Climate change and population: an integrated assessment of mortality due to health impacts

We develop an integrated assessment model with endogenous population dynamics accouting for the impact of global climate change on mortality through five channels (heat, diarrhoeal disease, malaria, dengue, undernutrition). An age-dependent endogenous mortality rate, which depends linearly on global temperature increase, is introduced and calibrated. We consider three emission scenarios (business-as-usual, 3°C and 2°C scenarios) and find that the five risks induce deaths in the range from 160,000 per annum (in the near term) to almost 350,000 (at the end of the century) in the business-as-annual. We examine the number of life-years lost due to the five selected risks and find figures ranging from 5 to 10 millions annually. These numbers are too low to impact the aggregate dynamics and we do not find significant feedback effects of climate mortality to production, and thus emissions and temperature increase. But we do find interesting evolution patterns. The number of life-years lost is constant (business-as-usual) or decreases over time (3°C and 2°C). For the stabilisation scenarios, we find that the number of life-years lost is higher today than in 2100, due to improvements in generic mortality conditions, the bias of those improvements towards the young, and an ageing population. From that perspective, the present generation is found to bear the brunt of the considered climate change impacts