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課程來源:TED
     
Lee Hotz談進入南極時間機器
Lee Hotz: Inside an Antarctic time machine
 
講者:Lee Hotz
20107月演講,20108月在TEDGlobal上線
 
翻譯:陳盈
簡體編輯:洪曉慧
簡繁轉換:劉契良
後制:陳盈
字幕影片後制:謝旻均
 
 
關於這個演講
科學專欄作家Lee Hotz講述南極洲WAIS分界線上的一個受矚目的專案。一組堅毅的團隊人員鑽探出萬年冰,以提取關於氣候變化的關鍵資料。
 
關於Robert Lee Hotz
Robert Lee Hotz是華爾街日報的科學專欄作家,他寫的文章都是關於氣候變化、宇宙論、分子藥學、人類大腦等等的最新研究。他去過三次南極。
 
為什麼要聽他演講:
Robert Lee Hotz是華爾街日報的科學專欄作家,他探索新研究的領域以及這對社會的影響。在專欄裡,他的研究範圍很廣泛,從氣候變化、宇宙論和分子藥學,再到進化、神經經濟學和人類大腦的新觀點。在1986年,Hotz憑藉基因工程學問題的報導,進入了普利茲獎的決賽。2004年,他憑藉哥倫比亞號太空船事故的報導,再一次進入決賽。1995年,Hotz和洛杉磯時報的搭檔一起憑藉「北嶺地震」的文章獲得普利茲獎。
 
Hotz是Alicia Patterson基金會的董事,這個基金會為世界各地獨立新聞專案提供資金。他是一位受聘於紐約大學的出色作家,。他是《關於生命的設計》(Designs on Life),《人類繁衍的新前線》(New Frontiers of Human Fertility)的作者,還為很多撰寫關於研究問題的書籍提供寶貴意見。
 
Robert Lee Hotz的網上英文資料:
 
[TED科技娛樂設計]
已有中譯字幕的TED影片目錄(繁體)(簡體)。請注意繁簡目錄是不一樣的。
 
Lee Hotz談進入南極時間機器
跟我去世界的底部——南極洲,世界上最高、最乾旱、風最大,是的,最冷的地方。比撒哈拉更乾旱,那裡有些地方比火星更冷。南極洲的冰發出炫目的光,讓沒有保護的眼睛變瞎。早期的探索者在眼裡擦可卡因來止痛。冰很重,以致整個大陸在它的重量之下,陷到海平面以下。然而南極洲的冰是氣候變化的指標,它記錄了溫室氣體和溫度,每年的升降。可回溯到最後的冰河世紀之前。世界上沒有其他地方給我們提供這樣完美的記錄。這裡,科學家正在深入探索地球的過去,尋找未來氣候變化的線索。
 
今年一月,我去到一個叫WAIS分界線的地方,離南極中心600英里。很多人說這是地球上研究氣候變化歷史最好的地方。那裡有約45名科學家,來自威斯康辛大學內華達沙漠研究院和其他機構。他們一直在尋找一個重要問題的答案,關於全球暖化,探索溫室氣體水平和星球溫度間有什麼確切的聯繫?這是很急切的研究。我們知道氣溫在上升,今年五月是全世界有史以來最熱的。我們知道溫室氣體的水平也在上升。我們不知道的是這些變化對自然氣候格局有什麼確切和直接的影響——風、洋流、降水率、雲的形成,這都關係數十億人的健康和福祉。
 
他們整個營地,所有的裝備都是從885英里之外的McMurdo站,用船運過來的。那裡是美國在南極海岸主要的供應基地。雖然WAIS分界線本身是雪裡的一個環狀帳篷。在大風雪中,隊員們在帳篷之間拉起繩子,這樣人們可以安全地走到最近的冰屋和廁所。在那裡雪下的極大,幾乎馬上覆蓋住營地。確實,研究者選擇在這裡紮營,因為這裡積雪的速度比南極洲其他地方快十倍,他們每天都要把自己挖出來。這種通勤方式又奇怪又寒冷。
 
