One Planet, Too Many People?

Professor Joel E. Cohen stood at the lectern, looked out over the crowd with his round, mischievous eyes and, with a click, posted a slide on the large screen to his right that brought a world of problems down to a more human scale.

There appeared two photos of door handles: one, a simple round knob, the second, a lever. This commonplace device, he explained, set the scale of the engineering challenge for a society whose population grows increasingly older: For the elderly who may have lost the hand-power of their youth, these two designs illustrate the difference between getting out and staying put.

The solution is a simple engineering fix, but on a daunting scale, when you think of all the doorknobs in all the cities of the world. But it’s possible. And that theme drove an Earth Institute-led discussion at Columbia Monday about the challenges faced in a world projected to reach 9.5 billion people by the year 2100.

Three-quarters of these people will be crowded into increasingly unmanageable cities. In some regions, such as North America and Europe, they will be older; in others, such as Africa, predominately under 30; many will be desperately poor. They will have different, and rising needs.

We’ll need to double food and energy production by 2050, experts say; the demand for water could rise 30 percent by 2030. Can we manage these needs without depleting our resources and ruining the environment? And how will we do that?

“The solutions are all within the capability of existing technology,” keynote speaker Tim Fox, head of energy and environment at the Institution of Mechanical Engineers in London, told the gathering at Lerner Hall. “There are no insurmountable engineering challenges.”

The barriers to this kind of progress, he said, are primarily financial, social and political—no small challenge.

The forum was cosponsored by the Lenfest Center for Sustainable Development, whose director, Klaus Lackner, moderated. Panelists were Cohen, of the Laboratory of Populations, Rockefeller University and the Earth Institute; Glenn Denning, director of the Center on Globalization and Sustainable Development; Elliott Sclar, director of the Center for Sustainable Urban Development; and Alex de Sherbinin, a senior staff associate at the Center for International Earth Science Information.

Fox’s presentation grew out of a 2011 report, “One Planet, Too Many People?” produced by the Institution of Mechanical Engineers, that lays out the challenges—and many possible engineering solutions—to the problems posed by growing population.

And the challenges as described by Fox vary from region to region around the globe. Populations in North America and Europe, which have seen huge gains in economic growth over the past 200 years, are growing more slowly now, or actually declining; and, they’re growing older. Meanwhile, Africa’s fastest-growing population will remain much younger in age over the coming decades, and much poorer. Asia represents the largest block of population, still growing, for now. As the fast-developing economies of countries like China become more affluent, their populations will tend to stabilize, but their demand for more products, food and energy will balloon.

So, too, grows the discrepancy between the affluent and the poor: The ratio of per capital income between North America and Africa was 3-to-1 in the early 1800s; it is 17-to-1 today.

All of these present different challenges for engineers.

Fox noted that as of 2010, half the population now lives in urban areas. We have 20 cities with populations over 10 million; that could grow to 29 such megacities by 2025. So, too, grow the slums. The need to adapt to this—from the standpoint of housing, sanitation, waste disposal, transportation, workplaces, food and energy—“is a significant challenge for the engineering community,” Fox said.

“We don’t have to repeat the mistakes of the 20^th century” as we design for the 21^st, said Sclar, of the Center for Sustainable Urban Development. He noted our cities were built on four assumptions: Energy is cheap, we can toss our garbage onto landfills, the climate is unchanging, and there’s safe drinking water nearby. “None of those assumptions can be taken for granted today,” he said.

The challenges we face will be exacerbated by dwindling resources and climate change, the panelists said. We will see increasingly extreme weather patterns, including more intense drought, floods and sea level rise—and the resulting displacement of perhaps as many as a billion people by 2050.

We have a finite amount of water—but enough, Fox said, to provide what we need, if properly used. Better systems of water capture and storage, desalinization, reducing waste and increasing use of recycled water can be accomplished using “well-known engineering practices.”

Fox sees “a unique opportunity with newly industrializing regions” to employ sustainable technologies … to make sure they learn from the mistakes we’ve already made.” An example of such “leapfrogging” technology: Many areas of Africa have skipped over landline telephones and gone straight to mobile phone use—a shift that has boosted economic activity and the provision of public health services.

Similarly, while the developed world struggles to reduce fossil fuel dependency and adopt large systems of renewable energy, in Africa the price of photovoltaic solar power used in small, localized power systems has become more affordable, compared to the cost of creating a national power grid to serve remote areas.

Denning, from the Center on Globalization and Sustainable Development, argued we must get past the “questionable science” clouding the political debate over the use of biotechnology. “We need to be able to adapt crops and crop improvement techniques in order to feed people,” he said. He also said we need to look more closely at our use of inorganic fertilizer, whose production is carbon-intensive in an era when we’re trying to reduce carbon emissions to curb global warming.

De Sherbinin cited consumption as a key issue—countries by and large want to increase demand to help their economies grow; but as more countries achieve greater affluence—driving more cars, eating more meat—that puts a greater strain on resources. From the standpoint of consumption practices, the technology that provides us with continually new and improved things like more advanced cellphones could have a negative impact.

Even if the population were not to grow, “Are we actually sustainable now?” he asked. Governments need to address the larger social issues such as population, habits of consumption and energy use. “It’s not a good idea to rely solely on science and technology to solve our problems.”

Population is where Cohen’s main message lies: We should be increasing the availability of voluntary contraception, as well as access to education, and maternal and early childhood health care. If the birth rate rises by a half a child per woman, he said, we’ll wind up with 16 billion people by 2100. If it drops a half a child, we’ll wind up with six billion—a billion fewer than today.

To see the engineering institute’s report, go here.

The “One Planet, Too Many People” forum was co-sponsored by the Lenfest Center, the Columbia Climate Center, the Department of Earth and Environmental Engineering and the Department of Mechanical Engineering and made possible by the Office of Academic and Research Programs.