PBS高端访谈:气候变化是否导致了飓风状况的恶化

 　　And the Associated Press now confirms that the death toll¹ from Harvey has risen to 12.

　　But as we focus on Texas and Louisiana, nature is also taking a devastating² toll elsewhere.

　　Heavy monsoons³ are paralyzing Mumbai, India, right now. More than 1,200 people have died so far.

　　Connecting the dots between a global warming and extreme weather is not a simple job for science.

　　That is the topic of our Leading Edge segment this week.

　　Scientists are loathe⁵ to get ahead of their data, but what they see in Houston fits like a key piece in a giant complex puzzle.

　　First, the disclaimers: It's difficult to say anything about individual events.

　　Kerry Emanuel is a professor of atmospheric⁶ science at the Massachusetts Institute of Technology.

　　We have a lot of extreme weather events. Whether or not the climate changes, to attribute a particular event to climate change is next to impossible.

　　Because, for those really rare events, it's hard to even know how common they are before you get to climate change.

　　Radley Horton is a climate scientist at Columbia University's Lamont-Doherty Earth Observatory⁷.

　　You probably want to have 500 years of data, 1,000 years of data to estimate those statistics.

　　And, of course, we don't have data records to go back 500 years or 1,000 years.

　　I'm very uncomfortable talking about causation of one particular storm,

　　in the same way that I can't identify what particular home run was hit by a baseball player because of steroid use.

　　Marshall Shepherd is a professor of geography and atmospheric sciences at the University of Georgia.

　　I think that we know that steroid use likely increases the probability or chance that there will be more home runs in baseball.

　　But can I conclusively⁸ say that that particular player hit that particular home run because of steroid use? I don't know that for a fact.

　　So, let's begin on the firmer ground, the facts.

　　Over the past hundred years, global temperatures have risen 1.5 degrees Fahrenheit⁹, and global sea level has risen about eight inches. No dispute about that.

　　It doesn't sound like much, but for a lot of the coastal¹⁰ cities in the U.S., places like Norfolk, Virginia, we're already seeing much more frequent nuisance flooding events.

　　And, in fact, while our eyes have been fixed¹¹ on Texas and Louisiana this week,

　　large parts of Norfolk are underwater because of a run-of-the-mill tropical system. And in India, monsoon⁴ rains caused floods that killed 1,000.

　　We're getting high water along the coast when there's no storm at all, water levels that used to happen maybe once every decade or so happening every couple of years.

　　And while the atmospheric temperature has increased, the real heating has occurred in the oceans. And warm water is like high-octane fuel for a hurricane.

　　Once those upper ocean temperatures, especially near the surface, get to about 80 degrees Fahrenheit or warmer, you now have a source of warm, moist air. That is the fundamental fuel of a hurricane.

　　This is where the science gets a little bit harder. Does this warmer water necessarily mean that there will be more powerful hurricanes?

　　What all the models and theories seem to agree on, at least globally, at this point is that the frequency of the very high intensity¹², Category 3 or 4 or 4 events, should go up.

　　If you look at the most powerful hurricanes on the planet, they have winds near the surface of about 200 Miles per hour.

　　It's conceivable that, 100 years from now, the top-ranking hurricanes will have wind speeds of, say, 220 miles per hour, OK, about a 10 percent increase.

　　Scary and foreboding as that is, the strength of a hurricane is just part of the picture. A warmer climate means more moisture in the air, and that is leading to more rainfall.

　　Even if the hurricane strengths stay the same, we will probably see more rainfall in those hurricanes in the future,

　　because the upper oceans are going to be warmer, because that warmer atmosphere can hold more moisture.

　　That means that, even if the storm strength is the same, you will probably see a little more rainfall occurring during those powerful hurricanes.

　　We're very confident that freshwater flooding will become more problematic as the climate warms, freshwater flooding in particular from hurricanes.

　　Models show that. It's a very simple theory. That's a big worry.

　　We're seeing quite a bit of urban flooding around the world, and particularly in this country,

　　many of our storm water management and built environment infrastructure¹³ is developed for what I call the 1950s rainstorm.

　　We have built our civilization right to the edge of safety for a very specific, and until recently, very stable climate.

　　There's something called stationarity. And what that essentially¹⁴ means is that storm water management, roads, building design, built infrastructure,

　　assume that the intensity of rainfall would basically stay the same forever.

　　And what we're seeing in the scientific literature is that the most intense rainstorms are now more intense, and this overwhelms that built infrastructure.

　　Going forward, I think the built environment infrastructure planning, engineering communities will have to increasingly consider these weather and climatic changes in their design.

　　This is going to happen quickly. That's what I'm signing today.

