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Transcript

A Little History Of The Earth · Luke's English Podcast

0:07
Speaker 1: Hello, so welcome to another edition of Science of the Times.
0:10
Speaker 1: Nice to see you, Tim.
0:12
Speaker 2: Lovely to see you too. How are you doing?
0:14
Speaker 1: I'm doing fine, yeah, all good. But you, you're doing
0:17
Speaker 1: really well. You're off to exotic parts, right?
0:20
Speaker 2: I've got a quick trip. I fly out tomorrow morning
0:22
Speaker 2: to Hong Kong. I give a talk in Hong Kong,
0:25
Speaker 2: and then I go to Singapore where I do the same,
0:28
Speaker 2: and then back. So tomorrow, whenever this comes out, but
0:32
Speaker 2: when we're recording it, tomorrow is Saturday, and I come
0:34
Speaker 2: back on Thursday. Thank you. So I'm traveling quite a
0:38
Speaker 2: long way around the world. And actually, this week's podcast
0:42
Speaker 2: is about how the Earth came to be and why
0:45
Speaker 2: it's like it is.
0:47
Speaker 1: Yeah, absolutely. And yeah, our guest is Jamie Woodward, and
0:51
Speaker 1: he's written a book all about the history of the planet.
0:55
Speaker 2: Yeah, The Little History of Earth by Yale. I've not
0:58
Speaker 2: met him before I read his book. Actually, I was
1:01
Speaker 2: asked whether I'd like to read it and provide an
1:04
Speaker 2: endorsement which I which I did and so and I
1:07
Speaker 2: really enjoyed it actually because sometimes you it's interesting sometimes
1:10
Speaker 2: you get asked to provide an endorsement and you read
1:12
Speaker 2: the book and you think I honestly can't think what
1:15
Speaker 2: I would say but this one was easy it was
1:17
Speaker 2: very easy to to rave about it's a great book
1:20
Speaker 2: and I hope our listeners think about buying.
1:22
Speaker 1: It cool so should we should we get him on let's.
1:25
Speaker 2: Get him on well thank you very much for joining
1:28
Speaker 2: us Jamie I wonder if you'd like to introduce yourself
1:31
Speaker 2: and say a little bit about who.
1:32
Speaker 3: You are Sure, great pleasure to be here. Well, I'm
1:34
Speaker 3: Jamie Woodward. I'm a professor of physical geography at the
1:38
Speaker 3: University of Manchester, where I do research and teach on
1:42
Speaker 3: landscape change and environmental change.
1:45
Speaker 2: Fantastic, and congratulations on your new book, which is just out,
1:49
Speaker 2: A Little History of the Earth, and that's published by Yale,
1:53
Speaker 2: Yale University Press. A really good read, well worth it,
1:56
Speaker 2: and a fantastic stocking filler for any ages.
2:00
Speaker 3: Thank you so much for saying that.
2:03
Speaker 2: Before we dive into the book, do you want to
2:05
Speaker 2: say a little bit about a bit more about your
2:08
Speaker 2: research and what you sort of do in your day job?
2:10
Speaker 2: So I think you're kind of interested in quaternary environmental
2:15
Speaker 2: change and human activity in ice age environments, if I've
2:20
Speaker 2: understood it correctly.
2:22
Speaker 3: Yeah, I'm interested in a range of things, actually. So
2:25
Speaker 3: the quaternary is the most recent geological period, covers the
2:29
Speaker 3: last two and a half million years. So that's where
2:32
Speaker 3: most of my research sits. So I work over sort
2:36
Speaker 3: of quaternary timescales, but I also work over sort of
2:38
Speaker 3: modern and historical timescales. I'm interested in contemporary processes as well.
2:42
Speaker 3: So much of my focus is actually on rivers. So
2:45
Speaker 3: I'm interested in how rivers behave in the present day
2:47
Speaker 3: and how humans interact with them. And I'm interested in
2:49
Speaker 3: how rivers behave in the past, right back to the
2:51
Speaker 3: Ice Age and beyond.
2:53
Speaker 2: And quite a lot of your fieldwork is in the
2:54
Speaker 2: Mediterranean area, if my digging around on the internet is correct.
2:59
Speaker 3: Indeed. I did my PhD in Greece, actually, working with archaeologists, actually,
3:03
Speaker 3: looking at some Ice Age rivers and Paleolithic settlements. So
3:07
Speaker 3: there's a thread that runs through my research that goes
3:09
Speaker 3: right through to the sort of microplastic stuff I've done recently.
3:12
Speaker 3: It's basically how humans interact with rivers. No, fantastic stuff.
3:17
Speaker 3: But your book is much, much deeper time than that.
3:21
Speaker 1: Yeah.
3:22
Speaker 2: Indeed, yes.
3:23
Speaker 3: So this is probably my most ambitious writing project to date.
