A warming surge, predicted by new climate models, means even less time to prevent a 1.5-2C world.

Like walking through a minefield.

“The further we go the more explosions we are likely to set off: 1.5C is safer than 2C, 2C is safer than 2.5C, 2.5C is safer than 3C, and so on. Stabilizing global warming at 1.5C will be extremely difficult if not impossible at this point,”  Michael Mann, climatologist, and director of the Earth System Science Center at Penn State.

Massive computer systems have been used for over forty years to predict how fast human-caused emissions will heat the world. According to Science Magazine, these models have been rather constant over the decades. But no more, next-generation science models developed for the 2021 United Nations assessment on global warming, show a new trend.

Science magazine reports these new models “are running hotter than they have in the past. Soon the world could be, too”.

Paul Voosen writes:

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 Nations’s Intergovernmental Panel on Climate Change (IPCC). But the trend “is definitely real. There’s no question,” says Reto Knutti, a climate scientist at ETH Zurich in Switzerland. “Is that realistic or not? At this point, we don’t know.”

That’s 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 levels—a 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 “it’s 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 that’s more pessimistic than it was in the past.”

Jeff Goodell shares the bitter truth below. He makes the case that we need to “embrace” the changes that are on our doorstep.

Such comparisons may help the modelers respond to the IPCC authors, who are peppering them with questions about the higher sensitivity, Gettelman says. “They’re asking us, what’s going on?” he says. “They’re pushing people. They’ve got about a year to figure this out.”

In assessing how fast climate may change, the next IPCC report probably won’t lean as heavily on models as past reports did, says Thorsten Mauritsen, a climate scientist at Stockholm University and an IPCC author. It will look to other evidence as well, in particular, a large study in preparation that will use ancient climates and observations of recent climate change to constrain sensitivity. IPCC is also not likely to give projections from all the models equal weight, Fyfe adds, instead weighing results by each model’s credibility.

Even so, the model results remain disconcerting, Gettelman says. The planet is already warming faster than humans can cope with, after all. “The scary part is these models might be right,” he says. “Because that would be pretty devastating.”

Not all scientists agree with the models, but they all believe that the world is getting hotter. The scientists are just disagreeing around the edges of scientifically known facts.

We Have Five Years To Save Ourselves From Climate Change, Harvard Scientist Says

People have the misapprehension that we can recover from this state just by reducing carbon emissions, Anderson said in an appearance at the University of Chicago. Recovery is all but impossible, he argued, without a World War II-style transformation of industry—an acceleration of the effort to halt carbon pollution and remove it from the atmosphere, and a new effort to reflect sunlight away from the earth's poles.

This has to be done, Anderson added, within the next five years.

"The chance that there will be any permanent ice left in the Arctic after 2022 is essentially zero," Anderson said, with 75 to 80 percent of permanent ice having melted already in the last 35 years.

"Can we lose 75-80 percent of permanent ice and recover? The answer is no."

The answer is no in part because of what scientists call feedbacks, some of the ways the earth responds to warming. Among those feedbacks is the release of methane currently trapped in permafrost and under the sea, which will exacerbate warming. Another is the pending collapse of the Greenland ice sheet, which Anderson said will raise sea level by 7 meters (about 23 feet).

"People at this point haven't come to grips with the irreversibility of this sea-level rise problem," Anderson said, displaying a map that shows the site of Harvard's new $10 billion Allston campus inundated after 3 meters of sea-level rise. He followed that map with images of Manhattan shrunken by encroaching waters and Florida missing its southern tip.

"When you look at the irreversibility and you study the numbers, this along with the moral issue is what keeps you up at night," Anderson said.

Emphasis mine. This news is devastating but not surprising. We are living this nightmare now, albeit just the beginning, and global warming will only get worse. There is no going back.