The world has gone through a revolution and it has changed a lot. We have cut the death rates around the world with modern medicine and new farming methods. For example, we sprayed to destroy mosquitoes in Sri Lanka in the 1950s. In one year, the average life of everyone in Sri Lanka was extended by eight years because the number of people dying from malaria suddenly declined. This was a great human achievement. But we cut the death rate without cutting the birth rate. Now population is soaring. There were about one billion people livi ....