3:26
Speaker 3: So I sit very much in the quaternary period. But
3:29
Speaker 3: I'm also interested in earlier geological periods and actually teach
3:33
Speaker 3: a first year course, a large course of physical geography,
3:36
Speaker 3: where we focus on the last 66 million years and
3:38
Speaker 3: the sort of the major climate changes for when the
3:40
Speaker 3: Earth was very, very hot into the present sort of
3:43
Speaker 3: cooler period. So I do delve into the deep past.
3:46
Speaker 3: But yes, it was a big challenge for me to
3:48
Speaker 3: take on the whole span of Earth history.
3:51
Speaker 1: So what inspired you to write that and tackle such
3:54
Speaker 1: a big topic?
3:57
Speaker 2: Good question.
3:58
Speaker 3: And I asked myself that question lots of times when
4:01
Speaker 3: I started doing it because there's lots of... I like
4:05
Speaker 3: the format of Little Histories. Maybe I'll come at it
4:08
Speaker 3: that way because the format of Little Histories is that
4:10
Speaker 3: there are 40 chapters, approximately 2,000 words per chapter. So
4:13
Speaker 3: there's sort of set of essays really. And a good
4:16
Speaker 3: friend of mine, Nigel Warburton, wrote A Little History of Philosophy,
4:19
Speaker 3: which was very successful. And so he tackled the whole
4:21
Speaker 3: of Western philosophy in sort of 40 bite-sized chapters. So
4:25
Speaker 3: I thought it would be a challenge to take on
4:27
Speaker 3: the history of the earth in that format. And the
4:31
Speaker 3: original Little History book was produced, was written by a
4:35
Speaker 3: man called Ernst Gombrich, who wrote A Little History of
4:37
Speaker 3: the World, A History of People, A Political History. He
4:39
Speaker 3: wrote his book in six weeks.
4:41
Speaker 2: Wow, wow.
4:43
Speaker 3: So there were a whole set of challenges associated with this,
4:46
Speaker 3: but I liked the format and I wanted to see
4:49
Speaker 3: if that would work to take on the whole history
4:51
Speaker 3: of the planet.
4:52
Speaker 2: And how many, did it take you a bit more
4:54
Speaker 2: than six weeks or? Yeah, much longer.
5:03
Speaker 1: Yes.
5:03
Speaker 2: Yeah. No, well, congratulations. It's a really good read and
5:06
Speaker 2: it is really accessible. Thank you. And I actually agree
5:10
Speaker 2: with you, I like that format because 2,000 words you
5:12
Speaker 2: can dip in and you can read a chapter, you know,
5:14
Speaker 2: even if you've only got sort of 15 minutes or so,
5:17
Speaker 2: you know, spare time. So, no, it works really well. So,
5:24
Speaker 2: I guess the, I mean, the Earth formed, what, about
5:27
Speaker 2: four and a half billion years ago? That's when the
5:30
Speaker 2: solar system formed, is that right?
5:31
Speaker 1: Yes.
5:32
Speaker 2: And how did it come about? How did it all start?
5:36
Speaker 3: Well, you've written about this, Tim, you know all about this. So, um,
5:39
Speaker 3: and I had to sort of, you know, really delve
5:41
Speaker 3: into the, into a lot of stuff that I knew about, but, um,
5:45
Speaker 3: but I hadn't, I hadn't taught and I hadn't researched
5:47
Speaker 3: and written about. So I started reading about accretion and
5:51
Speaker 3: the other formation of the solar system. So about four
5:53
Speaker 3: and a half billion years ago, we had the formation
5:55
Speaker 3: of the sun and the solar nebula, this huge, um,
5:59
Speaker 3: disc of dust and, and, and, and rocky material, um,
6:03
Speaker 3: And then gravitational processes took over and we started getting
6:06
Speaker 3: the formation of small plantesimals and this accretion process is
6:09
Speaker 3: where these particles are attracted together, sort of billions of
6:12
Speaker 3: particles attracting one another and gradually forming into larger bodies,
6:16
Speaker 3: plantesimals and eventually planets, which produced the rocky planets and
6:20
Speaker 3: then the ice planets and the gas planets in the
6:22
Speaker 3: solar system. So what we still don't fully understand all
6:26
Speaker 3: of those processes, of course, but in broad terms, that's
6:28
Speaker 3: kind of broadly what happened.
6:31
Speaker 1: And so I think, Just sort of going really sort
6:35
Speaker 1: of back to basics, a theme is this concept of
6:40
Speaker 1: deep time. Just for our listeners and viewers, can you
6:43
Speaker 1: tell us what you mean by deep time?
6:44
Speaker 3: Yeah, well, deep time in terms, you know, millions and
6:48
Speaker 3: billions of years, right, sort of the early history of
6:51
Speaker 3: the planet. But the idea of deep time was kind
6:54
Speaker 3: of formulated by James Hutton, one of my heroes, who
6:57
Speaker 3: was a sort of Scottish geologist, natural philosopher who worked
7:00
Speaker 3: extensively and wrote mainly the second half of the 18th century.
