Of the world population of about 6.5 billion, 57 percent is malnourished, compared with 20 percent of a world population of 2.5 billion in 1950, says a new study to be published in December by a Cornell professor and 120 graduate students.
The team examined data from more than 120 published papers on the effects of population growth, malnutrition and various kinds of environmental degradation on human diseases.
They found that malnutrition is not only the direct cause of 6 million children's deaths each year but also makes millions of people much more susceptible to such killers as acute respiratory infections, malaria and a host of other life-threatening diseases.
Among the study's other main points:
- Nearly half the world's people are crowded into urban areas, often without adequate sanitation, and are exposed to epidemics of such diseases as measles and flu.
- With 1.2 billion people lacking clean water, waterborne infections account for 80 percent of all infectious diseases. Increased water pollution creates breeding grounds for malaria-carrying mosquitoes, killing 1.2 million to 2.7 million people a year, and air pollution kills about 3 million people a year. Unsanitary living conditions account for more than 5 million deaths each year, of which more than half are children.
- Air pollution from smoke and various chemicals kills 3 million people a year. In the United States alone about 3 million tons of toxic chemicals are released into the environment -- contributing to cancer, birth defects, immune system defects and many other serious health problems.
- Soil is contaminated by many chemicals and pathogens, which are passed on to humans through direct contact or via food and water. Increased soil erosion worldwide not only results in more soil being blown but spreading of disease microbes and various toxins.