The Population ExplosionAccording to the Population Reference Bureau, in 1991, there were approximately 5.4 billion people in the world. The global birth-death rate was 27/9, meaning that for every person who dies, three more children are born. From 1990 to 1991 the population increased by 95 million people and now continues to grow at this rate. It may not seem like a danger, but if one thought of it as a pond doubling its quantity of water lilies for 40 days, one would see it differently. It would start with one water lily, the next day it would have two, and on the 39th day it would be half full. However, in one day, the 40th day, it will be completely filled. The Earth's population doubles approximately every 40 years. We don't want to wait until the 79th year to solve our problem, otherwise humanity will not have enough time to change the inevitable obstacles that come with overpopulation. In his book The Population Explosion, Paul Ehrlich, a famous population controller, came up with the equation I = PAT. He believes that the impact on the environment is equal to population multiplied by wealth (i.e. the amount of energy and food consumed by the population) multiplied by the amount of destructive technology a country has. It showed that the impact is directly influenced by the population. Therefore, with a larger population, there is a greater impact on the Earth's water, air and soil. A common problem that people think is associated with overpopulation is running out of space to live in, but there are also many other environmental problems that this causes. More and more people use more cars, need more firewood, drink more water. This causes more air pollution, more land ruined, and more water disappearing. Therefore, population control is necessary internationally to protect our environment. There are experts who believe that population control is not necessary, as in Singapore. The Singapore government decided that it would be best for the country to increase its population so that it could help its economy. Many less developed countries promote population growth because they want their economy to grow. Experts who believe that it is best to let the population increase or decrease on its own also think that overpopulation will never become a problem.