Another factor that has helped focus attention on global warming in recent years is the growth of environmental awareness. Over the last few decades, there have been several notable anthropogenic environmental disasters. These have made the public more aware of environmental damage; sometimes permanent.
One of the worst anthropogenic disasters was the explosion at the nuclear power plant in Chernobyl, USSR, on April 26, 1986. A reactor exploded during a failed cooling system test and ignited a massive fire that burned steadily for 10 days. The accident released radioactivity 400 times more intense than that of the Hiroshima bomb in World War II. The accident affected a huge area—the plume drifted over Europe, even to North America. Ukraine, Belarus, and Russia (an area of about 90,000 square miles; 233,000 km2) were badly contaminated with unhealthy levels of radioactive elements. More than 336,000 people were evacuated. The town of Pripyat, which was built specially to house the employees of Chernobyl, was evacuated. Today, more than 20 years later, the town has never been reoccupied. The 19-mile (30-km) area around the site is known as the Zone of Alienation. All residential, civil, and business activities are prohibited by law. People who lived in the area at the time of the accident who were not killed outright suffered many serious health problems, including radiation sickness, thyroid cancer, leukemia, and birth defects causing cancer and heart disease. Researchers have estimated that roughly 7 million people were affected by this accident.
Another major anthropogenic environmental disaster was the nuclear accident on the Susquehanna River in Pennsylvania at Three Mile Island in March 1979. This was the disaster that started the controversy in the United States over the safety of using nuclear energy. In this incident, the water pumps in the cooling system failed, causing cooling water to drain away from the reactor, which partially melted the reactor core. This accident released about 1/1000 of the amount of radiation as Chernobyl did. Scientists do not know for certain how much radiation was released during the accident. The reactor core escaped meltdown just in time because of the implementation of safety measures. There was an evacuation of a five-mile (8-km) radius as a safety precaution. Experts believe that several people died of exposure to radiation. Dairy farmers reported the deaths of many of their livestock, and some local residents developed cancer. Some studies also indicate premature death and birth defects resulted as well. The cleanup for the accident began in August 1979 and finally ended in 1993; the cost was $975 million. Nearly 100 tons (91 metric tons) of radioactive fuel was removed from the area.
Times Beach, Missouri, was the site of another well-known environmental disaster that got the public's attention. High dioxin levels were found in the soil. Dioxin is a hazardous chemical used in Agent Orange, a highly toxic chemical warfare agent. Levels in the soil were determined to be 100 times higher than the threshold considered toxic
Three Mile Island was the site of one of the nation's worst anthropogenic environmental disasters. (EPA)
for humans. The dioxin had been mistakenly added to an oil mixture that was used to spray the roads in the 1970s to keep dust under control. Many illnesses, miscarriages, and animal deaths at the time were blamed on the levels of dioxin in the area. This disaster spurred the enactment of federal legislation, Comprehensive Environmental Response Compensation and Liability Act (CERCLA), commonly referred to as the Superfund, because it established a fund to help with the cleanup of locations of environmental disasters.
In January 2000 in the Baia Mare gold mine in Romania, cyanide used to purify gold from rocks overflowed into the Tisza River. The wastewater that contained the cyanide also contained lead and other hazardous materials. By February, it had reached the Danube, a major river that flows through or borders 10 European countries. It poisoned many fish in the river and made many people along the river ill from eating contaminated fish.
According to the U.S. Environmental Protection Agency (EPA), Love Canal is one of the most horrifying environmental tragedies in U.S. history. Love Canal was originally planned as a perfect community on the eastern edge of Niagara Falls in New York. In order to generate power for the community, a canal was to be dug between the upper and lower Niagara River so that power could be generated inexpensively for the residents. The canal was never finished. In the 1920s, all that was left was a ditch, and it was turned into a chemical dumping ground. Then, in 1953, the Hooker Chemical Company, then owner of the property and the canal, covered all the waste with dirt and sold it to the city for the sum of one dollar.
