Mission Blue Voyage
Rob Dunbar: Discovering ancient climates in oceans and ice
Rob Dunbar 談論藉由海洋與冰層來了解古代的氣候狀況
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Rob Dunbar 藉由遠古的海床與珊瑚和冰層中找尋線索，來搜尋1萬2千年前至今的氣候資訊。他的工作對於設定底限以穩定目前的氣候以及追蹤致命的海洋酸化現象都是很重要的。
Rob Dunbar - Oceanographer, biogeochemist
Rob Dunbar looks deeply at ancient corals and sediments to study how the climate and the oceans have shifted over the past 50 to 12,000 years -- and how the Antarctic ecosystem is changing right now. Full bio
Rob Dunbar looks deeply at ancient corals and sediments to study how the climate and the oceans have shifted over the past 50 to 12,000 years -- and how the Antarctic ecosystem is changing right now. Full bio
Double-click the English transcript below to play the video.
00:15
If you really want to understand
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如果你真的想了解
00:18
the problem that we're facing with the oceans,
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我們目前所面對的海洋問題，
00:21
you have to think about the biology
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那麼在你思考生物學時
00:23
at the same time you think about the physics.
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也必須同時思考物理學。
00:26
We can't solve the problems
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除非我們能夠以跨領域的方式
00:28
unless we start studying the ocean
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來對海洋進行研究，
00:30
in a very much more interdisciplinary way.
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否則我們不可能解決這些問題。
00:33
So I'm going to demonstrate that through
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所以我將會藉由討論海洋面臨的一些氣候變遷
00:35
discussion of some of the climate change things that are going on in the ocean.
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來證明這些問題。
00:38
We'll look at sea level rise.
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我們會討論海面上升。
00:40
We'll look at ocean warming.
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以及海洋暖化現象。
00:42
And then the last thing on the list there, ocean acidification --
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然後是最後一個問題，海洋酸化現象 --
00:45
if you were to ask me, you know, "What do you worry about the most?
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如果你問我，"你最擔心的事情是什麼?
00:48
What frightens you?"
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什麼會令你恐懼?"
00:50
for me, it's ocean acidification.
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對我來說，那就是海洋酸化。
00:52
And this has come onto the stage pretty recently.
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這是最近剛浮上檯面的問題。
00:54
So I will spend a little time at the end.
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所以我會在最後花一點時間來討論它。
00:57
I was in Copenhagen in December
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在10月的時候，我參加了哥本哈根會議，
00:59
like a number of you in this room.
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如同在座部份人一樣。
01:01
And I think we all found it, simultaneously,
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我想我們都同時發現，
01:04
an eye-opening
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一個令人大開眼界
01:06
and a very frustrating experience.
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卻也令人沮喪的經驗。
01:08
I sat in this large negotiation hall,
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我坐在巨大的協商會議廳裡，
01:11
at one point, for three or four hours,
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在同一個位子上三~四個小時，
01:13
without hearing the word "oceans" one time.
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完全沒有聽見"海洋"這個字。
01:17
It really wasn't on the radar screen.
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它確實沒有被列入議題。
01:20
The nations that brought it up
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當各國領袖開始發言時，
01:22
when we had the speeches of the national leaders --
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它才被人提到 --
01:24
it tended to be the leaders of the small island states,
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但卻都只是一些小型島國的領袖，
01:27
the low-lying island states.
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一些地勢低窪的島國。
01:29
And by this weird quirk
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而由於這個詭異的
01:31
of alphabetical order of the nations,
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國名排列方式，
01:34
a lot of the low-lying states,
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許多地勢低窪的國家
01:36
like Kiribati and Nauru,
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例如吉里巴斯共和國以及諾魯共和國，
01:38
they were seated at the very end of these immensely long rows.
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他們都坐在這些長排座位的最尾端。
01:41
You know, they were marginalized
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你知道的，他們在這間會議廳中
01:43
in the negotiation room.
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被邊緣化了。
01:45
One of the problems
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其中一項問題
01:47
is coming up with the right target.
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是要找出一個正確的目標。
01:49
It's not clear what the target should be.
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他們並不清楚目標是什麼。
01:51
And how can you figure out how to fix something
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那麼你又怎麼可能在目標不明確時，
01:53
if you don't have a clear target?
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找出解決問題的辦法呢?
01:55
Now, you've heard about "two degrees":
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大家都聽過 "二度" 吧，
01:57
that we should limit temperature rise to no more than two degrees.
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我們應該避免溫度上升超過二度。
02:00
But there's not a lot of science behind that number.
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但這數字背後並沒有什麼科學根據。
02:03
We've also talked about
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我們還討論了
02:05
concentrations of carbon dioxide in the atmosphere.
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大氣層中二氧化碳的濃度。
02:07
Should it be 450? Should it be 400?
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它應該被設在450? 還是400呢?
02:10
There's not a lot of science behind that one either.
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這些數字同樣也沒有什麼科學根據。
02:13
Most of the science that is behind these numbers,
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這些數字背後大部分的科學根據，
02:15
these potential targets,
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這些重要的目標，
02:17
is based on studies on land.
