After Big Droughts Come Big Cities : Does Drought Drive Urbanization?

Existing research points to a possible link between slow-onset symptoms of climate changeand migration. It is also known that rates of urbanization are fastest in some of the world’s poorest countries, whichare incidentally also at greater risk of climate-induced migration. These separate findings suggest that slow-onsetclimate phenomena such as droughts have likely become a key driver of urbanization across much of the developing world.While intuitive, this link has not been convincingly established by extant research. This study examines theclimate-urbanization nexus by constructing a novel measure of urban growth that uses remotely sensed information fromthe World Settlement Footprint dataset. Relying on panel data that cover the entire globe between 1985 and 2014, thepaper shows that drought leads to faster urban growth. The results indicate that a hypothetical drought lasting 12months is associated with a 27 percent increase in the average annual increment of built-up area. The paperleverages novel data from several Sahelian cities to illustrate that much of this growth takes the form ofnon-infill development that extends outward from previously built-up localities.