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[Music]
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Oh
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oh here this is that is a top just there
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ah no this is fine faster what a view
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I'm back um I was last here 25 years ago
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25 years hello it's summer now run your
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left bahama oh look at this here we are
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Oh would you like it that's like a let's
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view this is what I remember this is our
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ancient heritage laid out before our
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very eyes
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[Music]
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scotland's landscape has an epic and
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violent past hidden in these mountains
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and Glen's
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is the history of the planet I'm gonna
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show you how this landscape was used by
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a bunch of brilliant maverick eccentric
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scientists to solve the greatest
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mysteries of the earth
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and following in the footsteps of these
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pioneers who blazed the trail where no
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one had been before
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[Music]
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they showed vision and determination
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[Music]
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to piece together baffling evidence and
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uncover the forces that shape our world
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Wow
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it's all right there if you know what to
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look for threaten into the Scottish
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landscape is a story of the entire
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planet
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[Music]
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[Music]
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let's bowl and I'm climbing there's a
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genuine puzzle and it's huge but the
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mystery isn't it sighs they said it's
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here at all the rocks around here are
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completely different must be 30 times my
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height and weigh in half of thousand
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tonnes so have enough did this alien
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rock get here
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this one stands completely alone in
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rolling Scottish countryside similar
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rogue boulders light scattered all over
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Northern Europe in the early 1800s
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people struggle to understand our
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presence scientists can ignore them but
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they couldn't explain them either the
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most extreme suggestion of the time the
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one that I liked best was by a Frenchman
00:03:20
Monsieur de Luke who figured that these
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huge borders were fired from underground
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caverns with the force of compressed air
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much like a cork exploding from a kid's
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pop gun the solution to these curious
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rocks lay in one of the most powerful
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forces of nature
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[Music]
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September 1840 the Scottish Highlands
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two close friends have been traveling
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through some of the wildest parts of
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Scotland eight hundred miles in just two
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weeks
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it wasn't easy to get around Halen's two
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men trek for miles clamber up steep
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hillsides and cross expanses of water to
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get closer to the rocks that they want
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to study they're on a mission to try to
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understand the very shape of the
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highlands why it's a land of great Peaks
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punctuated by magnificent locks the two
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men couldn't be more different
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Louis Agassiz an adventurous Swiss
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scientist serious-minded never devil the
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other miners Britain's leading Joel just
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William Buckland a bit of an eccentric
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he wears his academic gown and top hat
00:05:04
in the field whatever the weather
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William Buckland was a better only
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person around who believed that the
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young Swiss scientist I guess a was just
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33 yet had an idea that would
