'Sooner than expected' — 'Faster than previously thought' — 'Worse than was predicted' — Why do we keep hearing this over and over?

As the article excerpted below suggests, it's due to the difficulty of assessing risks and judging odds when climate tipping points are involved... 
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Many current changes are at the upper limit of scientific projections, and sometimes beyond them. This year, heat records have been smashed, and global ocean surface temperatures are at the top of the projected range. Other events, including sea-surface warming in the North Atlantic and the eye-watering decline of sea ice around Antarctica, have simply astounded scientists.

“On the one hand, we knew these things were going to happen. These have been the predictions for a long time,” Claudia Tebaldi, a scientist at the Pacific Northwest National Laboratory, told the Washington Post earlier this year. “But this year, in particular, has seemed so extreme. The size of the anomalies is surprising.”

This year, the Atlantic Meridional Overturning Circulation, or AMOC, has become a flashpoint for debating how to express and explain climate risk. This phenomenon refers to the complex web of ocean currents covering the breadth and length of the Atlantic, from the Southern Ocean to the Arctic, which help regulate global weather patterns. 

This system has already slowed by 15% since the mid-20th century, and in 2021 researchers concluded there is “strong evidence that the AMOC is indeed approaching a critical, bifurcation-induced transition” (in other words, a tipping point) but the timing was unclear.

Stefan Rahmsdorf, a professor of physics of the oceans at Potsdam University in Germany, said that while there is still “large uncertainty where the tipping point of the AMOC is, the scientific evidence now is that we can’t even rule out crossing a tipping point in the next decade or two. The conservative IPCC estimate, based on climate models which are too stable, is in my view outdated now.”
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There's much more in this highly informative piece from the Bulletin of the Atomic Scientists, and I suggest you read the whole thing.

FULL ARTICLE -- https://thebulletin.org/2023/09/betting-against-worst-case-climate-scenarios-is-risky-business/

#Environment #Climate #ClimateChange #ClimateCrisis #ClimateEmergency