Mexico City's green roofs help fight climate change

MEXICO CITY, Aug. 24 (Xinhua) -- More buildings in Mexico City are having plants on their roofs to help reduce pollution and lower the city's temperature to improve the environment for its population.

Mexico's Environment Ministry on Monday planted a cactus garden and a kitchen garden on the roof of its building in an effort to fight asphalt heat traps.

The garden, also working as a carbon trap, will help suck up carbon dioxide emitted by vehicles on nearby roads.

"Plants reflect less, which means less heat in the atmosphere," said Ramon Perez, who works for the North American Center for Environmental Information and Communication (CICEANA), a non-governmental organization that promotes sustainable development and provides environmental education. It also offers community-based ecological projects including green roofs.

Asphalt absorbs heat and then lets it back out into the environment, while plants absorb heat through chemical processes like photosynthesis, Perez said.

Maria de los Angeles Islas, director general of the CICEANA, told Xinhua that "It means buildings are cooler. Less air conditioning will be used or not used at all, especially on the top floor which is directly under the garden."

Islas estimated that around 10 percent of the city's rooftops could be turned into green spaces.

Over the last 50 years, Mexico City's urban sprawl has devoured over hundreds of hectares of green land and keeps on expanding. The diminishing of vegetation has caused dramatic climate changes in the Valley of Mexico that hosts the city.

Given the grave situation, green roofs can serve as a viable green solution to the city's climate change.