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都是依據在陸地上進行的研究。
02:19
And I would say, for the people that work in the ocean
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而我想說的是，對於那些研究海洋
02:22
and think about what the targets should be,
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以及思考該設定哪些目標的人來說，
02:24
we would argue that they must be much lower.
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我們都認為它們應該要更低才對。
02:26
You know, from an oceanic perspective,
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你知道嗎，對於海洋生態而言，
02:28
450 is way too high.
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450 實在太高了。
02:30
Now there's compelling evidence
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目前已經有強力的證據
02:32
that it really needs to be 350.
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來說明那必須設定在 350。
02:34
We are, right now, at 390 parts per million
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現在大氣中的二氧化碳濃度
02:37
of CO2 in the atmosphere.
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是 百萬分之390。
02:39
We're not going to put the brakes on in time to stop at 450,
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我們不可能在450的時候才踩煞車，
02:42
so we've got to accept we're going to do an overshoot,
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所以我們必須接受去設定一個嚴苛的標準，
02:45
and the discussion as we go forward
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而在我們接下來的討論中，
02:47
has to focus on how far the overshoot goes
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必須專注於這個嚴苛的標準要進行多久，
02:50
and what's the pathway back to 350.
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還有要如何讓它降回350。
02:53
Now, why is this so complicated?
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為什麼這件事會那麼複雜呢?
02:55
Why don't we know some of these things a little bit better?
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為何我們還不太了解這些事呢?
02:57
Well, the problem is that
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嗯，問題在於
02:59
we've got very complicated forces in the climate system.
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氣候系統裡有很複雜的力量存在。
03:01
There's all kinds of natural causes of climate change.
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有許多導致氣候變遷的自然因素。
03:04
There's air-sea interactions.
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有空氣和海洋的相互作用。
03:06
Here in Galapagos,
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在加拉巴哥群島這裡，
03:08
we're affected by El Ninos and La Nina.
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我們被聖嬰和反聖嬰現象所影響著。
03:10
But the entire planet warms up when there's a big El Nino.
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但是當巨大的聖嬰現象出現時，整個地球都會出現暖化現象。
03:13
Volcanoes eject aerosols into the atmosphere.
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火山噴出的氣體會曠散到大氣中。
03:16
That changes our climate.
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這會改變氣候。
03:18
The ocean contains most of the exchangeable heat on the planet.
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海洋含有地球上最大量的可交換熱能。
03:21
So anything that influences
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因此任何能夠影響
03:23
how ocean surface waters mix with the deep water
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海洋表層與深海海水混合的因素
03:26
changes the ocean of the planet.
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將會改變地球上的海洋。
03:28
And we know the solar output's not constant through time.
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我們知道太陽照射的能量並不是永遠都固定的。
03:31
So those are all natural causes of climate change.
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所以這些都是導致氣候變遷的自然因素。
03:34
And then we have the human-induced causes
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然而，我們還有因為人類所造成的
03:36
of climate change as well.
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氣候變遷因素。
03:38
We're changing the characteristics of the surface of the land,
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我們正在改變地表的特質，
03:40
the reflectivity.
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所謂的反射率。
03:42
We inject our own aerosols into the atmosphere,
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我們排放氣體到大氣中，
03:44
and we have trace gases, and not just carbon dioxide --
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我們追蹤了幾種氣體，不只是二氧化碳 --
03:47
it's methane, ozone,
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還有甲烷、臭氧、
03:49
oxides of sulfur and nitrogen.
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以及硫和氮的氧化物。
03:51
So here's the thing. It sounds like a simple question.
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所以事情就是這樣。聽起來似乎是個簡單的問題。
03:53
Is CO2 produced by man's activities
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人類活動所產生的二氧化碳
03:56
causing the planet to warm up?
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導致了全球暖化嗎?
03:58
But to answer that question,
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但是想回答那個問題，
04:00
to make a clear attribution to carbon dioxide,
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想了解二氧化碳扮演的角色，
04:03
you have to know something about
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你就必須先了解
04:05
all of these other agents of change.
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所有造成氣候變遷的其它因素。
04:07
But the fact is we do know a lot about all of those things.
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但事實上我們確實知道許多關於這些的資訊。
04:10
You know, thousands of scientists
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你知道嗎，有上千位科學家
04:12
have been working on understanding
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正在致力於了解
04:14
all of these man-made causes
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這些人為因素
04:16
and the natural causes.
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以及自然因素。
04:18
And we've got it worked out, and we can say,
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而且我們已經弄清楚了，我們可以說，
04:21
"Yes, CO2 is causing the planet to warm up now."
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"是的，二氧化碳正在造成全球暖化現象。"
04:25
Now, we have many ways to study natural variability.
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目前我們有許多方法來研究自然界的變異性。
04:28
I'll show you a few examples of this now.
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現在讓我給你們看一些例子。
04:30
This is the ship that I spent the last three months on in the Antarctic.
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這是我最近三個月來在南極待的那艘船。
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It's a scientific drilling vessel.
