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What is Global Warming ?
Global warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-twentieth century and its projected continuation. The global average air temperature near the Earth's surface rose 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the hundred years ending in 2005. Climet model projections summarized by the IPCC indicate that average global surface temperature will likely rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the twenty-first century. |
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Cause of Global Warming :
Almost 100% of the observed temperature increase over the last 50 years has been due to the increase in the atmosphere of greenhouse gas concentrations like water vapour, carbon dioxide (CO2), methane and ozone. Greenhouse gases are those gases that contribute to the greenhouse effect (see Picture). |
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Greenhouse Effect :
When sunlight reaches Earth's surface some is absorbed and warms the earth and most of the rest is radiated back to the atmosphere at a longer wavelength than the sun light. Some of these longer wavelengths are absorbed by greenhouse gases in the atmosphere before they are lost to space. The absorption of this longwave radiant energy warms the atmosphere. These greenhouse gases act like a mirror and reflect back to the Earth some of the heat energy which would otherwise be lost to space. The reflecting back of heat energy by the atmosphere is called the "greenhouse effect". |
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Consequences :
Increasing global temperatures are causing a broad range of changes. Sea levels are rising due to thermal expansion of the ocean, in addition to melting of land ice. Rise of sea levels by at least 25 meters (82 feet) by the year 2100. The total annual power of hurricanes has already increased markedly since 1975 because their average intensity and average duration have increased (in addition, there has been a high correlation of hurricane power with tropical sea-surface temperature). Changes in temperature and precipitation patterns increase the frequency, duration, and intensity of other extreme weather events, such as floods, droughts, heat waves, and tornadoes. Other effects of global warming include higher or lower agricultural yields, further glacial retreat, reduced summer stream flows, species extinctions. |
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Remedies :
To reduce greenhouse gases we must reduce the use of those things that rely on carbon dioxide, methane and CFCs. Instead of using Styrofoam cups and plates, use paper. The most significant reduction will be of carbon dioxide. If we want to slow down global warming, we must reduce this greenhouse gas drastically. Reducing the amount of cars emitting carbon or driving alternative energy cars will significantly slow down global warming. Solar energy is another alternative that has been experimented with for the replacement of oil and gas to heat our homes. |
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