泛读教程4--Is-Weather-Getting-Worse

Is Weather Getting Worse? Weather seems getting worse and wilder since Mother Nature is full of surprises these days. Global warming, a heated topic of today, is often taken for granted to be responsible for the harsh weather. However, scientists, like Kevin E. Trenberth, are cautious in making their judgment. Please read the following article and find out what role El Nio and La Nia play. As you read this, flip your eyes over to the window. The sky is clear, the wind light, and the sun brilliant. Or maybe not Mother Nature is full of surprises these days. The calendar says its spring, but there could just as easily be a winter blizzard, a summer swelter, or an autumn cold snap on the other side of that glass pane. Almost in an instant, it seems, the weather shifts from one season to another. And wherever it swings, it seems increasingly likely to be extreme. Consider what Mother Nature slung our way last year in May, typically the second worst month for tornadoes. In less than 24 hours, more than 70 hellholes of wind rampaged through Oklahoma and Kansas, killing 49 and causing more than $1 billion in damages. In June, it was heat, as the Northeast began roasting through weeks of the worst drought since the 1960s; 256 people died. This year in January, blizzards pounded the U.S. from Kansas to the Atlantic Ocean. In April, 25 inches of snow fell on parts of New England. Why has our weather gone wild? Its the question everyones asking, but a very tough one to answer. Although many scientists still arent convinced that it has gone wild, some have begun saying cautiously, hesitantly that extreme weather events are occurring with more frequency than at any time in this century, events consistent with the profile of a warming world. Global warming is real, says Kevin E. Trenberth, head of the Climate Analysis Section of the Center for Atmospheric Research in Boulder, Colorado. The mean temperatures are going up. The key question is: What will it do locally? I think were going to start feeling its effects in the changes on extremes. That doesnt mean you can indict weird weather in your neck of the woods as proof. Mother Nature knows how to hide her tracks. She hurls a torrential downpour today and a drought tomorrow followed by gentle rain the next week. To understand a pattern in natural variability, you cant look into the sky; you have got to study data. And for a host of reasons, that isnt easy. But tallying up the damage is. In the last 20 years, this country has been whacked by $I70 billion worth of weather-related disasters hurricanes, droughts, floods, and tornadoes. Thirty-eight severe weather events occurred in a single decade, between 1988 and 1999; seven events occurred in 1998 alone the most for any year on record. Globally, insurance companies are calling it a catastrophe trend. In a report issued last December, Munich Re, the worlds largest reinsurer, or insurer of insurance companies, noted that the number of natural disasters has increased more than fourfold since the 1950s. Earthquakes, which are not weather-related, caused nearly half the deaths in those catastrophes; storms, floods, and other weather woes killed the other half. In 1999, the number of catastrophes worldwide hit 755, surpassing the record of 702 set only the year before. In its five-point list of causes for increased damage claims, Munich Re blamed population growth first, climate change fifth. Critics may well seize upon this to diminish