The number of automobiles is growing three times faster than the human population. Fossil-fuel emissions and industrial pollutants are also increasing. Air pollution levels in the world's 20 largest cities exceed WHO guidelines. Fewer than 1 percent of 500 Chinese cities surveyed have clean air. Depletion of ozone in Earth's atmosphere.
Respiratory diseases are the leading cause of death in China.
The incidence of skin cancer in the United States jumped from 10,000 cases in 1975 to 40,000 in 1996. Global population expansion. Less cropland per person. More than half the world's population suffers from malnutrition. Close contact with white-tailed deer populations and thus the deer tick, which carries the bacterium Borrelia burgdorferi.