英语论文网

ist Kristina Brady affirms this through studies of the ice cores (Brady, 2007). Finally, the line of trees in the Alps, due to the warmth at higher altitudes, was much higher at that time than it was before that period or even is today (Gardiner, 2007). The question is, why did this happen? The answer is that we don't really know, simply because there are so many thousands of variables to consider when measuring climate. We can, however, safely say that it was not the result of man-made CO2. As Philip Stott, a professor at the University of London, pointed out, “we know very little about 80% of the factors behind climate change” (Lehrer, 2007). Hence, we must try to go beyond the natural instinct of blaming CO2 and judge other causes as well.

 

But speaking of CO2, a question that should be asked is, how much of it is really caused by man-made accessories? A part of the answer can be found in deforestation. Known as the rapid removal of indigenous plant-life and trees from forests and woodlands, deforestation is supposed to attribute to one third of the recent increases in CO2 levels (Matthews, 2006). This is not to say that CO2 is a major problem with climate, but it is to say that at most only 2/3 of it can be attributed to carbon-emitting, man-made machinery, and the rest goes to deforestation.

 

 This is mainly because trees are actually composed of 50% carbon, which is expelled into the air when they decompose. According to Christopher Matthews, “Trees are 50 percent carbon. When they are felled or burned, the C02 they store escapes back into the air. According to FAO figures, some 13 million ha of forests worldwide are lost every year, almost entirely in the tropics. Deforestation remains high in Africa, Latin America and Southeast Asia” (Matthews, 2006). While it is true that most deforested trees are not left to rot, and thus realistically, little carbon is expelled due to trees, this is not the real problem. What is most important is that trees are in fact major consumers of carbon, for, just as a human breathes oxygen, so too do trees breathe carbon dioxide. Thus, when trees die, they are no longer present to consume the excess carbon in the atmosphere (Matthews, 2006). So the question with CO2 is not always that of emission, but we must also consider the lack of consumption by trees.

 

Trees also, due to their immense amount of water consumption and emissions of water into the air, are very important to the water cycle. When trees are present, there is more moisture released into the air, which accumulates into rain and in turn cleans polluted air. As Jocelyn Stock affirms, “The forests have global implications not just on life but on the quality of it. Trees improve the quality of the air that species breath by trapping carbon and other particles produced by pollution. Trees determine rainfall and replenish the atmosphere.” Fewer trees mean less evaporation, which inevitably leads to warm, dirty air. While it is true that temperatures can be warmer due to cloud-cover, which tends to trap heat, it is also true that, in the long run, the natural cleansing of the air 本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。