All organisms use natural resources to sustain themselves.
Reproduction results in exponential growth of populations, but limits due to resource availability determine a carrying capacity for each population in a given ecosystem. The human population is currently in a stage of exponential growth. According to Garrett Hardin's essay, The Tragedy of the Commons, technology cannot possibly save humanity from the tragedy to be expected when the human population depletes natural resources and reaches limits due to the carrying capacity of the earth. One scenario would result in the extinction of the human race. Other researchers, however, see human beings as capable of altruistic behavior and capable of solving most environmental problems.