New Study: Greenhouse Gas Theory may need ‘deep re-examination’
Global warming over the past 15 years suggests that climate models “are very likely flawed,” a group of Italian scientists claimed in a study.
The study comes amid mounting evidence that climate model predictions have increasingly diverged from real-world observations during the so-called “hiatus” in warming during the 21st century.
Scientists often argue that global temperature observations are well within climate model predictions — albeit at the lower end. The recent spike in global average temperature in 2015 and 2016, scientists say, brought observations back in line with modeled predictions.
However, meteorologist Nicola Scafetta and his co-authors point out that the recent spike in global temperatures was brought on by an incredibly strong El Nino warming event — a naturally-occurring ocean cycle.
Correcting for the recent El Nino shows “the temperature trend from 2000 to 2016 clearly diverges from the general circulation model (GCM) simulations,” Scafetta and his co-authors wrote in their study.
“Thus, all evidences suggest that the IPCC GCMs at least increase twofold or even triple the real anthropogenic warming,” the scientists wrote. “The [greenhouse gas] theory might even require a deep re-examination.”
“The models now available, like the GCMs, are not yet completely reliable and need much more work,” they wrote.
Scafetta’s study comes on the heels of another that found models used by the Intergovernmental Panel on Climate Change (IPCC) overpredicted the amount of global warming.
That study, published in the journal Nature Geoscience, got significant media attention for its mainline finding that there was still time to meet the global warming target laid out in the Paris climate accord.
“We haven’t seen that rapid acceleration in warming after 2000 that we see in the models. We haven’t seen that in the observations,” co-author Myles Allen, a geosystem scientist at the University of Oxford, told The Times.
Some scientists were quick to pounce on Allen and co-author’s work. Berkeley Earth scientist Zeke Hausfather argued that the models matched temperature observations “quite well.”
But even Hausfather’s comparison of models to observations shows the recent El Nino boosted temperatures to the upper half of the climate model range. Before that, global average temperature ran well below the model mean.
Global warming skeptics argued for years that the models were showing more warming than actual observations. Cato Institute scientists Patrick Michaels and Chip Knappenberger showed that the climate models have been over-hyping warming for decades.
Scientist John Christy of the University of Alabama-Huntsville has testified before Congress on the matter. His research shows that climate models predicted 2.5 times more warming in the bulk atmosphere than has been observed.
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