusively to be wrong. That really is all that needs to be said about the matter. The fact that alarmists and their supporters in the media and in politics continue to try to foist discredited theories onto the public shows that their real interest is not science, but politics and power.