7:04
Speaker 3: And he was the first person really to write about
7:09
Speaker 3: the earth having a very, very deep, long history. Now,
7:11
Speaker 3: of course, you couldn't put a number on that. They
7:13
Speaker 3: didn't have any scientific dating, but he put forward the
7:15
Speaker 3: ideas that the geological record could only really be explained
7:18
Speaker 3: by having lots and lots of time to explain the
7:21
Speaker 3: rocks and the erosion features in the geological record.
7:24
Speaker 2: And I mean, it's really hard, isn't it? I think
7:26
Speaker 2: for people to get their head around quite how long,
7:30
Speaker 2: you know, even a million years is, let alone 4.5
7:33
Speaker 2: billion years. I mean, that was kind of one of
7:35
Speaker 2: the things that I find people really struggling with. I mean,
7:40
Speaker 2: have you got any sort of tricks, you know, to
7:42
Speaker 2: try and illustrate quite how vast amount of time the
7:46
Speaker 2: Earth has been around?
7:47
Speaker 3: Well, one of the favorite ones, and it was one
7:49
Speaker 3: of the favorite ones of Stephen Jay Gould as well,
7:51
Speaker 3: is the outstretched arm, you know, in my arm here.
7:54
Speaker 3: So the origin of the solar system, the origin of
7:57
Speaker 3: planet Earth is on your shoulder here. And then moving
8:00
Speaker 3: this way down to your elbow, down about, so this
8:03
Speaker 3: is about four and a half billion years ago, down
8:05
Speaker 3: to your elbow, the sort of lot of pre-Cambrian time,
8:07
Speaker 3: about two and a half billion years ago, you started
8:09
Speaker 3: to get the first life in the oceans. and then
8:14
Speaker 3: keep going down, of course, you know, the dinosaurs in
8:16
Speaker 3: the palm of your hand, and eventually humanity right at
8:18
Speaker 3: the sort of tip of the fingernail on the middle finger.
8:20
Speaker 3: So that's a nice analogy to illustrate deep time. But
8:23
Speaker 3: it's hard to think about those vast numbers because we
8:25
Speaker 3: live very much in the present. And one of the
8:29
Speaker 3: challenges for the book was, you know, how do I
8:31
Speaker 3: allocate all that time into 40 chapters? And how much
8:35
Speaker 3: time do I allocate to the pre-Cambrian or the last
8:38
Speaker 3: 4 billion years, which is 88% of Earth history? So
8:40
Speaker 3: that was a challenge as well about how to, compartmentalize
8:44
Speaker 3: those stories into the book.
8:46
Speaker 1: Sure and so jamie there's a you know it's as
8:49
Speaker 1: tim said it's very difficult for you know for us
8:52
Speaker 1: to sort of get our heads around this idea of
8:56
Speaker 1: time and deep time and just the scale of it
8:58
Speaker 1: all um temporally but also in terms of uh processes
9:03
Speaker 1: sort of earth shaping processes do you feel that there's
9:05
Speaker 1: some that are vastly misunderstood by the public Well, you.
9:09
Speaker 2: Mean like plate tectonics?
9:12
Speaker 1: Yeah, climate shifts, this sort of thing, just these big,
9:16
Speaker 1: you know, sort of macroscopic processes that have shaped the planet.
9:21
Speaker 3: Yeah, so sort of planetary scale processes, you know, and
9:24
Speaker 3: I think what's interesting when you sort of read about
9:27
Speaker 3: Earth history and read about the processes is that Very often,
9:30
Speaker 3: if you do geography A-level, for example, or Earth science,
9:33
Speaker 3: it very much focuses often on the surface of the Earth.
9:36
Speaker 3: And plate tectonics is very much framed in terms of hazards,
9:40
Speaker 3: where the earthquakes are, where the volcanoes are, where the
9:43
Speaker 3: tectonic plates meet, and often much less on the actual
9:47
Speaker 3: processes that are driving plate tectonics. And that's fascinating. And also,
9:51
Speaker 3: a big question, when did plate tectonics begin? Because Earth
9:55
Speaker 3: is the only planet in our solar system that has
9:58
Speaker 3: a fully active planetary's plate tectonics. It's one of the
10:01
Speaker 3: things that makes the Earth system unique. And then, of course,
10:04
Speaker 3: plate tectonics over much longer timescales influences the climate, the
10:07
Speaker 3: composition of the atmosphere, and life itself. So plate tectonics
10:12
Speaker 3: is a critical feature of the Earth system. And maybe
10:15
Speaker 3: that's not quite so widely appreciated as it could be.
10:19
Speaker 2: I mean, they got going quite a long time ago,
10:22
Speaker 2: as far as we can tell. I mean, I've seen those,
10:24
Speaker 2: and you talk about this in the book, obviously, but
10:27
Speaker 2: I've seen those videos online where you sort of see
10:29
Speaker 2: the continents, the ancient continents coming together and going apart,
10:34
Speaker 2: you know, Pangaea, and as I like to jokingly call it, again,
10:37
Speaker 2: to trouble, British Gondwana land, and, you know, them floating
10:42
Speaker 2: around everywhere. When did they really get, what's the best guess?
