Urban Green Council report: How New York City could cut emissions by 90 percent by 2050.

A Shockingly Simple Blueprint for Big Cities To Slash Their Emissions

A Shockingly Simple Blueprint for Big Cities To Slash Their Emissions

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Feb. 13 2013 4:06 PM

The Triple-Pane Windows Theory

A shockingly simple blueprint for big cities to save the planet without wrecking the economy.

People gather in Lower Manhattan on October 2012 in New York City.
People gather in Lower Manhattan on October 2012 in New York City.

Photo by Mario Tama/Getty Images

Climate scientists have estimated that, in order to avoid runaway global warming, the world would need to cut its carbon emissions roughly in half by 2050. Since emissions in developing countries like China and India are still rising fast, meeting this target would require developed nations to aim for a figure more like 80 percent. When you consider that the United States, the largest polluter in the developed world, has no real strategy in place to achieve that—and that no binding international agreements appear to be on the horizon—the goal can start to sound nigh impossible.

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Will Oremus is Slate's senior technology writer. Email him at will.oremus@slate.com or follow him on Twitter.

The task is so intimidating that even serious people are starting to entertain extreme-sounding geoengineering ideas like flying business jets into the stratosphere and spraying sulfuric acid all over the place to try to deflect sunlight before it reaches the Earth. Others reckon it’s already too late to prevent catastrophic warming—we’ll have to build sea walls and hope for the best. President Obama alluded to a possible cap-and-trade system in Tuesday’s State of the Union address, but few believe such a sweeping policy would pass Congress.

Yet in a report that will be released on Thursday, the nonprofit Urban Green Council makes the case that the country’s largest population centers needn’t rely on a federal breakthrough. Specifically, the 51-page report, titled “90 by 50,” finds that New York City could slash its emissions by a whopping 90 percent by 2050 without any radical new technologies, without cutting back on creature comforts, and maybe even without breaking its budget.


That’s a far more aggressive target than even the city’s own relatively ambitious goal of reducing emissions by 30 percent by 2030. How is it possible? The strategy has plenty of familiar components—electrifying the transit system, converting to renewable power sources. But it all hinges on one seemingly mundane yet surprisingly potent move: retrofitting almost every building in the city to keep the heat in during the winter and out during the summer. In a nod to Rudy Giuliani, Bill Bratton, and James Q. Wilson, I’ll call it the “triple-pane windows theory” of greenhouse-gas reduction.

The report takes as its starting point this foundational statistic: 75 percent of the readily measured carbon emissions in New York City come from buildings. That makes it very different from the nation as a whole, where agriculture and transportation are among the biggest culprits. At first glance, this looks like an obstacle: Inefficient buildings are much harder to replace than inefficient cars. And New York is already one of the country’s greenest cities per capita, which would seem to make a 90 percent cut more difficult than it would be elsewhere.

But the council’s report suggests the opposite: that a dense metropolis like New York is well-suited to lead the way on emissions reductions. The key, says the Urban Green Council’s executive director, Russell Unger, is that the city must begin to view buildings as infrastructure, like roads and sewers, rather than simply as private property. “It will require a mind shift for the public and the government,” Unger says. “But you know, most of these buildings will last longer than the Tappan Zee Bridge.” And they gobble carbon-fueled energy like crazy.

To get those emissions under control will require three main steps, all difficult but none inconceivable. The first is probably the most ambitious and innovative: gradually retiring the city’s massive, aging steam heat system and replacing it with high-efficiency electric heat pumps. Low-rise residential buildings would get individual mini-split pumps, a relatively easy fix, while high-rises would need to convert from steam to central geothermal heat pump systems. That’s an expensive proposition, but it would also save staggering amounts of energy over time, with cost savings that would help offset the capital outlay. And the retrofits wouldn’t happen all at once—they’d be done as each building comes in for renovations that it would need anyway.

A sample of the energy efficiency measures used in the 2050 building models.
A sample of the energy efficiency measures proposed in the Urban Green Council's "90 by 50" report

Courtsey of Urban Green Council

Heating the city’s buildings and water electrically would make it far easier to draw that energy from renewable sources. (The alternative is to run the steam system off biomass, but it’s not clear how feasible that would be.) The Urban Green Council’s report doesn’t prescribe exactly how New York should do that, but it’s a standard part of any serious carbon-cutting plan. Today the city gets about one-third of its electricity from natural gas and one-tenth from coal. The more it can replace those with nuclear, hydroelectric, wind, or solar power, the deeper the emissions cuts will be. Solar panels on every roof might be a nice supplement.

It’s the third step, though, that may make the above possible: energy conservation. Here, the report isn’t asking residents to cut back—it refers to stripping waste and leakage to the bare minimum. Tweaks that seem small—insulation, plugging air leaks, heat-recovery ventilation, fluorescent lighting—loom big. New buildings in the city already include some of those measures. But the Urban Green Council’s plans would carry these standards to unprecedented levels—not just double-glazed windows, but triple-glazed windows—and apply them to existing buildings as well whenever they’re updated. That’s an awful lot of work, but the potential payoff is bigger than you might expect. Think of how much a heater has to run just to keep a room at a constant 70 degrees on a 35-degree day—and then imagine instead that the room is so thoroughly sealed that it can stay near 70 for much of the day on its own.