claims that the weather is getting worse, but taken together, its a more frightening picture. Thanks to swelling populations in cities and along coastal areas, more of Earths passengers are living in the wrong place at the wrong time. Still, the statistics meteorologists have collected on extreme weather events arent enough to prove that the weather is getting worse. By their very definition, extreme events happen infrequently, and no one has been collecting scientifically sound data long enough to know how common they are. For example, a storm that happens once a century might require two millennias worth of storm data to draw conclusions. To top it off, the computer models scientists use to study climate crunch numbers on a scale of centuries at a time. Ideally, youd like data sets that go back several hundred years, says Philip Arkin, deputy director of the International Research Institute for Climate Prediction at the Lamont-Doherty Earth Observatory in New York. But they just dont exist. The U.S. data go back 50 years. Before World War II, its very difficult to come up with good numbers. We have some data on heavy rain events before 1900, but theres nothing useful. Even if scientists could find good numbers, computer resolution is still too coarse to be able to forecast how something as simple as warming might affect climate in specific spots on the globe. The smallest amount of space on land, sea, ice, and air that scientists can study is about the size of Virginia. If they crank up the resolution by 50 percent to focus on an area half that size, they pay for it in computing time a calculation that took 10 days to perform might now need three months. Keith Dixon, a research meteorologist at the National Oceanic and Atmospheric Administrations Geophysical Fluid Dynamics Laboratory in New Jersey, recalls once he was being asked precisely what global warming would mean for state ski resorts. More snow? (Good.) Or more rain? (Bad.) I can understand why businesspeople or politicians ask. If you want to cut fuel, spend money, and make decisions, you need to know why you should be doing this. Adds his colleague, Tom Knutson: I can certainly sympathize with them. But we cant answer it. Since 1995, the literature has suggested that there could be fewer frosts, more heat waves, more droughts, more intense rainfalls, tropical cyclones, and hurricanes in the 21st century when and if CO2 levels double. But these projections rank low on the confidence scale because scientists cannot say definitively if and how the events might occur. All of which doesnt do the average citizen much good. He doesnt worry about 30-to-100-year shifts in the climate. What gets him is day-to-day weather: This heats killing me. Crops have failed here five years in a row. There have been three bad tornadoes in as many weeks. We live in a society uniquely privileged to learn about weather events and to fear them. The Center for Media and Public Affairs, a watchdog group based in Washington, D.C., reports that media coverage of weather disasters more than doubled from 1997 to 1998 alone. Probably as a result, people are starting to blame harsh weather on global warming. Politicians are too. Jerry Mahlman, director of the GFDL, advises the White House on climate change. He remembers sitting in a conference with Vice President Gore, who asked: Can we say that storms will be more extreme in the greenhouse-enhanced earth? The scientist didnt flinch as he replied, No. Gores shoulders seemed