Главная > Реферат >Остальные работы
Global Warming Essay, Research Paper
For years, scientists have warned that pollution from burning fossil fuels would cause dangerous warming of the planet. The hottest 10 years on record have all occurred since 1980. 1998 was the hottest year ever recorded. With scientists predicting more violent weather, spread of infectious diseases, and rising sea levels.
According to Accu-Weather, the world?s leading commercial forecaster, Global air temperatures as measured by land-based weather stations show an increase of about 0.45 degrees Celsius over the past century. Satellite data indicate a slight cooling in the climate in the last 18 years.
98% of total global greenhouse gas emissions are natural, only 2% are from man-made sources. Man-made emissions have had no more than a little impact on the climate. Although the climate has warmed slightly in the last 100 years, 70% percent of that warming occurred prior to 1940, before the upsurge in greenhouse gas emissions from industrial processes.
The idea that global warming would melt the ice caps and flood coastal cities seems to be mere science fiction. A slight increase in temperature, whether natural or mankind induced, is not likely to lead to a massive melting of the earth ice caps, as sometimes claimed in the media. Also, sea-level rises over the centuries relate more to warmer and thus expanding oceans, not to melting ice caps.
Larger quantities of CO2 in the atmosphere and warmer climates would likely lead to an increase in vegetation. During warm periods in history vegetation flourished, at one point allowing the Vikings to farm in now frozen Greenland.
The hottest 10 years on record have all occurred since 1980. 1998 was the hottest year ever recorded. With scientists predicting more violent weather, spread of infectious diseases, and rising sea levels.
Scientists predict rising global temperatures and the melting of glaciers will directly impact ocean and coastal habitats. Ecosystems will be destroyed and species will die off, as sea levels rise, seasons shift, and glaciers and polar ice caps melt.
Some of the culprits of Global warming comes from burning fossil fuels like coal, oil and gas to produce electricity, to transport people and goods, and for use by industry. Burning fossil fuels causes carbon dioxide pollution to accumulate at alarmingly high levels and trap heat from the sun in our atmosphere. More than half of this pollution comes from power plants and cars.
The earth?s climate is predicted to change because human activities are altering the chemical composition of the atmosphere through the buildup of greenhouse gases?primarily carbon dioxide, methane, and nitrous oxide. The heat-trapping property of these gases is undisputed. Although uncertainty exists about exactly how earth?s climate responds to these gases, global temperatures are rising.
Some greenhouse gases occur naturally in the atmosphere, while others result from human activities. Naturally occurring greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Certain human activities, however, add to the levels of most of these naturally occurring gases. Carbon dioxide is released to the atmosphere when solid waste, fossil fuels, and wood and wood products are burned. Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from the decomposition of organic wastes in municipal solid waste landfills, and the raising of livestock. Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of solid waste and fossil fuels. Greenhouse gases that are not naturally occurring include byproducts of foam production, refrigeration, and air conditioning called chlorofluorocarbons (CFCs), as well as hydro fluorocarbons (HFCs) and per fluorocarbons (PFCs) generated by industrial processes.
Energy from the sun drives the earth?s weather and climate, and heats the earth?s surface; in turn, the earth radiates energy back into space. Atmospheric greenhouse gases (water vapor, carbon dioxide, and other gases) trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse.
Without this natural ?greenhouse effect,? temperatures would be much lower than they are now, and life as known today would not be possible. Instead, thanks to greenhouse gases, the earth?s average temperature is a more hospitable 60?F. However, problems may arise when the atmospheric concentration of greenhouse gases increases.
Since the beginning of the industrial revolution, atmospheric concentrations of carbon dioxide have increased nearly 30%, methane concentrations have doubled, and nitrous oxide concentrations have risen by about 15%. These increases have enhanced the heat-trapping capability of the earth?s atmosphere. Sulfate aerosols, a common air pollutant, cool the atmosphere by reflecting light back into space, however, sulfates are short-lived in the atmosphere and vary regionally.
Scientists generally believe that the combustion of fossil fuels and other human activities are the primary reason for the increased concentration of carbon dioxide. Plant respiration and the decomposition of organic matter release more than 10 times the CO2 released by human activities; but these releases have always been in balance with the carbon dioxide absorbed by plant photosynthesis. Energy burned to run cars and trucks, heat homes and businesses, and power factories is responsible for about 80% of society’s carbon dioxide emissions, about 25% of U.S. methane emissions, and about 20% of global nitrous oxide emissions. Increased agriculture, deforestation, landfills, industrial production, and mining also contribute a significant share of emissions. In 1994, the United States emitted about one-fifth of total global greenhouse gases.
Global mean surface temperatures have increased 0.6-1.2?F since the late 19th century. The 20th century’s 10 warmest years all occurred within the last 15 years. Of these, 1998 was the warmest year on record. The snow cover in the Northern Hemisphere and floating ice in the Arctic Ocean have decreased. Globally, sea level has risen 4-10 inches over the past century. Worldwide precipitation over land has increased by about one percent. The frequency of extreme rainfall events has increased throughout much of the United States.
Throughout the world, the occurrence of particular diseases and other threats to human health depend largely on local climate. Extreme temperatures can directly cause the loss of life. Also, several serious diseases only appear in warm areas. Finally, warm temperatures can increase air and water pollution, which in turn harm human health.
