In much of Africa and Latin America throughout the 1980s per capita income declined, although it grew in Asia and in industrialized countries (World Health Organization, 1990). Average per capita income in industrialized countries is about 50 times that of the least developed countries, and the annual increase alone in the richer countries is about as large as the whole per capita income in the poorest countries ($300).

It took about 130 years (from around 1800 to 1927) for the world to increase its population from 1 billion to 2 billion. Only 33 years (1927–1960) were necessary for the third billion, 14 years (1960–1974) for the fourth, and 13 years (1974–1987) for the fifth (World Health Organization, 1990). The world's population is expected to increase by 1 billion each decade well into the twenty-first century. Most of this growth will occur in developing countries. Their population (excluding China) is expected to increase from a total of 3 billion today to about 5.6 billion by the year 2035 (Population Reference Bureau, 1991). The percentage of the world's population living in developing countries will increase from 55 percent to 65 percent.

Leaders of developing countries in the humid tropics are also confronted by financial circumstances that have contributed to poverty. In the early 1980s, international assistance provided developing countries with a surplus of some $40 million. A decade later, developing countries had accumulated a total debt burden in excess of $1.3 trillion (Lean et al., 1990), partly as the result of inflation, global recession, increasing interest rates, poor returns on development investments, and trade imbalances. The costs of servicing these debts now outpace the amount of aid. As a result, spending to reduce poverty and help the poor is cut, and continued poverty contributes to population growth rates. Some of the highest debt loads (both absolute and relative to gross national product) have been incurred by Brazil, Mexico, and the Philippines.