Environment & Energy
Related: About this forumNewest Climate Models Show Equilibrium Returning At 5C Increase, Not 2-4.5C; IOW, Getting Hotter Yet
For nearly 40 years, the massive computer models used to simulate global climate have delivered a fairly consistent picture of how fast human carbon emissions might warm the world. But a host of global climate models developed for the United Nationss next major assessment of global warming, due in 2021, are now showing a puzzling but undeniable trend. They are running hotter than they have in the past. Soon the world could be, too.
In earlier models, doubling atmospheric carbon dioxide (CO2) over preindustrial levels led models to predict somewhere between 2°C and 4.5°C of warming once the planet came into balance. But in at least eight of the next-generation models, produced by leading centers in the United States, the United Kingdom, Canada, and France, that equilibrium climate sensitivity has come in at 5°C or warmer. Modelers are struggling to identify which of their refinements explain this heightened sensitivity before the next assessment from the United Nationss Intergovernmental Panel on Climate Change (IPCC). But the trend is definitely real. Theres no question, says Reto Knutti, a climate scientist at ETH Zurich in Switzerland. Is that realistic or not? At this point, we dont know.
Thats an urgent question: If the results are to be believed, the world has even less time than was thought to limit warming to 1.5°C or 2°C above preindustrial levelsa threshold many see as too dangerous to cross. With atmospheric CO2 already at 408 parts per million (ppm) and rising, up from preindustrial levels of 280 ppm, even previous scenarios suggested the world could warm 2°C within the next few decades. The new simulations are only now being discussed at meetings, and not all the numbers are in, so its a bit too early to get wound up, says John Fyfe, a climate scientist at the Canadian Centre for Climate Modelling and Analysis in Victoria, whose model is among those running much hotter than in the past. But maybe we have to face a reality in the future thats more pessimistic than it was in the past.
Many scientists are skeptical, pointing out that past climate changes recorded in ice cores and elsewhere dont support the high climate sensitivitynor does the pace of modern warming. The results so far are not sufficient to convince me, says Kate Marvel, a climate scientist at NASAs Goddard Institute for Space Studies in New York City. In the effort to account for atmospheric components that are too small to directly simulate, like clouds, the new models could easily have strayed from reality, she says. Thats always going to be a bumpy road. Builders of the new models agree. Scientists at the National Oceanic and Atmospheric Administrations Geophysical Fluid Dynamics Laboratory (GFDL) in Princeton, New Jerseythe birthplace of climate modelingincorporated a host of improvements in their next-generation model. It mimics the ocean in fine enough detail to directly simulate eddies, honing its representation of heat-carrying currents like the Gulf Stream. Its rendering of the El Niño cycle, the periodic warming of the equatorial Pacific Ocean, looks dead on, says Michael Winton, a GFDL oceanographer who helped lead the models development. But for some reason, the world warms up faster with these improvements. Why? Were kind of mystified, Winton says. Right now, he says, the models equilibrium sensitivity looks to be 5°C.
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https://www.sciencemag.org/news/2019/04/new-climate-models-predict-warming-surge
Ghost Dog
(16,881 posts)assuming corporations very soon stop pumping extra CO2 into the atmosphere. And, what, assuming current global population growth trends remain the same? Whole societies will not crash and burn?
NNadir
(33,528 posts)408 is so yesterday.
NickB79
(19,253 posts)hatrack
(59,587 posts)Other all-time daily records by year:
2018 - 3
2017 - 2
2016 - 2
2015 - 1
https://www.co2.earth/daily-co2
NNadir
(33,528 posts)...off the coast of Massachusetts on the benthic ecosystem to stick steel posts attached to giant bird grinders that will produce electricity whenever the wind is blowing, which is reported to not be 100% of the time, but who's counting?
Gas is "cheap," and we can burn it whenever the wind isn't blowing. Anyone who cares about the gas waste is not going with the program.
Stuff like that has been saving the day for my whole adult life, and I'm not young. I'm sure these 414+ numbers - I seem to have missed a few - are not as important as the concrete, steel, diesel ships and bird grinders which are very, very, very, very cheerful.