首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
The Greenhouse Effect Earth’s climate has been changing constantly over its 5-billion-year history. Sometimes, the clima
The Greenhouse Effect Earth’s climate has been changing constantly over its 5-billion-year history. Sometimes, the clima
admin
2009-04-23
38
问题
The Greenhouse Effect
Earth’s climate has been changing constantly over its 5-billion-year history.
Sometimes, the climate has warmed so that the oceans have risen and covered much of the Earth. Each of the changes may seem extreme, but they usually occurred slowly over many thousands of years.
Ancient Climate History
The first people arrived in America between 15,000 and 30,000 years ago. During that time, much of North America was covered by great ice sheets. Some 14,000 years ago, the last ice sheet began to melt very quickly. By 7,000 years ago, the ice was gone. This end to the ice ages caused big changes on the Earth. The changes caused many kinds of plants and animals to die. For example, mastodons—elephant-like animals—and other large mammals that preferred cold climates may not have been able to live in the warmer, drier conditions.
The Little Ice Age
Starting in the 14th century, Europeans lived through what is known as the "Little Ice Age." The Little Ice Age lasted for several hundred years. During the Little Ice Age, the advance of glaciers along with hard winters and famines caused some people to starve and others to leave their homes.
Recent Climate History
The Earth has warmed about 1°F in the last 100 years. And the four warmest years of the 20th century all happened in the 1990s. Periods of increased heat from the sun may have helped make the Earth warmer. But many of the world’s leading climatologists think that the greenhouse gases people produce are making the Earth warmer, too.
Scientists think the sea has risen partly because of melting glaciers and sea ice. When some glaciers melt, they release water into the sea and make it higher than it was before. Scientists also think that warmer temperatures in the sea make it rise even more. Heat makes water expand. When the ocean expands, it takes up more space.
What Might Happen?
Scientists are not fortune-tellers. They don’t know exactly what will happen in the future. But they can use special computer programs to find out how the climate may change in the years ahead. And the computer programs tell us that the Earth may continue to get warmer.
Together, the melting glaciers, rising seas, and computer models provide some good clues. They tell us that the Earth’s temperature will probably continue to rise as long as we continue increasing the amount of greenhouse gases in the atmosphere.
Scientists have to think like detectives. They look for clues to help them understand how the world works. Then they investigate the clues to find evidence—real facts that can give them a better idea of what is going on. Here are some of the ways that scientists gather evidence about climate, both past and present:
Weather Stations
Weather stations help us find out the temperature on the surface of the Earth. Weather stations use special thermometers that tell us the temperature. They can be set up almost anywhere on land. Weather stations also can tell us how fast the wind is moving and how much rain falls on the ground during a storm.
Weather Balloons
Almost everyone likes balloons—including scientists! Weather balloons are released to float high up into the atmosphere. They carry special instruments that send all kinds of information about the weather back to people on the ground.
Ocean Buoys
A buoy is an object that floats on water, and is often used to warn boats away from dangerous places in the ocean or on a river. But some buoys have special instruments on them. These buoys can tell us the temperature and other things about the conditions of the atmosphere.
Weather Satellites
Humans send satellites into space to travel around the Earth. The satellites send back information to scientists on the ground. Some of the information they give us is about the weather and the Earth’s temperature.
Ice Cores
Some scientists who want to find out more about climate study ice for clues. Not just any ice—they are studying the ice from glaciers that have been around for a very long time. They cut pieces of ice and look for air bubbles that were trapped in the ice hundreds or even thousands of years ago. The air bubbles help them discover what the climate used to be like on Earth. The evidence they uncover is creating a historical record of regional temperatures and greenhouse gas concentrations dating back 160,000 years.
Sediment Analyses
Sediment is the earth and rock that has built up in layers over time. Scientists are learning a great deal about past climate from studying these layers. Sediment layering provides information about where glaciers have been in the past. Ocean sediments provide a map of how ocean currents have flowed in the past. And fossilized pollen found in sediment layers tells us about where different plants have grown in the past.
Tree Rings
You can tell how old a tree is by counting its rings because it grows a new ring every year. Tree rings also can tell us how much precipitation fell each year in the place where the tree lives.
What Does All of This Mean?
