Modeling future population exposure to intra-urban extreme heat with fine-scale land use data

Large United States (U.S.) urban populations will disproportionately experience extreme heat, in part due to the urban heat island (UHI) observed in metropolitan areas. As part of the System for Integrated Modeling of Metropolitan Extreme Heat Risk (SIMMER) – a NASA-funded project – we sought to characterize and address extreme heat risk through interdisciplinary approaches in Houston, Texas, one of two North American case study cities. Houston is one of the most diverse and fastest growing cities in the United States, currently experiencing trends of increasing populations, changing demographics and urban sprawl. Urban morphology and vegetation are particularly influential in determining Houston's UHI. Recent regional climate simulations performed at the National Center for Atmospheric Research suggest that the number of ‘high heat stress' days and nights in Houston will more than double by mid-century. Public health and planning officials who are interested in reducing population exposure to extreme heat should consider how both the land use and climate change will modify the distribution of intra-urban extreme heat. We model the distribution of temperature for current and future (2040) Houston, using high-resolution (1 km) climatic and fine-scale land use (parcel-level) data. We will present results from meteorological and land use surface modeling components of SIMMER. We will also present a series of sensitivity simulations, where we evaluate how the intra-urban distribution of temperature responds to 1°C incremental climate perturbations. Lastly, we will demonstrate how future (2040) demographic projections correspond to the future Houston UHI. These results will be discussed in terms of the implications of land use and climate change on population exposure to extreme heat.