Global warming is the increase of average world temperatures because of what is known as the greenhouse effect. The greenhouse effect happens when solar energy reaches the Earth in the form of short-wave radiation. When that radiation strikes a surface, much of its energy is converted into heat, a form of radiation, which has a long wavelength. Carbon Dioxide, water vapour, and other gases present in the atmosphere absorb and retain long-wave radiation or reflect it back toward the surface of the Earth. These gases act like panes of a glass in a greenhouse, letting light in, but retaining some of the heat before it escapes into space. Therefore, this build up of heat has many dramatic effects, which affect the whole world.
The average surface temperature of earth has increased more than 1 degree Fahrenheit since 1900 and the rate of warming has been nearly three times the century-long average since 1970 greenhouse air conditioner. Almost all experts studying the recent climate history of the earth agree now that human activities, mainly the release of heat-trapping gases from smokestacks, tailpipes, and burning forests, are probably the dominant force driving the trend. The gases add to the planet’s natural greenhouse effect, allowing sunlight in, but preventing some of the resulting heat from radiating back to space.
The detailed causes of the recent warming remain an active field of research, but the scientific consensus identifies increased levels of greenhouse gases due to human activity as the main influence. Human activities such burning fossil fuels for energy etc. Other factors include solar activity, volcanic emissions and variations in the earths orbit.
Global warming has been in the news a lot recently. Is it our fault or does it just happen every one hundred and fifty years that is the question? The Intergovernmental Panel on Climate Change (IPCC) has said that temperatures will increase by up to 4C by the end of the century. This increase in temperature will have a very large effect on our planet. The panel has said sea levels will rise by 43cm due to ice caps melting, which could mean Bangladesh, which is 1 m above sea level, could be under water. In addition, this increase in sea levels is likely to influence the intensity of tropical storms, which can spread even more damage to other countries. We in today’s society must try to use our resources carefully so that future generations can live on this planet with as few environmental problems as possible. Global warming is mostly dew to countries developing very fast, to build the countries economy a country must have industry and infrastructure. Therefore, industries have opened and caused a lot of air pollution.
Another reason for the air pollution is due to the emissions from cars. There are now more than 28 mega cities and everyday most of their populations drive cars. More cars equal more pollution, which increase global warming. The rate we are burning fuel is not sustainable for future years and we must act now in order to save this planet from devastation.
One of the main greenhouse gases is carbon dioxide (CO2). As trees grow, they take in CO2 from the air. When the wood dies, the CO2 is returned to the air. Forest clearance and wood burning (deforestation) which happen in tropical rain forests is adding to the CO2 in the atmosphere. Deforestation is now out of control. For example in 1987 an area of the Amazon rain forest the size of Britain was burned, adding 500 million tonnes of CO2 to the atmosphere. The loss of the forests also means that there are fewer trees to absorb CO2.
Other greenhouse gasses include:
Methane – which is released during coal-mining activities, oil exploration and when vegetation is burnt during land clearance. The main source of methane though is agricultural activity. It is released from wetlands such as rice paddies and from animals, particularly cud-chewing species like cows. The problem with methane is that as the world population increases, agricultural activity must increase and so emissions of methane will increase. Since the 1960s the amount of methane in the air has increased by 1% per year – twice as fast as the build up of CO2 .
Nitrous oxide – comes from both natural and man-made processes. Man influenced sources, which represent about 45% of output to the atmosphere, are mainly: fossil fuel combustion, as in power stations; use of nitrogenous fertilizers; burning rain forests and human and animal waste. N2O contributes about 6% to the greenhouse effect at the moment.