Digging deeper: water and managing climate hazards
In El Alto, Bolivia, where families at the urban periphery are digging pirate wells, the impacts of climate change are self-reinforcing when it comes to water. Over 80 percent of the water supply for the area is from glacial ice melt in the Andes mountains, and that glacial area is shrinking dramatically, from 24 percent of land coverage to just 3 percent over the past several years. At same time, the rural-to-urban migration is intensifying, particularly as drought and volatile weather wreak havoc on farming. The migration suggests that the amount of urbanized land will double and quite possibly triple in the decades ahead. Demand for water will exceed supply by 2018.
The area is a compelling case study of the nexus of water scarcity and urbanization as cities come to terms with the impacts of climate change, says Jim Kostaras from the Institute for International Urban Development, who presented along with several others at a Lincoln Institute roundtable at the UN-Habitat's World Urban Forum VI in Naples, Italy today. The session was led by senior fellow Armando Carbonell, co-editor with Ed Blakely of Resilient Coast City Regions: Planning for Climate Change in the United States and Australia.
Climate change refugees and rural migrants settling on periphery areas are most vulnerable to water shortages, contamination, and price spikes. Was it possible, Kostaras wondered, to blend hydrological models and land use planning and analyze how urban development patterns lead to more or less water consumption? It might be possible to create green networks to reduce water pollution and increase aquifer recharge, and require rainwater catchment tanks through zoning – but somewhat counter-intuitively, Kostaras found that increased density leads to greater water consumption.
Other presenters included Juan Pablo Celemin, who examined the impacts of sea level rise in Mar del Plata, Argentina, whether coastal erosion or permanent or episodic inundation; Ashley Coles from the University of Arizona, who studied the management of hazards intensified by climate change, such as landslides, in Manizales, Colombia, a mountaintop town of 400,00 people; and Jennifer Graeff from the American Planning Association, who looked at sea level rise and land use planning in the Caribbean in Barbados, Trinidad and Tobago, Guyana and Para.