10:45
Speaker 2: Can you remember?
10:46
Speaker 3: Well, I'll give, I think there are, There's the sort
10:50
Speaker 3: of early plate tectonics that, you know, there's signs in
10:53
Speaker 3: the rocks or some of the ancient rocks that there's
10:55
Speaker 3: sort of, you know, there's sort of pillow lavas that
10:57
Speaker 3: may be subduction zones, you know, right back sort of
10:59
Speaker 3: 4 billion years ago. So some early plate tectonics. And
11:03
Speaker 3: it's interesting that when, how did plate tectonics begin? Did
11:05
Speaker 3: it begin on a local scale? Did it, you know,
11:07
Speaker 3: did it, did it, did it, was it a stop
11:09
Speaker 3: start process? It may have started and then stalled, but
11:12
Speaker 3: certainly by about three and a half billion years ago,
11:15
Speaker 3: plate tectonic processes was a planetary scale processes and was well-developed.
11:19
Speaker 3: And you mentioned Pangea there. What's also interesting about Earth
11:22
Speaker 3: history is that that's probably the supercontinent people are most
11:25
Speaker 3: familiar with, the one that was defined by Wegener. But
11:30
Speaker 3: Earth has gone through several sort of supercontinent cycles of
11:33
Speaker 3: the formation and the breakup of supercontinents. And that's another
11:36
Speaker 3: interesting feature of Earth history that isn't widely appreciated.
11:40
Speaker 2: Because the continents are spread out quite a lot at
11:43
Speaker 2: the moment, aren't they, compared to certainly sometimes in the
11:45
Speaker 2: Earth's history. Indeed. The ones we've got, yeah.
11:48
Speaker 3: So during Pangea, for example, say during the Triassic and
11:54
Speaker 3: the Jurassic when the dinosaurs were around, and many of
11:58
Speaker 3: those dinosaurs were striding around on a supercontinent. So you
12:02
Speaker 3: could walk across most of the existing continents because they
12:05
Speaker 3: were joined together. And it's predicted in 250 million years
12:09
Speaker 3: in the future, the continents may well be joined together again.
12:12
Speaker 3: So that cycle will continue.
12:15
Speaker 1: And so, Jamie, so in doing this, doing all of
12:18
Speaker 1: the research for your book, were there some ideas that
12:21
Speaker 1: maybe you had and, and sort of any, any, any
12:24
Speaker 1: recent developments or recent research that has sort of thrown
12:28
Speaker 1: those into question? Or has there been anything like that
12:30
Speaker 1: at all? Has changed the way you've thought about things?
12:33
Speaker 3: Um, it's, I, well, what changed my way of thinking
12:39
Speaker 3: about things?
12:40
Speaker 1: Um, I.
12:44
Speaker 3: Hadn't thought about this actually. I.
12:47
Speaker 1: Sorry, I always ask the question.
12:50
Speaker 3: I'm just trying to think of something that really did
12:52
Speaker 3: make me stop and think and make me change the
12:54
Speaker 3: way I thought about something. But one of the ideas
13:00
Speaker 3: that I do talk about in the book is about
13:02
Speaker 3: how mountain building can change the climate. Yeah. And this
13:07
Speaker 3: is an idea I teach at first year, actually. A
13:09
Speaker 3: lot of students find quite challenging. And also it's related, obviously,
13:14
Speaker 3: to plate tectonics. changing the climate it's called the uplift
13:17
Speaker 3: weathering hypothesis it was put forward by maureen ramo um
13:21
Speaker 3: um an earth scientist who's based based at columbia in
13:25
Speaker 3: in new york uh the idea that the formation of
13:28
Speaker 3: the himalayas for example um was was largely responsible for
13:32
Speaker 3: the global climate cooling we see over the last 50
13:34
Speaker 3: million years or so and um i i i maureen
13:38
Speaker 3: ramo is one of the sort of great women in
13:40
Speaker 3: earth sciences and a and a and a great sort
13:43
Speaker 3: of um hero, actually, and I use her as an
13:48
Speaker 3: example in my first year classes, because she got a
13:51
Speaker 3: lot of stick when she put forward that model with
13:53
Speaker 3: Bill Ruddiman in the 1980s. And it is broadly accepted
13:57
Speaker 3: now that so when mountains go up, you get a
13:58
Speaker 3: lot more weathering, you get a lot more erosion. And
14:01
Speaker 3: those minerals and those weathering processes involve interactions with carbon dioxide.
14:05
Speaker 3: So carbon dioxide is basically slowly taken out the atmosphere.
14:09
Speaker 3: It combines with new minerals and they get washed down
14:11
Speaker 3: to the ocean and then Fossils, not fossil, sort of forams,
14:16
Speaker 3: little tiny shells and corals, et cetera, use that carbon
14:20
Speaker 3: to make their shells, and then they get buried on
14:21
Speaker 3: the ocean floor. So when that process happens, it's accelerated
14:25
Speaker 3: because of the formation of big mountain belts. Carbon dioxide
14:30
Speaker 3: is progressively sucked out of the atmosphere, so the climate
14:32
Speaker 3: will cool because the greenhouse effect is weakened. So that's
14:35
Speaker 3: a really big idea, actually. A relatively recent idea in
14:40
Speaker 3: the earth sciences, but it's also been– really valuable because
14:44
Speaker 3: it's helped to explain climate cooling in the past as well,
14:47
Speaker 3: in deeper time.