to crumple. Globally, the 1990s stood as the warmest decade for which we have records. Scientists already predict that by 2100, Earth could warm up another 1.8 to 6.3 degrees Fahrenheit. Most of us think heat when we think global warming. Scientists think ice. Theyre worried about what will happen when all that extra heat hits the ice at Earths poles. A dominant hypothesis says that the water cycle will speed up: Heat will hasten ocean evaporation, and because hot air can hold more moisture, it could all be whisked away to rain more upon our heads. Five years ago the Intergovernmental Panel on Climate Change, an international collaboration of 2 000 scientists, theorized as much in a well-publicized 56-page report. That same year, a team of scientists led by Tom Karl, now director of the National Climatic Data Center (NCDC), studied 80 years of U.S. data and confirmed an increase in extreme precipitation events, altered patterns of rain and drought, and rising temperatures since 1970. But the scientists cautioned that the study analyzed only 80 years of data, confined itself to the United States which occupies a mere 2 percent of the globe and found nothing out of the realm of pure chance. Within months came another, stronger piece of real-world data, nailed down by one of the men caught in that January snowstorm. Sifting through historical data, Trenberth had found that more, longer, and stronger El Nios have occurred during the last 20 years than in the previous 120 years. That was unusual, a chance of 1 in 2 000. El Nio, the periodic warming of the equatorial Pacific that induces storms and other climatic events, historically occurs once every three to seven years and lasts for up to two years. But even as Trenberth presented his findings at a conference in Melbourne, Australia, the Pacific was experiencing an odd, double El Nio: The first had lasted from 1991 to 1993, a weaker one from 1994 to 1995. Trenberth floated an ideal past the audience in his native New Zealand accent: Could this be due to global warming? The idea, Trenberth modestly recalls, caused something of a stir in the audience. Scientists found themselves wondering: What would happen if one of natures storm machines not completely understood but still adhering to rhythms as regular as the seasons were pressed into service by global warming? Archaeological evidence suggests El Nio has been around for thousands, possibly millions of years. A known instigator of storms, floods, droughts, and secondary effects like fires, the El Nio-Southern Oscillation could go a long way toward explaining many weather extremes. Under normal circumstances, sea surface temperatures rise in the tropical Pacific, fueling strong thunderstorms. Like a vast climatic mailbag, El Nio-enhanced activity hand-delivers heat and moisture to parts of the globe where they would not normally go. Contrasting cool ocean currents in the Pacific can usher in the opposite phase, La Nina, which tends to dry out the southwestern and South Central states. La Nia also makes weather conditions worse but rarely bullies as harshly as El Nio. The Americas are greatly affected by El Nio, Trenberth says. Europe is much less affected. If things do become more El Nio-like, then it does have implications for different parts of the country. It means were more likely to have storms coming into southern California and going across the south, at least in the winter-time. If 1998 was any indication, you have to really watch out for the seasonal