Los Angeles' Plan to Cool Down

The Los Angeles Office of Sustainability is partnering with local universities on a plan to lower the average regional temperature by three degrees over the next 20 years.

Achieving that goal could reduce energy consumption, improve air quality, and prevent deaths caused annually by extreme heat. The Los Angeles Times looks into how much progress the city needs to make on science and policy to get there.

A variety of factors go into L.A.'s temperatures, but one well-known problem scientists are focusing on is the urban heat island effect: the phenomenon by which cities tend to be warmer than their surrounding areas because of heat absorbed by the built environment.

Over the years Los Angeles has tried, at different scales, a number of common approaches to this problem, including cool pavements and cool roofs, sustainably designed parks, and thoughtful urban forestry.

But because the effects of a heat island can be "hyper-local," its solutions have to be, too—sometimes varying "block to block." In one neighborhood, scientists tested different heat mitigation techniques in a computer model that accounted for every single tree and building.