He repeatedly talked about how urgent the issue was, but the announcement, reported by The Washington Post, contained few specifics.
De Blasio said the new program mandates the city's 14,500 least efficient buildings, which together produce nearly a quarter of New York City's total greenhouse gas emissions, to accelerate and deepen major efficiency upgrades.
"Time is not on our side", de Blasio stated.
"The city's goals could inadvertently promote buildings that use less overall energy without regard to how the energy is used", he said. "We must shed our buildings' reliance on fossil fuels here and now".
New York City Mayor Bill de Blasio's recent comments about private property rights have raised some eyebrows, both in the media and especially the real estate industry.
"I think people all over this city, of every background, would like to have the city government be able to determine which building goes where, how high it will be, who gets to live in it, what the rent will be". But of larger landlords, he said, "They can handle it".
DHS mulling deadline extension for Dreams to reapply for DACA
The president was talking with Democratic leaders to get their perspective. "But this, I think, does impact our community". After he landed in Florida, he declared repeatedly, "If we don't have a wall, we're doing nothing".
Offenders would face escalating penalties based on size and energy use. For instance, the owner of a 1 million-square-foot building could pay $2 million in fines per year if they do not conform to the new standards by 2030.
But there were many uncertainties about the proposal, and the mayor admitted that some elements still needed to be worked out.
"We're clear about the fact that we're not waiting on President Trump and cabinet of deniers to address this crisis, we have no such illusion", de Blasio said. He said he expects the plan to become legislation in the coming months.
"One partner in the dance has chose to dance without us, and that's his right", Mr. Constantinides said.
The initiative would reduce greenhouse gas emissions by 7 percent by 2035 - the equivalent of removing 900,000 vehicles from the streets per year, the mayor said.
"For this specific issue, there was not prior consultation or an opportunity to weigh in in a meaningful way", said John Banks, the president of the Real Estate Board of NY, although he said that the group had previously participated in many discussions with City Hall on issues related to sustainability.