The Carlisle Mosquito Online

Friday, January 13, 2006


How much is nature worth?

John Harte, a professor of Environmental Science at the University of California at Berkeley and brother of Carlisle resident Ken Harte, recently spoke on the value of our natural environment at a First Religious Society service. For many people, our natural environment has huge intrinsic aesthetic and spiritual value. Dr. Harte says that we can determine "hard economic numbers" that place a monetary value on wild nature.

According to the journal Nature, "Natural ecosystem services are worth $30 trillion per year to humanity" — more than the world's gross domestic product. Examples abound: over half of the world's medicines are derived from wild plants and animals. Yucca trees that were bound for extinction were found to give a drug that treats cancer patients. A substance found in the blood of the common western fence lizard kills Lyme disease bacteria in ticks that feed on it, explaining why there is less Lyme disease in California than in the eastern states. More pest control is done naturally by birds and snakes than by all of the pesticides that people produce. A variety of wild Mexican corn that was going to be destroyed for farming was determined to be "nitrogen fixing," meaning that it can grow in poor soil. Coastal mangrove forestlands in Indonesia, if left "undeveloped," would have reduced the effect of the devastating tsunami in 2004. The valuable Ogallala aquifer in the central U.S. recharges partly because prairie dog burrows improve drainage.

Unfortunately, mankind is rapidly changing our natural environment in many ways. An area of tropical rainforest the size of Pennsylvania is destroyed each year (a football field each second). In a remote region of Tibetan China, Dr. Harte has measured the most acidic rainfall ever recorded. As part of an innovative experiment in Colorado, he is quantifying species loss in a plot of prairie land that is being artificially heated to simulate the effects of global warming. Dr. Harte states simply, "Land-use practices are leading to an extinction episode that will, within 50 or 100 years, be comparable to one that occurred at the Cretaceous-Tertiary boundary when an asteroid impact resulted in the demise of dinosaurs and roughly half of all species on earth."

What can we do to maintain the long-term sustainability of our ecosystems? A reduction and shift in consumption is a start — for example, eating vegetables and other items low on the food chain. We can also concentrate on energy efficiency and renewable energy, as the campus of UC Berkeley has done by running largely on solar power.

Any estimate of the value of a healthy ecosystem is inherently inadequate. What is the value of a life saved by a new medicine developed from an endangered species, or a life lost due to flooding from sea-level rise caused by ocean warming? (For a transcript of the talk, see

2006 The Carlisle Mosquito