2. Global warming is the increase in the global temperature and the culprit identified to cause this is carbon dioxide. Answer the following questions?
a. When does carbon dioxide considered as a pollutant?
Carbon-dioxide levels in the Earth's atmosphere have fluctuated wildly for millennia; at one point billions of years ago, it was the dominant gas in the atmosphere.
We commonly think of pollutants as contaminants that make the environment dirty or impure. A vivid example is sulphur dioxide, a by-product of industrial activity. High levels of sulphur dioxide cause breathing problems. Too much causes acid rain. Sulphur dioxide has a direct effect on health and the environment. Carbon dioxide, on the other hand, is a naturally occuring gas that existed in the atmosphere long before humans. Plants need it to survive. The CO2 greenhouse effect keeps our climate from freezing over. How canCO2 be considered a pollutant?
A broader definition of pollutant is a substance that causes instability or discomfort to anecosystem. Over the past 10,000 years, the level of atmospheric carbon dioxide in theatmosphere has remained at relatively stable levels. However, human CO2 emissions over the past few centuries have upset this balance. The increase in CO2 has some direct effects on the environment. For example, as the oceans absorb CO2 from theatmosphere, it leads to acidification that affects many marine ecosystems. However, the chief impact from rising CO2 is warmer temperatures.
Rising CO2 levels causes an enhanced greenhouse effect. This leads to warmer temperatures which has many consequences. Some effects are beneficial such as improved agriculture at high latitudes and increased vegetation growth in some circumstances. However, the negatives far outweigh the positives. Coast-bound communities are threatened by rising sea levels. Melting glaciers threaten the water supplies of hundreds of millions. Species are becoming extinct at the fastest rate in...