Climate ‘tipping point’ theories called into question by new study – too many uncertainties 

A portion of the Atlantic meridional overturning circulation (AMOC) [image credit: R. Curry, Woods Hole Oceanographic Institution @ Wikipedia]

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The study knocks back some vague assertions from previous climate modelling efforts, that attempted to invent so-called tipping points to promote climate alarm and capture headlines in the usual media outlets. Over-reliance on questionable assumptions and use of low quality data are among the issues mentioned. Faulty AMOC predictions are highlighted as an example of the difficulties.
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A new study published in Science Advances reveals that current uncertainties are too large to accurately predict exact tipping times for critical Earth systems components like the Atlantic Meridional Overturning Circulation (AMOC), polar ice sheets, or tropical rainforests, says Eurekalert.

These tipping events, which might unfold in response to human-caused global warming, are characterized by rapid, irreversible climate changes with potentially catastrophic consequences.

However, as the new study shows, predicting when these events will occur is more difficult than previously thought.

Climate scientists from the Technical University of Munich (TUM) and the Potsdam Institute for Climate Impact Research (PIK) have identified three primary sources of uncertainty.

First, predictions rely on assumptions regarding the underlying physical mechanisms, as well as regarding future human actions to extrapolate past data into the future. These assumptions can be overly simplistic and lead to significant errors.

Second, long-term, direct observations of the climate system are rare and the Earth system components in question may not be suitably represented by the data.

Third, historical climate data is incomplete. Huge data gaps, especially for the longer past, and the methods used to fill these gaps can introduce errors in the statistics used to predict possible tipping times.

To illustrate their findings, the authors examined the AMOC, a crucial ocean current system. Previous predictions from historical data suggested a collapse could occur between 2025 and 2095. However, the new study revealed that the uncertainties are so large that these predictions are not reliable.

Using different fingerprints and data sets, predicted tipping times for the AMOC ranged from 2050 to 8065 even if the underlying mechanistic assumptions were true. Knowing that the AMOC might tip somewhere within a 6000-year window isn’t practically useful, and this large range highlights the complexity and uncertainty involved in such predictions.

The researchers conclude that while the idea of predicting climate tipping points is appealing [Talkshop comment – to media, Hollywood, alarmists etc.], the reality is fraught with uncertainties.

Full article here.
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Image: A portion of the Atlantic meridional overturning circulation (AMOC) [credit: R. Curry, Woods Hole Oceanographic Institution @ Wikipedia]