Whenever a new study is released on the environment predicting the devastating nature of the future of global warming, skeptics and doubters can rightfully wonder: How accurate are these studies at predicting the future? While only time can tell us how accurate the current studies are, a quick look into the past studies can show us how accurate scientists have been.
And that’s exactly what a recent study tells us. Twenty-two years ago, climate scientists accurately predicted the effects of warming over a span of twenty years. The report, issued by the Intergovernmental Panel on Climate Change (IPCC) in 1990, used simple computer models, in comparison to the ones currently used, to simulate the future. If these simplistic computer models managed to be accurate, then imagine the level of accuracy of the current models used.
The authors write: “It contained a prediction of the global mean temperature trend over the 1990–2030 period that, halfway through that period, seems accurate. This is all the more remarkable in hindsight, considering that a number of important external forcings were not included. So how did this success arise? In the end, the greenhouse-gas-induced warming is largely overwhelming the other forcings, which are only of secondary importance on the 20-year timescale.”
The authors of the report, published online Dec. 9 in the journal Nature Climate Change, write that scientists were unable to estimate the climate-altering events that would take place over two decades, including: the volcanic eruption of Mt. Pinatubo in 1991, which spewed sunlight-blocking particles into the atmosphere, as well as the collapse of industry in the Soviet Union or the economic growth of China, Stone and David Frame, of Victoria University Wellington in New Zealand.
“The prediction basically depended on how much carbon dioxide was already in the atmosphere, and that has been what’s important,” said one of the researchers behind the current analysis, Dáithí Stone.
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The 1990 report offered a best estimate of an increase of 2 degrees Fahrenheit (1.1 degrees Celsius) by 2030, which at the halfway point in 2010, translates to warming of 1 degree F (0.55 degrees C).
Stone and Frame compared this expected increase to two sets of temperature records for 1990 through 2010, which showed increases of 0.63 degrees F (0.35 degrees C) and 0.7 degrees F (0.39 degrees C), respectively.
The 1990 prediction did require an adjustment, since it did not take into account natural variability — which includes the chaotic nature of weather as well as longer-term natural patterns, such as the El Niño/La Niña cycle.
When Frame and Stone took natural variability into account, they found that the observed warming was consistent with the IPCC’s best estimate for warming.