(笑聲)
 
但在表面之下是一個工業活動的小房子,圍繞一部價值八百萬美元的鑽探裝置。定期地,這部鑽機就像活組織檢查的探針那樣鑽入幾千英尺深的冰裡,提取氣體精華和同位素作分析,每天10次,他們提取一個十英尺長的的壓縮冰晶柱。裡面有潔淨的空氣和微量化學物是跟著雪一起降下來的,經過千萬年,一季又一季,那真的像是時間機器。今年早些時候活動的高峰期,研究者每天把鑽探機再深入進冰下100英尺,這樣可以獲取過去更早365年的信息。他們定期把桶裡的冰柱拿出來,就像狩獵人把用完的彈殼從鑽探機桶裡取出一樣。他們研究這些冰,檢查裡面的裂紋、鑽探損害、碎片、碎裂。
 
更重要的是為美國和歐洲27個獨立實驗室的檢查和分析做準備。他們會查看裡面四十種不同的與氣候有關的微量化學物,有些是千的五次方的相關,是的,我說的是千的五次方。他們把冰柱切分成三英呎的部分,這樣更容易操作和運回這些實驗室。有些離鑽探地有八千英里。每個冰柱都是時間的一部分。
 
15800年前這些冰由雪積成。那時我們的祖先在身上塗顏料,並思考字母表的先進新技術。沐浴在偏光下橫截切開,這塊古老的冰顯露出自己馬賽克的顏色拼胋,每一種顏色都顯示出冰裡面的狀態如何深深地影響這種物質。其中每深入一英寸平方,壓力就增加一噸。每年開始都有雪花,通過挖掘新雪,我們可以看到今天這仍在進行。這是一堵安靜的冰牆,背後照著太陽光,顯示出冬雪和夏雪的條紋,一層一層。每個風暴都穿越大氣層,沖走灰塵、煤灰、微量化學物,把它們沉澱在雪塊上。年復一年,幾千年又幾千年,產生元素週期表。在這點上,厚度超過11000英尺。從這裡我們可以探測到大量的東西,可以從世界的沙漠裡看到鈣,從遠處野火裡看到煤灰。甲烷是太平洋季候風的指標,全部是暖一些的地區通過風吹到達這個遙遠且寒冷的地方。
 
最重要的是這些冰柱和這雪可以儲存空氣。每個冰柱裡有10%是古代的空氣,一個原始的時間膠囊。含有溫室氣體,二氧化碳、甲烷、一氧化二氮。這從雪形成並第一次落下來時就沒有變。這是他們審查的對象,但我們還不知道應該掌握哪些關於溫室氣體的東西嗎?為什麼我們還需要研究這個?我們不是已經知道它們如何影響氣候嗎?我們難道不知道氣候變化的後果對我們文明的建立已有影響嗎?事實是,我們只知道大概不完全瞭解的情況下,我們不能適當地加以處理。我們確實冒著使情況惡化的風險。
 
想想20世紀最成功的一個國際環境的努力成果,蒙特婁協議。地球各國聯合起來保護地球,遠離破壞臭氧的化學物的有害影響。那時,這些有害物質用於空調、冰箱和其他空調設備。我們禁止那些化學物的使用,我們不知不覺地用其他物質來代替它們。每個分子作為儲熱的溫室氣體,效力比二氧化碳高一百倍。
 
這個過程要求很高的警惕性。科學家必須保證冰沒有受污染。還有,在八千英里的航程中要保證冰不融化,想像一下拋著雪球穿越熱帶。事實上,他們要保證冰的溫度不會超過零下二十度,否則,裡面主要的氣體就會消散。所以,在地球上最冷的地方,他們在冷藏庫裡工作。事實上,在他們處理冰的時候,他們帶著一雙在爐子裡熱過的備用手套。這樣,在他們的工作手套凍住,他們的手指發僵的時候就可以換一雙新的。他們看著鐘和溫度計來工作。
 