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這是一艘科學鑽探船。
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We go out for months at a time and drill into the sea bed
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每次出海都會航行好幾個月，然後鑽入海床
04:39
to recover sediments
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收集一些沉積物，
04:41
that tell us stories of climate change, right.
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這東西可以讓我們了解氣候變遷的狀況，對吧。
04:44
Like one of the ways to understand our greenhouse future
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例如，想了解未來溫室效應狀況的其中一個方法
04:47
is to drill down in time
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就是下向挖掘，從現今的部份
04:49
to the last period
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到最後一個時期，
04:51
where we had CO2 double what it is today.
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我們發現那裡的二氧化碳含量是現在的兩倍。
04:53
And so that's what we've done with this ship.
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那就是我們在這艘船上完成的工作。
04:55
This was -- this is south of the Antarctic Circle.
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這邊是南極圈的南邊。
04:58
It looks downright tropical there.
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它看起來簡直就像熱帶地區。
05:00
One day where we had calm seas and sun,
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某天海水平靜，陽光和煦的時候，
05:03
which was the reason I could get off the ship.
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也就是我能夠下船的原因。
05:05
Most of the time it looked like this.
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在大部分時候看起來就像這樣。
05:07
We had a waves up to 50 ft.
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海浪高達50呎，
05:10
and winds averaging
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而在大部分航行中
05:12
about 40 knots for most of the voyage
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風速平均是40節(約時速74公里)，
05:14
and up to 70 or 80 knots.
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最高可達70~80節(時速130~150公里)。
05:16
So that trip just ended,
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於是那趟旅程到此結束，
05:18
and I can't show you too many results from that right now,
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我現在還有沒辦法給你們看許多當時的結果，
05:20
but we'll go back one more year,
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但我們來看看前一年，
05:22
to another drilling expedition I've been involved in.
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我曾參予過的另一項鑽探工程。
05:25
This was led by Ross Powell and Tim Naish.
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這是由Ross Powell和Tim Naish所主導的。
05:28
It's the ANDRILL project.
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這個項目叫ANDRILL。
05:30
And we made the very first bore hole
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而我們所鑚的第一個鑽孔，
05:32
through the largest floating ice shelf on the planet.
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是從地球上最大的浮冰層開始的。
05:34
This is a crazy thing, this big drill rig wrapped in a blanket
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這是一件很瘋狂的事。這個巨大的鑚探設備被毛毯包裹著，
05:37
to keep everybody warm,
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以保持大家的溫暖，
05:39
drilling at temperatures of minus 40.
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在零下40度的低溫下進行鑚探作業。
05:41
And we drilled in the Ross Sea.
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我們在羅斯海中進行鑽探。
05:43
That's the Ross Sea Ice Shelf on the right there.
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那邊那個就是羅斯海的冰層。
05:46
So, this huge floating ice shelf
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那麼，這塊有如阿拉斯加那麼大的
05:48
the size of Alaska
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巨大浮冰層，
05:50
comes from West Antarctica.
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是從西南極飄過來的。
05:52
Now, West Antarctica is the part of the continent
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現在，西南極成為大陸版塊的一部份，
05:55
where the ice is grounded on sea floor
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冰層在海底積聚，
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as much as 2,000 meters deep.
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在深達2000公尺的地方。
06:00
So that ice sheet is partly floating,
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因此那塊冰層有一部分是浮起來的，
06:02
and it's exposed to the ocean, to the ocean heat.
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它暴露在海洋中，在海洋的熱氣中。
06:06
This is the part of Antarctica that we worry about.
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這是南極令我們擔心的其中一件事。
06:08
Because it's partly floating, you can imagine,
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由於它有部份是浮起來的，你可以想像，
06:10
is sea level rises a little bit,
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只要海平面上升一點點，
06:12
the ice lifts off the bed, and then it can break off and float north.
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冰層會從海底浮上來，然後會裂開，並朝向北邊漂移。
06:15
When that ice melts, sea level rises by six meters.
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一旦冰層溶化，海平面就會上升6公尺。
06:19
So we drill back in time to see how often that's happened,
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所以我們利用鑚探方式來研究這種事發生的頻率，
06:22
and exactly how fast that ice can melt.
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以及冰層實際溶化的速度有多快。
06:25
Here's the cartoon on the left there.
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左邊這裡有一個插畫。
06:28
We drilled through a hundred meters of floating ice shelf
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我們鑽過厚達一百公尺的浮冰層，
06:31
then through 900 meters of water
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然後穿過900公尺深的海水，
06:33
and then 1,300 meters into the sea floor.
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然後再往下進入海底1300公尺深。
06:36
So it's the deepest geological bore hole ever drilled.
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這是有史以來最深的地質鑚探。
06:39
It took about 10 years to put this project together.
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這個項目大概花了10年的籌備工作。
06:42
And here's what we found.
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這是我們所發現的東西。
06:44
Now, there's 40 scientists working on this project,
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現在，有40位科學家正在進行這個項目，
06:46
and people are doing all kinds of really complicated
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還有許多人在進行各種既複雜
06:48
and expensive analyses.
