填空题
Climate Disaster? Here"s What the US Could Look Like in 2100
A. You"ve been hearing about the negative impacts of global warming for years. Sometimes you read with worry the news about forest fires, hurricanes, droughts and heat waves. And you wonder, "Is climate disaster already upon us?" Scientists say the answer is "Yes." We are now experiencing the effects of human-caused climate change and say, even if we drastically alter our polluting behavior today, we"ll continue to see changes over the next two to three decades and researchers predict it may be worse than the depressing situation.
B. Although the future seems gloomy, there is hope. While we can"t change the polluting that has already occurred, we can make changes now that will leave a cleaner world for our children and grandchildren. "One important message to convey is we can very much affect what happens 90 years from now by the decisions we make today," says Jim Hurrell, Ph.D., a senior atmospheric researcher with the National Center for Atmospheric Research (NCAR).
C. But what happens if we don"t act now? Here is how the parts of the United States could be affected in the year 2100 if we don"t turn it around.
1. Pacific Northwest
D. Climate changes in the Northwestern states as a result of global warming will include heavier rainfall and higher temperatures. The slow steady drizzle so familiar to Northwest residents will change.
E. By 2100 there will be very dramatic warming over the higher latitudes of both hemispheres. Studies on temperature changes that have already occurred show that Alaska has experienced a 3.6 degree Fahrenheit increase since 1951 and western states in the US are experiencing warmer summer temperatures.
F. The Northwest will also be affected by the anticipated two to three feet of sea level rise, though cities in this area will suffer less than coastal cities in the Southwest and Southeast. "The sea level rise will be global, but it becomes a big problem when three things come together, high tides, a higher sea level, and a storm surge," says Kevin Trenberth, head of the Climate Analysis Section with NCAR. "The worst storm surges are associated with hurricanes. You don"t get hurricanes in the Northwest, so the Northwest is not as vulnerable as the Southeast in that regard."
2. Rocky Mountains
G. Scientists predict that by 2100 increasingly early snowmelts will put a strain on water supplies in Denver, Salt Lake City and other communities fed by Rocky Mountain rivers. Winter snowpack is a vital part of life in the Mountain West. Snow piles up in the winter, melts in late spring and summer, and rivers flow, providing water everywhere. But global warming is changing all that. In the future, the snow season will get shorter, the snowpack will be less, and
runoff
(径流) could easily occur a month or two earlier. Consequently, the ski industry, now a main source of revenue for Rocky Mountain ski towns, will no doubt be put on notice, as will states downstream from the mountains. Less water in the Southwest will lead to drought conditions, more wildfires and stressed fish and other
aquatic
(水栖的) species. An earlier spring disrupts natural systems in ways that lead to human health issues. A longer summer and short winter also allow insects to thrive, threatening the health of trees and contributing to the risk of forest fires.
3. Northeast
H. The largest metropolitan areas along the seaboard are especially at risk for stronger storms and flooding. East Coast cities will also be more affected by sea level rise than other areas of the US. Today"s coastal areas will be very different by the end of this century if we do nothing. On average, global sea levels will go up two to three feet. But scientists expect that in some coastal cities, such as Boston and New York, complex ocean currents that will change as our climate changes will add an extra 8 inches to that increase in water level. Rising sea levels could flood subways and underground
sewage
(污水) and transportation systems if left unchecked. Or, these cities could become similar to New Orleans, in that they"d need to build infrastructure to protect them from rising sea levels.
I. An increase in the number of extreme storms would cause public health issues by creating a higher risk of
waterborne
(由水传播的) illnesses. Some estimates suggest that at our current rate of climate change, temperature in the Northeast will increase as much as 6 degrees Fahrenheit by century"s end. That will make the public health risks during heat waves immeasurably worse than they already are today.
4. Southeast
J. The Southeastern states will experience less extreme temperature increases than northern and western states, but they will see stronger storms and find themselves more vulnerable to sea level rise. "There are two major factors in terms of sea level rise," says Hurrell. "The first is thermal expansion. The second is that more fresh water will be added to the oceans."
K. "There are three main risks in the Southeast," says Trenberth. "There is risk for increased wind damage, risk for a storm surge, which is very coastal and worsened by higher sea levels, and then a bit further inland, there is an increased risk of flooding from heavy rains." Waterborne diseases are more likely to be prevalent in a flood zone and will create additional risk to public health.
5. The Northern Plains, Midwest and Great Lakes
L. Scientists predict that the Northern Plains, Midwest and Great Lakes areas will experience stronger storms, longer storm seasons and an increase in temperatures. Temperature changes as high as 5 to 12 degrees Fahrenheit in winter, and 5 to 20 degrees Fahrenheit in summer by 2100. Warmer winters can lead to an increase in infectious diseases as warmer winter weather allows insect populations to remain active longer each year.
M. An extended summer will translate to a longer growing season, but also to an increased risk of drought and extreme heat. That heat will create evaporation that will lower water levels, especially in the Great Lakes. While there will be little change in overall average
precipitation
(降雨量), this region will experience longer storm seasons.
6. Southwest
N. The Southwestern states, including California and Nevada, will experience intense heat waves, poorer air quality, wildfire, water shortages, drought and expanding risks to agriculture. In general, the main worry in the Southwest is water resources. Water is already a scarce resource what with increasing population demands. These areas are already quite dependent on water flowing from the mountains, so any changes in snowpack will exert an impact on water sources in places like California.
O. Dry conditions and" high temperatures will increase risk for heat waves and wildfires. Along with that come issues with insects and diseases. Some insects flourish with a longer summer season, and the dead trees they create lead to higher wildfire risk.