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纽约市屋顶花园的苹果树。( AP Images)

水泥建筑林立的城市正在日益变绿。城市屋顶花园和社区蔬菜园可能很快就会像摩天大楼和出租车一样司空见惯。

鉴于全球趋势，城市是最适合生活的地方。全世界一半以上（54％）的人口生活在城市，预计到2050年这个数字将上升到66%。几乎达1960年的两倍。

估计全球有8亿人在城市种植水果和蔬菜，其中包括美国的纽约市(New York City)、费城(Philadelphia)和芝加哥(Chicago)等城市。

许多人转向城市农业，因为他们想要新鲜的农产品，更便宜的食物，还可以稍微缓解一下城市的酷热。
人们还有其他一些原因需要依靠社区菜园和都市农业。

保护环境。创造一块绿色空间可以吸收温室气体排放；提供一个将城市有机废物转化成肥料的场所；收集降雨，防止径流造成侵蚀。

降低房产税。根据不同的区域，部分业主可以建造屋顶花园减少暴雨径流，从而降低房产税。除了创造一个美丽的荫凉空间，花园也可提供冷热绝缘，降低能源成本。

节省金钱。各市镇、当地学校和宗教场所可以允许城市农民耕种他们本来需要花钱维护的闲置土地，使各方都受益。 学校一般非常欢迎有一个“动手”课堂的教育机会，让学生学习有关农业的知识。

Urban farming: The green answer to city growth?

An apple tree grows in a rooftop garden in New York City. ( AP Images)  

The concrete city is getting more green. Rooftop gardens and neighborhood vegetable patches may soon be as familiar in cities as skyscrapers and taxi cabs.

Given global trends, the city is the place to be. More than half of the world’s population (54 percent) live in an urban area, and that figure is expected to grow to 66 percent by 2050. That’s nearly twice the figure of 1960.

Of that, an estimated 800 million people worldwide grow fruits and vegetables in cities. That includes places like New York City, Philadelphia and Chicago in the U.S.

Many turn to urban farming because they want fresh produce, cheaper food and some relief from the city’s sweltering heat.

Here are some other reasons to consider neighborhood gardens and urban farming:

Protect the environment. Creating a pocket of green space can absorb greenhouse gas emissions; provide an area to convert urban organic waste into fertilizer; and capture rainfall that would otherwise cause erosion from street runoff.

Lower property taxes. Depending on the area, some building owners can reduce property taxes by installing a rooftop garden that cuts down on storm-water runoff. Along with creating an attractive shady space, the garden also can reduce energy costs by providing insulation from both the heat and cold.

Save money. Municipalities, local schools and places of worship can benefit by allowing urban farmers to cultivate unused land they would otherwise have to pay to maintain. Schools often welcome the educational opportunity for a “hands on” classroom for students to learn about agriculture.