change, where it can go from wet conditions to quite dry conditions when the storm tracks move farther north. In the early 1990s, El Nio helped dry Indonesia and other tropical Pacific climate and blister southern Africa, but it drenched California. Together Nio and Nia did a number on the Americas. From 1992 to 1993: winter floods in California. In 1993: flooding in the Mississippi Basin, drought in the Carolinas. From 1994 to 1995: more floods in California. In 1996: drought in the South Central states, flooding in the Midwest. The strongest El Nio on record, from 1997 to 1998, registered water temperatures as high as nine degrees above normal. A normal, run-of-the-mill El Nio is about two or three degrees Fahrenheit above normal, says Trenberth. This one was nine, so it was a real granddaddy in that respect. That was the year Hurricane Mitch left at least 11 000 dead in Central America. The NCDC calls Mitch the deadliest Atlantic hurricane since 1780. Today Trenberths hypothesis is high on the agenda in such climate labs as the Geophysical Fluid Dynamics Laboratory in Princeton, the Max Planck Institute in Hamburg, Germany, and others in England, Australia, Canada, and Japan. Says Lamont-Dohertys Arkin, It would be hard to talk about extreme weather without considering his work. But Mahlman says: Its a good hypothesis; theres a shred of truth to it. But it still seems like a coin flip. Reviewing results in his lab in the foothills of the Rockies, Trenberth is the first to poke holes in his own work. Part of the problem is that all the models tend to give different answers to this question, he says, But a lot of these models dont reproduce El Nio very well in the first place. So the confidence in what theyre telling you is undermined. Still, Trenberth believes we are likely in the coming century to see ever longer El Nios fluctuating with shorter La Nias. Weather, including bad weather, might therefore appear to be more fixed. Thats the main thing El Nio or La Nia does for you, he says, It locks the patterns in. So once you get into a dry regime, you stay in a dry regime. If you get into a wet regime, you stay in a wet regime. And so you tend to get these extremes you get battered by one storm after another. Or else you get dry spells time after time. Baltimore residents may recall that they sweltered in last summers heat wave and drought only to be soaked by Hurricane Floyd whisking through in September. Scientifically, one cannot directly blame that mess on El Nio or global warming. It was very regional, Trenberth says, There are a number of factors that go into that, part of which was La Nia, part of which was whats going on in lots of other places around the world except that if it happens more and more in different places around the world, the evidence mounts that something is pushing you in that direction. The global perspective is important with regard to the global warming issue. Just watching things go by locally can help to create the overall picture, but it doesnt confirm it at all. So, is the weather getting worse and wilder? Maybe. Perhaps the best line on this topic was penned by the director of the Geophysical Fluid Dynamics Laboratory. In an article published last year, Mahalman wrote: For me, the new data.indicate that we appear to be nudging noticeably closer to the smoking gun demanded by people who require very high levels of proof. Trenberth regards extreme weather as an analogue, a dry run to the future. And it isnt