The End Is Nigh, Again

Environmentalists insist that humanity really has overshot the earth's carrying capacity this time.


The United Nations Summit on Sustainable Development is coming up at the end of August, so expect to see a spate of news stories warning that humanity is on an unsustainable economic path. To bolster this notion, environmentalists are positioning their views to make it easy for the press to echo them.

In an article published this week by the prestigious journal Proceedings of the National Academy of Sciences, a group of environmentalists led by Mathis Wackernagel of Redefining Progress claim that human consumption and waste production have overshot the earth's capacity to create new resources and absorb waste. They calculate that "humanity's load corresponded to 70% of the biosphere's capacity in 1961," and "this percentage grew to 120% in 1999." They explain that "20% overshoot means that it would require 1.2 earths, or one earth 1.2 years, to regenerate what humanity used in 1999."

Such worries about overpopulation and resource scarcity have a long history. The Roman writer Tertullian warned in 200 A.D. that "we men have actually become a burden to the earth" and that "the fruits of nature hardly suffice to support us." In 1798 the Rev. Thomas Robert Malthus published An Essay on the Principle of Population, in which he claimed that population growth would always outstrip food supplies, inevitably resulting in famine, pestilence, and war. Biologist Paul Ehrlich notoriously updated Malthus' gloomy predictions in his 1968 book The Population Bomb, which predicted that hundreds of millions of people would die of famine in the 1970s.

Well, are the alarmists right this time around? Is the end finally nigh? No.

Wackernagel et al. focus their analysis of how humanity uses the biosphere on six areas: growing crops, grazing animals, harvesting timber, fishing, building infrastructure, and getting energy from fossil fuels and nuclear power. According to their own calculations, humanity has not exceeded the biosphere's capacity in the first five of these areas, although they say we are close to the limits for growing crops and fishing. This leaves fossil fuels and nuclear energy, which they claim account for fully half of humanity's biosphere use. By their account, then, humanity would be using only 60 percent of the biosphere's capacity if energy use weren't a problem.

To estimate our impact on the biosphere, Wackernagel et al. calculate an average of how many hectares it takes to support each person. The reason energy use figures so prominently in their calculations is that they are looking at how many hectares it would take to absorb the carbon dioxide produced by burning fossil fuels. Their concern is that burning fossil fuels adds carbon dioxide to the atmosphere, which traps heat, which leads to global warming.

These calculations embody an ideal of stasis, both ecological and economic. What the authors miss is that for every one of the six areas they are looking at humanity's ecological footprint probably is going to become smaller, not larger, during this century.

Jesse Ausubel, director of the Program for the Human Environment at Rockefeller University, believes the 21st century will see the beginning of a "Great Restoration" as humanity's productive activities increasingly withdraw from the natural world. For example, Ausubel and his colleagues calculate, "If the world farmer reaches the average yield of today's US corn grower during the next 70 years, ten billion people eating as people now on average do will need only half of today's cropland. The land spared exceeds Amazonia." If 10 billion people choose meat-rich diets in 2070, then farmers will need only 75 percent of today's cropland. In other words, through technologically improved farming, millions of acres will revert to nature.

With regard to grazing animals, many environmentalists paradoxically oppose intensive meat production that can spare millions of acres. "If you very efficiently produce grain to feed chickens rather than allowing free range cattle," explains Ausubel, "it's hard to see how you have a problem with increased meat consumption."

Ausubel also notes that "forest regrowth appears part of modernity." He points out that U.N. Food and Agriculture Organization studies "of forest biomass for the decade of the 1990s in the boreal and temperate region in more than 50 countries show the forests expanding in every one of them." As global cropland and grazing area shrink, forests will continue to expand. Ausubel estimates that humanity will need to use 20 percent or less of the world's 3 billion hectares of forest to sustainably supply all of our wood needs in the 21st century.

"The fish situation is much more difficult," Ausubel cautions. Many fisheries are being harvested at or over their sustainable limits. Ausubel notes that humanity consumes about 800 million tons of animal products–meat and milk–produced on land, compared to 80 million tons caught wild in the oceans. His solution to overfishing? "The ancient sparing of land animals by farming shows us how to spare fish in the sea," he says. "We need to raise the share we farm and lower the share we catch."

Already, 20 percent of seafood is produced by aquaculture that can be expanded in sustainable ways, relieving pressure on wild species such as cod and rockfish. In addition, as Iceland's and New Zealand's fisheries show, privatizing fisheries dramatically increases the incentives to conserve and protect wild stocks.

As for infrastructure, Ausubel calculates that if an additional 4 billion people (who are unlikely to materialize, according to the latest U.N. population projections) chose to occupy as much land as the average Californian does today, they would cover 240 million hectares of land, about 2.5 percent of the earth's terrestrial surface.

So we come to Wackernagel et al.'s chief concern: energy use. "Some people try to use the climate change issue as a trump card," says Ausubel. "It sounds like they're doing that." Keep in mind that despite Wackernagel et al.'s certitude, there are still serious questions about whether adding cabon dioxide to the atmosphere is really causing significant problems for humanity or the biosphere.

Assuming that man-made global warming is a real problem, there are plenty of ways to handle it. One is to deploy technologies we already have to mitigate its effects on humanity: heating, air conditioning, seawalls, irrigation of farmland, crop switching, and so forth. We could also choose to sequester extra carbon dioxide by pumping it back into the ground whence it came, fertilizing the tropic ocean deserts so that they bloom with phytoplankton that absorbs it from the air, or planting more trees.

In any case, Ausubel doesn't think that carbon dioxide is a long-term problem because the world's energy system has been inexorably decarbonizing for the past two centuries. His research traces humanity's steady progress from wood to coal to oil to natural gas and, eventually, to hydrogen. At each stage, consumers, without being commanded to do so by regulators, have chosen fuels containing more hydrogen over fuels containing more carbon.

Ausubel sees that trend continuing until carbon-based fuels are eliminated by the end of the century. He expects that carbon dioxide concentrations, now about 360 parts per million (ppm), will peak at 450 ppm. That is 100 ppm less than the U.N.'s sometimes stated goal of "stabilizing" carbon dioxide at 550 ppm, and it would happen without draconian increases in energy prices or the creation of global bureaucracies aimed at regulating the atmosphere.

So Wackernagel et al. are wrong on every measure they chose to analyze with regard to the future sustainability of the human enterprise. How could they get it so wrong?

"Biologists and ecologists tend to overlook the power of technical progress compounded over the years," says Ausubel. "If you're trained in ecology and botany, you think of technology as a bulldozer, but what it really is, is efficiency, using less to do more."

Technological progress has already dramatically expanded the carrying capacity of the earth. In the 21st century it will so outpace the increasing demands of a growing and wealthier population that more and more land will revert to nature.

"It looks like over the next 100 years, for most environmental concerns, we will do better," concludes Ausubel. "You get smarter as you get richer."

Ausubel's own article in the June 11 issue of the Proceedings of the National Academy of Sciences concludes, "An annual 2-3% progress in consumption and technology over many decades and sectors provides a benchmark for sustainability." In other words, economic growth and technological progress are sustainable in the long run and make it less and less likely that humanity will overshoot any limits the biosphere may have.

Let the Great Restoration begin!