至今,他們已經打包了大概4500英尺的冰蕊,可以運回美國。過去的一季,他們用人手推著這些,穿越冰雪,送到等候的飛機上。空軍第109國民警衛大隊把最近一批冰雪送回南極洲海岸,然後放到貨船上,穿越熱帶航行回加州,然後卸下來搬到貨車上,穿過沙漠送到科羅拉多州丹佛市的國家冰雪核心實驗室。我們之前說過,在那裡,科學家正把這些材料切開,用作標本、進行分析,把它們分送到全美各地和歐洲的的實驗室。南極洲是地球最後空置的地區,是我們對世界日漸寬闊視野中的一個盲點。早期的探索者坐著船走出了地圖的邊界,發現了一個地方,在那裡時間和溫度的正常規律暫停了。這裡,冰似乎是活著的超自然力量。冰上刮過的風讓它有了自己的聲音。這是經驗的聲音,這是我們要留意的聲音。
 
謝謝。
(掌聲)
 
 
 

以下為系統擷取之英文原文

About this talk

Science columnist Lee Hotz describes a remarkable project at WAIS Divide, Antarctica, where a hardy team are drilling into ten-thousand-year-old ice to extract vital data on our changing climate.

About Robert Lee Hotz

Robert Lee Hotz is the science columnist for the Wall Street Journal, where he writes about cutting-edge research on climate change, cosmology, molecular medicine, the human brain and much… Full bio and more links

Transcript

Come with me to the bottom of the world, Antarctica, the highest, driest, windiest, and yes, coldest region on Earth -- more arid than the Sahara and, in parts, colder than Mars. The ice of Antarctica glows with a light so dazzling, it blinds the unprotected eye. Early explorers rubbed cocaine in their eyes to kill the pain of it. The weight of the ice is such that the entire continent sags below sea level, beneath its weight. Yet, the ice of Antarctica is a calendar of climate change. It records the annual rise and fall of greenhouse gases and temperatures going back before the onset of the last ice ages. Nowhere on Earth offers us such a perfect record. And here, scientists are drilling into the past of our planet to find clues to the future of climate change.

This past January, I traveled to a place called WAIS Divide, about 600 miles from the South Pole. It is the best place on the planet, many say, to study the history of climate change. There, about 45 scientists from the University of Wisconsin, the Desert Research Institute in Nevada and others have been working to answer an essential question about global warming. What is the exact relationship between levels of greenhouse gases and planetary temperatures? It's urgent work. We know that temperatures are rising. This past May was the warmest worldwide on record. And we know that levels of greenhouse gases are rising too. What we don't know is the exact, precise, immediate impact of these changes on natural climate patterns -- winds, ocean currents, precipitation rates, cloud formation, things that bear on the health and well-being of billions of people.

Their entire camp, every item of gear, was ferried 885 miles from McMurdo Station, the main U.S. supply base on the coast of Antarctica. WAIS Divide itself though, is a circle of tents in the snow. In blizzard winds, the crew sling ropes between the tents so that people can feel their way safely to the nearest ice house and to the nearest outhouse. It snows so heavily there, the installation was almost immediately buried. Indeed, the researchers picked this site because ice and snow accumulates here 10 times faster than anywhere else in Antarctica. They have to dig themselves out every day. It makes for an exotic and chilly commute.

(Laughter)

But under the surface, is a hive of industrial activity centered around an eight-million-dollar drill assembly. Periodically, this drill, like a biopsy needle, plunges thousands of feet deep into the ice to extract a marrow of gases and isotopes for analysis. 10 times a day, they extract the 10-foot long cylinder of compressed ice crystals that contain the unsullied air and trace chemicals laid down by snow, season after season for thousands of years. It's really a time machine. At the peak of activity earlier this year, the researchers lowered the drill an extra hundred feet deeper into the ice every day and another 365 years deeper into the past. Periodically, they remove a cylinder of ice, like gamekeepers popping a spent shotgun shell from the barrel of a drill. They inspect it, they check it for cracks, for drill damage, for spalls, for chips.

