Lecture 28 Biodiversity & Human Impact Global Changes & Challenges Damage done to one of the world’s ecosystems can have ill effects on many others Widespread effects on the worldwide ecosystem are termed global change Patterns of global change include Pollution Acid precipitation
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Industrial pollution is one of the key problems
It results from a failure of our economy to set a proper price on environmental health
The reason is money!
Economists have identified an “optimum” amount of pollution based on how much it costs to reduce pollution versus the social and environmental cost of allowing pollution
However, The indirect costs of pollution often are not taken into account!Reducing Pollution
All cars are required to eliminate automobile smog
Catalytic converters, more efficient gas engines, hybrids, and alternate fuel vehicles are a result
The Clean Air Act of 1990 requires that power plants eliminate sulfur emissions
In effect, a government-imposed price hike that adds the “hidden” environmental costs to the price of production.
This can discourage consumption or encourage desired behavior
The recycling tax on bottles and cans is an example
Pollution trading (being tried in California)
“Acceptable” pollution totals are set for each pollutant
Companies own rights to pollute a given amount
If one company wants to pollute more, or a new company wants to add pollution, they have to buy the rights from someone who is not using theirs or who will change behavior to produce less
The cost of polluting then becomes subject to market values while the overall level of pollution is kept within target levelsReducing Pollution
In addition to fossil fuels, key nonreplaceable resources are:
BiodiversityPreserving Nonreplaceable Resources
Is being lost at a rate of centimeters per decade
The US has lost 25% of its topsoil since 1950!
Terracing to recapture lost topsoil
Alternate farming methods that do not rely on nitrogen fertilizers
Creating ethanol from corn is trading topsoil for energy!
Creating ethanol from cellulose biomass is potentially better for the soil
Seeped into its underground reservoir very slowly during the last ice age over 12,000 years ago
It is being wasted and polluted
While we should all conserve our personal use of water
It is also notable that if Californians quit watering all lawns (home and golf course) it would reduce California water use by < 10%
Agriculture consumes 85% of all freshwater resourcesPreserving Nonreplaceable Resources
In the last 20 years, ~ 1/2 of the world’s tropical rain forests have been either burned or cut
Animal and plant species are becoming extinct
Species from these areas have been the basis of many of our modern wonder drugs
Marshes and swamps have been and continue to be drained for economic development
They play a major role in cleaning the water in our aquifers
Commercial seed companies are replacing local farmers’ seeds and reducing the genetic base of food crops
In the early the 1970s 70% of the U.S. corn crop was lost to Southern corn blight due to the narrow genetic base of commercial seed corn
Marine resources are being threatened by over fishing, pollution, and global warming.
Loss of species entails three costs
Directeconomic value of the products
Indirecteconomic value of the benefits
For example, water purification by marshlands
Ethical and aesthetic valuePreserving Nonreplaceable Resources
Fears of vast radioactive contamination
Spent nuclear fuel remains radioactive for thousands of years
Fears of terrorists getting their hands on plutonium
Insuring energy payback
Is nuclear really an alternative energy?
In a study for the U.S. Department of Energy in the 1960s, Howard Odum showed that the amount of fossil fuel energy required to:
Mine and refine the uranium
Build & maintain the nuclear power plant
Deactivate the plant at the end of its life
Was equal to the amount of nuclear generated electricity the plant produced during its life
Note that his calculations did not include storing and monitoring the radioactive waste for hundreds or thousands of yearsThe Costs of Nuclear Energy
Growth rate in developed countries is 0.1% per year
Growth rate in developing countries is 1.9% per yearTrends in Human Population Growth