868. Aggregation of Experts Opinions and the Assessment of Tipping Points. Catastrophic Forecasts for Higher Temperature Changes

Working Paper n.868 Dicembre 2021

Marcello Basili

DEPS, USiena

Federico Crudu

DEPS, USiena e CRENoS

Abstract

This paper assesses the probability of occurrence of tipping points conditional on a given temperature scenario by combining probability intervals from elicited experts opinions using the data of Kriegler et al. (2009). The computation of such conditional probabilities is based on the aggregation of imprecise probability judgments through the Steiner point. In addition, the probability of a tipping point can be updated via the standard Bayes rule to generate tipping point scenarios. Our results suggest that tipping events may happen with relatively large probabilities, in contrast with the view that tipping points are low-probability-high-impact events.

Keywords

Bayesian updating; aggregation; global warming; judgmental forecasting; Steiner point; tipping points.

Jel Codes

Q54; D81; C10