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revolutionize our understanding of the
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geological world together they looked at
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the shape of the glans
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they examine the isolated boulders that
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dot the Highlands at all struck the
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young scientists are strangely familiar
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it's seen this type of landscape back
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home agassi's radical idea had first
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come to him in his homeland of
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Switzerland
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[Music]
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this is the mortar at Glacia in the
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Swiss Alps Agassiz grew up with his
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world of snow and ice on his doorstep in
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the late 1830s he devoted his time to
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studying great glaciers like this vast
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sheets of ice that covered the Saints of
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the Alps oh those are nice crevasses
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over there
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let's cross what I guess his journal
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tells us how he was lured right down
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inside iglasia to try to discover its
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scale in size with the help of mountain
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guide Jan Luke I hope to do the same
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it's amazing all this modern equipment
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that we've got now compared to what
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years ago was much harder than now I
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think when I guess II came here here da
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it half made of Marmot skin he probably
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came in like lederhosen in the tweed
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suits or something well I just thought
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of how far it goes actually trouble aigo
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staying in there's a let me just going
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dark when I guess he went dead
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he got himself Lord forty meters down
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right but he got to the bottom he
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feigned
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that he found himself and not hot water
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fat cold water he was in the melt water
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and iglasia he ended up in like half
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drained that did Holloway the colder is
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his descent into hell
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all right yeah
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as I climb down it's hard to forget that
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Agassi nearly died in his crevasse okay
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yep keep going keep going keep good Hey
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it was like woods of what a good stream
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and Diana st. the overall sense again
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it's about feeling a bit it's really
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Donnelly
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but I guess you really noticed was the
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weight of the ice above compress and
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down on the layers below then you can
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tell that crash has been building up
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because the eighth thing is but see blue
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it's really find all the air bubbles
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have been squeezed there today much like
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a hug and squeeze the next moment
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[Music]
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then here you got a real sense of the
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sheer scale and mass of the Glacia in
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fact a glace had a hundred meters thick
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will bear down with the force of eight
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eight tons per square meter every summer
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for five years I guess he returned to
00:09:20
the mountains to study the ice he wanted
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to find out if the immense pressure of
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the Galatia was somehow put into action
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first clue that Agassiz noticed was
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something peculiar going on with his
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research shot that he'd belt off on the
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Glacia it wasn't ready to laughter every
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season they came back the hot seems to
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be closer and closer to the end of the
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valley he must have thought that's about
00:09:45
odd even the mountains or the hot must
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be moving okay Agassiz was determined to
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discover why is hot moved he's carried
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out an experiment the first of its kind
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I'll recreate it with Glacia expert
00:10:09
during a Leone I think we put the next
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one about here it's as simple as it is
