DIRECTIONS for questions 2 to 6: Read the passage and answer the questions based on it.
Global warming is called the greenhouse effect because the gases that are gathering above the earth make the planet commensurate to a greenhouse. By trapping heat near the surface of the earth, the greenhouse effect is warming the planet and threatening the environment. Current fears stem largely from the fact that global warming is occurring at such a rapid pace. Models are predicting that over the next century, the global temperature will rise by several degrees. Some scientists still do not think that the effects of global warming are as severe as some people say. They think that droughts, hurricanes, and floods often blamed on global warming might actually have other causes. One major difficulty in studying global warming is the fact that weather data only exists for the last century and a half. As a result, understanding the present and predicting the future are very difficult. Global warming has a variety of causes. One of the largest factors contributing to global warming is the general problem of overpopulation and its many effects. The greater number of people consumes more items which take more energy to make, they drive more cars, and create larger amounts of garbage. These factors all increase the global warming problem. Many different gases can increase the planet's temperature. The number of different products and human activities that contribute to global warming are so numerous that finding solutions to the problem is very difficult. Using a refrigerator releases dangerous gases, turning on the lights requires energy from a power plant, and driving to work causes gas emanations from the car. Countless other normal activities lead to global warming. Though having an atmosphere is important, the greenhouse effect may be making it excessively thick. The levels of gases covering the Earth have soared with industrialization, and developed countries now produce about 75% of greenhouse gases. The most common gas is carbon dioxide, accounting for about 50% of all greenhouse gases. Other gases, including methane, CFCs, nitrogen oxides, and ozone, also contribute to forming the greenhouse layer. Because these gases are produced by so many important and common processes, limiting their production to prevent global warming will be difficult. As population increases and Third World countries begin to use greater amounts of energy, the problem may aggrandize rather than contract. A whole host of consequences will result. Some are probably already occurring. Temperature measurements of the sea surface and Deep Ocean indicate that the oceans are warming. Rising ocean temperature causes rising sea level from thermal expansion of the water. Rising temperature also means melting glaciers and rising sea level through addition of melt water to the oceans. Sea level rose about 1 foot during the last century, mostly from thermal expansion of the oceans. Sea level is expected to rise closer to 3 feet during the coming century. Rising sea level will cause increasing coastal erosion, flooding, and property damage during coastal storms on top of the potential for major loss of life from storms in low-lying coastal countries like Bangladesh and island nations in the Indian and Pacific Oceans. Warmer sea surface temperatures will result in more and stronger tropical storms (hurricanes and typhoons). Coastlines already ravaged by these storms will expect to see more strong storms than before, increasing the loss of life and damage to infrastructure. It is much more difficult to predict how regional and local weather patterns will change but there will certainly be changes. While higher temperatures will produce more rainfall across the globe, the regional rainfall patterns will likely change. Some areas will get more, some areas will get less. The timing of wet and dry periods may change. But higher temperatures will also mean more evaporation. Higher temperatures may also mean stronger storms with damaging winds. All of these mean new risks and changing conditions for agriculture. Centuries old farming practices will have to change. Some areas may go from being marginal to becoming a breadbasket region, while other regions may go from major agricultural production to marginal.