14:48
Speaker 2: So one of the most remarkable things that happened in
14:51
Speaker 2: Earth's history is obviously the emergence of life and how
14:54
Speaker 2: life got started. And that's a very complicated process. We
14:59
Speaker 2: don't know a lot about it. How did you go
15:01
Speaker 2: about addressing that in the book? Because, you know, that's
15:03
Speaker 2: something that I really struggled with when I was kind
15:06
Speaker 2: of thinking, how on earth do you deal with something
15:08
Speaker 2: like that?
15:09
Speaker 3: Well, this is your expertise, Tim. And I mean, if
15:11
Speaker 3: you struggle with this, you know, yeah, I am. Essentially,
15:16
Speaker 3: when I wrote the book, I thought, well, the first
15:18
Speaker 3: half of the book writing about sort of, you know,
15:20
Speaker 3: the deep time would be would be really hard. And
15:22
Speaker 3: I want to get to the second half of the
15:23
Speaker 3: book in the more recent theological periods. I kind of
15:25
Speaker 3: thought that would be much faster that I'll be able
15:27
Speaker 3: to get on with. And then I found that, well,
15:29
Speaker 3: I knew too much then. So that got even slower.
15:31
Speaker 3: So what do I leave out? So I couldn't win.
15:34
Speaker 3: But in terms of the evolution of life, we still
15:36
Speaker 3: don't understand those big questions and some of the processes.
15:39
Speaker 3: And I talk about the two main environments, and correct
15:43
Speaker 3: me if I'm wrong here, You know, the idea that
15:47
Speaker 3: some of the processes that happen on spreading ridges where
15:50
Speaker 3: you've got lots of sort of minerals and fluids coming
15:54
Speaker 3: out of the mantle into the oceans, that sort of
15:57
Speaker 3: mix of chemistry and energy could have driven the early
16:02
Speaker 3: forms of life. Alternatively, they could have been on sort of,
16:05
Speaker 3: you know, salty lagoons in the bright tropical sunshine. That
16:09
Speaker 3: might have been the cradle of life. We still don't
16:11
Speaker 3: fully understand that. But they're two of the candidates that
16:16
Speaker 3: I write about. And I kind of leave it as
16:17
Speaker 3: an open question, I think.
16:20
Speaker 2: I think I did pretty much the same.
16:24
Speaker 3: That's the relief, yeah.
16:27
Speaker 2: Sorry, Simon, you were going to say something. No, sorry.
16:29
Speaker 1: No, no, it was just, but I was just wondering
16:32
Speaker 1: sort of, You know, given that you do now have
16:36
Speaker 1: this kind of broad picture that you've painted so nicely
16:39
Speaker 1: in your book, if you could choose a period to
16:43
Speaker 1: go back to and witness, what do you think, you know,
16:46
Speaker 1: witness events unfolding ahead of you, what do you think
16:49
Speaker 1: you would choose and why?
16:50
Speaker 3: Wow, what a question. I mean, I think there'd probably
16:54
Speaker 3: be a very long list of things I'd like to
16:55
Speaker 3: go back and see. But the cryogenium, for example, Snowball Earth,
17:00
Speaker 3: is a fascinating period because... One of the things that's,
17:03
Speaker 3: I think, become apparent in the earth sciences, maybe this
17:05
Speaker 3: is an answer to the question you asked me earlier, Simon,
17:10
Speaker 3: is that, you know, the pre-Cambrian, the first four billion
17:12
Speaker 3: years of earth history were often seen as a sort
17:14
Speaker 3: of geological dead end. You know, there weren't any fossils.
17:16
Speaker 3: There wasn't, you know, just a few blobs and evidence
17:18
Speaker 3: of primitive life. And it was a kind of not
17:20
Speaker 3: worth studying. And all the excitement was in the Jurassic
17:22
Speaker 3: and the Cretaceous and the Cambrian way we had complex life.
17:26
Speaker 3: But the cryogenies are really interesting. This is the period
17:29
Speaker 3: where we think there were snowball Earth events, you know,
17:32
Speaker 3: where the planet was frozen. And there are big debates
17:35
Speaker 3: to the extent to which the Earth looked like a
17:37
Speaker 3: snowball and the extent to which those. But we certainly
17:39
Speaker 3: have big ice sheets in the tropics, large glaciers in
17:42
Speaker 3: the tropics. So very different from the scenarios that we
17:44
Speaker 3: have today. And then but also shortly after this, this
17:48
Speaker 3: was the time when complex life evolved. So there must
17:50
Speaker 3: have been life surviving beneath these ice sheets and beneath
17:53
Speaker 3: the sea ice. And then towards the end of the cryogenium,
17:56
Speaker 3: we get very rapid global warming driven by volcanic activity.