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clever
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I guess you drove wooden stakes across
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the Glacia one stake every 50 meters or
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so now you wouldn't expect something as
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solid as ice to move but Agassiz he
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suspected otherwise he tracked the
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positions of those stakes over one year
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over two years went on now even though
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he attained to hang around and wait for
00:10:42
that but I can show you what he found
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I guess he discovered the stakes did
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move and if they moved men the entire
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Glacia millions of tons of ace was also
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moving slowly and inexorably down the
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mountain a remarkable finding as team
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made beautiful engravings of fast rivers
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of ice which flowed down the valleys of
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the Alps another experiments like the
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steak experiment seem very simple but
00:11:19
they gave him really interesting results
00:11:21
to me yes it was their method of
00:11:23
measuring the speed of the ice how much
00:11:26
advance during one year or two years or
00:11:28
three years it was the only way of doing
00:11:30
it to tell me how fast were some of
00:11:32
these glaciers moving well they found
00:11:34
out that the ice moves 30 or even 60
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meters in the middle of the glacier in
00:11:39
one year that is because you know the
00:11:41
ice is rock-hard right you can hit that
00:11:43
Italy breaks like us but on a different
00:11:48
time scale it's it's like a slowly
00:11:51
moving fluid so it changes from year to
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year
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[Music]
00:11:59
you're aliens webcams exposes secret
00:12:02
life of Galatia in 15 seconds we can see
00:12:06
but Agassiz took five years to record
00:12:09
[Music]
00:12:12
for me it's impressive for seeing a
00:12:14
family in Mobile Glacia really flowing
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with just sticks and clever logic Agassi
00:12:22
had proved that glaciers traveled down
00:12:24
the mountain
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and that's not all he found out the
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pressure of all that eight grains open
00:12:31
rocks in its path and skips them up
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[Music]
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this is the kind of thing that I can see
00:12:46
would have been absolutely intrigued by
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a boulder imbedding there's plenty of
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smaller ones Melissa's the biggest one
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I've seen and Agassi realized that it's
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less rocky debris it was essentially the
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teeth of the Glacia it was less it was
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eaten away at the line I guess he had a
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further revelation in the foothills of
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the Alps were huge boulders he suspected
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they had something to do with the
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glaciers further up the mountains now
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here's a familiar sight it's one of
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these mysterious alien balls the French
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called them air attics wonders and
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Agassiz was convinced that these were
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transported by ice these boulders
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fascinated him he and his colleagues
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mapped the positions over wider and
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wider areas
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what Agassiz found would lead him to an
00:13:54
extraordinary theory about the Earth's
00:13:56
past
00:13:57
I love old maps this one is especially
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beautiful I mean look at this picture of
00:14:04
an erratic boarder the map itself covers
00:14:07
most of Switzerland and goes up into
00:14:09
France and the creamy areas show the
00:14:12
distribution of these erratic borders
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the glaciers were only in the mountains
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yet many borders were down in the
00:14:20
lowlands far from any ace the glaciers
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seemed to have once covered a much
00:14:26
larger area
00:14:29
trapped within that massive a ship were
00:14:32
borders like this borders that when the
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climate warmed and the ice thawed were
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left scattered across a country seat
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it's a beautifully elegant and simple
00:14:40
idea if the glaciers had been far more
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extensive and Agassiz believed he should
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be able to find other evidence of the
00:14:51
rot in the landscape he proposed that
00:14:56
these shallow grooves were created by
00:14:58
rocks and the Glacia scraping over the
00:15:00
land and even more spectacularly that
00:15:04
the great u-shaped valleys of the alps
00:15:07
or giant grooves carved by glaciers he
00:15:12
called the glaciers God's great plan
00:15:20
but I guess he didn't stop there what if
00:15:25
it wasn't only the glaciers of
00:15:27
Switzerland that had melted and shrunk
00:15:31
what if long ago that had been iced
00:15:34
everywhere that had no vanished this is
00:15:39
how one of the most radical ideas in the
00:15:41
history of science began to take shape
00:15:43
the idea that the climate was once much
