Category: biodiversity

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biodiversity Carrying Capacity Environment

Tragedy of the Commons

“In every deliberation, we must consider the impact on the seventh generation….”
Great Law of the Iroquois

 

            “They know that they shouldn’t fish closer than 500 meters from the coast, but I’ve seen these boats with their nets out just 200 or 300 meters offshore. The officials don’t enforce the laws.”

We were visiting the Greek island of Mykonos while on tour with the Durango Choral Society. We walked along the harbor with our guide, David, admiring the many small fishing boats. He explained facets of the failing Greek economy as well as the ancient and modern sites on this beautiful island. The Aegean Sea around Mykonos was so overfished, David said, that there were few fish left to catch.

We found proof that David was correct when we sat down to eat. Restaurants, even those overlooking the beautiful blue Aegean, had menus that listed few seafood dishes. Any seafood was prohibitively expensive since it had been caught in distant seas.

The situation that we encountered in Greece is a good illustration of the “tragedy of the commons”. That tragedy can occur when a limited resource is open to uncontrolled use by many people. Any one user may think he can benefit from taking as much of the resource as possible. This behavior is rational only in the narrow sense of self-interest. Regrettably, unbridled use of a resource is likely to lead to its depletion.

The term “commons” referred to pastureland that was available for everyone to graze his sheep in old England. Now it includes many different vital resources such as the air we breathe, the water we drink and the fish in the Aegean.

Most of us learned to share in kindergarten. Unfortunately, some adults never mastered that lesson or have forgotten it.  When there are many people using the same resource, any person who takes more than his share may deprive others of their fair share. Even worse, selfish people can deplete the resource, so eventually no one benefits from it.

In the case of fishing off Mykonos, there had been plenty of seafood for centuries. In the past the boats and fishing techniques only allowed small, sustainable catches, so the small proportion of sea life that ended up in nets was quickly replaced. Now, with more fishermen and more effective fishing techniques and many more mouths to feed, the fish supply has been exhausted. The Greek government has tried to prevent depletion by having a “no fish” zone, with poor results. People don’t seem to pay attention to the law, or the reason that it is needed.

Human population growth is one factor leading to the tragedy of the commons: more people using the same resource means less for all.

Ironically, some of the pollutants we have unintentionally added to drinking water may serve as a feedback mechanism to slow human population growth. Endocrine disruptors are chemicals that have unintended hormonal effects. They are found in much of our country’s drinking water. Some come from insecticides and other agricultural chemicals. Many plastics contain BPA, which has undesirable effects. Another source is the waste of women taking hormones. These chemicals have been shown to produce fish and other animals with sexual aberrations. It is possible that endocrine disruptors will lead to decreased human fertility.

The amount of fresh water on the planet is limited and, in some cases, is very slow to be replenished. The Ogallala aquifer is an example of a resource that is being used in an unsustainable manner. Much of the food grown in our country’s midwestern breadbasket depends on water from this aquifer. Tragically, there are some places in eastern Colorado (and in other states) that rely on the Ogallala where the water table has dropped 40 feet in just 15 years!

As our human population has grown, the apparent size of the commons has shrunk. Although the first few wells in the Ogallala made little difference to the water table, now we seem to be sucking it dry. Dumping waste into a river or the atmosphere made little difference with few people and fewer factories, but these resources have become toxic in our populous, industrialized nation. We are learning the problems that can be caused by abusing the commons.

The people who will suffer the most may be those who come after us, the “seventh generation” in the Iroquois law. Unless we think and plan ahead, our progeny will not have the use of many of the resources that we have enjoyed.

© Richard Grossman MD, 2012

Categories
biodiversity Durango Herald Environment Public Health

Benefit from the Natural World

Benefit from the Natural World

© Richard Grossman MD, 2009

There is a fountain of youth, and it may be very close to you. A remarkable new study shows a way to prolong life.

People who live near green space live longer than those who live surrounded by treeless city. Research from England describes the value of green space. This careful study controlled for potential confounding factors. The researchers looked at the death rates of over 40 million people during a five-year period and found that people were less likely to die if they lived near green space.

The authors hypothesize that green space, defined as “open, undeveloped land with natural vegetation,” promotes health by encouraging exercise. Indeed, it is estimated that every hour of physical exercise prolongs a person’s life by two hours. This study’s authors also theorize that green space is psychologically and physiologically restorative. Being in nature can promote relaxation and lower a person’s blood pressure. Presumably, it is the tranquil vistas, pleasant odors and the sounds of nature that are pleasing and beneficial.

Of these two factors, the researchers felt that exercise is valuable, but relaxation is even more important. There is a possible third factor that they did not mention, however.

A couple of years ago a news release puzzled me. It stated that people in some of Colorado’s highest counties were the longest lived in the whole nation. At first, this report didn’t make sense, since life is arduous in the high, cold mountains. Then I learned the importance of air quality; put simply, bad air kills. Very fine particles in the air, such as from diesel exhaust, are serious contributors to heart and lung disease. Presumably people who live at altitude breathe purer air and are poisoned by fewer of these tiny particulates. This may be why they approach Methuselah in longevity.

It turns out that plant life helps filter out air impurities. Particles settle on plant surfaces, and then are washed to the ground by rain. In addition, vegetation absorbs some impurities and makes them harmless. This may be a third way that green space helps people live longer. Promoting exercise, promoting relaxation and purifying air are all important rôles for the natural world, even though they are poorly recognized by our capitalistic system.

Business and politics attach little value to undeveloped natural resources. The above study illustrates how valuable land with natural vegetation really is. There are many other examples of how the natural world benefits mankind.

New York City learned the value of environmental resources when its water quality deteriorated. Its water comes from the Catskill Mountains, where natural processes had always purified the water. With the growing human population, the streams and lakes became contaminated by agricultural runoff and sewage. The City considered building a huge water purification system, but found that it was much less expensive to rehabilitate the watershed. By purchasing more land and cleaning up the pollution they regained pure water, saved money, and avoided the continuing cost of running a decontamination system.

Honey bees (Apis mellifera) are appreciated for their sweet product. The value of the honey produced in the USA is about $150 million each year. We benefit from bees in another way that is even more important. These little insects are invaluable for pollinating crops. The worth of this service has been estimated at $15 billion annually—one hundred times as much as honey production! We are starting to realize how truly helpful bees are now that they are disappearing for mysterious reasons. The impact on agriculture—and on natural vegetation—will be tremendous if this loss continues.

Closer to home, beavers (Castor canadensis) are seldom seen, but their dams and lodges are common. They almost became extinct in the American west during the 19th century when they were trapped for their fur. Without beaver ponds to hold water, stream beds washed out, resulting in floods and droughts. The dams and ponds create fertile bottom land and help purify water by filtering out impurities. Fortunately, beavers were reintroduced starting in the 1950s, helping to provide pure water for communities downstream.

It is difficult to assign a value to natural resources. In the past green space was considered pleasant, but optional. Our perception of its value may increase now that we know that it promotes health and longevity.

Preserving and restoring as much as possible of the natural world, especially green space, has benefits that may not be immediately evident. We should resist the urge to destroy natural resources before understanding their true value.

This article first appeared in the Durango Herald 1-2009

The article above may be copied or published but must remain intact, with attribution to the author. I also request that the words “First published in the Durango Herald” accompany any publication. For more information, please write the author at: richard@population-matters.org.