18:00
Speaker 3: And so we have these glacial deposits that are overlain
18:02
Speaker 3: by tropical limestones. So the climate flipped profoundly from a
18:06
Speaker 3: sort of deep Antarctic conditions to tropical conditions. So that
18:11
Speaker 3: was a really interesting period where the habitability of the
18:15
Speaker 3: planet was under threat. And yet it flipped from super
18:18
Speaker 3: cold to super warm. And And the irony there is,
18:22
Speaker 3: is that in the following period, the Ediacaran, we get
18:24
Speaker 3: complex life forms. And it may well be the glaciation
18:27
Speaker 3: was putting lots of erosion and lots of nutrients into
18:31
Speaker 3: the oceans. And that might have, you know, turbocharged evolution
18:34
Speaker 3: at that time. It's a really interesting period.
18:37
Speaker 2: And then just, you know, so as you said, life really,
18:40
Speaker 2: complex life really took off and the Eudacaran, we, you know,
18:43
Speaker 2: we start to see the first animal communities coming together.
18:47
Speaker 2: And then the Cambrian is the really exciting bit as well,
18:50
Speaker 2: isn't it? So that's when then you see this explosion,
18:53
Speaker 2: you know, the Cambrian explosion in all sorts of new
18:56
Speaker 2: forms and what have you. Any kind of particular animals
19:00
Speaker 2: or innovations, evolutionary innovations from that period that really caught
19:04
Speaker 2: your attention?
19:05
Speaker 3: The Cambrian explosion has fascinated geologists, paleontologists, evolutionary scientists for
19:13
Speaker 3: 150 years and longer. So just all those life forms
19:17
Speaker 3: suddenly appeared and there's just new ways of moving around,
19:19
Speaker 3: whether you were burrowing and scurrying across the floor, the
19:22
Speaker 3: early swimmers, et cetera. And the Cambrian is fascinating because
19:27
Speaker 3: I also write about the idea of it being Darwin's dilemma. Suddenly,
19:31
Speaker 3: for a long time, people thought pre-Cambrian, just a few
19:35
Speaker 3: simple cells and life forms, simple life forms. There's certainly
19:37
Speaker 3: this Cambrian explosion, but Darwin did allow enough time there
19:41
Speaker 3: for evolution to happen. And Darwin was kind of seriously
19:44
Speaker 3: worried about this, that it might be hijacked by creationists,
19:46
Speaker 3: for example. But we now know from the study of
19:49
Speaker 3: the previous geological period, the idea current is that complex
19:52
Speaker 3: life forms evolved and occurred much, much earlier. So yeah,
19:56
Speaker 3: the Cambrian is still a remarkable period of, um, evolutionary
20:00
Speaker 3: diversity where you get all these weird and wonderful life forms,
20:03
Speaker 3: particularly from the Burgess shales in, um, in North America. Um,
20:08
Speaker 3: And so some spectacular life forms and weird and wonderful
20:11
Speaker 3: creatures like shrimps with five eyes, for example. It's a
20:14
Speaker 3: remarkably interesting period. But also we now know because of
20:17
Speaker 3: dating that actually the explosion took place over tens of
20:20
Speaker 3: millions of years. It didn't happen overnight. So there was
20:22
Speaker 3: enough time for evolution to take place. So it kind
20:25
Speaker 3: of does fit within Darwin's model. It makes sense. But
20:27
Speaker 3: it's an interesting kind of, the ideas around that are
20:32
Speaker 3: really interesting about how people struggle with the explanations for
20:34
Speaker 3: that reality of the fossil record.
20:37
Speaker 2: Sure.
20:37
Speaker 1: I mean, just as a sort of a scientist at
20:40
Speaker 1: the more molecular scale of things, I guess, you know,
20:43
Speaker 1: a lot of those sort of extremophiles that you talk
20:46
Speaker 1: about that existed in these extreme sort of frozen environments
20:49
Speaker 1: and stuff, if we could bring them back, there's probably
20:52
Speaker 1: a hell of a lot we could learn from surviving
20:55
Speaker 1: in these extreme weather conditions that might even be useful now, right?
20:59
Speaker 3: Yeah, indeed. And I should thinking about snowball earth events
21:02
Speaker 3: and you know what's what's going to survive between the
21:04
Speaker 3: ice sheets i mean some of the recent work in
21:05
Speaker 3: antarctica looking at the life forms on the bed of
21:08
Speaker 3: the southern ocean and on the seas around antarctica beneath
21:11
Speaker 3: the ice shelves show incredible diversity of of life forms
21:15
Speaker 3: um at the present date so um it's not unusual
21:18
Speaker 3: therefore to expect maybe similar diversity in earlier geological periods
21:22
Speaker 3: under under those harsh harsh environments so another answer to
21:26
Speaker 3: the Maybe this isn't the answer to your question, Sam,
21:28
Speaker 3: but I'm thinking, you know, do you want to go
21:30
Speaker 3: back to another geological period? One of the things in
21:33
Speaker 3: the book is I write about a lot of the
21:35
Speaker 3: characters and the scientists and the people who kind of
21:37
Speaker 3: made a lot of the key advances. I would like
21:39
Speaker 3: to have a stroll along the beach with Mary Anning.