00:15:45
colder and the glaciers smothered much
00:15:48
of the area of northern Europe I guess
00:15:57
his theory of a great and ancient ice
00:16:00
age was bald
00:16:01
but so far he'd only studied the area
00:16:04
around the Swiss Alps to prove it he'd
00:16:08
have to go much further afield he hoped
00:16:11
to find a killer clues and a foreign
00:16:14
land it showed signs of having once had
00:16:16
glaciers but which is no ice-free the so
00:16:19
began the whole Scottish adventure
00:16:32
this is why I guess it came to be in
00:16:34
Scotland in the autumn beating Authority
00:16:36
along with fellow scientist William
00:16:38
Buckland he wanted to discover in
00:16:42
Scotland the same signs of ancient
00:16:44
glaciers he'd seen in Switzerland if he
00:16:48
succeeded his theory of a huge a siege
00:16:51
would be vindicated together
00:16:54
Victor of the Highlands I guess he was
00:16:57
sure that only huge frozen forces could
00:16:59
have gouged this gland into a ueshiba
00:17:02
just like the alpine valleys back home
00:17:05
or carried this wrong ball that across
00:17:08
the wand similar to those he'd found in
00:17:11
the Alps but agassi's theory of a frozen
00:17:17
past didn't just explain the obvious
00:17:19
features of the highlands
00:17:27
one of the most dramatic is best seen
00:17:30
from the air
00:17:31
[Music]
00:17:38
the great plan here we come
00:17:44
ah
00:17:47
to geology mother that's for spike
00:17:49
rubbish seven years ago
00:17:52
[Music]
00:18:03
as their journey continued up the west
00:18:05
coast of Scotland Buckland was keen to
00:18:08
show Agassiz the highlight of the tour
00:18:10
just north of Ben Nevis is Glen Roy
00:18:17
in this Glen was an extraordinary
00:18:20
phenomenon that no one had been able to
00:18:22
explain
00:18:29
magazine funnily came here because it is
00:18:31
peculiar lights that are etched straight
00:18:34
along the size of the glaad but early
00:18:36
consider these parlor lights the
00:18:39
greatest geological mystery in Britain
00:18:41
all the great minds of the day could be
00:18:43
like Charles Darwin would come here to
00:18:46
try to study them
00:18:47
[Music]
00:18:51
the three ledges are each ten metres
00:18:54
wide and tens of kilometers long the
00:18:59
lanes run parallel and completely level
00:19:06
more bake some so and aquatics appeared
00:19:09
as a NASA regular I mean big just like
00:19:12
man-made elixir might be the sum of the
00:19:14
contemporaries of Buckland thought that
00:19:16
they were created with some ancient
00:19:19
human civilizations and the three routes
00:19:22
and read of prophecies what was her
00:19:23
humans what was for horse-drawn
00:19:25
carriages the other was for LA he
00:19:27
stopped
00:19:31
[Music]
00:19:34
when Agassiz study them he realized they
00:19:36
weren't obsolete highways to him these
00:19:39
inscrutable features screamed ice he
00:19:46
believed he knew what happened during
00:19:49
the Ice Age a glacier comes down from
00:19:51
the mountains and blocks the mouth of
00:19:53
Glenroy and the river that runs through
00:19:55
it behind this wall of ice a lake slowly
00:20:00
forms the water level rises to a certain
00:20:05
level for hundreds of years waves battle
00:20:08
the lakeside ruining it and creating a
00:20:11
flat shoreline
00:20:13
as it gets colder the Galatia increases
00:20:17
in hate blocks the valley further up and
00:20:20
the lake level rises another shoreline
00:20:23
is created higher up the valleys saved
00:20:28
this happens three times and all finally
00:20:33
they claim it warms the glacier melt and
00:20:36
the lake pours out leaving behind the
00:20:40
strange marks on the health side
00:20:42
[Music]
00:20:51
you know it's so clear from up here but
00:20:53
what's astonishing is the accuracy what
00:20:55
they say but they're there on the grave
00:20:58
in just a couple of days but probably
00:21:00
low lights of Glenroy well via piped
00:21:03
shorelines of an ancient glacial lake
00:21:09
[Music]
00:21:14
Glenroy was the crucial piece of the
00:21:17
puzzle
00:21:20
[Music]
00:21:24
it was no credible that huge ice sheets
00:21:27
used to call Scotland a country far from
00:21:30
modern-day glacials
00:21:33
and Agassiz believed that ice as deep as
00:21:36
a huge ice sheet that covers Greenland
00:21:38
today must have one smothered much of
00:21:41
the world
00:21:45
[Music]
00:21:48
for Agassiz this beautifully sculpted
00:21:50
indistinct and landscape provided the
00:21:52
best evidence for this theory it was in
00:21:54
Scotland he said that I achieved
00:21:56
precision in my ideas regarding ancient
00:21:59
glasses for the very first time Agassiz
00:22:03
had confirmed glaciation outside the
00:22:05
Alps
00:22:05
[Music]
00:22:13
one of the joys that'd be the joel is
00:22:15
just as if once you get your iron
00:22:17
once you've trained your mind to see
00:22:18
what's important you'd start to make
00:22:20
sense of the world around you in a
00:22:22
completely fresh way for Agassi and
00:22:26
Botwin
00:22:27
what they saw in places like this told
00:22:29
them that this landscape had been carved
00:22:31
by a massive ice sheet and that sense
00:22:34
there were visionaries but not everyone
00:22:36
shared that vision
00:22:39
[Music]
00:22:48
I guess they rushed back to Edinburgh
00:22:50
with ease ACH theory in 1840 many of the
00:22:54
world's most important geologists lived
00:22:56
here he had to win them over for his
00:22:59
idea to be accepted he couldn't drag
00:23:04
them up to the Highlands but he could
00:23:06
show them evidence of ace just round the
00:23:08
corner
00:23:12
he took some top geologists for a tour
00:23:14
around the city
00:23:22
I'm with present-day members of the
00:23:24
Android Geological Society as we had for
00:23:27
a site their predecessors visited
00:23:29
Blackford quarry in the city outskirts
00:23:35
what I wanted assure them were scratches
00:23:38
and grooves in the rock you have to
00:23:40
really know what you're looking for
00:23:42
because to the untrained eye these look
00:23:44
just like girls and it's what they mean
00:23:47
look there's some really nice set here
00:23:49
if you could see that he looks like I'm
00:23:51
taking the fingernails and just scratch
00:23:53
that along here what I guess he thought
00:23:56
was that this was caused by storms been
00:23:59
dragged in the ice and scaring across a
00:24:01
rock ends up being really beautifully
00:24:03
polished and molded lovely when Agassiz
00:24:07
saw that's here at Lightford quarry
00:24:08
famously said yes this is the work of
00:24:12
ace Agassiz was convinced had been
00:24:17
iglasia here but what about his
00:24:19
companions they start feeling I guess of
00:24:26
trying to imagine this place here
00:24:28
covered in ice as well I mean that would
00:24:29
be I'll be quite difficult how many of
00:24:38
you be convinced of a completely new
00:24:41
theory that Britain was covered in ice
00:24:43
based on that is there any who would I'm
00:24:47
interested in the silence
