The World Population
A very important world problem--in fact, I think it may be the most important of all the great world problems which face us at the present time--is rapidly increasing pressure of population on the land.
Suppose we first take a look at the map of the world. The position today is very different from what it was only, shalI we say, 150 or 200 years ago. If we go back to that time, there were large parts of the world which had not then been explored(开发). For example, Australia was unknown; the great west of Canada and the United States had not been opened up; the heart of South America was almost entirely unknown;and on the map of the period you will find the heart of Africa is just marked as unexplored.
The position at the present day is absolutely different. We now know roughly the actual extent of the earth's surface. Even the outline of the Antarctic continent(南极洲) is shown in a solid line on the latest maps. It is only in the last two or three years that we have been able to remove the last doubtful lines, and have settled down to the idea that the earth's land surface is something fixed,and will not extend any more.
But what about population? The population of the world today is about 6000000000. That is an enormous number, yet it is known quite accurately, because there are very few parts of the world which have not carried out a modern census(人口普查). China was the big unknown quantity untill 1953, when a census was carried out. The population is over 1200000000.
The important thing is not so much the actual population of the world,but its rate of increase. It works out to be about 1.6 percent annual net increase. In numbers this means something like forty to forty-five million additional people every year. Canada has a population of twenty million--rather less than six month' s increase in world population. Take Australia . There are ten million people in Australia . So it takes the world less than three months to add to itself a population which peoples(vt. 使住满人) that vast country. Let us take our own crowded country, England and Wales --forty-five to fifty million people. This is just about a year's supply.
By this time tomorrow, and every day, there will be added to the earth about 120,000 extra people--just about the population of the city of York .
This enormous increase of population will create immense problems. By AD. 2020, unless something terrible happens, there will be as many as 7000000000 people on the surface of the earth! So this is a problem which you are going to see in your lifetime.