The city used the ground to build a new development and constructed about 100 homes and a school on it. During an extremely wet period, the process of leaching began. The waste disposal drums that were buried underground began to corrode and started breaking up in residents' backyards. Vegetation in the area—trees, shrubs, gardens, and grass—began to die and turn black. Chemicals began to pool in people's backyards and basements. Children would get burns on their hands and faces when they played outside. Birth defects were on the rise as well. At the time, according to a report issued by the EPA, one father whose child was born with birth defects remarked: "I heard someone from the press saying that there were only five cases of birth defects here. When you go back to your people at EPA, please don't use the phrase 'only five cases.' People must realize that this is a tiny community. Five birth defect cases here is terrifying."
On August 7, 1978, New York governor Hugh Carey told the residents at Love Canal that the New York State government would purchase the homes affected by the chemicals. The same day, President Jimmy Carter approved emergency financial aid for the area. These were the first emergency funds ever to be approved for a man-made rather than a natural disaster. In addition, the U.S. Senate approved a sense of Congress amendment saying that federal aid should be forthcoming to relieve the serious environmental disaster that had occurred.
Valley of the Drums. This site was used as a disposal area for hazardous chemical waste, causing serious environmental pollution. Today, it is still remembered as an example of environmental irresponsibility.
President Carter remarked of the situation: "The presence of various types of toxic substances in our environment has become increasingly widespread—one of the grimmest discoveries of the modern era."
A total of 221 families had to be relocated as a result of this disaster. Today, agencies such as the EPA, working under governing laws such as the Clean Air Act, the Clean Water Act, the Federal Environmental Pesticide Control Act, the Resource Conservation and Recovery Act, and the Toxic Substances Control Act, strive to protect the American public and the environment.
The Valley of the Drums near Louisville, Kentucky, gained national attention in 1979 and quickly became known as one of the country's worst abandoned hazardous waste sites. Over a period of 10 years in Bullitt County, industry disposed of thousands of barrels of hazardous wastes on a 23-acre site. They had been haphazardly thrown in pits, trenches, or just strewn about. The drums sat so long exposed to the outdoor elements that they began to deteriorate and leak. When it rained, the barrels would fill with water, overflow, and wash the chemicals into nearby Wilson Creek, which led to the Ohio River. Chemicals found in the drums included toluene (associated with liver and kidney damage, respiratory illness, damage to developing fetuses, and death) and benzene (causes leukemia, neurological problems, and weak immune systems). This incident was another national spur to the creation of the Superfund.
In March 1989, the Exxon Valdez struck Bligh Reef in Prince William Sound, Alaska, unleashing the largest oil spill in U.S. history. The oil slick spread more than 3,000 square miles (7,770 km2) and onto more than 350 miles (563 km) of beaches in Prince William Sound, at that time known as one of the most pristine and beautiful natural areas in the world. The spill polluted about 1,180 miles (1,900 km) of shoreline and was devastating to wildlife in the fragile ecosystem. It killed about 250,000 sea birds, 2,800 sea otters, 250 bald eagles, and roughly two dozen killer whales.
Oil spills can be very harmful to marine birds and mammals, such as sea otters. They can also harm fish and shellfish. Oil destroys the
The tanker Exxon Valdez accident in Prince William Sound, Alaska, in March 1989. NOAA responders survey the oil-soaked beaches of Prince William Sound. (NOAA)
insulating ability of fur-bearing mammals, such as sea otters, and the water-repelling abilities of a bird's feathers, thereby exposing these creatures to the harsh elements. Many birds and animals also ingest oil when they try to clean themselves, which can poison them.
The Exxon Valdez spill released more than 11 million gallons (42 million liters) of oil and cost more than $3.5 billion to clean up. It received a great deal of media attention and raised the public's environmental awareness. Many people were outraged at the damage done to wildlife and their fragile ecosystems, and this single incident in particular served as a strong reminder that human behavior can have far-reaching consequences for the environment. Although these incidences were all tragedies and should never have happened, they did help raise awareness of the serious, and often tragic, effects that people's actions can have on the environment.
