If a country's carrying capacity is 10, and the population is 11, then you get starvation. If you raise the carrying capacity to 20, the starvation ends. Until the population hits 21. That is not a sustainable process.
Meanwhile, the ratio of people to non-food natural resources has increased, resulting in pollution and crowding.
"Besides increasing the worldwide food supply, Borlaug has repeatedly stated that taking steps to decrease the rate of population growth will also be necessary to prevent food shortages. In his Nobel Lecture of 1970, Borlaug stated, "Most people still fail to comprehend the magnitude and menace of the 'Population Monster'...If it continues to increase at the estimated present rate of two percent a year, the world population will reach 6.5 billion by the year 2000. Currently, with each second, or tick of the clock, about 2.2 additional people are added to the world population. The rhythm of increase will accelerate to 2.7, 3.3, and 4.0 for each tick of the clock by 1980, 1990, and 2000, respectively, unless man becomes more realistic and preoccupied about this impending doom. The tick-tock of the clock will continually grow louder and more menacing each decade. Where will it all end?"[20]"
He caused a problem by solving another apocalyptic scale problem. Like Julian Simon, I am confident that new technology will emerge to solve any overpopulation problems.
The crowding is not due to too many people. There are lots of places on the planet with very few people; it's just that many people (when free to travel) prefer crowding to solitude.
Meanwhile, the ratio of people to non-food natural resources has increased, resulting in pollution and crowding.