Urbanization and Fire Risk at the Global Wildland-Urban Interface: A Multi-Satellite Study of Past and Future Trends

The wildland-urban interface (WUI), a transition area where urban areas are intermixed with wildlands, is at high risk to wildfires due to human-caused ignitions in close proximity to areas with high fuel load. The expansion of urban areas over the next thirty years is likely to increase the size of the WUI globally. Combined with climate change and expected changes in temperature, the growth in the WUI is likely to increase the frequency of wildfires. Although there have been some studies of how urbanization affects the WUI and wildfires, there is little scientific understanding of how past patterns of urban land expansion globally has affected wildfire risk at the WUI and how future patterns of urban expansions will increase WUI fire risk.

This project aims to fill these knowledge gaps using optical and thermal sensors, including Landsat, ECOSTRESS, MODIS and Sentinel 1. Although there are many pathways of how urbanization and forest degradation affect fire risk, we will investigate one mechanism in this project: land surface temperature increase due to urbanization and forest degradation and these combined effects on increased fire risk. Our hypothesis is that the spatial and temporal patterns of urbanization and forest degradation increase surface temperature and then increase risk of wildfires at GWUI. The overarching research question of this project is: How has urbanization affected fire risk at the global WUI, and how will future urbanization expand the GWUI?

The project aims has five research goals:

1. Identify hotspots of historical urbanization within the GWUI and analyze the intensity of urbanization.
2. Assess forest degradation within urbanization hotspots in the GWUI.
3. Investigate the effects of urbanization and forest degradation on land surface temperature within urbanization hotspots in the GWUI.
4. Explore the effects of changes in land surface temperature on fire hazard.
5. Project future WUI in the urbanization hotspots and identify areas with potential high risk.