Climate Change Essay, Research Paper
Weather changes all the time. The average pattern of weather, called climate, usually stays pretty much the same for centuries if it is left to itself. However, the earth is not being left alone. People are taking actions that can change the earth and its climate in significant ways. Carbon dioxide is the main culprit. The single human activity that is most likely to have a large impact on the climate is the burning of “fossil fuels” such as coal, oil and gas. These fuels contain carbon. Burning them makes carbon dioxide gas. Since the early 1800s, when people began burning large amounts of coal and oil, the amount of carbon dioxide in the earth’s atmosphere has increased by nearly 30%, and average global temperature appears to have risen between 1. and 2.F.
Carbon dioxide gas traps solar heat in the atmosphere, partly in the same way as glass traps solar heat in a sunroom or a greenhouse. For this reason, carbon dioxide is called a “greenhouse gas.” As more carbon dioxide is added to the atmosphere, solar heat has more trouble getting out. The result is that, if everything else stayed unchanged, the average temperature of the atmosphere would increase. As people burn more fossil fuel for energy they add more carbon dioxide to the atmosphere. If this goes on long enough, the average temperature of the atmosphere will almost certainly increase.
Most scientists believe that if significant climate change occurs it will take place gradually over a period of many decades. If change is gradual, the overall economic impact on wealthy countries such as the United States will probably be modest although some regions or groups may experience large costs and others may experience large benefits. After all, American society already exists very successfully in Alaska, Arizona, and Florida and these states span a range of climates much wider than any predicted changes. Farmers would have to adjust their crops, and in some cases, farming regions and other land use patterns would shift. Some water supply systems would have to be modified. Low coastal areas would have to make adjustments. But, our society regularly makes changes to adapt to natural and man-made fluctuations. It could probably handle these additional changes without much trouble, although nationally the total costs could add up to many billions of dollars.
While many of the impacts of climate change would be negative, some might be positive. Heating costs in northern areas might decline, agricultural productivity in places such as Canada, Scandinavia and northern Japan might be improved, and the amount of sunlight available for grain crops might increase as the regions where they grow shifts further north. Of course, not all northern regions would benefit. Some northern soils are not suitable for agriculture, some areas of permanently frozen ground (permafrost) might become large impassable bogs, and various insect pests and diseases might move north.
Several economists have tried to estimate the overall economic cost of climate change for the United States. For the sorts of gradual changes being predicted over the next century, they estimate costs in the vicinity of a quarter of one percent per year of GDP (gross domestic product). Such calculations are, of course, very uncertain.
There is some chance that climate change will be abrupt, perhaps brought on by a sudden shift in the general pattern of ocean circulation. If that happens, the economic costs to wealthy countries like the United States could be very large. Much new investment might be needed in a very short period of time. Agricultural and water systems might not easily be modified in just a few years, especially if uncertainty makes planning difficult. Most scientists believe that such catastrophic change is unlikely, but not impossible.
An international group of agricultural researchers used climate projections from three climate models (GCMs) to project regional climate changes at 112 locations in 18 countries under the assumption that the amount of carbon dioxide in the atmosphere had doubled. Average global temperature increased about 8.F (4.5.C). Regional agricultural experts projected the yields of wheat, corn, soybeans, and rice at each location. An economic model was then used to estimate patterns of world food prices and trade. Assuming that farmers employ simple adaptation practices, such as changing planting times and seed varieties to match the changed local climates, they estimate global food output to be unaffected for the case of one climate model, and to drop by 2% and 6% respectively for the other two climate models studied. The developing world is hit harder than the developed world. Including the effects of comparative costs in world trade, developed country output is predicted to rise between 4 and 14% and developing country output to fall by 9 to 12%. World food prices go up. The number of people at risk of hunger (due to higher prices) probably also goes up, perhaps by 50%. This analysis assumed that no major changes, such as construction of new irrigation projects, are undertaken. If such changes are included, the agricultural impact on all but the poorest developing countries probably becomes very small