One topic that has been in the news recently that has made an impression on the public is the melting of the polar ice. Time magazine has run several special editions covering the melting of glaciers, rising seas, and diminishing icepack (April 9, 2001, April 3, 2006, April 9, 2007, and October 1, 2007, editions). National Geographic featured an article on melting icecaps and rising sea levels in their June 2007 issue. Environmental scientists say that because Arctic ecosystems are so sensitive and fragile, they respond quickly when they are stressed. Because of this, they provide early warning about the effects of global warming.
Scientists at the National Oceanic and Atmospheric Administration (NOAA) and the National Aeronautics and Space Administration (NASA) believe the Arctic is the first area to react to global warming. The polar regions are predicted to be affected first by global warming because warming in these regions is enhanced by positive feedback at a level unlike any other area on Earth; polar areas are extremely sensitive. The major feedback mechanism has to do with polar albedo. Snow and ice's high albedos naturally reflect 80 to 90 percent of the incoming solar radiation back into space, keeping these areas frozen. But when the polar areas begin to warm due to increased CO2 levels in the atmosphere, the snow and ice begin to melt, greatly reducing the highly reflective surface areas. As these surfaces disappear, more of the Sun's radiation is absorbed by the underlying land or sea as heat. The result ing heat then begins to melt even more snow and ice, exposing more dark surfaces to absorb additional radiation—and a positive feedback cycle is set up. It becomes self-perpetuating, enabling the process to accelerate and feed off of itself.
Another reason why the polar areas are so sensitive is that the atmosphere in these regions is extremely dry compared to the air at lower latitudes. Because of this, less energy is used to evaporate water, which keeps the energy in the form of heat.
Further positive feedback is the resultant vulnerability to vegetation shifts in the polar regions. The boundary between forest and tundra is highly sensitive to increases in temperature. Today, global warming has caused rapid changes to take place. Over the past 50 years in northern Canada, for example, tree lines have advanced 279 feet (85 m) in elevation on warm, south-facing slopes and tree density has increased significantly (up to 65 percent) on cooler, north-facing slopes.
According to Dr. Ryan Danby of the department of biological sciences at the University of Alberta in Canada, "The mechanism of change appears to be associated with occasional years of extraordinarily high seed production—triggered by hot, dry summers—followed by successive years of warm temperatures favorable for seedling growth and survival." He warns that "Widespread changes to tree lines will have significant impacts. As tundra habitats are lost, species are forced to move upward in elevation and northward in latitude. The problem is that in mountainous areas species can only migrate so high, so they get forced into smaller and smaller areas until there is no room left for them to survive in. These results are very relevant to the current debate surrounding climate change because they provide real evidence that vegetation change will be quite considerable in response to future warming, potentially transforming tundra landscapes into open spruce woodlands."
These predictions of accelerated warming in the polar regions are also supported by climate models. According to Pal Prestrud, vice chairman of the steering committee for the Arctic Climate Impact Assessment (ACIA) report, "The projections for the future show a two to three times higher warming rate in the polar areas than for the rest of the world. That will have consequences for the physical, ecological, and human systems." Most climate models now predict the following:
• increased CO2 concentrations will lead to a polar warming greater than the global average with more warming over land than sea and maximum warming in the winter
• a decrease in the extent and thickness of sea ice
• melting of permafrost
• a retreat of ice shelves
• migration of forests/retreat of tundra
• shifts in freeze/thaw zones to the north
• changes in polar freeze/melt cycles
According to Warwick Vincent, director of the Centre for Northern Studies at Laval University in Quebec, "Climate models indicate that the greatest changes, the most severe changes, will happen earliest in the highest northern latitudes. This will be the starting point for more substantial changes throughout the rest of the planet . . . our indicators are showing us exactly what the climate models predict. I think we're at a point where it is not stoppable but it can be slowed down. And if you think about the magnitude of effects on our society, then we really need to buy ourselves more time to get ready for some very substantial changes that are ahead." Melting ice is having a significant negative impact on the wildlife in the Arctic, such as the polar bears.