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又昂貴的分析作業。
06:51
But it turns out, you know, the thing that told the best story
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但結果呢，最能說明一切的
06:54
was this simple visual description.
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就是這個簡單的視覺描述。
06:56
You know, we saw this in the core samples as they came up.
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當樣品被採集出來時，我們在核心樣品中發現這個。
06:59
We saw these alternations
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我們在沉積物裡面發現
07:01
between sediments that look like this --
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這些交替層，看起來就像這樣 --
07:03
there's gravel and cobbles in there
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裡面有碎石和圓石，
07:05
and a bunch of sand.
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還有大量的沙子。
07:07
That's the kind of material in the deep sea.
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這就是深海裡面的物質。
07:09
It can only get there if it's carried out by ice.
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它是被冰層所帶過去的。
07:12
So we know there's an ice shelf overhead.
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我們知道冰層就在它的上面。
07:14
And that alternates with a sediment that looks like this.
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而這個含有沉積物的交替層看起來就像這樣。
07:17
This is absolutely beautiful stuff.
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這絕對是很美的東西。
07:19
This sediment is 100 percent made up
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這些沉積物是百分之百
07:21
of the shells of microscopic plants.
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由微小植物的外皮所形成的。
07:24
And these plants need sunlight,
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而這些植物需要陽光，
07:26
so we know when we find that sediment
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所以當我們找到那些沉積物時便知道，
07:28
there's no ice overhead.
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它的上面沒有冰層。
07:30
And we saw about 35 alternations
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在開放水域和冰層覆蓋的水域中
07:32
between open water and ice-covered water,
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我們發現了大概35個交替層，
07:35
between gravels and these plant sediments.
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位於碎石和這些植物沉積物之間。
07:38
So what that means is, what it tells us
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所以意思是說，它能告訴我們，
07:41
is that the Ross Sea region, this ice shelf,
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在羅斯海域的這塊冰層，
07:44
melted back and formed anew
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曾經溶化又再次形成冰層
07:46
about 35 times.
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重複大約35次。
07:48
And this is in the past four million years.
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而這是在過去400萬年發生的事。
07:52
This was completely unexpected.
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這是完全出乎意料的。
07:54
Nobody imagined that the West Antarctic Ice Sheet
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沒有人能夠想像西南極洲冰原
07:56
was this dynamic.
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是如此多變的。
07:58
In fact, the lore for many years has been,
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事實上，多年來的認知一直以為，
08:01
"The ice formed many tens of millions of years ago,
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"這些冰層是在幾千萬年前形成的，
08:03
and it's been there ever since."
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並且從未改變過。"
08:05
And now we know that in our recent past
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現在我們知道在接近現今的過去，
08:07
it melted back and formed again,
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它曾經溶化又再次形成冰層，
08:09
and sea level went up and down, six meters at a time.
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每次海平面上升和下降幅度大約6公尺。
08:12
What caused it?
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這是什麼造成的呢?
08:14
Well, we're pretty sure that it's very small changes
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嗯, 我們非常確定在南極洲
08:16
in the amount of sunlight reaching Antarctica,
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太陽光的照射量並沒有什麼改變，
08:19
just caused by natural changes in the orbit of the Earth.
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只有因為地球軌道造成的少許自然變異。
08:22
But here's the key thing:
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但是，接下來的才是關鍵：
08:24
you know, the other thing we found out
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你知道嗎, 我們發現另一件事情，
08:26
is that the ice sheet passed a threshold,
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就是冰層已經超過了一個臨界點，
08:28
that the planet warmed up enough --
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地球暖化的程度已經高到足以 --
08:30
and the number's about one degree to one and a half degrees Centigrade --
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大概在 1 到 1.5 攝氏度 --
08:32
the planet warmed up enough that it became ...
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地球暖化的程度已經高到足以讓 ...
08:35
that ice sheet became very dynamic
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冰層變得非常的不穩定，
08:37
and was very easily melted.
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變得很容易溶化。
08:39
And you know what?
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你能想像嗎?
08:41
We've actually changed the temperature in the last century
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我們在上一個世紀，
08:43
just the right amount.
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讓溫度上升的幅度就是這個數字。
08:45
So many of us are convinced now
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因此我們大多都相信，
08:48
that West Antarctica, the West Antarctic Ice Sheet, is starting to melt.
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西南極，西南極洲冰原已經開始溶化了。
08:51
We do expect to see a sea-level rise
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我們已經可以預期在這個世紀末，
08:54
on the order of one to two meters by the end of this century.
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海平面將會上升一到兩公尺高。
08:57
And it could be larger than that.
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而且還可能會更高。
09:00
This is a serious consequence
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這對吉里巴斯這類的國家，
09:02
for nations like Kiribati,
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會是一個很嚴重的結果，
09:04
you know, where the average elevation
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你知道的，他們地表的平均高度
09:06
is about a little over a meter above sea level.
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只比海平面高出一公尺左右。
09:08
Okay, the second story takes place here in Galapagos.