00:24:52
[Laughter]
00:24:54
to most geologists of the time these
00:24:57
tiny scratches appeared of little
00:24:59
consequence
00:25:00
so Agassiz turned to other grander rocks
00:25:03
one in particular that's visible from
00:25:05
all Edinburgh from the top of black rot
00:25:08
hair you can get a really good view of
00:25:10
the gently sloping Royal Mile coming off
00:25:12
the back of the hub Castle Rock and it's
00:25:15
this kind of feature that Agassiz
00:25:17
believed must have been carved out by
00:25:19
ace ace reach the hard Castle Rock of
00:25:23
sports to squeeze around the side all
00:25:27
the surrounding area was carved away by
00:25:29
the ace except for the land protected
00:25:32
behind the castle rock and so the gently
00:25:35
sloping shape of the Royal Mile was
00:25:37
created
00:25:42
the thing about geology is it's often a
00:25:44
lot less clear-cut than you might think
00:25:46
I mean on the face of it whose features
00:25:48
I Agassiz pointed out well not exactly
00:25:51
blindingly obvious and it takes a huge
00:25:53
leap of faith to go from small scratch
00:25:56
he's not a shape a castle rock so the
00:25:58
notion of a have agree a siege luckily
00:26:08
for Agassi one man on his tour of Emre
00:26:11
was the editor of the Scotsman newspaper
00:26:14
[Music]
00:26:19
in a tavern round the corner from the
00:26:22
newspaper offices
00:26:23
I guess his theory was a hot topic
00:26:25
amongst journalists back then the very
00:26:31
idea of an ice age scarcely to be
00:26:34
contemplated even so the editor dared to
00:26:39
publish his scoop and here's the article
00:26:44
Wednesday October the 7th 1840
00:26:47
sandwiched between a review of the
00:26:49
Adelphi Theatre and ten counts of
00:26:51
proceedings is the world's first
00:26:53
announcement of the ACH discovery of the
00:26:57
former existence of glaciers and
00:26:59
Scotland it's incredible professor
00:27:03
Agassiz could seize that at a certain a
00:27:05
POC all the north of Europe and also the
00:27:08
north of Asian America were covered with
00:27:10
a mass of ice he's written the ground of
00:27:15
Europe inhabited by hounds of giant
00:27:17
elephants enormous hippopotami and
00:27:19
gigantic carnivore became suddenly
00:27:22
buried under a vast expanse of ice
00:27:27
silence of death fold it's hard to
00:27:34
emphasise what earth-shattering news
00:27:36
this was been for your average reader
00:27:38
and that Wednesday morning is this
00:27:40
equivalent to I don't know teeth reading
00:27:42
that a double deck and boss has been
00:27:44
phoning them with the world
00:27:46
you know our understanding upon its past
00:27:48
would never be the same again this is
00:27:51
essentially the arrival of the eighties
00:27:53
[Music]
00:28:07
paying close attention to this new idea
00:28:10
of an ice age was the most influential
00:28:12
geologist of the day
00:28:15
Roderick MP moccasin former Army officer
00:28:19
who his approach to geology was somewhat
00:28:22
like a military campaign he was one of
00:28:25
geology's rising stars
00:28:27
what do you thought of I guess his new
00:28:29
theory would make it or break it
00:28:36
Marcin didn't believe a word of it
00:28:41
yeah sarcastically of the scratches in
00:28:43
Polish and on London streets would also
00:28:45
be attributed to the action of ace the
00:28:48
day will come he said when we shall
00:28:49
apply it to all Highgate Hill will be
00:28:52
the site of a glacier and Hyde Park and
00:28:55
Belgravia square the scene of its
00:28:57
influence you can just hear the snort of
00:29:00
derision
00:29:04
Roderick Morrison was a traditional man
00:29:07
with traditional views he believed the
00:29:10
Earth's climate remained largely steady
00:29:12
over time there'd been a gradual cooling
00:29:17
since the earth formed but no extreme
00:29:19
swings and temperature resistant to new
00:29:23
ideas Murchison dismissed the theory of
00:29:26
an ancient a siege as poppycock
00:29:33
and he wasn't above stooping to
00:29:36
underhand measures these appear to be
00:29:50
the transactions of the Geological
00:29:52
Society from 1842 but in fact that
00:29:55
evidence of a dastardly deed a crime
00:29:57
against science because Agassiz
00:29:59
submitted two of his key papers that his
00:30:01
publication but she flicked through I
00:30:04
just don't see them as present of the
00:30:07
society much as in use these power abuse
00:30:10
this power to constantly delay
00:30:12
publication they never came out in
00:30:14
effect he says of them and in the face
00:30:17
of that constant onslaught from Marxism
00:30:19
even Buckland's convictions over the ACH
00:30:22
theory began to falter this
00:30:27
groundbreaking theory was frozen out by
00:30:29
a geological buoy
00:30:34
Louie Agassiz left for America he felt
00:30:38
he'd taken his ideas on the a sage as
00:30:40
far as he could
00:30:41
[Music]
00:30:46
but the controversy rumbled on
00:30:52
you know joel is just fun it's so hard
00:30:54
to accept the idea of the ACH for one
00:30:56
simple reason and that is there was no
00:30:59
explanation as to why the planet got
00:31:01
jelly enough for the pasta crate let's
00:31:03
suppose that anything is I mean how does
00:31:05
the earth go cold and then hot again
00:31:07
what sends into the freezer only to
00:31:10
thought I don't just doesn't seem to
00:31:12
make any sense
00:31:13
[Music]
00:31:20
for nearly 20 years the puzzle of the
00:31:23
cause of an ice age remained unsolved
00:31:26
help came from a most unlikely source in
00:31:33
1859 a man and poor health or with a
00:31:36
patchy employment record applies for a
00:31:39
job at Anderson College in Glasgow
00:31:42
James cruel has variously ran a tea shop
00:31:47
managed at temperance hotel what's in a
00:31:50
mill and been an insurance salesman
00:31:54
crawls career changes yet again when he
00:31:57
lands a job at the college not as a
00:31:59
lecturer he's got no qualifications as a
00:32:02
janitor
00:32:13
this shy silent brooding Scot had little
00:32:17
formal education but he did have a
00:32:20
brilliant mind he would clean the rooms
00:32:30
after the students had laughed and had
00:32:32
no doubt eavesdrop into sinus science
00:32:34
classes pondering what was left on the
00:32:37
board James Croll applied his mind there
00:32:43
was controversial theory of the day the
00:32:47
origin of the a seizure
00:32:51
in his spare time he taught himself
00:32:54
physical astronomy and the complex laws
00:32:57
of motion light and heat crow fascinates
00:33:04
me he wasn't interested in my new shy of
00:33:06
Georgie he wanted to get a big picture
00:33:08
and what gave him the edge was while
00:33:10
most geologists was staring in the rocks
00:33:12
underfoot he was looking to the heavens
00:33:16
[Music]
00:33:17
[Applause]
00:33:19
[Music]
00:33:23
rules mastery of astronomy give him an
00:33:26
original take on the most familiar of
00:33:29
objects that's the lovely beautiful
00:33:32
color I mean fantastic isn't a color
00:33:35
through that well I say I mean just