As the ice melts, it keeps the polar bears from being able to hunt for food. The 2007 film Arctic Tale was a documentary that illustrated the fate of Arctic ecosystems that are now facing the problem of global warming. NASA has taken satellite images of the polar ice cap and has determined that it is shrinking at a rate of 9 percent each decade. They predict that if this trend continues, there may not be any ice left in the Arctic during the summer season by the end of this century. According to the IPCC, the average annual temperature in the Arctic has increased by 1.7°F (1°C) over the last century—a rate roughly twice as fast as the global average. Over the past 100 years, winter temperatures alone have warmed 3.3°F (2°C) in the Arctic, most of it occurring in the past 30 years. Permafrost melting has been observed in Russia, Canada, Alaska, and China. In some places so much ice has thawed, it has caused the ground to subside 16 to 33 feet (5-10 m), damaging homes, roads, and other structures.
Ice in the Arctic is melting earlier each year. Scientists expect this to continue as the Earth continues to warm, which will cause problems for wildlife such as the polar bear. (Rear Admiral Harley D. Nygren, NOAA)
Arctic sea ice is declining 3 to 7 percent each decade. Measurements taken by submarines indicate a 40 percent reduction in ice volume across the entire Arctic Ocean basin as compared to 20 to 40 years ago. Delays in the forming of sea ice and early melt are playing havoc on physical, biological, and human systems. According to the Union of Concerned Scientists, newborn seals and walrus pups do not have sufficient time to wean adequately, causing them to die. The sea ice is also used by polar bear and caribou as a migration corridor. With weather extremes, such as heavier snowfall or freezing rain, it taxes the energy of the wildlife when they migrate and search for food, killing numerous members of the herds.
The indigenous peoples of the Arctic—such as the Yupik, Inuit, and Eskimo—also depend on the natural resources currently found in the Arctic, and their survival depends on the ecosystem remaining healthy and functioning. Global warming is already having a huge impact on them. For example, delay in the formation of sea ice has decreased the length of their hunting season, leaving them with significant food
shortages. There has also been an increase in cloudy skies, fog, and rain during the spring and summer "drying season," when their traditional foods are air-dried for winter storage.
Melting ice also contributes to rising sea levels. Today, many of the native villages that have existed for centuries along the coasts are being flooded as the sea levels rise. Global warming is threatening the identity, culture, way of life, and very existence of cultures.
The effects of the melting of the polar ice are not just confined to the Arctic region; they will be felt worldwide. The melting of the polar ice cap is like a runaway train. As the ice melts, it actually speeds up global warming. Layers of snow and ice in the Arctic act as a type of insulating, protective blanket. By their very existence, they help keep the Arctic cool. As sunlight hits the snow and ice, it is reflected back into space because snow and ice have a high albedo (are highly reflective). Because of this, the ground does not absorb the heat from the Sun. When this protective ice layer melts it allows the Earth to absorb more sunlight and get warmer. As the ground's surface gets warmer, it melts more ice, which allows more bare ground to absorb more sunlight. The process continues: heating and melting, heating and melting.
Climate change scientists have recently announced that rising temperatures are already affecting Alaska. According to Deborah Williams, executive director of the Alaska Conservation Foundation, annual temperatures have increased 4° to 5°F (6.7° to 8.3°C) and winter temperatures have warmed 8° to 10°F (13° to 17°C)—more than any other place on Earth; more than four times the global average. Permafrost is melting, causing more than 600 families so far to lose their homes. The polar bears are also feeling the effects. According to Steven Amstrup, a polar bear specialist with the U.S. Geological Survey (USGS), "As the sea ice goes, that will direct to a very great extent what happens to polar bears." Polar bears could become extinct within the next century because they have adapted to hunting on the ice. If they try to swim, they are more likely to tire and drown.
Insects that spread disease in warmer weather have begun to migrate and damage forested areas farther north in Alaska than they ever have before. In particular, the spruce bark beetle, which breeds faster in warmer weather, has been able to reproduce at a faster rate now than it ever has in the past. It has actually sped up the breeding time by eliminating delays from one hatch to another. Today, it has destroyed almost 3.5 million acres of forests in Alaska.
As glaciers and ice sheets on land melt, the meltwater runs off the land and enters the oceans. This causes sea levels to rise; which then causes other areas to have their beaches flooded and eroded. This will affect people worldwide. Some climate change scientists have predicted the oceans could rise three feet (1 m) by the end of this century, significantly flooding many coastal areas.
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