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第二個問題發生在加拉巴哥群島。
09:11
This is a bleached coral,
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這兒發生了珊瑚的白化現象，
09:13
coral that died during the 1982-'83 El Nino.
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珊瑚因為1982-83年的聖嬰現象而死亡。
09:16
This is from Champion Island.
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這件事發生在冠軍島上。
09:18
It's about a meter tall Pavona clavus colony.
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那是長達1公尺的柱形雀屏珊瑚群。
09:21
And it's covered with algae. That's what happens.
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最後它被海藻所覆蓋。事情就這樣發生了。
09:24
When these things die,
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當這些珊瑚死亡後，
09:26
immediately, organisms come in
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立刻有一些有機生物了進來，
09:28
and encrust and live on that dead surface.
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包覆並寄居在這死掉的珊瑚表面上。
09:31
And so, when a coral colony is killed
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所以，當珊瑚群
09:33
by an El Nino event,
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因為聖嬰現象而死亡後，
09:35
it leaves this indelible record.
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便會留下這個無法消去的紀錄。
09:37
You can go then and study corals
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你可以到那兒，然後研究這些珊瑚，
09:39
and figure out how often do you see this.
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看看你有多常遇到這種事情。
09:41
So one of the things thought of in the '80s
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所以在80年代有一個概念，
09:43
was to go back and take cores
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就是到那兒去，
09:45
of coral heads throughout the Galapagos
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將散落於加拉巴哥群島的珊瑚頭部核心取出，
09:47
and find out how often was there a devastating event.
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研究這種毀滅性事件發生的頻率。
09:50
And just so you know, 1982-'83,
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如你所知的，在1982-83年間，
09:53
that El Nino killed 95 percent
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聖嬰現象導致加拉巴哥群島
09:55
of all the corals here in Galapagos.
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95%的珊瑚死去。
09:58
Then there was similar mortality in '97-'98.
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而在1997-98年間有著類似的死亡率。
10:01
And what we found
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而我們因為挖掘而發現
10:03
after drilling back in time two to 400 years
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追朔過去2年到400年間，
10:05
was that these were unique events.
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這是很罕見的現象。
10:07
We saw no other mass mortality events.
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我們沒有發現其他大量死亡的事件。
10:10
So these events in our recent past really are unique.
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所以這些事件在最近幾百年中是相當罕見的。
10:13
So they're either just truly monster El Ninos,
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所以這些聖嬰現象要不就是一個大怪獸，
10:15
or they're just very strong El Ninos
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又或者只是很強烈聖嬰現象
10:17
that occurred against a backdrop of global warming.
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恰巧遇上了全球暖化。
10:21
Either case, it's bad news
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不論是哪一種狀況，
10:23
for the corals of the Galapagos Islands.
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對於加拉巴哥群島的珊瑚來說都是壞消息。
10:27
Here's how we sample the corals.
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接下來是我們採集珊瑚樣本的方式。
10:29
This is actually Easter Island. Look at this monster.
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這兒是復活節島。看看這個怪物。
10:32
This coral is eight meters tall, right.
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這珊瑚長達八公尺。
10:35
And it been growing for about 600 years.
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它已經生長了大約六百年的時間。
10:37
Now, Sylvia Earle turned me on to this exact same coral.
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Sylvia Earle 曾經用同樣的珊瑚引起我的興趣。
10:40
And she was diving here with John Lauret -- I think it was 1994 --
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她曾經和 John Lauret 在這兒潛水 -- 我想那是 1994 年的事 --
10:43
and collected a little nugget and sent it to me.
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並且收集了一些碎片寄給我。
10:45
And we started working on it,
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然後我們開始進行研究，
10:47
and we figured out we could tell the temperature of the ancient ocean
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於是我們發現我們藉由分析這類珊瑚
10:49
from analyzing a coral like this.
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來得知古代海洋的溫度。
10:52
So we have a diamond drill.
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所以我們準備了鑽石鑽頭。
10:54
We're not killing the colony; we're taking a small core sample out of the top.
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我們不會毀掉整個珊瑚群，我們只是拿取核心頂端的一小塊樣本。
10:57
The core comes up as these cylindrical tubes of limestone.
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當石灰岩柱被推到上方時，這些核心就會跑上來。
11:00
And that material then we take back to the lab and analyze it.
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之後我們會將這些物質帶回實驗室進行分析。
11:04
You can see some of the coral cores there on the right.
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你可以在右邊看見一些珊瑚的核心。
11:07
So we've done that all over the Eastern Pacific.
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我們已經針對整個東太平洋進行了這個分析。
11:09
We're starting to do it in the Western Pacific as well.
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我們也開始針對西太平洋進行研究。
11:12
I'll take you back here to the Galapagos Islands.
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接下來我們在繼續談加拉巴哥群島。
11:14
And we've been working at this fascinating uplift here in Urbina Bay.
