New York City has plans to limit emissions from its skyscrapers:

Point is, 70 percent of NYC emissions come from heating and cooling a million buildings—and a third of that carbon comes from just 50,000 buildings of 25,000 square feet or more. Blame the skyscrapers. Trump Tower is apparently a representative of the 2 percent of very, very bad emitters, for what it’s worth. So one of the new bills tells the owners of those big buildings they have to cut their emissions by 40 percent in 2030, and 80 percent by 2050. That’s a lot. “We have to pay attention. The water is speaking to us. In the last century New York Harbor is up one foot,” says John Mandyck, CEO of the Urban Green Council, which helped design the bill. “There’s no question that this bill sets tough, tough carbon limits. It’s not going to be easy. That’s a reflection of the fact that climate change is a tough issue.”

As to how those buildings get there, their owners have a few paths. They can buy green power, which is really more hopeful than realistic at this point; 70 percent of New York City’s power comes from carbon-emitting fossil fuels. But ideally this option will incentivize a market for wind turbines and hydro power, and in fact another bill in the omnibus aims to pave the way for green rooftops with solar panels. Also the building can work with the city to figure out what kinds of improvements would get emissions down—new boilers, better insulation, new windows, all kinds of new investments that would, not coincidentally, translate to thousands of construction and building-trade jobs in the city. Ey, these boilers ain’t gonna install themselves, knowwutImean?

And in an approach out of Kim Stanley Robinson’s post-climate-flood novel New York 2140 (or maybe the Crimson Permanent Assurance) individual buildings would be able to trade carbon credits. “That’s a real breakthrough policy tool. It’s never been done at this scale at a city level,” Mandyck says. “It’s a flexible tool especially for building owners that own portfolios.” So those folks could trade credits among their own buildings, or form alliances and breakaway archipelagos of skyscraping carbon trade routes.

I would guess that few residents would think about buildings as large sources of carbon. This could be for a variety of reasons: building occupants may rarely notice when the heating or cooling is on (though they may be aware of the temperature); carbon reduction efforts have targeted other sources, such as vehicles; and the percent of carbon emissions in New York in buildings may reflect both the number of large buildings and a region unusually dependent on mass transit.

All that said, it will be interesting to watch how these efforts to alter buildings go. The article says little about how building owners have responded. For many, New York will still be a desirable enough market that leaving over these changes i unlikely. Would it make any property owner or potential owner refocus their attention elsewhere? And buying green power or buying and trading credits could prove popular compared to actually making significant changes to buildings which could be costly and require a lot of time and effort. Finally, could alterations remake or restyle some large buildings and introduce a different aesthetic to one of the most important skylines in the world? Images of future cities tend to show more curvy skyscrapers covered in greenery instead of the glass and steel that dominate New York and other American cities. I’m sure there would be ways to make changes that would not just reduce emissions but also push a new look.