How to cool a city
LOS Angeles street services crews have begun slathering a new light grey coating on some boring old black asphalt streets. They’re not just changing the colour scheme. The city is testing whether so-called cool pavements can lower the temperature in the surrounding area and help counter the effects of global warming.
For a decade California has launched some of the world’s most ambitious programmes to cut greenhouse gas emissions in an attempt to slow climate change. But in a shift driven by the stark reality that the planet is already warming, there are more projects in the state, like the cool streets experiment, aimed at preparing communities for the now-inevitable impacts of climate change.
Santa Monica, for instance, has planted native dune plants on three acres of sand to test whether beach restoration could help protect coastal development from rising sea levels and storm surges. Los Angeles and other cities have begun requiring lighter coloured roofs to reflect sunlight and reduce the urban heat island effect that causes developed areas to be hotter than open spaces.
Researchers suggest the impacts of global warming will only get more serious. Scientists say glaciers and sea ice in the Arctic are melting faster than expected, meaning that sea levels are also likely to rise faster than predicted. And yet, LA’s cool pavement project also demonstrates why progress in climate adaptation is so challenging for cities and counties, and so frustratingly slow. It took the Bureau of Street Services four years to go from idea to execution. Four years! The bureau had to find a commercially available cool pavement product and, since there were no examples of publicly-travelled cool streets in California, they had to test it for durability, as well as skid and slip potential.
So far, most of the climate-change-related technological advances and regulations have been focused on reducing greenhouse gas emissions. Rightfully so – the world must act quickly to slow climate change if it is to reduce the predicted damage from rising temperatures. But there’s also a tremendous need for creativity, funding and innovation to help communities adapt to the change we’re already seeing and the change we are expecting in the years ahead.