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我們在爾比納海岸針對這令人感興趣的地層隆起進行研究。
11:17
That the place where,
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這個地方，
11:19
during an earthquake in 1954,
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在1954年的地震當中，
11:21
this marine terrace was lifted up
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這個海階相當迅速地
11:23
out of the ocean very quickly,
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從海裡被推出海平面，
11:26
and it was lifted up about six to seven meters.
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它被提升了大約六到七公尺高。
11:29
And so now you can walk through a coral reef without getting wet.
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所以現在你可以走過珊瑚礁都不會碰到水。
11:32
If you go on the ground there, it looks like this,
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如果你在這兒晃的話，看起來就像這樣，
11:34
and this is the grandaddy coral.
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這是一株老祖父級的珊瑚。
11:36
It's 11 meters in diameter,
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它的直徑有十一公尺寬，
11:38
and we know that it started growing
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我們知道它從1584年
11:40
in the year 1584.
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就開始生長到現在。
11:42
Imagine that.
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想像一下。
11:44
And that coral was growing happily in those shallow waters,
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這珊瑚本來開心的在淺水灘裡生長著，
11:47
until 1954, when the earthquake happened.
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直到1954年地震發生。
11:50
Now the reason we know it's 1584
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我們之所以知道它生長於1584年，
11:52
is that these corals have growth bands.
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是因為珊瑚有這些年輪。
11:54
When you cut them, slice those cores in half and x-ray them,
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當你將它們切開，將核心切成一半然後用X光分析，
11:57
you see these light and dark bands.
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你會看見這些黑白相間的環。
11:59
Each one of those is a year.
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每一圈代表一年。
12:01
We know these corals grow about a centimeter and a half a year.
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我們知道這些珊瑚每年大約生長1.5公分左右。
12:03
And we just count on down to the bottom.
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我們由下面計算到底部。
12:06
Then their other attribute is
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它們另一個性質是，
12:08
that they have this great chemistry.
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它們有著很棒的化學成份。
12:10
We can analyze the carbonate
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我們可以針對碳酸鹽
12:12
that makes up the coral,
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珊瑚的主成份進行分析，
12:14
and there's a whole bunch of things we can do.
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還有許多分析我們可以作。
12:16
But in this case, we measured the different isotopes of oxygen.
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在這個例子裡，我們量測了不同氧的同位素。
12:19
Their ratio tells us the water temperature.
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它們的比例可以讓我們知道海水的溫度。
12:21
In this example here,
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在這個例子裡，
12:23
we had monitored this reef in Galapagos
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我們藉由這個溫度紀錄器
12:25
with temperature recorders,
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來監測加拉巴哥群島的珊瑚礁。
12:27
so we know the temperature of the water the coral's growing in.
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於是我們可以得知珊瑚生長環境的海水溫度。
12:30
Then after we harvest a coral, we measure this ratio,
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當我們採收珊瑚之後，我們量測這個同位素的比例，
12:33
and now you can see, those curves match perfectly.
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然後你可以發現，這些曲線的結果相當吻合。
12:36
In this case, at these islands,
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在這個例子中，在這些島嶼裡，
12:38
you know, corals
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如你所見，珊瑚在水裡
12:40
are instrumental-quality recorders of change in the water.
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可以當作測溫度變化的高品質記錄器。
12:43
And of course, our thermometers
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當然，我們的溫度計
12:45
only take us back 50 years or so here.
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只能讓我們知道近50年左右的溫度。
12:47
The coral can take us back
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而這些珊瑚
12:49
hundreds and thousands of years.
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可以讓我們知道近百年甚至千年的溫度。
12:51
So, what we do:
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所以我們做了什麼呢？
12:53
we've merged a lot of different data sets.
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我們整合了許多不同的數據組。
12:56
It's not just my group; there's maybe 30 groups worldwide doing this.
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並不只有我的團隊，世界上還有將近30組的團隊在進行這件事。
12:59
But we get these instrumental- and near-instrumental-quality records
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但是，我們使用這種高品質記錄器
13:02
of temperature change that go back hundreds of years,
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得出幾百年來的溫度變化紀錄，
13:04
and we put them together.
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然後我們將這些數據整合在一起。
13:06
Here's a synthetic diagram.
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這是一個綜合的圖表。
13:08
There's a whole family of curves here.
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有許多的曲線組在這裡。
13:10
But what's happening: we're looking at the last thousand years
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這代表什麼呢? 我們正在看的，
13:13
of temperature on the planet.
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是這個星球幾百年來的溫度紀錄。
13:15
And there's five or six different compilations there,
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這裡有5~6種不同的版本，
13:17
But each one of those compilations reflects input
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但每一種版本所對應的是
13:20
from hundreds of these kinds of records from corals.
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由幾百種珊瑚所取得的溫度紀錄。
13:23
We do similar things with ice cores.
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我們也對冰核作同樣的分析研究。
13:26
We work with tree rings.
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我們研究這些冰輪。
13:28
And that's how we discover
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這是我們用來發掘
13:30
what is truly natural
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真正的自然現象
13:32
and how different is the last century, right?
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以及上一個世紀有什麼不同的方式，對吧。
13:35
And I chose this one
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因為它的複雜且紊亂的外表，
13:37
because it's complicated and messy looking, right.
