Jeffrey Sachs is the director of the Earth Institute at Columbia University in New York. He has served as an adviser to many poor-country governments and was formerly head of the Harvard Centre for International Development. He is one of the world's foremost authorities on develpment
The fastest population growth is taking place in the world's poorest regions. As a result of high fertility rates, the UN Population Division shows a doubling of Africa's population from around 900 million today to around 1.8 billion in 2050.
In Europe, the trends run in the other direction, with the United Nations projecting a decline in population to around 630 million in 2050 from around 725 million people today. With few children and longer life expectancy, the median age of the population will rise sharply, from 39 years in 2005 to around 48 years in 2050. The world's population is expected to grow by 2.5 billion from 2005 to 2050. All of that growth will be in the developing world.
Adding another 2.5 billion people to the planet will put enormous strains not only on societies where populations are rising but on the entire planet. Total energy use is soaring, reflecting the combined effect of rising per-capita incomes person - and thus rising per-capita energy use - and growing populations. But higher energy use changes the world's climate in dangerous ways: deforestation, depletion of fisheries, land degradation, the loss of habitat and extinction of animal and plant species.
Population growth in developing regions - especially Africa, India and other parts of Asia - needs to slow. Public policies can play an important role by extending access to family-planning services to the poor, expanding social-security systems, reducing child mortality through public-health investments, and improving education and job opportunities for women.
On the other hand, a part of the European public, looking at Europe's looming population decline, wants to promote a return to larger families, worrying that there won't be enough young workers to pay for public pensions. But this concern can be met through increased savings by today's young and middle-aged to prepare for retirement, and by working past the age of 65.
Moreover, these workers will reap huge benefits. Most obviously, they will spend less to raise children. They will also save on investments in new roads, power plants, schools and other public services. They will enjoy less congested cities and fewer environmental pressures on the countryside. European economies will face lower costs in limiting emissions of greenhouse gases from energy use, leading to more-effective control of climate change. In short, the quality of life will tend to improve.
There is nothing radical about slower population growth. For thousands of years, the human population rose and fell without a substantial long-term trend. Only in the past two centuries, with the rise of modern economic life, did the world's population soar, from around one billion people in 1820 to 6.3 billion today.
This explosive growth was made possible by huge advances in science and technology, but it has put tremendous pressures on the planet. We should intensify efforts to slow population growth through voluntary means and should recognize that leveling off the Earth's population now will add to human happiness and strengthen environmental sustainability later.
Jeffrey D. Sachs is professor of economics and director of the Earth Institute at Columbia University.
This article first appeared in the Miami Herald.
©2004 Project Syndicate
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