Specifically, environmental sustainability refers to humans living on Earth and utilizing our natural resources in a way to ensure they are available for future generations. The factors that are important to sustainability are biological diversity, human population levels, resource consumption, CO2, CH4 and other greenhouse gas concentrations, and food production.
An important concept related to food production is a sustainable yield. Sustainable yield is the amount of food that can be harvested without decreasing the food supply. This concept applies to timber harvesting, freshwater, fish populations as well as all crops.
Areas that have historically not been able to manage a sustainable yield are resources that are considered a commons. Fishers worldwide are being fished at a rate faster than they can reproduce causing their populations to crash. This crash often results in one of two outcomes, extinction of the species or a regulation that stops harvesting. Either option results in humans losing access to that resource. If the fishers are managed at a sustainable yield then they should be able to have a consistent population and be able to provide that resource to humans.