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所以我選了這個。
13:40
This is as messy as it gets.
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這和剛取得時一樣紊亂。
13:42
You can see there's some signals there.
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你可以看見這兒傳遞出一些訊息。
13:45
Some of the records
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某些紀錄
13:47
show lower temperatures than others.
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顯示著溫度比其它還來得低。
13:49
Some of them show greater variability.
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某些顯示著很大的變異性。
13:52
But they all tell us
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但這也正告訴我們，
13:54
what the natural variability is.
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自然有多麼的多變。
13:56
Some of them are from the northern hemisphere;
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有一部分是來自於北半球。
13:58
some are from the entire globe.
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某些是來自世界各地。
14:00
But here's what we can say:
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不過我們可以這樣說，
14:02
what's natural in the last thousand years is that the planet was cooling down.
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在過去千年的時間中，這個星球溫度一直在下降。
14:05
It was cooling down
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它不停的降溫，
14:07
until about 1900 or so.
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直到1900年左右。
14:09
And there is natural variability
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然而，有一些自然的變數，
14:11
caused by the Sun, caused by El Ninos.
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例如太陽的影響，例如聖嬰現象的影響。
14:14
A century-scale, decadal-scale variability,
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累計數十年到數百年的變化，
14:16
and we know the magnitude;
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我們知道他的影響性，
14:18
it's about two-tenths to four-tenths of a degree Centigrade.
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大概是在0.2到0.4攝氏度左右。
14:21
But then at the very end is where
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但是在最後，
14:23
we have the instrumental record in black.
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我們發現了隱藏的紀錄。
14:25
And there's the temperature up there in 2009.
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在2009年的溫度是一個高點。
14:28
You know, we've warmed the globe
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你知道我們在上一個世紀，
14:30
about a degree Centigrade in the last century,
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讓地球上升了一攝氏度，
14:33
and there's nothing
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而在自然界的紀錄中，
14:35
in the natural part of that record
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從未曾有過任何跡象顯示，
14:37
that resembles what we've seen in the last century.
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過去這個世紀的問題曾經發生過。
14:39
You know, that's the strength of our argument,
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這就是我們論點的說服力所在，
14:41
that we are doing something that's truly different.
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我們所做的是完全不一樣的事情。
14:45
So I'll close with a short discussion
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所以我將再談一小段海洋酸化問題
14:48
of ocean acidification.
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來作為今天的結論。
14:51
I like it as a component of global change to talk about,
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我想將它視為地球暖化問題的一部分來談，
14:54
because, even if you are a hard-bitten global warming skeptic,
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因為，即使你不相信地球暖化問題，
14:58
and I talk to that community fairly often,
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我常和這種人談話，
15:00
you cannot deny
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但你不能夠否認
15:02
the simple physics
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二氧化碳會溶入海水
15:04
of CO2 dissolving in the ocean.
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這種簡單的物理現象。
15:07
You know, we're pumping out lots of CO2 into the atmosphere,
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你知道我們正在排放大量的二氧化碳到大氣層中，
15:10
from fossil fuels, from cement production.
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不論是從石化原料或是水泥製品。
15:13
Right now, about a third of that carbon dioxide
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現在, 大概有1/3的二氧化碳
15:15
is dissolving straight into the sea, right?
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會直接溶入海水中，對吧?
15:17
And as it does so,
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而當它發生的時候，
15:19
it makes the ocean more acidic.
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它就會讓海水變得更酸一點。
15:22
So, you cannot argue with that.
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所以你無法去爭論這件事。
15:24
That is what's happening right now,
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這就是正在發生的事情，
15:26
and it's a very different issue
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而這個和地球暖化
15:28
than the global warming issue.
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是完全不同的事情。
15:30
It has many consequences.
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這會造成許多後果。
15:32
There's consequences for carbonate organisms.
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對於碳酸鹽類的有機生物會產生影響。
15:35
There are many organisms
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有許多有機生物
15:37
that build their shells out of calcium carbonate --
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居住在碳酸鈣作成的甲殼之中 --
15:39
plants and animals both.
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不論是植物或動物。
15:42
The main framework material of coral reefs
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像是珊瑚礁的主要骨架原料
15:44
is calcium carbonate.
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就是碳酸鈣。
15:46
That material is more soluble
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這種原料在酸性的液體中
15:48
in acidic fluid.
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會比較容易溶解的。
15:51
So one of the things we're seeing
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所以我們會發現
15:53
is organisms are having
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這些有機生物必須
15:55
to spend more metabolic energy
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付出更多的新陳代謝能量
15:57
to build and maintain their shells.
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來製造或是維持它們的甲殼完整。
15:59
At some point, as this transience,
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就在這個現象發生的同時，
16:01
as this CO2 uptake in the ocean continues,
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當二氧化碳持續溶入海水中，
16:04
that material's actually going to start to dissolve.
