As usual, the so-called “carrying capacity” of the planet – the total number of people who can sustainably live on Earth – is hotly debated. Experts generally fall into two camps. There are those who argue that we must drastically reduce the human population to avoid ecological disaster. And then there are those who believe that technology will find smart solutions without the need to actively address the problem.
Scholars have debated such demographic questions since at least the 18th century, when Thomas Malthus published An Essay on the Principle of Population, arguably the first global treatise on the relationship between population growth and scarcity. A few decades later, however, the Industrial Revolution (which the British economist failed to foresee) ushered the world into an era of plenty and relegated Malthus’s grim predictions of the inevitability of scarcity to the margins of scientific debate.
In his late 1960s bestseller, The Population Bomb, Stanford professor Paul Ehrlich brought the theme back and advocated immediate action to limit population growth on a finite planet. This recommendation was repeated a few years later by the Club of Rome, an international network of scientists and industrialists. His 1972 report The Limits to Growth aptly demonstrated the dynamic relationship between increasing consumption and the idea of ”planetary limits” that cannot be crossed without risking serious environmental change.
It is true that some technologies have made production more efficient (fertilizers, for example) and thereby mitigated the impact of population growth on resource use. A smaller population could be increasingly destructive However, it is difficult to estimate how many people the planet can sustainably support.This is often overlooked in policy debates, which generally deal with the problem rather simplistically, based on the assumption that rising living standards will lead to lower birth rates.
Therefore, the argument goes that global population will decline once continents like Asia and Africa reach similar levels of development to Europe and North America. It is a mistake to assume that only technology and population matter. Currently, environmental scientists generally agree that total impact is also a function of well-being (the so-called I=PAT equation).
This can easily create a paradox. Countries continue to raise their living standards by increasing per capita consumption, resulting in smaller populations but much greater environmental impacts. Take China. The population growth rate fell significantly from 2.8% in the 1970s to its first absolute decline this year.
