6.4 CHARTING A COURSE FOR THE FUTURE
Research are gathering data to monitor and evaluate the effects of human activities on important systems in the biosphere. Two of these systems are the ozone layer high in the atmosphere and the global climate system. Between 20 and 50km above the Earth's surface, the atmosphere contains a relatively high concentration of ozone gas called the ozone layer. Molecules of ozone consists of three oxygen atoms. Even though the ozone ground level is a pollutant, it still absorbs harmful ultraviolet. Without this protection, we may die from cancer and a few other problems.
Scientists found out that the ozone layer is in trouble because gases called chlorofluorocarbons, or CFCs, can damage the ozone layer. CFCs during the 1700s are widely used but now, CFCs are banned due to the harms it cause to the ozone layer. Scientist now predict that the ozone holes should shrink and disappear within 50 years.
Climate is a major factor because it determines the temperature and rainfall. Global warming is the term used to describe the increase in the average temperature of the biosphere. Geological record shows that Earth climate has changed repeatedly during its history. Therefore, researches must determine whether this is a natural cycle or is caused by human activity, The mostly widely accepted theory is because of theory activities due to humans adding carbon dioxide and other greenhouse gases to the atmosphere. If global warming continues, sea level may rise enough to flood coastal area. If this happens, coastal ecosystems will be in terrible danger. Some models suggest parts if North America will experience more droughts during the summer growing seasons. New organisms may live in places where they once could not and other organisms may be threatened or be extinct. Ecosystem provide many services. Therefore, biologists are concerned that human activities may affect them in unexpected ways. People can make wise choices in the use and conservation of resources. Trash and other wastes could be recycled, and dangerous chemicals should be dispose in ways that will not harm the ecosystem.
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