00:33:37
because it's so harsh to look at you
00:33:38
just think it's like white see anything
00:33:40
but beautiful orange and red
00:33:44
[Music]
00:33:48
in a leap of imagination crawl made a
00:33:51
connection between the Sun and the Ice
00:33:53
Age nowadays we have modern technology
00:33:59
to map and understand the solar system
00:34:03
crawl and none of us yet working on his
00:34:08
own you suspected the Ice Age was all to
00:34:12
do how the earth orbiting the Sun this
00:34:19
is an orrery I kind of amazing
00:34:22
contraption that simulates the orbits of
00:34:24
the planets it's wonderful to see the
00:34:26
choreography of all the planets tonin
00:34:29
you know this device is incredibly
00:34:31
simple and elegant but it really makes
00:34:33
you realize just how hard the job crawl
00:34:35
hard cuz he had to work it the orbits
00:34:37
all the different planets and then
00:34:38
trying determine the end the fluids you
00:34:41
had
00:34:44
[Music]
00:34:58
who like to grapple with these difficult
00:35:01
problems over the course of long walks
00:35:14
imagine that less this is the Sun that
00:35:20
imagine this rock its planet Earth guess
00:35:25
that most people would assume that the
00:35:27
earth comes
00:35:28
Rhona Sun over a year and a broadly
00:35:31
circular orbit nice and symmetrical but
00:35:37
the orbit it's actually slightly
00:35:39
elliptical it's more of an oval
00:35:43
exaggerated for effect
00:35:47
now all the long periods of time that
00:35:51
and let's gets more and more skewed and
00:35:54
stretched out to be even more oval
00:35:58
all the stretching is caused by the
00:36:01
gravity of the other planets pulling the
00:36:03
earth out of position another thing is
00:36:08
when this happens the earth spends more
00:36:12
of its orbit away from the Sun than it
00:36:15
does towards it when does that happen
00:36:17
when the earth is out here at its
00:36:19
farthest distance tend to be more
00:36:21
intense and the best possession follow
00:36:25
this from the Sun the most stretched
00:36:27
orbit comes around every 100,000 years
00:36:35
Cruel took into account other factors
00:36:37
which also change over time such as a
00:36:40
tilt of the earth when these coincide
00:36:46
with the most extreme orbit the winter
00:36:48
temperature of the earth is at its
00:36:50
lowest 20 percent colder saves a lot but
00:36:56
it's still not enough to unleash a
00:36:58
full-blown a siege crew believed there
00:37:03
had to be something else to make the
00:37:05
earth even colder speech has become a
00:37:09
bit of a size lab there are two sets of
00:37:17
different ice cubes here same size but
00:37:20
slightly different colors of water this
00:37:22
one here is your regular water source
00:37:24
mister transponders clear the best one
00:37:26
has a tiny amount of black dye in it
00:37:29
now all I need to do is keep them out in
00:37:31
the Sun to melt Oh cold ed was applying
00:37:38
its simple physics of reflected late to
00:37:41
the office climate it's something we all
00:37:43
know that light colored surfaces reflect
00:37:46
more sunlight than dark ones so what
00:37:48
should happen is that these light
00:37:50
colored transparency should reflect off
00:37:54
to bounce off more of the sun's energy
00:37:56
and take longer to melt whereas these
00:37:58
darker ones will absorb all that heat
00:38:00
and melt much quicker
00:38:04
[Music]
00:38:17
look at that all of the ice has gone
00:38:19
from the black one and there knows what
00:38:21
one two three four five six ice cubes
00:38:26
still laughter ah I call that a success
00:38:31
[Music]
00:38:33
the ability of late suffices to reflect
00:38:36
heat it's called the old B to effect it
00:38:39
supposes to many janitors we would have
00:38:41
wondered that the effect of that Earth's
00:38:43
climate
00:38:45
[Music]
00:38:45
[Laughter]
00:38:49
think of the clear ice cubes as the ice
00:38:52
sheets at the North and South Poles
00:38:54
cruel argue to every 100,000 years the
00:38:58
extreme orbit of the earth triggers the
00:39:00
growth of these ice sheets the more the
00:39:04
ice expands the more heat from the Sun
00:39:06
is blends the way the more heats
00:39:09
reflected the colder the earth gets and
00:39:12
yet more ice grows eventually it covers
00:39:16
much of the earth in an Isis it can last
00:39:18
tens of thousands of years they'll be to
00:39:25
affect is one of the most powerful
00:39:26
drivers of the earth climate for cruel
00:39:29
and explained how the world could cool
00:39:31
rapidly cool enough to start an a siege
00:39:35
[Music]
00:39:44
cruel rates up is what gets it published
00:39:47
in a science journal the paper comes to
00:39:50
the attention of the Geological Survey
00:39:53
they are blown away by some regional
00:39:55
ideas but the causes of erasing what
00:40:00
genius came up with s they think
00:40:02
astonished to discover this character
00:40:05
crawl as a janitor it doesn't put them
00:40:08
off they offer this new phone genius are
00:40:10
a sales job
00:40:12
no more dead-end jobs James crawl has
00:40:16
arrived a professional position gave him
00:40:26
the space to develop his ideas further
00:40:28
he spent the next ten years writing his
00:40:31
book claim it and Taemin but aren't many
00:40:34
books have changed the world
00:40:36
but James crawls book is as important to
00:40:38
claim its science as Darwin's Origin of
00:40:41
Species is to biology yeah how many
00:40:44
people have heard of it it's largely
00:40:46
forgotten and I must confess that even I
00:40:48
have read it which is why I'm so excited
00:40:50
and I'm about to see it for the very
00:40:52
first time
00:40:53
[Music]
00:40:58
so this is that this is the hallowed Tom
00:41:02
this is the diagram that lies really I
00:41:05
guess at the heart of Truls book no the
00:41:08
kid gives it a kind of drama this
00:41:10
graphic presentation of the variation in
00:41:14
temperature cruel had calculated the
00:41:18
changes in the temperature of the earth
00:41:19
over the last three million years so
00:41:22
this is time this is 1 million two
00:41:25
million three million years in the past
00:41:27
who's saying there's been these swings
00:41:28
yeah very arousing not very erotic kind
00:41:31
of behavior but behavior nonetheless
00:41:34
that could be predicted yeah orderly
00:41:36
erotic but orderly the same absolutely
00:41:38
the key thing that jumps out here is
00:41:40
multiple ages and he carries it back and
00:41:43
says look this should be an a sees maybe
00:41:44
they're here only there yeah and then
00:41:47
suddenly he and I certainly hear prompts
00:41:49
all these questions about the climate in
00:41:51
the past as you look I know the traction
00:41:54
actually down here as 1880 as has
00:41:56
present-day any projected into the
00:41:58
future a million years into future
00:42:00
thinking about when the next day's ages
00:42:02
would be it's clear this mind has a
00:42:04
brain the size of a planet never mind
00:42:06