The most direct effect of climate change would be the impacts of hotter temperatures themselves. Extremely hot temperatures increase the number of people who die on a given day for many reasons. People with heart problems are vulnerable because one?s cardiovascular system must work harder to keep the body cool during hot weather. Heat exhaustion and some respiratory problems increase.
Higher air temperatures also increase the concentration of ozone at ground level. The natural layer of ozone in the upper atmosphere blocks harmful ultraviolet radiation from reaching the earth?s surface; but in the lower atmosphere, ozone is a harmful pollutant. Ozone damages lung tissue, and causes particular problems for people with asthma and other lung diseases. Even modest exposure to ozone can cause healthy individuals to experience chest pains, nausea, and pulmonary congestion. In much of the nation, a warming of four degrees could increase ozone concentrations by about 5 percent.
Global warming may also increase the risk of some infectious diseases, particularly those diseases that only appear in warm areas. Diseases that are spread by mosquitoes and other insects could become more prevalent if warmer temperatures enabled those insects to become established farther north; such “vector-borne” diseases include malaria, dengue fever, yellow fever, and encephalitis. Some scientists believe that algal blooms could occur more frequently as temperatures warm–particularly in areas with polluted waters–in which case diseases such a cholera that tend to accompany algal blooms could become more frequent.
The projected 3.6?F warming could shift the ideal range for many North American forest species by about 200 mi. to the north. If the climate changes slowly enough, warmer temperatures may enable the trees to colonize north into areas that are currently too cold, at about the same rate as southern areas became too hot and dry for the species to survive. If the earth warms 3.6?F in 100 years, however, the species would have to migrate about 2 miles every year.
The potential impacts of climate change on forest wildlife are poorly understood. If habitats simply shift to cooler areas, many forms of wildlife could potentially adapt to global warming, just as they have adapted to the changes in climate that have occurred over the last several million years. Unlike previous climatic shifts, however, roads, development, and other modifications to the natural environment may block the migration routes. Nature reserves, often established to protect particular species, may no longer be located in a climate hospitable to that species.
Sea level is rising more rapidly along the U.S. coast than worldwide. Studies by EPA and others have estimated that along the Gulf and Atlantic coasts, a one foot (30 cm) rise in sea level is likely by 2050 and could occur as soon as 2025. In the next century, a two foot rise is most likely, but a four foot rise is possible, and sea level will probably continue to rise for several centuries, even if global temperatures were to stop rising a few decades from now.
Industry can take a leading role in focusing serious attention on global warming by developing a portfolio of actions that save money, improve productivity, and protect the environment. Companies pursuing energy efficiency and pollution prevention projects stand to gain a competitive edge over firms that fail to make these changes.
Transportation specifically contributes to global warming through the burning of gasoline and diesel fuel. Any process that burns fossil fuel releases carbon dioxide, a greenhouse gas, into the air. Based on global warming potential, carbon dioxide accounts for over 80 percent of total greenhouse gas emissions in the United States. In 1997, transportation sources emitted approximately 31 percent of carbon dioxide from fossil fuel combustion (or 460.4 million metric tons of carbon) in the United States.
Once, all climate changes occurred naturally. However, during the Industrial Revolution, we began altering our climate and environment through changing agricultural and industrial practices. Before the Industrial Revolution, human activity released very few gases into the atmosphere, but now through population growth, fossil fuel burning, and deforestation, we are affecting the mixture of gases in the atmosphere.
We track the gases that we release into the atmosphere in emission inventories. An emission inventory is an accounting of the amount of air pollutants discharged into the atmosphere. It is generally characterized by the following factors. The chemical or physical identity of the pollutants included, the geographic area covered, the institutional entities covered, the time period over which emissions are estimated, and the types of activities that cause emissions.
Projections of future climate changes are uncertain. Although some computer models predict warming in the next century, these models are very limited. The effects of cloud formations, precipitation, the role of the oceans, or the sun, are still not well known and often inadequately represented in the climate models — although all play a major role in determining our climate. Scientists who work on these models are quick to point out that they are far from perfect representations of reality, and are probably not advanced enough for direct use in policy implementation. Interestingly, as the computer climate models have become more sophisticated in recent years, the predicted increase in temperature has been lowered.
We chose this topic because we didn?t know much about global warming and it seemed to be the most interesting subject. We learned many new things about how global warming like how it effected are lives. Global warming is important to others because it could effect them in the future. The most important information that I have learned would be the how Global Warming can effect our health.
- Global Warming Essay, Research Paper This essay will address the question, what is global warming, and how is ... life. In recent years, the term global warming has been associated with ... humans are primarily responsible for global warming and therefore it is ...
- Global Warming Essay, Research Paper Meghan McDonald McDonald 1 Mr.Hrkal ... for the 1?F (.5?C) rise in global average temperature documented over the past 100 years ... fuels, and in turn prevent global warming. For example, things as simple as ...
- Global Warming Essay, Research Paper There are many problems concerning ... comes to global warming. Almost all of the solutions for stopping global warming involve the ... 1862 (Global Warming). The rate of global warming in the last 20 years has been ...
- Global Warming Essay, Research Paper Is it hot in here, ... of fossil fuels cause global warming? Is global warming bad for the earth? Is there ... make it as a civilization for many years to come. This is something ...
- Global Warming Essay, Research Paper EFTHIMIOS MARIAKAKIS The greenhouse effect and global warming are issues that are ... dying in the past few years because of increased water temperatures ... for them and many salmon would die. Another impact of global warming ...