As the Earth’s surface warms, climate models predict that the amount of fresh water for humans will likely decrease in some parts. While that prospect looms for many cities around the world, a new study finds a more imminent threat to water supplies of cities in the tropical Andes, such as Lima, Peru and Quito, Ecuador, reports Jessica Orwig at the American Geophysical Union’s Blogosphere. “Despite all the uncertainty of the future impact of climate change, the impact of population growth is much bigger,” said Wouter Buytaert, lead author of the study. This could mean harsher times ahead for millions including nearly 10 million in the fast growing cities of Lima and Quito. Parts of the tropical South American Andes already experience water scarcity. While climate models project anywhere from a 10 percent decrease to 10 percent increase in water availability, models of population growth impacts indicated a roughly 40 to 60 percent decrease in available water there. The relative impacts of climate change and population growth can vary widely globally, however, say the authors, so individual cities need to analyze local factors in water scarcity studies.
Water scarcity in the tropical Andes: Population growth outweighs climate change AGU (American Geophysical Union) Blogosphere. http://blogs.agu.org/geospace/2012/07/17/water-scarcity-andes-population-growth/