In the past, man did not have to think about the protection of his environment. There were few people on the earth, and natural resources seemed to be unlimited. Today, things are different . The world has become too crowded. We are using up our natural resources too quickly, and at the same time we are polluting our environment with dangerous chemicals. If we continue to do this, life on the earth will not survive.
Everyone realizes today that if too many fish are taken from the sea, there will soon be none left. Yet, with modern fishing methods, more and more fish are caught. We know that if too many trees are cut down, forests will disappear and nothing will grow on the land. Yet we continue to use more powerful machines to cut down more and more trees.
We realize that if rivers are polluted with wste products from factories, we will die. However, in most countries, waste products are still put into rivers or into the sea, and there are few laws to stop this.
We know, too, that if the population of the world continues to rise at the present rate, in a few years there will not be enough food.
What can we do to solve these problems?
If we eat more vegetables and less meat, there will be more food available for everyone. Land that is used to grow crops feeds five times more people than land where animals are kept.
Our natural resources will last longer if we learn to recycle them.
The world’s population will not rise so quickly if people use modern methods of birth control.
Finally, if we educate people to think about the problems, we shall have a cleaner planet in the future.

过去，人们很少考虑保护环境。地球上的人类很少，自然资源看上去是无限的，今天，情形不同了。世界便的太拥挤了，我们用自然资源太快了，与此同时，我们用危险的化学物来破坏我们的环境。如果我们继续破坏下去，地球上的生命将不能幸免。
今天人们意识到如果人们从海中捕太多的鱼，很快就没多少鱼能够留下来，但是，人们还是用现代的捕鱼机器捕获了更多的鱼。我们知道如果太多的树木被砍伐的话，森林会消失，陆地上没有什么能在生长，但是我们仍旧用马力更强大的机器砍伐更多的树木，我们意识到如果河水被工厂的废渣污染的话，我们会死亡的，但是，在大多数的国家中，废渣仍旧被排入河流或海洋，并且没有什么法律可以制止这些污染举止。我们也知道，如果世界人口以现在的速度增长的话，不出几年，食物就不够了。
我们如何解决这些问题呢？
如果我们多吃蔬菜少吃肉，每个人就会有足够的食物，陆地种植的谷物能够养5倍于动物的人类。
如果我们学会回收利用自然资源的话，我们的自然资源能够持续更长。
如果人们用现代方式控制生育的话，世界人口将不会增长的如此迅速
最后，如果我们这些受过教育的人思考这些问题的话，我们将有一个更干净的地球。