Реферат на тему Atmosphere Crisis Essay Research Paper We are
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Atmosphere Crisis Essay, Research Paper
We are living in the midst of a great chemical experiment, and some serious consequences are becoming apparent to scientists. More than two billion pounds of chemicals are spewed into the air each year. These chemicals are brewing a disastrous stew, resulting in an atmosphere crisis. The greatest consequences of the atmosphere crisis may be the greenhouse effect( global warming) and the ozone deletion. If humankind wants to survive well into the next millennium, than we must stop this horrid destruction of our own environment.
The Earth appears to be warming due to the greenhouse effect. Scientists estimate that average temperature could climb about 2 degrees Celsius in 20 years. This change in the global climate would have disastrous results, including drought, coastal flooding and increased species extinction. And, scientists have discovered a hole in the ozone layer. The ozone layer is the only protection for life on Earth against deadly ultraviolet radiation from the sun. Once the ozone layer is completely destroyed, all life on Earth will cease to exist, killed by the deadly radiation. The planet will become a barren rock devoid of all life.
Global warming is the predicted result of the greenhouse effect, created by so-called greenhouse gases, such as carbon dioxide and methane, in the atmosphere. The increase in these gases is thought to be caused by industrialization, especially by the use of fossil fuels such as coal and oil. These gases act much like the glass in the greenhouse: They let sunlight in and keep the heat from escaping. As these gases increase in our atmosphere, concern has grown that temperatures will increase around the globe, just as in the inside of a greenhouse. Global warming will have wide spread impacts on health, economics, politics, and the environment. A warmer climate will actually increase crop yields and open more land to farming in upper latitude countries like U.S., Canada, and Russia, but for the poor countries of equatorial Africa, Asia, and South America, crop yields will most likely decline. That is because many crops currently grown there will not be able to tolerate the additional heat. In addition, these countries are also burdened with the highest rates of population growth on the planet. So, there will be less food in exactly the places where food supplies are needed most. Changing sea levels and precipitation patterns could also affect health. Ironically, as the sea levels rise, the water many people depend on for drinking and sanitation may become scarce or of poorer quality. Rising sea water levels would send salty water farther up rivers.
Every spring, scientists announce the dimensions of the year s ozone hole over Antarctica. Currently, about 80% of the ozone layer disappeared from an area centered on Antarctica that was nearly the size of North America. This time of the year, however, it s the Northern Hemisphere that commands most attention. Ozone loss peaks during fall, when the Earth s angle of orbit to the sun puts the Northern Hemisphere almost directly in the path of the sun s deadliest radiation, which triggers ozone-destroying reactions in our atmosphere. Solar ultraviolet radiation has created a shield of ozone in the high stratosphere that absorbs the biologically dangerous mid-ultraviolet wavelengths. In recent decades, however, chlorine has been migrating into the stratosphere in molecules of industrial substances called CFC s. Once freed, chlorine catalytically attacks ozone, and as it nibbles away the shield, more and more lethal radiation reaches Earth, causing an epidemic of skin cancer and all kinds of other harmful biological effects.
The pollution is causing a global warming and the ozone deletion. Every day, every single human being, contributes in some way, to the destruction of the ozone layer, from using deodorant sprays, to throwing away perfectly recyclable materials.
If we don t stop polluting our planet now, it may become impossible to live on the surface of the Earth in twenty years.