Throughout history humans have both affected, and been affected by, the natural world. While a good deal has been lost due to human actions, much of what is valued about the environment has been preserved and protected through human action. While many uncertainties remain, there is a realization that environmental problems are becoming more and more complex, especially as issues arise on a more global level, such as that of atmospheric pollution or global warming.
Interactions between human society and the environment are constantly changing. The environment, while highly valued by most, is used and altered by a wide variety of people with many different interests and values. Difficulties remain on how best to ensure the protection of our environment and natural resources. There will always be tradeoffs and, many times, unanticipated or unintended consequences. However, a well-managed environment can provide goods and services that are both essential for our well being as well as for continued economic prosperity.
The environment has become one of the most important issues of our time and will continue to be well into the future. The challenge is to find approaches to environmental management that give people the quality of life they seek while protecting the environmental systems that are also the foundations of our well being. In order to face these challenges, students today will need more than superficial knowledge or awareness of disconnected environmental issues. A multidisciplinary approach to learning can build upon the strengths of a wide range of fields of study, providing a deeper understanding of the technological, political, and social options and strategies for both studying and managing the relationship between our society and the environment.
Changes in population can have a variety of economic, ecological, and social implications. One population concern is that of carrying capacity, the number of individuals an ecosystem can support without having any negative effects. It also includes a limit of resources and pollution levels that can be maintained without experiencing high levels of change. If carrying capacity is exceeded, living organisms must adapt to new levels of consumption or find alternative resources. Carrying capacity can be affected by the size of the human population, consumption of resources, and the level of pollution and environmental degradation that results. Carrying capacity, however, need not be fixed and can be expanded through good management and the development of new resource-saving technologies.
Throughout the late 1960s and 1970s, Garrett Hardin and Paul Ehrlich, both authors on overpopulation, contended that the human population had already exceeded the carrying capacity. Hardin is best known for his paper The Tragedy of the Commons, in which he argues that overpopulation of any species will deplete shared natural resources. Ehrlich, who wrote The Population Bomb in 1968, predicted a population explosion accompanied by increasing famine and starvation. Although his prediction did not come true, in fact, in 1970 there was a slight decline in the population growth rate, Erlich was correct in pointing out that, with the exception of solar energy, the Earth is a closed system with limited natural resources.
The standard of living in a region can also help to alter an area's carrying capacity. Compared to areas with a lower standard of living, areas with a higher standard of living tend to have a reduced carrying capacity due to greater access to and demand for more resources. Nevertheless, there is the suggestion that beyond some point, increased income and environmental improvement often goes hand-in-hand. The effect of an individual or a population on an ecosystem is called an ecological footprint, which can be used to measure and manage the use of resources throughout an economy. It is also widely used as an indicator of environmental sustainability.
Carrying capacity often serves as the basis for sustainable development policies that attempt to balance the needs of today against the resources that will be needed in the future. The 1995 World Summit on Social Development defined sustainability as 'the framework to achieve a higher quality of life for all people in which economic development, social development, and environmental protection are interdependent and mutually beneficial components'. The 2002 World Summit furthered the process by identifying three key objectives of sustainable development: eradicating poverty, protecting natural resources, and changing unsustainable production and consumption patterns.
While the exact value of the human carrying capacity is uncertain and continues to be under debate, there is a question as to the strain that population and consumption has placed on some societies and the environment. Economists, ecologists, and policy analysts continue to study global consumption patterns to determine what the human carrying capacity is and what steps can be taken to ensure it is not exceeded. In the meantime, actions to ensure natural resource recovery for the future will depend on an increase of sustainable development policies worldwide.