More importantly, they prepare it for inspection and analysis by 27 independent laboratories in the United States and Europe, who will examine it for 40 different trace chemicals related to climate, some in parts per quadrillion. Yes, I said that with a Q, quadrillion. They cut the cylinders up into three-foot sections for easier handling and shipment back to these labs, some 8,000 miles from the drill site. Each cylinder is a parfait of time.

This ice formed as snow 15,800 years ago, when our ancestors were daubing themselves with paint and considering the radical new technology of the alphabet. Bathed in polarized light and cut in cross-section, this ancient ice reveals itself as a mosaic of colors, each one showing how conditions at depth in the ice have affected this material at depths where pressures can reach a ton per square inch. Every year, it begins with a snowflake, and by digging into fresh snow, we can see how this process is ongoing today. This wall of undisturbed snow, back-lit by sunlight, shows the striations of winter and summer snow, layer upon layer. Each storm scours the atmosphere, washing out dust, soot, trace chemicals, and depositing them on the snow pack year after year, millennia after millennia, creating a kind of periodic table of elements that at this point is more than 11,000 ft. thick. From this, we can detect an extraordinary number of things. We can see the calcium from the world's deserts, soot from distant wildfires, methane as an indicator of a Pacific monsoon, all wafted on winds from warmer latitudes to this remote and very cold place.

Most importantly, these cylinders and this snow trap air. Each cylinder is about 10 percent ancient air, a pristine time capsule of greenhouse gases -- carbon dioxide, methane, nitrous oxide -- all unchanged from the day that snow formed and first fell. And this is the object of their scrutiny. But don't we already know what we need to know about greenhouse gases? Why do we need to study this anymore? Don't we already know how they affect temperatures? Don't we already know the consequenses of a changing climate on our settled civilization? The truth is, we only know the outlines, and what we don't completely understand, we can't properly fix. Indeed, we run the risk of making things worse.

Consider, the single most successful international environmental effort of the 20th century, the Montreal Protocol, in which the nations of Earth banded together to protect the planet from the harmful effects of ozone-destroying chemicals used at that time in air conditioners, refrigerators and other cooling devices. We banned those chemicals, and we replaced them, unknowingly, with other substances that, molecule per molecule, are a hundred times more potent as heat-trapping, greenhouse gases than carbon dioxide.

This process requires extraordinary precautions. The scientists must insure that the ice is not contaminated. Moreover, in this 8,000-mile journey, they have to insure this ice doesn't melt. Imagine juggling a snowball across the tropics. They have to, in fact, make sure this ice never gets warmer than about 20 degrees below zero, otherwise, the key gases inside it will dissipate. So, in the coldest place on Earth, they work inside a refrigerator. As they handle the ice, in fact, they keep an extra pair of gloves warming in an oven, so that, when their work gloves freeze and their fingers stiffen, they can don a fresh pair. They work against the clock and against the thermometer.

So far, they've packed up about 4,500 ft. of ice cores for shipment back to the United States. This past season, They manhandled them across the ice to waiting aircraft. The 109th Air National Guard flew the most recent shipment of ice back to the coast of Antarctica, where it was boarded onto a freighter, shipped across the tropics to California, unloaded, put on a truck, driven across the desert to the National Ice Core Laboratory in Denver, Colorado, where, as we speak, scientists are now slicing this material up for samples, for analysis, to be distributed to the laboratories around the country and in Europe.

Antarctica was this planet's last empty quarter -- the blind spot in our expanding vision of the world. Early explorers sailed off the edge of the map, and they found a place where the normal rules of time and temperature seem suspended. Here, the ice seems a living presence. the wind that rubs against it gives it voice. It is a voice of experience. It is a voice we should heed.

Thank you.

(Applause)

 


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