COP26 Pledges will have Catastrophic Consequences, says Ex-NASA Climate Chief – Byline Timeshttps://bylinetimes.com/2022/02/16/cop26-pledges-will-have-catastrophic-consequences-says-ex-nasa-climate-chief/The academic argues that, within the next six months, there will be a rise in the 12-month running-mean temperature due to the El Nino cycle, which will “be accelerated by Earth’s largest energy imbalance in the past half century”.
By the second half of the 2020s, a further 0.1C will be added due to increased solar irradiance. The combined effect means that “there is now no chance whatever of keeping global warming below 1.5°C,” he says.
Prof Hansen has also criticised COP26 President Alok Sharma who, after the summit in Glasgow, said “we can say with credibility that we have kept 1.5°C degrees within reach, but its pulse is weak”.
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Prof Hansen pointed to a range of evidence consistent with an imminent rapid sea level rise, including a brief time of rapid coral reef ‘backstepping’, and the vulnerability of the West Antarctic and later the East Antarctic ice sheets. “The eventual sea level rise for global temperatures expected by the middle of this century is at least 10 to 15 meters,” he concludes.
Major cities at risk of being submerged in this way include New York City, Mumbai, Lagos, Shanghai, Miami, Dhaka and Tokyo.
“The fact is that ice sheet disintegration is an exponential process with a characteristic time-scale (doubling or e-folding time that characterises exponential growth) of 10 to 20 years at maximum,” says Prof Hansen’s memo. “That statement is proven by the fact that sea level rise of several meters per century has occurred many times in Earth’s history.”
The UN IPCC has under-estimated this danger due to simplistic ice sheet models that “are unable to reproduce rapid changes of sea level that occur repeatedly in the paleoclimate record,” Hansen states.
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Business as usual’ growth of greenhouse gases, he further argues, “likely will cause shut-down of the overturning North Atlantic and Southern Ocean overturning circulations by the middle of this centuryBoth circulation systems play a critical role in regulating the stability of the Earth’s climate system. Recent models show that their shut-down could bring extreme cold to Europe and parts of North America, raise sea levels along the US East Coast, disrupt seasonal monsoons that provide water to much of the world, and further endanger the Amazon rainforest and Antarctic ice sheets.
According to Prof Hansen, the most important effect may be reducing heat transfer from the southern to northern hemispheres, which would increase warming of the Southern Ocean at depth, accelerating Antarctic ice melt and driving sea level rise.