Weather stations, balloons, ocean buoys, and satellites tell us the Earth’s temperature today. Ice cores, sediment layers, and tree rings tell us about what the Earth’s climate has been like in the past. With this evidence, scientists are learning how climate changes over time.
What Are Scientists Still Unsure About?
How do clouds respond to changes in temperature and precipitation? How do oceans transport heat? How do climate and intense weather events like hurricanes affect each other? As scientists try to answer these and other questions, they will discover many more clues about how the Earth’s climate system works.
It may seem hard to believe that people can actually change the Earth’s climate. But scientists think that the things people do that send greenhouse gases into the air are making our planet warmer.
Once, all climate changes occurred naturally. However, during the Industrial Revolution, we began altering our climate and environment through agricultural and industrial practices. The Industrial Revolution was a time when people began using machines to make life easier. It started more than 200 years ago and changed the way humans live. Before the Industrial Revolution, human activity released very few gases into the atmosphere, but now through population growth, fossil fuel burning, and deforestation, we are affecting the mixture of gases in the atmosphere.
Since the Industrial Revolution, the need for energy to run machines has steadily increased. Some energy, like the energy you need to do your homework, comes from the food you eat. But other energy, like the energy that makes cars run and much of the energy used to light and heat our homes, comes from fuels like coal and oil-fossil fuels. Burning these fuels releases greenhouse gases.
选项
A、Y
B、N
C、NG
答案
B
解析
The passage gives a general description of ancient climate history.这是主旨题,观察词汇线索 ancient climate history。通过观察小标题可以发现,ancient climate history是文章某个部分的内容,不能涵盖文章全部范围,则该题正确答案N。
转载请注明原文地址:https://kaotiyun.com/show/PyR7777K
0
大学英语四级
相关试题推荐
A、Closebutunequal.B、Friendlybutformal.C、Strainedandformal.D、Equalandinformal.D
A、Workaholic.B、Self-disciplined.C、Active.D、Creative.B
A、Itismoreentertainingandenlightening.B、Itavoidshurtingothers’feelings.C、Itcanberememberedbetter.D、Itsavestime
A、Itcanreducetheriskofheartdisease.B、Itcanimprovetheeffectofexercise.C、Itcanmakeusfeelhappy.D、Itcancures
根据《期货交易管理条例》规定,下列关于交割制度的说法,不正确的有()。
A、Runninggetsapersonwetterwhileraining.B、Runningfastkeepsapersontotallydrywhileraining.C、Runninghasalittleim
A、Feelingisexpressedbyusing"Ifeelasif..."B、Feelingisexpressedbyusing"Ifeelit."C、Thoughtisexpressedbyusing"
N此处需填入修饰谓语动词categorizes(分类)的副词。根据空格后的forceshimto…(强迫他……),可推断把个人进行分类是一个长期的过程,故constantly“经常地,不断地”最合适。
A、Lesscasesoffood-relatedillnesses.B、Theextinctionofbadfood.C、ThePresident’sapprovalofthenewact.D、Thechangeof
A、Anunexpectedevent.B、Themeaningwegivetoanevent.C、Thethoughtofabnormalthingsinourlives.D、Thementionofthewo
随机试题
Barrett食管是指Barrett溃疡是指
以下哪种患者不适宜床上擦浴
压疮发生的主要因素是
一电焊学徒工,无防护条件下电焊操作半天后,次日出现眼痛、流泪、怕光。检查见球结膜充血、水肿。对该职业的防护措施最重要的是
居民生活用气与公建用气一日中一般有()用气高峰。
X企业为增值税一般纳税企业,在对其期末存货进行财产清查中发现,A商品溢余20件,单价20元,共计400元,因数目较小,可直接记入“管理费用”进行调整处理。()
由目标或对象引导、激发和维持个体活动的内在心理过程或内部动力叫()
光年是天文学中一种表示速度的单位。()
针对近年来青蒿素在全球部分地区出现的“抗药性”难题,屠呦呦及其团队经过多年攻坚,在“抗疟机理研究“抗药性成因”“调整治疗手段”等方面取得新突破,于近期提出应对“青蒿素抗药性”难题的切实可行治疗方案,并在“青蒿素治疗红斑狼疮等适应症”“传统中医院科研论著走出
删除考生文件夹下QIAO文件夹中的WIN.TXT文件。
最新回复
(
0
)