21:41
Speaker 3: That would have been fun. Back to the 1820s, maybe
21:46
Speaker 3: after a big storm in Dorset and see some of
21:49
Speaker 3: the fossils emerging out of the Jurassic cliffs there. That
21:51
Speaker 3: would have been an interesting insight.
21:54
Speaker 2: So, I mean, one of the themes that kind of
21:56
Speaker 2: runs through your book is, as we talked about, snowball
22:00
Speaker 2: or earth. But the fact that the climate has swung
22:02
Speaker 2: backwards and forwards, sometimes you say reasonably, reasonably quickly. And
22:07
Speaker 2: what do you think the sort of deep time climate
22:09
Speaker 2: variability teaches us about life's resilience? But also, I guess
22:13
Speaker 2: it's fragility, you know, on earth and any lessons for
22:17
Speaker 2: us going forward? Absolutely.
22:19
Speaker 3: I mean, you know, carbon dioxide, we know greenhouse gases
22:23
Speaker 3: have been a key driver of climate change over millions
22:27
Speaker 3: and billions of years. And so that, you know, very
22:30
Speaker 3: often when the climate has been warm in the past,
22:33
Speaker 3: it's because carbon dioxide has been high. We've had super
22:35
Speaker 3: greenhouse conditions and the various processes have weakened the greenhouse
22:39
Speaker 3: effect and the climate has become cooler. And most recently
22:42
Speaker 3: in the ice core records, say in the Pleistocene, the
22:45
Speaker 3: quaternary period of the last two million years, we show
22:47
Speaker 3: that carbon dioxide and global temperature are in lockstep. So
22:51
Speaker 3: the lessons for now is that we understand what drives
22:55
Speaker 3: the climate system and the warming of the planet over
22:58
Speaker 3: the coming decades will be determined by how much carbon
23:01
Speaker 3: dioxide we continue to put into the atmosphere. So the
23:03
Speaker 3: lessons from the geological record in that respect are very,
23:05
Speaker 3: very clear indeed. What's also clear is that in the past,
23:09
Speaker 3: the natural processes driving those have happened rather slowly. And
23:14
Speaker 3: we're not going to be saved by those natural processes.
23:16
Speaker 3: It's up to us to try to reduce carbon dioxide
23:18
Speaker 3: concentration of the atmosphere or to certainly to limit their increase.
23:23
Speaker 2: And are you an optimist? I am.
23:25
Speaker 3: I'm always an optimist. I think one of the themes
23:28
Speaker 3: in the book is that I talk a lot about
23:30
Speaker 3: the habitability of the planet and the unique set of
23:33
Speaker 3: ingredients that make Earth habitable. But that habitability isn't guaranteed.
23:39
Speaker 3: It isn't something we should take for granted. I mean,
23:41
Speaker 3: look at Venus and look at Mars, you know, They're
23:44
Speaker 3: in the habitable zone of our solar system, but things
23:46
Speaker 3: went badly wrong there in the past under natural processes.
23:50
Speaker 3: And we're currently driving the earth to, you know, strong
23:55
Speaker 3: greenhouse warming more rapidly than we've seen in the recent
23:59
Speaker 3: geological past. So I am optimistic. I mean, I do
24:03
Speaker 3: a lot of work on water pollution and microplastics in
24:05
Speaker 3: the last few years. And I've seen real change and
24:10
Speaker 3: investment in where activists and campaigners are making the most noise.
24:15
Speaker 3: So if you're concerned about the environment, get involved, ask questions,
24:19
Speaker 3: be active, and that can be a seed for change.
24:22
Speaker 3: So I am an optimist.
24:24
Speaker 1: And so, yeah, just on that note, I mean, would
24:27
Speaker 1: you care to speculate, given sort of, you know, current
24:30
Speaker 1: trajectories and things sort of geopolitically, what the next chapter
24:34
Speaker 1: might be for planet Earth?
24:36
Speaker 3: Well, it's very easy to get depressed with the current
24:40
Speaker 3: political situation. I mean, look at the COP, the recent
24:42
Speaker 3: COP conference down in Brazil. And, you know, the number
24:47
Speaker 3: of delegates there were almost outnumbered by the number of
24:49
Speaker 3: lobbyists for fossil fuel firms. So the politics is going
24:53
Speaker 3: to get... nastier before it gets better, I think. But
24:57
Speaker 3: we understand the fundamental processes. And actually, interesting, I think
25:01
Speaker 3: maybe it's insurance firms and investment in green infrastructure and in.
25:09
Speaker 3: More sustainable ways of developing a sustainable production of energy,
25:13
Speaker 3: green energy. That is the way forward. And even if
25:16
Speaker 3: some of the politicians at the time are arguing against that,
25:18
Speaker 3: I think the insurance companies and investment is still happening.
