Avoiding population exposure to heat-related extremes: Demographic change vs climate change
About Dr. Bryan Jones
Bryan is a NSF Science, Engineering, and Education for Sustainability Fellow at the CUNY Institute for Demographic Research (CIDR). Additionally, he has appointments as a scientific visitor with the Global Dynamics Division at the National Center for Atmospheric Research, and as a consultant with the World Bank Climate Policy Team. He holds a Ph.D. in Geography from the University of Colorado-Boulder as well as an M.A. in Geography and B.A. in Economics from the University of Connecticut.
Bryan’s interests include the relationship between spatial population dynamics, urbanization, and climate change vulnerability. His current work examines spatially explicit patterns of physical and socioeconomic exposure/vulnerability to climate-related hazards by incorporating new high-resolution, multi-scale models of spatial population change with concurrent projections of climate-hazards under alternative socio-economic and biophysical scenarios.
About the Seminar
Heat waves are among the most dangerous climate-related hazards, and they are projected to increase in frequency and intensity over the coming century. Exposure to heat waves is a function of the spatial distribution of the physical events and the corresponding population distribution, and future exposure will be impacted by changes in both distributions. We project future exposure using ensembles of climate projections under two alternative emission scenarios (RCP4.5/RCP8.5) combined with two alternative population (SSP3/SSP5) outcomes. We characterize exposure at the global, regional, national, and grid-cell level, and estimate the potential avoided exposure that would result from mitigating future levels of climate change (RCP4.5) and the dependence of exposure on population outcomes. Additionally, we introduce alternative methods for explicitly considering urban and rural heat extremes.
We find that climate change is a stronger determinant of exposure outcomes than demographic change in these scenarios, with a global reduction in exposure of over 50% under RCP4.5 relative to RCP8.5, regardless of SSP, while a slower population growth pathway (SSP5) leads to roughly 30% less exposure relative to SPP3 in both the RCP4.5 and RCP8.5 scenarios. At the regional level results vary in terms of relative reduction in exposure, but in almost all cases the RCP remains more influential than the SSP. We also find that uncertainty in outcomes is dominated by inter-annual variability in heat extremes and that, for some regions, this variability is large enough that a reduction in annual exposure is not guaranteed in each individual year by following the lower emissions pathway.