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This time for sure... again

11 Dec 2019 | News Roundup

The latest news on the climate front is that all the models you thought weren’t working secretly are. An article in Science, published by the American Association for the Advancement of Science (and who could oppose that?) says “Even 50-year-old climate models correctly predicted global warming”. Which they did… once their inaccurate predictions were kluged to fit known data. Alas, when asked to predict the future not the past, even the newest and best face-plant.

The article’s author, Warren Cornwall, admits up front that “Climate change doubters have a favorite target: climate models. They claim that computer simulations conducted decades ago didn’t accurately predict current warming, so the public should be wary of the predictive power of newer models.” And certainly climate change alarmists have jumped to embrace his claim that “Now, the most sweeping evaluation of these older models—some half a century old—shows most of them were indeed accurate.”

Cornwall reports on a study by Zeke Hausfather and others looking at 17 forecasts by 14 models, some so creaky they used punch cards and their results had to be scanned off printed charts because the actual data was beyond recovery. Whereas today, Cornwall intones, “Mainframe computers driven by paper punch cards have given way to supercomputers running trillions of calculations in 1 second. Modern models account for myriad interactions, including ice and snow, changes in forest coverage, and cloud formation—things that early modelers could only dream of doing.”

You’d wonder why it’s even exciting, since according to Hausfather according to Cornwall, even back in the clunky old days “Most of the models accurately predicted recent global surface temperatures, which have risen approximately 0.9°C since 1970. For 10 forecasts, there was no statistically significant difference between their output and historic observations, the team reports today in Geophysical Research Letters.” Wow. Even the old models worked. Silly doubters. It’s a miracle.

Uh except for one thing. As Cornwall admits, “Seven older models missed the mark by as much as 0.1°C per decade. But the accuracy of five of those forecasts improved enough to match observations when the scientists adjusted a key input to the models: how much climate-changing pollution humans have emitted over the years. That includes greenhouse gases and aerosols, tiny particles that reflect sunlight.” Abracadabra.

Hang on a sec. The problem is that the models predicted something would happen and it didn’t. So then the programmers went back and said OK, if we assume there was this much aerosol or other pollution and we also assume it causes this much cooling, then look, we can push the prediction around until it fits the known data.

Clever, to be sure. But not wise. As John von Neumann once said, “With four parameters I can fit an elephant, and with five I can make him wiggle his trunk.” And all the tweaked models prove is that if you add some more compensating assumptions to your previous failed assumptions you can predict the past. As to the future, which is what matters, Cornwall concedes way down deep that “even today’s computer programs have some uncertainties.” But he quotes a climate modeler that climate modelers are now great and know everything: “’We know enough to trust our climate models” and their message that urgent action is needed, [“Piers Forster, an expert in climate modeling at the United Kingdom’s University of Leeds”] says.”

Not true. The new models still run hot when asked about the future. Often very hot. Like the rhetoric, even hotter than the old stuff. And while it may be possible to correct their predictions once we know what corrections are needed, they still can’t do their #onejob, namely tell us what’s going to happen.

So no. The old models didn’t work and neither do the new ones. They all predict runaway warming, and it’s not happening.

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