pretty. Droughts rob us of sustenance and leave us vulnerable to fire. In wet, warm conditions, insects thrive. The United Nations World Health Organization already reports that mosquitoes carrying malaria and dengue fever have hit new highs in Latin America, Africa, and Asia. In the United States, cycles of rain and drought seven years ago permitted a deadly form of pulmonary hantavirus, carried by mice, to flourish in the Southwest. Handed a dress rehearsal, perhaps we should use it. We can develop strategies to cope. We can cultivate an interest in the weather outside of our commutes. And we can shake the habit of sampling locally and extrapolating globally. (2420 words) TOP 课文一天气正越变越糟？ 因为“这些日子大自然母亲充满着意想不到的事情”，看起来天气在越变越糟，越来越狂野。全球变暖是现在的热门话题，常常理所当然地被看成恶劣气候的罪魁祸首。但是，凯文E川伯斯这样的科学家在下定论时态度谨慎。请阅读以下文章，看一看厄尔尼诺和拉尼娜现象所起的作用。 当你阅读本文时，请把目光轻快地投向窗外。天空澄净，微风轻拂，日光明媚。也许并不是这样这些日子， 大自然母亲充满着意想不到的事情。日历上说现在是春天，但窗外完全可能是一场冬季的暴风雪，一阵夏日的酷暑或一股秋天的寒流。几乎是在一瞬之间，气候就好象从一个季节转到了另一个季节。而且不管天气转向何方，它看起来变得越来越极端。 想想看去年五月大自然母亲都给我们带来了些什么，那是第二个遭受龙卷风袭击最严重的月份。在不到二十四小时之内，七十多个“地狱”风暴在俄克拉何马和堪萨斯州横行肆虐，造成49人死亡以及十多亿美元的损失。六月，天气酷热，东北部连续几周在热浪下炙烤，遭受了自六十年代以来最严重的旱情，256人丧生。今年一月，暴风雪横扫美国，从堪萨斯州直至大西洋沿岸。四月，新英格兰部分地区下的雪厚达二十五英 吋。 为什么我们的天气变得如此狂野？这是每个人都在问的问题，但是很难回答。虽然许多科学家仍然不相信天气已经失控，但有些人虽然态度谨慎，仍存疑虑已经开始说，与本世纪任何时段相比，极端性天气出现的频率愈加频繁，这与全球变暖的量变曲线是吻合的。凯文E川伯斯是设在科罗拉多州博耳德市的大气研究中心气候分析部的主任，他说：“全球变暖是事实。”“平均气温在上升。但关键问题是，它会给具体地区带来什么？我认为我们已开始感受到它的影响，天气的变化趋于极端。” 这并不意味着你可以用某一有限区域的怪异天气作为控诉的证据。大自然母亲知道该如何隐藏她的行踪。她今天猛地来一场倾盆大雨，明天是干旱，紧接着是一周柔柔细雨。你不能靠察看天象来了解自然变化的模式，你必须得研究数据。但由于种种原因，这并不容易。 但是计算一下灾害损失却是容易的。过去的二十年里，我们这个国家与气候相关的灾难飓风、干旱、洪水及龙卷风造成了高达一千七百亿美元的损失。仅1988年至1999年这十年间就发生了38起严重的气候事件，仅1998年就有7起气候事件，这是有史以来受灾最多的一年。 从全球范围来看，保险公司把天气变暖称为“灾难趋势”。世界最大的再保险商，即为保险公司提供保险的墨尼黑再保险公司在去年十二月份发行的一份报告中指出，自20世纪50年代以来，自然灾害的数量已经增长了四倍有余。在这些灾难中，和气候无关的地震造成了近一半人的死亡；风暴、洪灾以及其它气候性灾难夺去了另一半人的生命。1999年，全世界的灾难数目达到755起， 超过前一年才创下的702起的记录。 墨尼黑再保险公司在其列出的索赔要求日益增加的五点原因，认为人口增长首当其冲，天气变化则列在第五。一些批评家也许会紧抓住这一点来 轻视天气正越变越糟的观点，但综合起来考虑，这是幅更可怕的画面。幸亏人口增长主要在城市和沿海地区，更多的“地球过客们”是在不适当的时间住在了不适当的地方。 尽管这样，气象学家收集的有关极端性气候事件的统计数据，还不足以证实天气正越变越糟。根据他们的定义，极端性气候事件并不经常发生，而没有人收集的可靠的科学数据 ，在时间上长到足以弄清极端性气候事件怎样的频率才算正常的问题。例如，一场百年一遇的风暴也许需要两千年间的风暴数据，才能得出结论。为了得出结论，科学家研究气候所用的计算机模型每一次都需要以世纪为级别来处理数据。纽约拉蒙特-多尔蒂地球观测站国际天气预报研究所副主任菲利普阿尔金说，“理想的状况是，你最好拥有数百年的数据。但根本就没有 这样的数据。美国有五十年前的数据。二战以前则很难弄到理想的数据。我们有一些1900年以前的暴雨灾害的数据，但派不上用场。” 即使科学家们能够找到可用的数据，但由于计算机演算解析率仍然太粗糙，无法预测象天气变暖这样一个如此简单的变化会对地球上某个特定地点的气候产生怎样的影响。科学家们在陆上、海上、冰层及大气中能够研究的最小的的范围，相当于弗吉尼亚州的大小。如果他们想研究上述一半大小的区域，提高50%的解析率，那么代价就是计算时间。先前十天的计算现在也许要三个月。 新泽西国家海洋和大气局大气物理流体动力学实验室气象学研究人员基思迪克森回忆说，有一次有人问全球变暖对各州的滑雪胜地具体意味着什么。会下更多的雪？（好。）或者雨量会增加？（不好。）“我明白为什么商人或政界人士要问这些问题。如果你要减少燃料、投资以及做决策，你得知道你为什么要做这些。”他的同事汤姆克努特森补充说：“当然我很同情他们，但是我们无法回答这个问题。” 1995年以来，文献显示，二氧化碳的含量翻番时或如果翻番，那么21世纪则意味着霜冻减少，更多的热浪、旱灾，更多的降水、热带气旋和飓风。但是这些预测都底气不足，因为科学家不能肯定这些会不会发生以及如何发生。 这一切不能给普通公民带来什么实惠。他并不关心30-100年跨度的气候变化，他只在意每天的天气：“我要热死了。”“连续五年这儿的庄稼收成都不好。”“三周内刮了三次糟糕的龙卷风。”我们生活在这样一个社会中，有独一无二的特权来知悉天气事件-以及畏惧它们。设在华盛顿特区的一个监察组织媒体与公共事务中心报道说，仅1997至1998年一年间，媒体关于灾难性天气的报道就增加了一倍多。 也许结果就是，人们开始把恶劣天气怪罪于全球变暖。政界人士同样如此。大气物理流体动力学实验室主任杰里马尔曼就天气变化为白宫提供咨询。他记得有一次参加会议时，副总统戈尔问：“我们能说在地球温室效应越发严重的情况下，风暴就会变得更厉害吗？”他毫不畏缩地回答：“不能。”戈尔的肩膀似乎耷拉了下来。 从全球范围来看，20世纪90年代是我们记录在案的最暖和的十年。科学家们已经预测，到2100年，地球的温度还要再提高1.8F-6.3F。我们中的大多数人一提到全球变暖就会想到热浪。科学家们想到的则是冰。他们担心，一旦多余的热量袭击地球两极的冰，会发生什么情况。一种主导的假设是，水循环将加快：热量将加快海水的蒸发，因为热空气可以含更多的湿气，就会朝我们的头上降更多的雨。 五年前，一个由两千名科学家组成的国际联合组织，跨政府的气候变迁专家小组，在一份长达五十六页、引起公众广泛注意的报告中也提出了这一理论。同年，现任国家气象数据中心（NCDC）主任的汤姆卡尔领导一个科学家小组,对80年的美国数据进行了研究，证实自1970年以来，极端性降水事件有所增加，旱涝模式改变，气温升高。但科学家提醒说，该研究只分析了80年的数据，且仅限于占全球2%面积的美国境内，没有从纯粹偶然王国中得出任何东西。 几个月之后又得到一份来自现实世界的、更有力的数据，由一位经历了那场一月暴雪的人精确地提供。对历史数据进行筛选后，川伯斯发