Humanity has, by most measures, done extraordinarily well over the past century. People on average live longer and eat better. The share of the global population living in poverty is lower than ever before. But supplying food, energy, materials, and water to a growing and increasingly wealthy population has come at a steep cost for the natural world. Humans today use at least half of all ice-free land, mostly for farming and forestry. Habitat loss, overexploitation, pollution, and other environmental impacts have on average reduced wildlife populations by more than half since 1970. Hundreds of species of birds and mammals have gone extinct over the past few centuries, and many more are threatened today.
But there are glimmers of hope. Even as biodiversity continues to be lost, there are signs that economic growth and human welfare are becoming increasingly decoupled from environmental impacts. While many of humankind’s environmental impacts have grown in absolute terms, several have started to flatten out or even decline. Per-capita impacts have in many cases gone down, in large part because the technologies used to produce goods have become less environmentally harmful. If these decoupling trends continue, it is possible that human impacts on the environment will peak and decline this century, even as the global population approaches 10 billion and people around the world become more materially rich and secure.
“Peak impact” offers an inspiring vision for global conservation. It can be achieved by accelerating beneficial economic and technological processes while continuing to use protected areas, payments for ecosystem services, and other conventional conservation tools at a landscape levels. Here is how it works.
Taking A Burden Off Nature
While population and per-capita consumption have added to humanity’s overall burden on the environment, technological shifts have for the most part reduced it. These shifts can be reduced to two mechanisms: substitution and intensification.
The substitution of tractors for horses eliminated the need to dedicate about one-quarter of all U.S. farmland to feed draft animals. The introduction of synthetic nitrogen meant farmers no longer needed to keep as much as half of their cropland in fallow to replenish soil nutrients. Together with agricultural intensification in the forms of rising crop yields and greater efficiencies in meat
production, these technological advances have allowed the area of farmland per capita to fall by half over the last half century, even as diets have gotten richer. While global farmland area has increased by about 10 percent since 1960—causing widespread habitat loss—it has barely grown since the early 1990s. During that period, global population rose by more than 20 percent and GDP per capita nearly doubled.
The transition from fuelwood to fossil fuels, nuclear power, and hydro as sources of energy has also contributed to flattening global demand for wood. In fact, per-capita wood consumption has declined so much as to offset the concurrent increase in food consumption, such that the total per-capita demand for biomass has stayed constant for more than a century. Today, it takes on average less than one hectare to provide food, energy, and living space per person, compared to an estimated four hectares per person among early agriculturalists some 7,000 years ago.
Through similar mechanisms, farmed meat and fish have taken pressure off wild populations. Petroleum- and plant-based substitutes for whale oil spared global whale populations—not just in the 19th century when kerosene replaced whale oil in lighting, but also in the 20th century when innovations made whale products unneeded for lubricants, soap, and margarine. Shifting from coal to natural gas to nuclear and hydro—and wind and solar power more recently—has gradually reduced the amount of carbon emissions per unit of energy, even as total global carbon emissions have continued to rise. As humans shift from harvesting goods in the wild—such as bushmeat hunting or whaling—to farming them, or to producing goods in factories, the amount of environmental harm per unit produced tends to fall.
In other words, in most cases, the more synthetic our consumption, the less nature we destroy. We spare nature by using less of it.