Environmental Group Targets Spewing Buildings in Pollution Report When people consider the prime sources of carbon gas emissions in New York City, cars, trucks and buses belching smoke are often the first culprits to come to mind. In fact, homes and offices spew far more carbon into the atmosphere than all motor vehicles in the city combined. Some 75 percent of all carbon emissions in the city come from the buildings. Using that sometimes surprising fact as a starting point, the nonprofit Urban Green Council has outlined a series of measures that it says could result in the city's reducing carbon emissions by 90 percent by 2050 - a far more ambitious figure than the city's current goal [pdf] of 30 percent by 2030. Perhaps most striking about the report, "90 by 50" [pdf], released on Thursday, is that it does not assume any fancy new technology or major change in how people live. Instead, it relies on a strategy that many people have been reminded of by a grandparent at one point or another: keep the heat in during the winter and out during the summer. In an article in Slate - and a nod to the "broken windows" crime-fighting approach made famous during the Giuliani administration - the proposal was called "the triple-pane windows theory." The council's report calls for buildings to be viewed not as objects trapped in the amber of outdated heating and cooling technology, but more as infrastructure similar to roads and sewers. The report outlines several steps to make buildings more efficient and outlines different approaches for eight different building types most common in the city - from low-slung brownstones to towering skyscrapers. First, it envisions ridding the city of its increasingly aging system of heating many buildings with steam-generated power and ending all dependence on coal. Instead, buildings would be connected to the grid with high-efficiency electrical pumps. Beyond the major infrastructure changes, the report says that a series of seemingly small changes could have a striking impact. It calls for better insulation, heat recovery ventilation and plugging of air leaks, among other actions. It also proposes using triple-glazed windows. The report estimates that such an effort would require a capital outlay of $94 billion over 35 years. But it also estimates that the savings from increased energy efficiency would be $87 billion over that time. Of course, the impact would go far beyond the financial. The ultimate goal is to combat climate change, which Mayor Michael R. Bloomberg has recommitted himself to battling in the wake of Hurricane Sandy. "Our climate is changing," Mr. Bloomberg wrote days after the storm. And while the increase in extreme weather we have experienced in New York City and around the world may or may not be the result of it, the risk that it might be - given this week's devastation - should compel all elected leaders to take immediate action. The city is already a global leader in reducing greenhouse gases, the report notes. "But it is not enough," the report states. To ensure a global environment in which human society can bring security and prosperity to all its members, climate science tells us we must reduce carbon pollution dramatically. A figure of 80 percent globally by 2050 is often cited. A reduction of 90 percent in the readily measured fraction of the city's emissions will be necessary to meet this goal, and this study outlines an energy economy for New York City in 2050 that will match this challenge.