actually a thinking about planner says
00:42:08
colleagues thought he was a genius
00:42:10
there might have been might have been
00:42:11
right about the past the genius Johnny
00:42:15
I'm absolutely bowled over by this book
00:42:18
in this ordinary looking graph is a
00:42:21
great scientific breakthrough really
00:42:24
shows how the temperature fluctuates all
00:42:26
the time which was kind of a real
00:42:29
maverick idea and real almost heresy
00:42:31
people prevailing notion that that's
00:42:34
just cool steadily over time and here it
00:42:36
was this irregularity but what was cruel
00:42:40
genius was to see that within that
00:42:41
irregularity that was order it was all
00:42:43
to do the astronomical changes this is a
00:42:47
what Rafael says the rhythms of the
00:42:49
Asian and they can apiece me
00:42:53
[Music]
00:42:57
Cruel gave us the history of all these
00:43:00
ice ages the waxing and waning of the
00:43:03
ice sheets over tens of thousands of
00:43:05
years but when he walked this road there
00:43:09
was no geological evidence to support it
00:43:12
his research was theoretical worked out
00:43:15
entirely from first principles this is
00:43:21
impressive science
00:43:28
for me James Croll was an unsung hero as
00:43:32
so often happens from science someone
00:43:35
else stole his thunder when I was
00:43:37
learning about the ACS and university
00:43:39
these astronomical principles were
00:43:41
attributed to a Serbian guy called
00:43:43
Milankovitch and the periods of warming
00:43:45
and cooling called Milankovitch cycles
00:43:48
what I didn't know was that malankov
00:43:51
it's largely Beasties work on the ideas
00:43:53
of James crawl so it's nice to set the
00:43:55
record straight to give credit where
00:43:58
credit's due
00:44:02
[Music]
00:44:07
crawls boot came out in 1875 Queen
00:44:11
Victoria was on the throne the
00:44:14
Industrial Revolution was in full swing
00:44:16
new canals railway lanes and roads cut
00:44:19
through the landscape all this digging
00:44:22
exposed the earth itself geologist now
00:44:30
had the perfect opportunity to paint
00:44:31
real evidence on the ground of what cold
00:44:34
predicted on people multiple a sieges
00:44:39
stepan james geeky he's bought into the
00:44:43
notion of recurrent ice ages and he's
00:44:45
determined to find a proof of it in
00:44:47
scotland yuki actually what's alongside
00:44:54
crawl at the geological survey the whale
00:44:56
crawled theorized yuki like to get his
00:44:59
hands doctor
00:45:00
[Music]
00:45:02
and that's all where we're cutting we
00:45:04
can uncover layers laid down over
00:45:06
thousands of years and just as Beauty
00:45:09
dead reveal oh I see parsley I think I
00:45:16
said biggest reason ever be it might not
00:45:24
look much but what excites us geologists
00:45:27
is what it means the top gray layer on
00:45:30
the bottom red one at both ice ages
00:45:33
they're separated by a thin black layer
00:45:37
[Music]
00:45:39
the thing jumps out immediately at us is
00:45:41
the black the organic layer in the
00:45:43
middle doing here yeah and if you pull a
00:45:46
lump of that out yeah you'll see that
00:45:50
there are bits and pieces of twig and
00:45:51
leaf various bits of vegetation so it's
00:45:55
the kind of a song it's entually a soil
00:45:57
yeah
00:45:57
so this soil is from a warm period when
00:46:01
there were trees and other plants around
00:46:02
very different from the layer above and
00:46:05
the layer below now underneath that we
00:46:08
get this red sandy material if we dig
00:46:11
through it we see there's also some very
00:46:13
large stones in it then as we go up
00:46:17
through that we eventually come into now
00:46:19
again a sticky clear sticky muddy clay
00:46:21
but make very large stones in it yeah
00:46:23
and this is very similar to the material
00:46:26
we just talked about at the bottom and
00:46:28
that's what glacier ice
00:46:29
tends to deposit so what we're looking
00:46:31
at here then is essentially an ACH
00:46:34
deposit yes and then we've got a soil so
00:46:36
warm period vegetation yes comes back
00:46:39
and then below it another races another
00:46:42
Ice Age deposit so ace no nice faces
00:46:45
that's it
00:46:49
and it wasn't just here was it I mean
00:46:51
they've owned several they say it's all
00:46:53
of geeky compiled a huge number of these
00:46:55
sites in his textbook which he published
00:46:57
in in the early 1870s and he compiled
00:47:00
all the sites from the various railway
00:47:02
cuttings around Scotland I'm not gonna
00:47:04
cry yes you're a kid Oberg things of
00:47:07
Scott James geeky had phoned direct
00:47:12
evidence of multiple ice ages in the
00:47:15
landscape it was the first indication
00:47:18
that Krall was on the right lanes with
00:47:20
his concept of the natural rhythms of
00:47:22
the planet but geek ease research could
00:47:26
not reveal the precise dates of the ice
00:47:28
ages it was impossible to tie his work
00:47:31
in definitively with crows astronomical
00:47:34
cycles
00:47:38
[Applause]
00:47:41
in recent years scientists are given as
00:47:44
ever more accurate timings of the ice
00:47:46
ages
00:47:48
[Music]
00:47:58
here in sunny Cambridge the British
00:48:00
Antarctic Survey has a collection of ice
00:48:03
going back nearly a million years
00:48:06
[Music]
00:48:08
[Applause]
00:48:12
they use this ice to discover more about
00:48:15
the past
00:48:15
temperature of the earth
00:48:17
[Music]
00:48:19
[Applause]
00:48:22
okay hello I can't see me you mean avert
00:48:27
wrapping up what is the temperature
00:48:31
minus 20 degrees minus 20 their
00:48:35
conditions that we'd work in in
00:48:36
Antarctica we're wearing the same
00:48:38
clothes
00:48:38
we're in Antarctica I miss this what you
00:48:40
again obesity it's cause like the cause
00:48:49
of drilled out of the Antarctic Ice
00:48:51
Sheet the deeper the core the older it
00:48:54
is by measuring the depth of the ice
00:48:57
samples the scientists can work out when
00:48:59
the ice formed it's call that I've just
00:49:04
pulled out here is probably about a
00:49:05
twenty-year section of ice it got there
00:49:08
I'm just thinking if this is 20 years
00:49:10
then 800,000 years
00:49:12
it's just ginormous yes over three
00:49:16
kilometers down we had to drill a new
00:49:18
ice to get make hundred thousand year
00:49:20
records so you don't have a hole here no
00:49:21
that's for sure
00:49:25
now we can use the the pencil here to
00:49:28
actually cut some samples through the
00:49:29
ice but then find out more about the
00:49:31
planet
00:49:33
oh yes
00:49:37
they got glistening a sugary texture hey
00:49:40
oldest this piece of ice is around about
00:49:42
ten thousand years old so where's the
00:49:45
scroll I see we got my flight article so
00:49:47
this is the core we collected from James
00:49:48
Ross Island which is right on the tip of
00:49:50
the Antarctic Peninsula
00:49:52
[Music]
00:49:58
the Antarctic team is most interested in
00:50:01
the temperature of the earth at the time
