题型：阅读理解 题类：模拟题 难易度：普通
天津市南开中学2019届高三英语校模拟检测试卷
Against the supposition that forest fires in Alaska, Canada and Siberia warm the climate, scientists have discovered that cooling may occur in areas where burnt trees allow more snow to mirror more sunlight into space.
This finding suggests that taking steps to prevent northern forest to limit the release of greenhouse gases may warm the climate in northern regions. Usually large fires destroyed forests in these areas over the past decade. Scientists predict that with climate warming, fires may occur more frequently over next several centuries as a result of a longer fire season. Sunlight taken in by the earth tends to cause warming, while heat mirrored back into space tends to cause cooling.
This is the first study to analyze all aspects of how northern fires influence climate. Earlier studies by other scientists have suggested that fire in northern regions speed up climate warming because greenhouse gases from burning trees and plants are released into the atmosphere and thus trap heat.
Scientists found that right after the fire, large amounts of greenhouse gases entered the atmosphere and caused warming. Ozone (臭氧) levels increased, and ash from the fire fell on far-off sea ice, darkening the surface and causing more radiation from the sun to be taken in. The following spring, however, the land within the area of the fire was brighter than before the fire, because fewer trees covered the ground. Snow on the ground mirrored more sunlight back into space, leading to cooling.
"We need to find out all possible ways to reduce the growth of greenhouse gases in the atmosphere." Scientists tracked the change in amount of radiation entering and leaving the climate system as a result of the fire, and found a measurement closely related to the global air temperature. Typically, fire in northern regions occurs in the same area every 80 to 150 years. Scientists, however, found that when fire occurs more frequently, more radiation is lost from the earth and cooling results. Specifically, they determined when fire returns 20 years earlier than predicated, 0.5 watts per square meter of area burned are soaked up by the earth from greenhouse gases, but 0.9 watts per square meter will be sent back into space. The net effect is cooling. Watts are used to measure the rate at which energy is gained or lost from the earth.
Bulletin Board Workshops are held at Women's Health Centre, 1441 29 St. N.W. If you are interested, please call 944-2260 or visit www.womenhealthcentre.ca. | |
Eating to Get to Your Healthiest Weight | If you are seeking professional help with your weight-loss efforts, then this workshop series, presented by Dawn Peacock, BSc, RD, is for you. The workshop will take place on Fridays, July 10 between 1:30 p.m. and 3:30 p.m. or July 24 between 7 p.m. and 9 p.m. Fee: $120 |
How to Reduce Depression & Anxiety | Depression and anxiety are two disorders that often affect women at the same time. They may go unrecognized and cause needless suffering. This four-part class, offered by Elizabeth Miles, MSc, Rpsych, will help reduce the suffering. The classes will be held on Wednesdays, July 8, between 1:30 p.m. and 3:30 p.m. or July 22 between 7 p.m. and 9 p.m. Fee: $120. |
How Do I Protect My Bones? | Osteoporosis (骨质疏松) is a serious health condition that affects women as they age. Come to this workshop, presented by Irene Jackson, RN, MN, to find out more about osteoporosis and learn how you can reduce your risk factors and protect your bones. The workshop will take place on Tuesday, Aug. 16, 8 a.m. to 8 p.m. Fee: $150. |
Raising Your Child in a Weight Obsessed World | We live in a world where television and restaurants are pushing super-sized hamburgers and soft drinks, while magazines feature pencil-thin models. This presentation, by Keri Sullivan, MSc, RD, Eating Disorder Program, will offer ways to build healthy environments and behaviours for children. The presentation will be offered on Wednesday, Aug. 24, 8 a.m. to 8 p.m. Fee: $150. |
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