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這些物質將會開始溶解。
16:06
And on coral reefs,
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於是那些居住在珊瑚礁
16:08
where some of the main framework organisms disappear,
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主骨架上的那些有機生物逐漸消失，
16:11
we will see a major loss
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我們將會發現海洋生物的多元性
16:13
of marine biodiversity.
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正在逐漸的減少。
16:15
But it's not just the carbonate producers that are affected.
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但並不只是碳酸鹽產物會受到影響。
16:18
There's many physiological processes
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許多的生理現象也會
16:21
that are influenced by the acidity of the ocean.
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因為海洋的酸化而受到影響。
16:24
So many reactions involving enzymes and proteins
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許多跟酵素和蛋白質相關的反應
16:27
are sensitive to the acid content of the ocean.
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對於海洋的酸度都很敏感。
16:30
So, all of these things --
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所以，所有這類的事情 --
16:32
greater metabolic demands,
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造成更大的新陳代謝需求，
16:34
reduced reproductive success,
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改變了呼吸系統與新陳代謝系統，
16:36
changes in respiration and metabolism.
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同時降低了受孕的成功率。
16:39
You know, these are things that we have good physiological reasons
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我們可以找出許多完整的生理學解釋，
16:42
to expect to see stressed
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讓我們知道這個現象
16:44
caused by this transience.
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會導致這些可預期的問題。
16:46
So we figured out some pretty interesting ways
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於是我們發現了一些有意思的方式
16:48
to track CO2 levels in the atmosphere,
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來追蹤過去幾百年中
16:51
going back millions of years.
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二氧化碳跑進大氣中的數量。
16:53
We used to do it just with ice cores,
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我們原本只是把它用在冰核之中，
16:55
but in this case, we're going back 20 million years.
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但是在這裡，我們將可以追朔到兩千萬年前。
16:58
And we take samples of the sediment,
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我們取了一些沉積物的樣品，
17:00
and it tells us the CO2 level of the ocean,
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它可以讓我們知道海洋中的二氧化碳含量，
17:03
and therefore the CO2 level of the atmosphere.
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於是可以知道大氣中二氧化碳的含量。
17:05
And here's the thing:
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這就是怎麼作到的：
17:07
you have to go back about 15 million years
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你必須先回到一千五百萬年前，
17:09
to find a time when CO2 levels
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找到二氧化碳含量
17:12
were about what they are today.
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和今日差不多的時代。
17:14
You have to go back about 30 million years
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你必須到三千萬年前，
17:16
to find a time when CO2 levels
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找到二氧化氮含量
17:18
were double what they are today.
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是今日兩倍的時代。
17:20
Now, what that means is
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意思是說，
17:22
that all of the organisms that live in the sea
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居住在海中的生物
17:24
have evolved in this chemostatted ocean,
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在這個穩定的海洋之中演化，
17:27
with CO2 levels lower than they are today.
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從海中的二氧化碳含量比現今更低的時候開始。
17:30
That's the reason that they're not able to respond or adapt
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因為它們無法承受或適應
17:33
to this rapid acidification
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現在正在逐漸
17:36
that's going on right now.
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不停的變酸的海水。
17:38
So, Charlie Veron
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所以 Charlie Veron
17:40
came up with this statement last year:
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去年說了這段話：
17:42
"The prospect of ocean acidification
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"海洋酸化現象將會是
17:44
may well be the most serious
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所有人為二氧化碳排放
17:46
of all of the predicted outcomes
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所導致的可預期問題中
17:48
of anthropogenic CO2 release."
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最嚴重的一個。"
17:51
And I think that may very well be true,
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而我想這將會成真，
17:54
so I'll close with this.
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所以我用這個來做為結論。
17:56
You know, we do need the protected areas, absolutely,
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我們絕對需要去規劃出保護區，
17:59
but for the sake of the oceans,
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但是為了海洋的未來，
18:01
we have to cap or limit CO2 emissions
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我們需要的是去遮蔽或限制二氧化碳的排放量，
18:03
as soon as possible.
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而且是越快越好。
18:05
Thank you very much.
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謝謝大家。
18:07
(Applause)
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(掌聲)
ABOUT THE SPEAKER
Rob Dunbar - Oceanographer, biogeochemistRob Dunbar looks deeply at ancient corals and sediments to study how the climate and the oceans have shifted over the past 50 to 12,000 years -- and how the Antarctic ecosystem is changing right now.
Why you should listen
Rob Dunbar's research looks at the earth and ocean as an interconnected system over time. With his group at Stanford, he makes high-resolution studies of climate change over the past 50 to 12,000 years.
Where does 12,000-year-old climate data come from? It's locked in the skeletons of ancient corals from the tropics and the deep sea, and buried in sediments from lakes and other marine environments. His lab measures the chemical and isotopic makeup of these materials, and looks at how they've changed in response to changes in the solar and carbon cycles.
Dunbar's also studying the reverse equation -- how climate change is affecting a modern environment right now. He's working in the Ross Sea of Antarctica with the ANDRILL project to study the ocean's ability to take up carbon, drilling for ice cores to uncover the history of the climate of Antarctica.
Rob Dunbar | Speaker | TED.com