美国各个城市已成为推行创新性政策的试点，以减轻气候变化、逆转环境退化以及支持使用可替代性能源。美国联邦制度的特性使城市的创新性政策往往能被州政府及联邦政府采纳，将城市置于环保运
动的核心地位。【请见相关文章：欧巴马总统认为气候变化对我们构成的威胁最大、北极冰层消融危及北极动物的生存、美国风力发电前景光明】

光明的绿色城市

组成纽约市（New York City）的五个行政区拥有北美地区最环保的交通运输系统之一。纽约市的公交车队有一半以上使用可替代性燃料。新型地铁列车的制动系统能够进给能量，而过去当列车停车回到电动第三轨时，这种能量会变成热量丧失。

纽约市用更清洁的燃料来替代污染严重的供暖燃油，从而改善了空气质量。纽约市人均二氧化碳排放量低于美国其他城市。

纽约市在土地使用方面的环保努力也很突出。该市通过重新开发后工业化设施及废置地块来扩大绿地面积，争取实现让全体居民出门不到10分钟就能走到公园的目标。截至2014年，新开发的公园用地增加了44公顷。

纽约市植树百万棵（MillionTreesNYC）计划到2015年年底将会完成。该市将在街道、公园及其他公共场所栽种的树木占植树总数的70%。另外30%将由屋主、公司企业所有人以及非营利组织种植在自己的地块上。

纽约市通过改善水质及滨水区通道来扩大用于休闲娱乐的滨水区面积。该市计划到2030年向居民开放90%的滨水区域。


Cities as policy labs: New York retools

This is third in a series on U.S. cities’ environmentalism, following Chicago and Pittsburgh.

American cities have become laboratories for novel policies to reduce climate change, reverse environmental degradation and support alternative energy. Because of the nature of the U.S. federal system, cities’ policies are often adopted at the state or national level, putting cities at the center of the environmental movement.

Bright lights, green city

The five boroughs that make up New York City are home to one of the most environmentally friendly transportation systems in North America. More than half of the city’s bus fleet runs on alternative fuel. New subway trains have brakes that feed energy that would otherwise be lost as heat when a train stops back into the electric third rail .

The city has improved its air quality by replacing heavily polluting heating oils with cleaner fuels. Its carbon-dioxide emissions per capita are lower than those in other U.S. cities.

New York’s environmental land-use effort also stands out. By redeveloping postindustrial sites and vacant lots, New York  expands its green spaces, with the goal of ensuring that all New Yorkers live within a 10-minute walk of a park. As of 2014, 44 hectares of new parkland had been added.

The MillionTreesNYC program will have finished planting by the end of 2015. The city will plant 70 percent of the trees along streets, in parks and in other public spaces. The other 30 percent will be planted by homeowners, business owners and nonprofit organizations on their own properties.

The city is restoring its shorelines for recreational use through improved water quality and waterfront access. It plans to open 90 percent of its shoreline to residents by 2030.