00:50:03
the ice formed each sample has a
00:50:07
distinctive chemical makeup the
00:50:10
scientists use this fingerprint to
00:50:12
measure how hot a called the F was then
00:50:18
they found out that over the last
00:50:21
800,000 years the temperature of the
00:50:23
earth does fluctuate and these changes
00:50:26
closely follow the Earth's orbit
00:50:29
[Music]
00:50:34
James crawl didn't get all the details
00:50:37
spot-on
00:50:38
but his general principle has been
00:50:40
vindicated what do you know of James
00:50:47
crawl not very much I only know that he
00:50:50
was involved in some of the early ideas
00:50:53
about natural changes in the Earth's
00:50:55
climate yeah I'm trying to bring him out
00:50:57
the ice closet really but then I was
00:50:59
just thinking he would love to have got
00:51:02
his hands I'm nice to have seen what
00:51:03
you're doing with these ice cores
00:51:04
because this is really nailing it isn't
00:51:06
it
00:51:13
I'll tell her that if I come out with a
00:51:15
slice of Ace I can hear something weird
00:51:23
don't you dare NAT all
00:51:29
but I should be here mrs. Li is the ice
00:51:31
starts to melt the air bubbles pop
00:51:42
crackle crackle
00:51:45
and what I'm hearing is the sound of the
00:51:47
atmospheres from thousands of years ago
00:51:49
coming out the sound of the ACH
00:51:56
[Music]
00:52:00
these days we've learned more about the
00:52:03
ECGs and crawl could ever have dreamt of
00:52:07
where they began how long they lasted
00:52:10
and how extensively were the last a
00:52:13
sheet to cover most of the British Isles
00:52:15
was just 20,000 years ago you may assume
00:52:19
it started in the North Pole and spread
00:52:22
southward but reading the rocks reveals
00:52:26
that Britain's a siege began in the
00:52:27
middle of the Scottish Haley's
00:52:49
[Music]
00:52:52
in the British Isles the ice sheet was
00:52:54
born here ranek more Evaristo maximum
00:52:58
thickness of a kilometer thousand meters
00:53:01
of ice which is similar to present-day
00:53:02
greenland that was the beating heart of
00:53:06
the a siege from here glaciers have
00:53:08
moved slowly down these valleys towards
00:53:10
the sea carving out these magnificent
00:53:13
glands
00:53:15
[Music]
00:53:17
we known or that have been 10 major ice
00:53:19
ages in the past million years so what
00:53:25
does the future hold for us
00:53:26
[Music]
00:53:34
[Music]
00:53:35
today scientists follow in the footsteps
00:53:38
of James crawl they to predict that an
00:53:42
ice age is coming on this board in the
00:53:50
west coast of Scotland they work out
00:53:52
where the glaciers of the next Ice Age
00:53:53
will go
00:53:56
and the best way of doing this is to
00:53:59
look where the eggs went last time
00:54:04
[Music]
00:54:07
this is a first of long that I've been
00:54:10
here loads days but never like this this
00:54:12
is it's like I'm milk it might seem odd
00:54:19
to study glaciers out at sea but
00:54:21
thousands of years ago this wasn't see
00:54:24
it was land land covered by ice during
00:54:28
the Ice Ages the so much water gets
00:54:30
locked up in the ashes that around the
00:54:32
world sea levels fall and they fall by
00:54:35
as much as a hundred and fifty meters
00:54:41
when the ice sheets melt the sea floods
00:54:44
back and so by mapping the seabed John
00:54:48
Howe and Tom Bradwell can find the
00:54:50
tracks of these ancient glaciers you can
00:54:55
see on here the footprint of a glass
00:54:57
here or an ice sheet as it's come down
00:54:59
in LA and we can see these beautiful
00:55:02
ridges that cut across and this was
00:55:05
produced by a glass here and presumably
00:55:07
get better preserved on the seabed
00:55:09
because there's nothing to ruin diverse
00:55:11
range that's exactly what happens we've
00:55:12
seen these features preserved better
00:55:14
offshore than we ever do on shore
00:55:18
the first time we can actually see where
00:55:20
the ice got to they're actually real
00:55:22
limits this is a guess work we were
00:55:24
actually getting real data on where the
00:55:25
ice got to at a certain point in time
00:55:27
the team has made a computer model that
00:55:30
shows what the next ice age in Britain
00:55:32
could be like how far these giant
00:55:35
glaciers would extend depends on how far
00:55:37
the temperature drops an eighth degree
00:55:40
fall would plunge Britain into a
00:55:42
full-blown Passage and so that's telling
00:55:46
us what that ace is gonna be in the
00:55:47
future it's gonna cover this area again
00:55:50
absolutely there will be another huge
00:55:52
ice sheet of hundreds of meters of ice
00:55:54
and the ice will just scrape across and
00:55:56
remove the remains of advisory in their
00:55:59
cities you know everything we think of
00:56:01
it so scenario enough because as weak
00:56:03
wheezing as that yeah people bulldozed
00:56:05
away all gonna be trashed
00:56:08
[Laughter]
00:56:09
[Music]
00:56:12
it's not just tones in Scotland that
00:56:15
will be obliterated the next ice age
00:56:19
will be a global catastrophe millions of
00:56:23
people will be displaced America Europe
00:56:26
and Asia will be gripped by ice
00:56:35
[Music]
00:56:40
this is one of the things that geology
00:56:42
so gritter is you have to imagine
00:56:44
strange other worlds you get tantalizing
00:56:48
clues here and there but actually a lot
00:56:50
of it's in your head how do you
00:56:51
visualize this with I don't know several
00:56:53
hundred meters of ice above you just
00:56:55
just hard to do
00:57:00
but how soon will this happen a
00:57:04
million-dollar question when is the
00:57:05
earth going to go into the next ice age
00:57:08
forty to fifty thousand years from now
00:57:10
it will definitely be an ice age and
00:57:12
Scotland will be plunged back into the
00:57:14
the conditions that we saw about 12 to
00:57:17
20 thousand years ago but that timing
00:57:19
then is still based on those natural
00:57:21
rhythms that crawl in my wine cave it's
00:57:23
really tied there that's right those
00:57:25
natural frequencies are going to are
00:57:26
going to exist into the future and we
00:57:29
know that looking back into the past
00:57:30
over the last two million years we've
00:57:32
seen this natural frequency
00:57:34
[Music]
00:57:39
this is a vision of our future we've
00:57:42
only come to realize it thanks to the
00:57:44
pioneers of the past
00:57:46
[Music]
00:57:51
people like Louie Agassiz who opened our
00:57:54
eyes to the power of ice that carved our
00:57:56
landscape
00:57:58
[Music]
00:58:02
and James call the looked up to the
00:58:06
heavens to solve the mystery of Earth's
00:58:08
ice ages these men of rock gave us the
00:58:14
tools to make sense of our planet
00:58:19
[Music]
00:58:26
eastenders next tonight here on BBC HD
00:58:29
stay with us and right behind daft stuff
00:58:32
at the airport Matt Lucas and David
00:58:34
Williams we've come flying with me
00:58:36
[Music]
00:58:38
[Applause]
00:58:39
[Music]
00:58:48
you
