Earth’s Carrying Capacity

Have we reached the Earth’s carrying capacity?  Well, perhaps I can offer my answer to this question by first defining carrying capacity and then establishing the Earth’s carrying capacity as assessed under current natural and social conditions.

As defined in The American Heritage® Dictionary of the English Language, Fourth Edition:

  • car·ry·ing (kār’ē-ĭng) ca·pac·i·ty (kə-pās’ĭ-tē) n.  
    • The maximum number of persons or things that a vehicle or a receptacle can carry: a van with a carrying capacity of 12.
    • Ecology The maximum number of individuals that a given environment can support without detrimental effects.

As explained by the Carrying Capacity Network, a watchdog organization of sorts, presenting “Real Solutions for America’s Problems”:

A common fallacy is to equate existing and seemingly open or “unused” spaces with the kind of resources and ecologically productive land needed to support human life under modern conditions. In fact, the criterion for determining whether a region is overpopulated is not land area, but carrying capacity.

Carrying capacity refers to the number of individuals who can be supported in a given area within natural resource limits, and without degrading the natural social, cultural and economic environment for present and future generations. The carrying capacity for any given area is not fixed. It can be altered by improved technology, but mostly it is changed for the worse by pressures which accompany a population increase. As the environment is degraded, carrying capacity actually shrinks, leaving the environment no longer able to support even the number of people who could formerly have lived in the area on a sustainable basis. No population can live beyond the environment’s carrying capacity for very long.

The average American’s “ecological footprint” (the demands an individual endowed with average amounts of resources, ie, land, water, food, fiber, waste assimilation and disposal, etc. puts on the environment) is about 12 acres, an area far greater than that taken up by one’s residence and place of school or work and other places where he or she is.

We must think in terms of “carrying capacity” not land area. The effects of unfettered population growth drastically reduce the carrying capacity in the United States.

In a post titled “Living Above the Line,” Environmental Research Foundation Precaution Reporter, Peter Montague, reiterated the assessment by the United Nations Environment Programme‘s fourth Global Environmental Outlook Report (GEO-4) in order to answer this question

…GEO-4 concluded that we humans presently require 22 acres per person to support our global average lifestyle — but, the report said, Earth has only 15 acres per person available.

In other words, we have already exceeded the Earth’s “carrying capacity” — it’s capacity to “carry” (or support) 6 billion humans. And the human enterprise is poised for a massive spurt of economic and population growth — expected to raise our numbers to 9 billion by roughly mid-century and to double the size of the human economy every 23 years….

Looking at the findings for the world as a whole presented in GEO-4, taking into consideration my own personal results I found in the ecological footprint quiz, and taking into consideration all of the other factors we have been discussing in People and the Environment lectures, such as the rate at which the Earth’s population is doubling, it is hard to argue against the fact that not only have we reached the Earth’s carrying capacity, but for many reasons we have long since exceeded the upper limits of population the global ecosystem can support.  However, I hope that we have recognized these statistics in time to correct the situation.  I believe the global society’s recognition of the mismanagement of our natural capital in time to continue to make strides toward a sustainable society, and setting and attaining hard and fast goals to meet sustainability, may provide the hope for our future and our grandchildren’s future.

Campus Environmental Tour

Talloires DeclarationOn Tuesday we took a little stroll around campus discussing some of the ways Bemidji State University demonstrates its responsibility as an institution for higher education by creating an educational environment that pledges to work towards sustainability.  As a public educational institution producing tomorrow’s leaders, the university needs to set an example for the generations of the current and future environmental stewards it prepares for graduation into society.  If our society is to change its practice of mismanagement of our natural capital, we have to learn how to change.  By establishing educational resources for the study of how we can successfully become a sustainable society, Bemidji State University joins a commitment to environmentalism with other leading institutions and organizations working to provide a healthier future for our local and global ecosystem.  The president of the university, Dr. Jon Quistgaard, promises this obligation by uniting with over 350 university presidents and chancellors in over 40 countries around the world in the Association of University Leaders for a Sustainable Future through the Talloires Declaration, and the university community expects a proposal to further this promise with a future signing of the American College & University Presidents Climate Commitment.

Other examples of Bemidji State University’s commitment to an ecocentric environmental worldview are detailed in these press releases from the university on November 29, 2007:

Other campus projects I find to be equally important, if not on the same scale as the above mentioned movements of environmentalism, then on the measure of what can be done by the individual or small group to renew and improve our campus and community are:BSU Campus Shoreline Habitat Restoration Project on Lake Bemidji

  • The Shoreline Habitat Restoration Project performs the following benefits for our local ecosystem and our downstream neighbors:
    • Restores a buffer zone using native plants
    • Provide habitat for a wide variety of wildlife
    • Filter out pollutants and runoff that degrade water quality
    • Prevent shoreline erosion by absorbing wave action
  • The implementation of a Rain Garden to reduce runoff and naturally filter storm water.

What is a Rain GardenA BSU Rain Garden

  • Landscaping with Native Plants such as a Butterfly Garden provide multiple benefits:
    • Native plants have evolved and adapted to local conditions over thousands of years.  Once established, they require no irrigation or fertilization.  They are resistant to most pests and diseases, and require no mowing.  Thus, native plants, conserving water and fossil fuels, and requiring less work to maintain, are less costly in the long term.
    • Native plants have longer root systems than non-native species which helps rainfall percolate into the soil, reducing erosion and runoff, and recharging ground water and improving water quality.
    • Native plants provide food and shelter for birds, butterflies and other desirable wildlife.

BSU Butterfly GardenThis little tour around campus inspired me to begin planning some improvements to my own property’s landscape.  I have always favored native plants for their simplistic beauty and minimal maintenance.  I especially have affinity for trees.  After discussing the question of why we mow and manicure our lawn with Professor Bailey-Johnson when a thoughtfully landscaped native plant ecosystem provides habitat for beneficial species, such as dragonflies – which prefer longer grasses while mosquitoes do not and dragonflies eat mosquitoes, I would rather have more habitat and wildlife on my property than an aesthetically pleasing keeping-up-with-the-Jones’-look.  Also, there is the consideration of time spent mowing – three hours per tour for me, but I have plans to cut that in half – and the incredible fact that 5% of all emissions in this country come from lawnmowers.  I mean really – why?