Mayor de Blasio has announced a plan for the city to reduce its greenhouse gas emissions 80 percent by 2050, starting with efforts to make the city's buildings more energy efficient.
De Blasio unveiled the retrofitting plan on Sunday, the same day the People's Climate March was taking place in Manhattan.
Most of the city's greenhouse gas emissions can be traced to the energy needed to power electrical, heating and cooling systems in its buildings.
The plan calls for about 3,000 city-owned buildings that have "significant" energy use to be retrofitted by 2025. That includes schools, hospitals and libraries. The city will also offer incentives for private owners to upgrade their buildings.