Our Ailing Planet
      The Human Factor Fossel Fuel Use Municipal Solid Waste Fresh Water Depletion Loss of Bio-Diversity Household Hazardous Waste Ocean Pollution Endangered Species Causes Why Be Concerned? Interesting Facts Species Profiles Ways You Can Help Urban Sprawl Solving Sprawl Open Spaces Land Use Transportation Communities Politics & The Environment Sierra Club Endorsements Take The Money...And Run The Center for Innovation & the Environment 24 Hours In Cyberspace Al Gore US Senate Environmental Scorecard US House of Representatives Environmemtal Scorecard |
Global Warming A Palo Perspective On Global Warming No longer is there a question about the reality of global warming. There is a world-wide consensus among climate scientists that global average temperature will rise over the next 100 years if the release of greenhouse gases from human activity continues to grow. Assessments by the U.S. National Academy of Sciences and the United Nations' Intergovernmental Panel on Climate Change (IPCC) project that Earth could experience the fastest warming in the history of civilization during the 21st century. Specifically, according to the IPCC, Earth may warm by 1.8oF to 6.3oF by the end of the next century, potentially making it warmer than at any time since the evolution of modern humans. Such a global temperature rise would be associated with significant climate change. The difference in global average temperature between modern times and the last ice age -- when much of Canada and the northern United States were covered with a thick ice sheet -- was only about 9oF. A temperature rise of similar magnitude could have serious, potentially devastating effects on society and ecosystems. Deforestation The Speed of Deforestation Deforestation increases the amount of carbon dioxide (CO2) and other trace gases in the atmosphere. The plants and soil of tropical forests hold 460-575 billion metric tons of carbon worldwide with each acre of tropical forest storing about 180 metric tons of carbon. When a forest is cut and burned to establish cropland and pastures, the carbon that was stored in the tree trunks (wood is about 50% carbon) joins with oxygen and is released into the atmosphere as CO2. The loss of forests has a profound effect on the global carbon cycle. From 1850 to 1990, deforestation worldwide (including the United States) released 122 billion metric tons of carbon into the atmosphere, with the current rate being approximately 1.6 billion metric tons per year. In comparison, fossil fuel burning (coal, oil, and gas) releases about 6 billion metric tons per year, so it is clear that deforestation makes a significant contribution to the increasing CO2 in the atmosphere. Releasing CO2 into the atmosphere enhances the greenhouse effect, and could contribute to an increase in global temperatures (see Global Warming Fact Sheet, NF-222). Deforestation and the Hydrologic Cycle Tropical deforestation also affects the local climate of an area by reducing the evaporative cooling that takes place from both soil and plant life. As trees and plants are cleared away, the moist canopy of the tropical rain forest quickly diminishes. Recent research suggests that about half of the precipitation that falls in a tropical rain forest is a result of its moist, green canopy. Evaporation and evapotranspiration processes from the trees and plants return large quantities of water to the local atmosphere, promoting the formation of clouds and precipitation. Less evaporation means that more of the Sun's energy is able to warm the surface and, consequently, the air above, leading to a rise in temperatures. Deforestation and Biodiversity Worldwide, 5 to 80 million species of plants and animals comprise the "biodiversity" of planet Earth. Tropical rain forests-covering only 7% of the total dry surface of the Earth-hold over half of all these species. Of the tens of millions of species believed to be on Earth, scientists have only given names to about 1.5 million of them, and even fewer of the species have been studied in depth. Many of the rain forest plants and animals can only be found in small areas, because they require a special habitat in which to live. This makes them very vulnerable to deforestation. If their habitat is destroyed, they may become extinct. Every day, species are disappearing from the tropical rain forests as they are cleared. We do not know the exact rate of extinction, but estimates indicate that up to 137 species disappear worldwide each day. The loss of species will have a great impact on the planet. We are losing species that might show us how to prevent cancer or help us find a cure for AIDS. Other organisms are losing species they depend upon, and thus face extinction themselves. Urban Sprawl Urban Sprawl: The Invisible Crisis In this article from Pioneer Planet, Lynda McDonnell traces the history of what we know today as "urban sprawl" back to the 1950s, using the Twin Cities-Minneapolis/St. Paul--as an example. She describes the slow-growing crisis resulting from "centrifugal forces" and "growth at the edge, decline at the core." The effects of urban sprawl have been diffused and slow to evolve and, therefore, have not grabbed the attention of a public accustomed to confronting much more acute, visible crises. While recognition is growing among policy-makers in the Twin Cities area, McDonnell finds it unlikely that this awareness will translate into quick, substantive changes to the process behind land-use decisions. Endangered Species Deanne's Endangered Species Archive Ever since life began on our planet many different species have come and gone through the natural process of extinction. If extinction is sometimes brought about by natural causes then why should we make such efforts to save endangered species? Many people ask this question. But, each and every different species has a unique purpose, and, if it dies out, the planet that we live on will not operate as well. The U.S. Fish and Wildlife service estimates that losing one plant species can trigger the loss of up to thirty other insect, plant and higher animal species. As well as this domino effect on endangering other species, our planet as a whole may face detrimental consequences. By removing living plant matter from our sensitive planet, the ability to absorb carbon-based greenhouse gasses is lost. Plants naturally convert CO2 into O2. A lot of CO2 is produced from the burning of materials, such as gasoline. Without a sufficient amount of plant matter CO2 cannot be converted into oxygen. This can result in the so called greenhouse effect, leaving CO2 floating around. Another reason species should be saved is that of their medicinal value. Many plant species save lives. Out of all the known plant species to exist only a small fraction of them have been screened for there medicinal values. A recent breakthrough of a promising treatment for ovarian and breast cancer was identified. This treatment comes from a substance called Taxol which is derived from the bark of the Pacific yew, a very slow growing tree that is found in the ancient forests of the Pacific North West. This tree used to be considered a "trash" tree and was burned after clearcutting. This tree is now endangered. Today forty percent of all prescriptions that are written are either based on or synthesized from natural compounds from different species. * These species save lives. Species also have great agricultural importance as well. Some time ago leaf fungus wiped out fifteen percent of the United States corn crop, but in the 1970's genetic material was discovered from a wild corn species that grows in Mexico and was used to stop the leaf fungus. This discovery proved to be very useful to the United States corn crop.* Wild species also provide people with the ability to grow crops in poor soils or areas with a lack of water and feed many people in hunger stricken areas. Some farmers have decided to use insects and other animals to prey on their crop pests. They also use plants containing toxin compounds that repel crop pests as well. These types of controls are called "biological controls." Species and their ecosystems form the basis of our multi billion dollar tourism industry, and supply jobs and recreation. Over fifty-nine billion dollars is spent every year by people in the United States on travel, lodging, equipment, and food to participate in wildlife recreation.* Some of these activities include fishing, hunting, and non-consumptive recreation. |