A recent study shows that meat consumption is one of the main ways that humans can damage the environment,
最近一项研究表明，肉类消费已经成为人类危害环境的主要方式之一，
second only to the use of motor vehicles.
仅次于机动车的使用。
So how can eating meat have a negative effect on the environment?
那么吃肉是如何对环境造成负面影响的呢？
For a start, all animals, such as cows, pigs and sheep, release a gas named methane,
首先，所有的动物，比如牛、猪、羊，都会释放出一种叫做甲烷的气体，
which is the second most common green-house gas after carbon dioxide.
而甲烷是仅次于二氧化碳的最常见的温室气体。
Many environmental experts now believe that methane is more responsible for global warming than carbon dioxide.
如今许多环境专家认为，相比于二氧化碳，甲烷对全球气候变暖负有更大的责任。
It is estimated that 25% of all methane released into the atmosphere comes from farm animals.
据估计，排放到大气中的25%的甲烷来自于家畜。
Another way in which meat production affects the environment is through the use of water and land.
肉类消费影响环境的另一种方式便是对水资源和土地资源的占用。
2,500 gallons of water are needed to produce one pound of beef,
生产一磅牛肉，需要2500加仑的水，
whereas 20 gallons of water are needed to produce one pound of wheat.
而生产一磅小麦，只需要20加仑的水。
One acre of farmland used for raising cows can produce 250 pounds of beef.
一英亩农地用于养牛，可以产出250磅牛肉。
One acre of farmland used for crop production can produce 50,000 pounds of tomatoes.
一英亩农地用于种植作物，则可以产出5万磅西红柿。
Many people now see the benefits of switching to a vegetarian diet which excludes meat and fish,
如今，许多人已经意识到了改吃素食、拒绝肉类鱼类的好处，
not just for health reasons, but also because it plays a vital role in protecting the environment.
不仅仅是因为健康方面的原因，还因为素食在环保方面扮演着至关重要的作用。
However, some nutritionists advise against switching to a totally strict vegetarian diet.
然而，一些营养学家并不赞成完完全全的素食主义。
They believe such a diet which includes no products from animal sources
他们认为，这样一种不含任何动物制品的膳食
can be deficient in many of the necessary vitamins and minerals our bodies need.
缺乏人体所必需的维他命和矿物质。
Today many people have come to realize that to help the environment and for the human race to survive,
如今许多人已经意识到，为了保护环境，为了人类的生存，
more of us will need to become vegetarian.
越来越多的人将有必要加入素食主义者的行列。