Guest essay by Eric Worrall

In the face of a complete lack of problems to date, climate scientists appear to be amping up the “woo woo” factor of predicted climate catastrophes. But they are not adding a firm timescale, and refuse to call their warnings “predictions”.

Climate tipping points could topple like dominoes, warn scientists

Analysis shows significant risk of cascading events even at 2C of heating, with severe long-term effects

Damian Carrington
Environment editor @dpcarrington
Fri 4 Jun 2021 02.34 AEST

Ice sheets and ocean currents at risk of climate tipping points can destabilise each other as the world heats up, leading to a domino effect with severe consequences for humanity, according to a risk analysis.

Tipping points occur when global heating pushes temperatures beyond a critical threshold, leading to accelerated and irreversible impacts. Some large ice sheets in Antarctica are thought to already have passed their tipping points, meaning large sea-level rises in coming centuries.

The new research examined the interactions between ice sheets in West Antarctica, Greenland, the warm Atlantic Gulf Stream and the Amazon rainforest. The scientists carried out 3m computer simulations and found domino effects in a third of them, even when temperature rises were below 2C, the upper limit of the Paris agreement.

“We provide a risk analysis, not a prediction, but our findings still raise concern,” said Prof Ricarda Winkelmann, at the Potsdam Institute for Climate Impact Research (PIK) in Germany. “[Our findings] might mean we have less time to reduce greenhouse gas emissions and still prevent tipping processes.”

“The study suggests that below 2C of global warming – ie in the Paris agreement target range – there could still be a significant risk of triggering cascading climate tipping points,” said Lenton. “What the new study doesn’t do is unpack the timescale over which tipping points changes and cascades could unfold – instead it focuses on the eventual consequences. The results should be viewed as ‘commitments’ that we may be making soon to potentially irreversible changes and cascades, leaving as a grim legacy to future generations.”

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The abstract of the study;

Interacting tipping elements increase risk of climate domino effects under global warming

Nico Wunderling1,2,3, Jonathan F. Donges1,4, Jürgen Kurths1,5, and Ricarda Winkelmann

Received: 26 Mar 2020 – Discussion started: 03 Apr 2020 – Revised: 15 Mar 2021 – Accepted: 07 Apr 2021 – Published: 03 Jun 2021

With progressing global warming, there is an increased risk that one or several tipping elements in the climate system might cross a critical threshold, resulting in severe consequences for the global climate, ecosystems and human societies. While the underlying processes are fairly well-understood, it is unclear how their interactions might impact the overall stability of the Earth’s climate system. As of yet, this cannot be fully analysed with state-of-the-art Earth system models due to computational constraints as well as some missing and uncertain process representations of certain tipping elements. Here, we explicitly study the effects of known physical interactions among the Greenland and West Antarctic ice sheets, the Atlantic Meridional Overturning Circulation (AMOC) and the Amazon rainforest using a conceptual network approach. We analyse the risk of domino effects being triggered by each of the individual tipping elements under global warming in equilibrium experiments. In these experiments, we propagate the uncertainties in critical temperature thresholds, interaction strengths and interaction structure via large ensembles of simulations in a Monte Carlo approach. Overall, we find that the interactions tend to destabilise the network of tipping elements. Furthermore, our analysis reveals the qualitative role of each of the four tipping elements within the network, showing that the polar ice sheets on Greenland and West Antarctica are oftentimes the initiators of tipping cascades, while the AMOC acts as a mediator transmitting cascades. This indicates that the ice sheets, which are already at risk of transgressing their temperature thresholds within the Paris range of 1.5 to 2 C, are of particular importance for the stability of the climate system as a whole.

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Imagine if someone was designing a new bridge, and the architect admitted they cannot compute the stability of the bridge or predict the time when predicted events were due to occur, due to “missing and uncertain process representations of certain tipping elements”. Would you take that analysis seriously?

via Watts Up With That?

June 4, 2021