NEW YORK CITY—Mayor Bill de Blasio has announced that New YorkCity plans to reduce its greenhouse gas emissions by 80% over 2005levels by 2050. The plan—called One City, Built to Last:Transforming New York City's Buildings for a Low-CarbonFuture—includes the intention to retrofit public and privatebuildings to dramatically reduce the city's contributions toclimate change while spurring cost savings and creating newjobs.

This effort makes New York the largest city to commit to the 80%reduction by 2050 and charts a long-term path for investment inrenewable sources of energy and a total transition from fossilfuels. Nearly three quarters of New York City's greenhouse gasemissions come from energy used to heat, cool, and power buildings,making building retrofits a central component of any plan todramatically reduce emissions, according to the Mayor's office.

Every city-owned building with any significant energyuse—approximately 3,000 buildings—will be retrofitted within thenext ten years, by 2025, with interim goals along the way. The cityalso will spur private building owners to invest in efficiencyupgrades, setting interim targets and incentives and implementingmandates that trigger if interim reduction targets are not met.