GLOBAL WARMING

What is global warming?

Scientific evidence has recently shown that the earth is warming up. This has been caused mainly by an increase in the proportion of carbon dioxide gas in the atmosphere. Presently, carbon dioxide in the atmosphere rises by 1 percent each year. If this trend continues, the world will experience a temperature rise of 3° C by the year 2100, making the earth warmer than at any time during the last 100,000 years. To give an idea of how serious this is, a rise of 4º C would mean that the earth would be exposed to temperatures not experienced since 40 million years ago.

As trees grow they absorb carbon dioxide from tones of carbon. This is locked up in complex chemicals, such as fats and proteins, found in living and dead organic material. However, when organic matter, such as wood, decompose or is burnt it release most of its stored carbon into the atmosphere as carbon dioxide gas. Cutting down forests has produced half of all man made emissions over last 130 years. The other half has come from burning fossil fuels such as coal, oil and gas, which are the compressed remains of plants that grew millions of years ago.

Scientists have proposed trees as a way of collecting and storing carbon to help counteract the build up of carbon dioxide. Their research has shown that while fast growing plantation trees could help, protecting ‘old growth’ forests is a much more efficient way of string carbon. Each year 16 per cent of atmospheric carbon dioxide is cycled through plants, and forests contain up to 85 per cent of all carbon that is bound up in living organisms.

 CLIMATE

The weather in forested regions is generally milder, moister and less variable than in treeless regions. The borer forests, for example, warm the sub Arctic region by providing a dark mass capable of absorbing heat from the sun. Threes in hot areas, on the other hand, have a cooling effect.

SOIL LOSS

Trees catch much of the rain falling on to a forest, softening its destructive power before it reaches the ground. Tree roots create spaces for the water to soak away through and help to bind the soil. When trees are removed, especially from mountain sides, the soil is soon washed away by rain. A recent study in cote D’lvoire has shown that a deforested hill loses 500 times as much soil as one covered with trees. Forest destruction around the world causes the loss of 50 billion tones of topsoil every year.   

              

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