　　But 10 days before Harvey hit Houston, the Trump¹⁵ administration moved in the opposite direction,

　　overturning an Obama era rule that federal projects be designed to account for the risk posed by climate change.

　　And yet the data is clear: There will be more events like this to follow.

　　We see that when those climate models are run in the future, with those higher greenhouse gas concentrations,

　　we see more extreme events of certain types, more heat waves, more heavy rain events and more frequent coastal flooding.

　　We're inside the experiment. It's the largest experiment we have ever done on the Earth system, for sure.

　　We produced that story in conjunction with PBS NOVA and the online weather app MyRadar, part of an upcoming series on the link between weather and climate. undefined

1 toll   

n.过路(桥)费；损失，伤亡人数；v.敲(钟)

参考例句：

• The hailstone took a heavy toll of the crops in our village last night.昨晚那场冰雹损坏了我们村的庄稼。
• The war took a heavy toll of human life.这次战争夺去了许多人的生命。

2 devastating   

adj.毁灭性的，令人震惊的，强有力的

参考例句：

• It is the most devastating storm in 20 years.这是20年来破坏性最大的风暴。
• Affairs do have a devastating effect on marriages.婚外情确实会对婚姻造成毁灭性的影响。

3 monsoons   

n.（南亚、尤指印度洋的）季风( monsoon的名词复数 )；（与季风相伴的）雨季；（南亚地区的）雨季

参考例句：

• In Ban-gladesh, the monsoons have started. 在孟加拉，雨季已经开始了。 来自辞典例句
• The coastline significantly influences the monsoons in two other respects. 海岸线在另外两个方面大大地影响季风。 来自辞典例句

4 monsoon   

n.季雨，季风，大雨

参考例句：

• The monsoon rains started early this year.今年季雨降雨开始得早。
• The main climate type in that region is monsoon.那个地区主要以季风气候为主要气候类型。

5 loathe   

v.厌恶，嫌恶

参考例句：

• I loathe the smell of burning rubber.我厌恶燃着的橡胶散发的气味。
• You loathe the smell of greasy food when you are seasick.当你晕船时，你会厌恶油腻的气味。

6 atmospheric   

adj.大气的，空气的；大气层的；大气所引起的

参考例句：

• Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
• Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

7 observatory   

n.天文台，气象台，瞭望台，观测台

参考例句：

• Guy's house was close to the observatory.盖伊的房子离天文台很近。
• Officials from Greenwich Observatory have the clock checked twice a day.格林威治天文台的职员们每天对大钟检查两次。

8 conclusively   

adv.令人信服地，确凿地

参考例句：

• All this proves conclusively that she couldn't have known the truth. 这一切无可置疑地证明她不可能知道真相。 来自《简明英汉词典》
• From the facts,he was able to determine conclusively that the death was not a suicide. 根据这些事实他断定这起死亡事件并非自杀。 来自《简明英汉词典》

9 Fahrenheit   

n./adj.华氏温度；华氏温度计(的)

参考例句：

• He was asked for the boiling point of water in Fahrenheit.他被问到水的沸点是华氏多少度。
• The thermometer reads 80 degrees Fahrenheit.寒暑表指出华氏80度。

10 coastal   

adj.海岸的，沿海的，沿岸的

参考例句：

• The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
• This country will fortify the coastal areas.该国将加强沿海地区的防御。

11 fixed   

adj.固定的，不变的，准备好的；(计算机)固定的

参考例句：

• Have you two fixed on a date for the wedding yet?你们俩选定婚期了吗？
• Once the aim is fixed,we should not change it arbitrarily.目标一旦确定，我们就不应该随意改变。

12 intensity   

n.强烈，剧烈；强度；烈度

参考例句：

• I didn't realize the intensity of people's feelings on this issue.我没有意识到这一问题能引起群情激奋。
• The strike is growing in intensity.罢工日益加剧。

13 infrastructure   

n.下部构造，下部组织，基础结构，基础设施

参考例句：

• We should step up the development of infrastructure for research.加强科学基础设施建设。
• We should strengthen cultural infrastructure and boost various types of popular culture.加强文化基础设施建设，发展各类群众文化。

14 essentially   

adv.本质上，实质上，基本上

参考例句：

• Really great men are essentially modest.真正的伟人大都很谦虚。
• She is an essentially selfish person.她本质上是个自私自利的人。

15 trump   

n.王牌，法宝；v.打出王牌，吹喇叭

参考例句：

• He was never able to trump up the courage to have a showdown.他始终鼓不起勇气摊牌。
• The coach saved his star player for a trump card.教练保留他的明星选手，作为他的王牌。