Early climate modelers got global warming right, new report finds
https://news.berkeley.edu/2019/12/04/early-climate-modelers-got-global-warming-right-new-report-finds
Source: By Robert Sanders, UC Berkeley News.
Excerpt: Climate skeptics have long raised doubts about the accuracy of computer models that predict global warming, but it turns out that most of the early climate models were spot-on, according to a look-back by climate scientists at the University of California, Berkeley, Massachusetts Institute of Technology and NASA. Of 17 climate models published between the early 1970s and the late 2000s, 14 were quite accurate in predicting the average global temperature in the years after publication, said Zeke Hausfather, a doctoral student in UC Berkeley’s Energy and Resources Group and lead author of a new paper analyzing the models. “The real message is that the warming we have experienced is pretty much exactly what climate models predicted it would be as much as 30 years ago,” he said. “This really gives us more confidence that today’s models are getting things largely right as well.” The results were published today in the journal Geophysical Research Letters and will appear, with Hausfather as a contributing author, as part of the first chapter of the next climate assessment by the Intergovernmental Panel on Climate Change, due out in 2021. ...One of the iconic climate models, and one that first brought the issue of climate change to broad public attention, was published by James Hansen of NASA in 1988. However, his predictions for temperatures after 1988 were 50% higher than the actual global mean temperatures in those years. That is in part because Hanson did not anticipate the Montreal Protocol, a treaty that went into effect in 1989 and which banned chlorofluorocarbons, which are potent greenhouse gases. His estimates of future methane emissions were also off, Hausfather said. “If you account for these and look at the relationship in his model between temperature and radiative forcing, which is CO2 and other greenhouse gases, he gets it pretty much dead on,” he said. “So the physics of his model was right. The relationship between how much CO2 there is in the atmosphere and how much warming you get, was right. He just got the future emissions wrong.” Most of the other models also accurately predicted the average temperature when they were given real-world greenhouse gas levels....
Source: By Robert Sanders, UC Berkeley News.
Excerpt: Climate skeptics have long raised doubts about the accuracy of computer models that predict global warming, but it turns out that most of the early climate models were spot-on, according to a look-back by climate scientists at the University of California, Berkeley, Massachusetts Institute of Technology and NASA. Of 17 climate models published between the early 1970s and the late 2000s, 14 were quite accurate in predicting the average global temperature in the years after publication, said Zeke Hausfather, a doctoral student in UC Berkeley’s Energy and Resources Group and lead author of a new paper analyzing the models. “The real message is that the warming we have experienced is pretty much exactly what climate models predicted it would be as much as 30 years ago,” he said. “This really gives us more confidence that today’s models are getting things largely right as well.” The results were published today in the journal Geophysical Research Letters and will appear, with Hausfather as a contributing author, as part of the first chapter of the next climate assessment by the Intergovernmental Panel on Climate Change, due out in 2021. ...One of the iconic climate models, and one that first brought the issue of climate change to broad public attention, was published by James Hansen of NASA in 1988. However, his predictions for temperatures after 1988 were 50% higher than the actual global mean temperatures in those years. That is in part because Hanson did not anticipate the Montreal Protocol, a treaty that went into effect in 1989 and which banned chlorofluorocarbons, which are potent greenhouse gases. His estimates of future methane emissions were also off, Hausfather said. “If you account for these and look at the relationship in his model between temperature and radiative forcing, which is CO2 and other greenhouse gases, he gets it pretty much dead on,” he said. “So the physics of his model was right. The relationship between how much CO2 there is in the atmosphere and how much warming you get, was right. He just got the future emissions wrong.” Most of the other models also accurately predicted the average temperature when they were given real-world greenhouse gas levels....