councilor.org
| Source | Louis Proyect |
| Date | 99/08/05/22:54 |
| Humans altering Earth for the worse Thursday, August 5, 1999 Close to 50 percent of the Earth's land mass has been altered from its original state by humans. Recent research shows that humans are responsible for serious changes in the Earth's chemical, biological and physical structure — and the changes are not for the better. The data indicate that the human transformation of lands and oceans is severely disrupting the fragile ecological systems that people depend on for the basics of existence such as clean air, clean water, food and shelter, as well as safety from natural disasters such as flood and drought. The data was collected and analyzed by Dr. Jane Lubchenco, distinguished professor of Zoology of Oregon State University, and Dr. Harold A. Mooney and Dr. Peter M. Vitousek of Stanford University. Lubchenco presented their findings this week at the XVI International Botanical Congress hosted by the Missouri Botanical Garden in St. Louis. Some of the findings include: --Close to 50 percent of the land surface of the planet has been altered from its original state by humans, such as filling wetlands, converting tall grass prairies into cornfields, or converting forests into urban areas. --Humans have more than doubled the amount of available nitrogen in the environment because of excess fertilizer use and burning of fossil fuel. --Rates of extinction are 100 to 1,000 times what they would be without human-induced changes in the planet. On land, this is largely caused by habitat loss and species invasions that are crowding out native species. In water, this is caused by overfishing, as well. --The year 1998 was Earth's hottest on record, as human activities continue to increase the concentrations of carbon dioxide and other heat-trapping gases in the atmosphere. While the affect of humans on the available land mass is obvious — just drive Interstate 80 through the Midwest in the United States — the affect on the oceans is not as apparent. Lubchenco's research showed that approximately 50 "dead zones" — areas of water with little to no oxygen — have developed in ocean coastal areas, the worst of which is in the Gulf of Mexico near the mouth of the Mississippi River. This dead zone is caused by high levels of phosporus and nitrogen from agricultural run-off that ends up in the river and ultimately in the gulf. "We've long thought of oceans as having an infinite ability to provide food and other goods and services to humans. But the massive human-wrought changes in our oceans are impairing their ability to function as we assume they will," said Lubchenco. "We're degrading the water, changing our coastlines, filling in our estuaries and changing our rivers. And we're witnessing many signals of the problems that will result from these changes, including toxic algal blooms, coral bleaching and sudden disappearance of fish from key fisheries." According to Lubchenco, humans are degrading the Earth's rivers, oceans and lakes in many ways: Half of the mangrove forests, which serve as estuaries in the tropics, have been lost to a combination of coastal development and conversion to aquaculture. Global aquaculture now accounts for more than one-quarter of all fish consumed by humans. In the case of shrimp and salmon, which comprise the fastest growing segment of aquaculture, two to three pounds of fish are needed to grow one pound of the raised seafood. Thus this practice is depleting the oceans of food for wild fish, birds and marine mammals. About 3,000 species of marine life are in transit in ballast water of ships around the world, resulting in a serious invasion of non-native species in our waterways. A minor but increasing contributor to the problem is escape of non-native fish and plants from aquariums. The human alterations to the ecological systems of the Earth are affecting more than just food supply. "In addition to the direct [ecological] services of food, fiber, shelter and medicines, many other inter-dependent services are being disrupted," Lubchenco said. For example, forests, grassland and coral reefs contribute to flood control and climate regulation. Mangroves, estuaries, coral reefs, and kelp forests protect shores from erosion besides providing nursery areas or spawning habitat for economically important species. The environmental changes that are taking place can have political repercussions as well. "Scarce resources such as water or fishing rights lead to battles between states and nations. Environmental degradation resulting in food shortages lead to civil unrest and migration into neighboring countries," said Lubchenco. This situation will only worsen as the world population continues to increase. But with the increasing number of people around the world taking notice of environmental issues and getting involved in finding solutions, Lubchenco does feel hopeful that the situation can turn around. "It is encouraging that there is an increasing focus on the part of the private sector, religious groups, and individual citizens to take responsibility and undertake innovative action." "As inhabitants of Earth, we need to take stock of these massive changes, understand their implications and change our direction, " Lubchenco said. "We are currently inattentive stewards. It is in our best interests to be more fully engaged in ensuring our own health, prosperity and well-being." Copyright 1999, Environmental News Network, All Rights Reserved |
Copyright (c) 1998, Joongpil Cho