Home North pole ice It’s not the heat, it’s the damage

It’s not the heat, it’s the damage


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The hot summer of 2021 is hammering home what we know and what we don’t know about climate change. It can be summed up in two paragraphs, neither of which is heartwarming.

1. We understand how much the temperature will rise if we continue to pump greenhouse gases into the atmosphere. This has been the central scientific concern for more than three decades, translating gigatons of carbon and methane into degrees of warming, and researchers are more or less right, from original predictions by James Hansen in the late 1980s to secret reports. according to which Exxon scientists provided frameworks during the same period. The precision of these estimates increases as we learn; This year’s new data on the effect of clouds, for example, clearly shows that they will do more to warm the earth than to cool it, which was one of the last remaining uncertainties. Simply put, doubling the amount of pre-Industrial Revolution greenhouse gases in the atmosphere would raise the earth’s temperature by about three degrees Celsius. This is what we are doing right now. That’s a scary high number.

2. We understand much less the damage these three degrees would do. It’s difficult to build computer models powerful enough to calculate the increase in temperature, but infinitely more difficult to predict the resulting havoc, because it’s a function of many things we can’t really measure. Some of these things are human: how will we as societies react to a disaster? (It might not be a good sign that many Americans worried about climate change are now heading to a survival school. In the words of one participant, “Now I’m like, ‘Oh, my God, I can set up a mud hut. ”). But many of these unpredictables are physical. Consider the jet stream: it clearly governs a lot about life in our hemisphere, but until recently few scientists have suggested that it could fundamentally change its behavior. Now, the melting of the Arctic has reduced the temperature gradient between the equator and the North Pole, and this reduction, in turn, appears to be slowing the jet stream, causing events such as devastating flooding in Europe. “We had a low pressure field over central Europe that was not moving, it was persistent and long lasting,” said a researcher from the Potsdam Institute for Climate Impact Research. Financial Time. “Normally our weather conditions were moving from west to east,” but “this engine” – the temperature gradient – “that we have is weakened”.

There are a lot of other systems that we are now starting to really worry about. The marine equivalent, the Gulf Stream, slows down quite suddenly, probably because fresh water pours out of the Greenland ice sheet and disrupts the differences in density that drive large ocean currents. We don’t know how close we are to poorly understood “tipping points” that could quickly turn the Amazon from rainforest to savannah. Kelp forests, the “rainforests of the sea” that cover a quarter of the planet’s coastline, appear to have shrunk by a third over the past decade. In fact, name a large physical system on the planet, and there is a good chance that it is now in a chaotic flow.

The lessons to be learned from all of this are not new. The first is that we need to reduce greenhouse gas emissions at an incredible rate, in order to reduce the total amount of warming, and therefore reduce the pressures and jostling on basic physical systems. The other is that we need to prepare ourselves and our civilizations for massive upheaval.

But we really need to make ourselves think about what it means to fly blindly in the future. We focus a lot on increasing the temperature, as this is a knowable number; our political, diplomatic and economic debates are conducted as if they were the essentials. But the scariest question is what each tenth of a degree will do. We don’t know, and we can’t really know: these fundamental systems are clearly intertwined, and their failures are likely to cascade.

When a team of researchers from the Massachusetts Institute of Technology published their landmark study “The Limits to Growth” in 1972, the strangest part of their prediction was that the collapse of society, predicted for some time to come. decades, would occur from the somewhat opaque interactions of the world’s systems. That is, the MIT team did not name a single cause that would inflict fatal damage to the planet – their computer modeling (necessarily crass, at the time) simply showed that beyond ‘at some point, chaos would ensue. Since then, a few people have followed their predictions; a self-paced KPMG accounting firm released a recent assessment, and it shows that we are following some of their predicted scenarios too closely.

In that kind of world, we should hit the brakes and make sure the seat belts and airbags are working, not to mention an ambulance standing next to it. We are not an accident about to happen – from now on we are an accident happening.

Pass the microphone

WJ Herbert’s next collection of poems, “Dear Specimen,” has been chosen by Kwame Dawes for the National Poetry Series and will be published by Beacon Press in the fall. A five-part series of interwoven poems from a dying parent to his daughter, he examines “the human capacity for grief, guilt and love, asking: as a species, do we deserve to survive?” Herbert lives in Kingston, New York, and Portland, Maine; our conversation has been edited for length and clarity.

You have thought of the other creatures we share the earth with, many of whom could be made to become extinct during this century. How is this conversation?