Estimation of the safe operating space with a probabilistic assessment of future regional temperatures, based on the notion of lost options commitment

Details

Supervisors

Crucifix, Michel

Faculty

Faculté des sciences

Degree label

Master [120] en sciences géographiques, orientation climatologie, à finalité approfondie

Abstract

The safe operating space expresses the idea that there is a boundary that humanity should not exceed in order not to compromise the favourable conditions in which it has been able to develop. The lost options commitment measures the number of policy options, out of a predetermined set of options, which result in transgressing a predetermined ethical state. In this work, we combine the two notions to determine which policy options result in transgressing the safe operating space. The boundary of the safe operating space is simplified: the limit is set at 35°C mean annual temperature. Our study uses as climate target exceeding an average annual temperature of 35°C in one region of the world within a time horizon of 2000 years and a set of 9 long-term scenarios as possible options. To achieve this, the SURFER and MESMER models are combined. SURFER models global warming curves up to the year 4000. MESMER adds noise to these curves and produces temperature distribution maps for each year. Analysis of the results shows that some scenarios are safe, while others are not. The longer we wait to make a commitment, the more future generations lose options. The longer we wait before drastic reductions in emissions, the more we commit future generations to using technologies that do not exist, yet. The regions most often at risk are Western Africa, the Arabian Peninsula, India and the Amazon rainforest. When the limit is set at 30°C rather than 35°C, more options are lost. The work also shows the contribution of stochastic rather than deterministic trajectories. However, given the inherent complexity of the climate system, the uncertainties associated with climate models and some decisions relating to the work method, these results must be interpreted with caution.