Only speculated on several years ago. Feedback Loops are things that speed up or slow down climate change. The two that concern us here are the most obvious, clouds and ice shrinkage. The more water in the atmosphere the more clouds and the hotter the earth – the more water. But the killer one is, ice is very very reflective. What replaces it it is not and in the case of “dark” water, it is incredibly absorptive. The question has always been when would they kick in? I always said we would know when it was too late. Here we are.
Climate Models Are Running Red Hot, and Scientists Don’t Know Why
The simulators used to forecast warming have suddenly started giving us less time.
There are dozens of climate models, and for decades they’ve agreed on what it would take to heat the planet by about 3° Celsius. It’s an outcome that would be disastrous—flooded cities, agricultural failures, deadly heat—but there’s been a grim steadiness in the consensus among these complicated climate simulations.
Then last year, unnoticed in plain view, some of the models started running very hot. The scientists who hone these systems used the same assumptions about greenhouse-gas emissions as before and came back with far worse outcomes. Some produced projections in excess of 5°C, a nightmare scenario.
The scientists involved couldn’t agree on why—or if the results should be trusted. Climatologists began “talking to each other like, ‘What’d you get?’, ‘What’d you get?’” said Andrew Gettelman, a senior scientist at the National Center for Atmospheric Research in Boulder, Colorado, which builds a high-profile climate model.
“The question is whether they’ve overshot,” said Mark Zelinka, staff scientist at Lawrence Livermore National Laboratory. Researchers are starting to put together answers, a task that will take months at best, and there’s not yet agreement on how to interpret the hotter results. The reason for worry is that these same models have successfully projected global warming for a half century. Their output continues to frame all major scientific, policy and private-sector climate goals and debates, including the sixth encyclopedic assessment by the UN’s Intergovernmental Panel on Climate Change due out next year. If the same amount of climate pollution will bring faster warming than previously thought, humanity would have less time to avoid the worst impacts.
Go there and read. More next week.