THE FIRST upright (bipedal) animals that closely resembled modern humans can be traced back about 1.5 million years. The number of humans increased relatively slowly for most of the time since then, but over the past several hundred years it has increased very rapidly.
In the year A.D. 1 the world population was roughly 250 million. By the year 1850, it had increased to nearly 1 billion. Over the next 100 years the number increased to 2.5 billion. And between 1950 and 1987, global population again doubled, to 5 billion. That increase in less than 40 years equaled the total increase from the time the human species first emerged until the middle of this century.
The current net rate of increase is more than 10,000 people per hour. Of the 5.6 billion people who now inhabit the Earth, more than 40 percent are under the age of 15, setting the stage for a continued mushrooming of the world's population.
Afghanistan, Bangladesh and several African countries can expect a doubling of population by 2010. In the next 20 years, the Philippines may increase from 59 million to 92 million; Iran from 53 million to 95 million; Mexico from 83 million to 125 million; and Brazil from 144 million to 207 million. Java, an Indonesian island the size of New York state, has the densest population on Earth, 120 million, and by the turn of the century is expected to have 160 million.
On the other hand, all countries that are part of the Organization for Economic Cooperation and Development as well as the Eastern European countries had low population growth rates during the 1980s. Over the next 20 years the populations of these countries will barely rise.
Faster growth rates characterize Asian countries, although the low overall figure for the Asian planned economies (Myanmar, Cambodia, China, North Korea, Laos, Mongolia and Vietnam) is heavily influenced by China's efforts to keep its vast population under control.
In the 1980s China managed to decrease the birth rate steadily, sparking a fall from 23.33 births per
1,000 women in 1987 to 18.2 per 1,000 in 1992. Despite this change, it would still take about 50 years to be able to detect a decrease in China's growth. Growth rates in many Latin American countries are also slowing substantially.
The United Nations has estimated that by the year 2055 the world's population will have risen to 8.5 billion, a 60 percent increase over the current figure, before stabilizing at over 10 billion by the end of the 21st century.
While every effort should be made to curb the growth of population, it will continue to rise, at least over the next hundred years.
Coastal environments will be degraded and important habitats lost unless decisive actions are taken now to help areas at greatest risk. Contamination of drinking water supplies and bathing and fishing areas by human wastes could lead to epidemics. Governments should determine the threatened coastal areas and act now to minimize the threats to human health and welfare.
J. R. Schubel is a contributor to the Earth Times.