Earth’s carrying capacity is an inescapable fact

Physicists understand the mathematics of exponential growth. They, along with the rest of us often ignore its consequences, including the first law of sustainability: “Neither population growth nor consumption can be sustained indefinitely.”

Sustainability is a buzzword about environmental balance, recycling, energy and food production. It is a simple concept that brings a sense of environmental virtue if we feel that we are living “sustainably.” We know what it is but maybe can’t quite define it.

The report “Our Common Future” — also known as the Brundtland report (1987) from the World Commission on Environment and Development of the United Nations — defined sustainability as “meeting the needs of today without compromising the ability of future generations to meet their needs.” This definition of sustainability says nothing specifically about the environment, but a clean environment better meets those needs, and it is not only we humans that have needs.

Sustainability is related to carrying capacity, which is the maximum load that a given environment can support without detrimental effects.