Risk tails should be prioritized to limit the probability of catastrophe

[John Nissen]

Hi Chris,

Thanks for the link in yesterday's NOAC chat [1] with the actual report here [2].  The message is good, strong and clear.  Climate risks have been underestimated.  Economic collapse could occur between 3°C and 4°.  A paradigm shift is required: moving from best-estimate scenarios to a precautionary approach that limits the probability of catastrophic outcomes.

Does anyone have contacts in the Policy Commons group?  Prof Steve Keen, who was consulted for the report, has been mentioned by Kyle Kimball as a maverick economist who challenges the Neoliberal Economics approach to future risk espoused by Nordhaus et al. and adopted by the IPCC in their risk assessments and attributions.  The report comes over more as a warning to investors than a call for action to reduce risks of catastrophic climate change or sea level rise.  Nevertheless, one can take the latter as a core message, to which we would respond that only direct cooling intervention can significantly reduce risks (tail or not) on a meaningful timescale.  And only with prompt cooling intervention will it be possible to reverse climate change and return the planet to a safe, sustainable, biodiverse and productive state.

Cheers, John

[1] Abrams et al. (Policy Commons, February 2026)

Recalibrating Climate Risk: Aligning damage functions with scientific understanding

https://policycommons.net/artifacts/42997651/recalibrating-climate-risk-report-final/43896702/

Recalibrating Climate Risk addresses the critical disconnect between current economic models and the scientific understanding of climate impacts. While mainstream economic forecasts often predict minimal GDP losses even at significant warming levels, this report, which draws on the views of over 60 climate scientists, argues that such models dangerously underestimate systemic risk. The findings highlight that global mean temperature and GDP are inadequate proxies for climate damages, as they fail to capture extreme events, tipping points, and cascading societal disruptions that define real-world impacts. The report challenges the assumption of indefinite economic growth, revealing that experts identify meaningful probabilities of economic collapse at warming levels between 3°C and 4°C . It argues that damage functions must evolve from smooth, linear projections to frameworks that account for non-linear thresholds and capital destruction. Consequently, the authors recommend a paradigm shift for policymakers and investors: moving beyond "best-estimate" scenarios to a precautionary approach that prioritizes tail risks and strictly limits the probability of catastrophic outcomes.

[2] Actual report

https://greenfuturessolutions.com/wp-content/uploads/2026/01/Recalibrating-Climate-Risk-Report-Final.pdf