25:21
Speaker 3: And look at China's producing more solar panels and more
25:24
Speaker 3: wind farms than anybody else. So I think those changes
25:26
Speaker 3: will happen. Whether they'll happen quickly enough is a moot point.
25:30
Speaker 3: It's hard for anybody to say. But I'm optimistic that
25:34
Speaker 3: things will get better.
25:37
Speaker 1: Good.
25:37
Speaker 2: So one of the themes that runs through your book
25:39
Speaker 2: and something that, you know, I think is fascinating as
25:42
Speaker 2: well is the sort of the way that life has,
25:46
Speaker 2: the way that Earth has shaped life, but also the
25:49
Speaker 2: other way around, the way that life has kind of
25:52
Speaker 2: shaped Earth in terms of, you know, whether it's the
25:55
Speaker 2: cyanobacteria helping oxygenate the atmosphere or what have you, you know,
26:01
Speaker 2: it's an And how do you kind of go about
26:03
Speaker 2: dealing with that interplay in the book? What's the sort
26:05
Speaker 2: of key feedbacks that really impressed you?
26:09
Speaker 3: Yeah, well, I talk very early on in the first
26:13
Speaker 3: chapter about, you know, we're thinking very much on this
26:16
Speaker 3: journey of the Earth. He's thinking about the Earth as
26:17
Speaker 3: a system and thinking about the great spheres of the Earth.
26:22
Speaker 3: And one of those, of course, is the biosphere, which
26:25
Speaker 3: starts to kick in, you know, in terms of you
26:28
Speaker 3: mentioned there, about the production of oxygen and increasing the
26:34
Speaker 3: oxygen content of the atmosphere. So that was a critical milestone,
26:39
Speaker 3: what's known as the great oxygenation events with when the
26:42
Speaker 3: oxygen concentration of the atmosphere increased and which then eventually
26:45
Speaker 3: allowed complex life forms to develop. So that feedback is
26:49
Speaker 3: really very, very important. And then more recently, right back
26:56
Speaker 3: into the ice ages, for example, the swings between carbon
26:59
Speaker 3: dioxide production and global warming, global cooling. And one of
27:05
Speaker 3: the things, even very, very recently, I mean, it was
27:09
Speaker 3: Keeling who produced the Keeling curve, for example, was the
27:11
Speaker 3: first person to recognize that carbon dioxide increased and decreased
27:15
Speaker 3: on a seasonal basis in relation to biomass production. production
27:24
Speaker 3: in the Northern Hemisphere in terms of the production of
27:27
Speaker 3: leaves and life forms and plants in the springtime. And then,
27:29
Speaker 3: of course, in the fall when those leaves die and
27:31
Speaker 3: they degrade. And the seasonal cycling of carbon dioxide, the
27:38
Speaker 3: seasonal cycling of warming over that period is a really
27:40
Speaker 3: interesting feedback, actually.
27:43
Speaker 2: So I think we're kind of running out of time
27:45
Speaker 2: because we're, unfortunately, it's gone incredibly quickly. But I really
27:50
Speaker 2: enjoyed chatting to you and congratulations again on a fantastic book.
27:54
Speaker 2: A Little History of Earth, published by Yale. Do you
27:57
Speaker 2: have a final question, Simon, you want to ask?
28:01
Speaker 3: Not really.
28:01
Speaker 1: I just want to encourage people to, you know, to
28:04
Speaker 1: have a look at Jamie's book and buy it for
28:05
Speaker 1: Christmas because, yeah, it's great.
28:08
Speaker 2: Thank you very much, Jamie. It's been a pleasure talking
28:11
Speaker 2: to you. Thanks for taking the time.
28:12
Speaker 3: Thank you so much for inviting me. I've thoroughly enjoyed it.
28:14
Speaker 3: Thank you.
28:15
Speaker 2: What do you make of that then, Simon? The history, 4.5
28:18
Speaker 2: billion years in half an hour.
28:21
Speaker 1: Oh, it was excellent. I thought it was really... Yeah,
28:24
Speaker 1: really interesting and really well contextualised.
28:27
Speaker 2: I know, when we moan about the weather now, when
28:33
Speaker 2: you hear about Ice House Earth, Ice Ball Earth, whatever
28:37
Speaker 2: it is, Snowball Earth, Snowball Earth, you hear about Snowball Earth,
28:42
Speaker 2: you realise that a little bit of rain isn't quite
28:45
Speaker 2: that bad. Yeah, yeah.
28:48
Speaker 1: And especially if to survive, I have to have five
28:50
Speaker 1: eyes or whatever it was he said.
28:52
Speaker 2: Oh, in the Cambrian Explosion.
28:54
Speaker 1: Yeah.
28:56
Speaker 2: Some of those organisms are really difficult to interpret, the fossils.
29:00
Speaker 2: And yeah, we don't, I mean, we don't know a
29:04
Speaker 2: huge amount about a lot of them. But it was
29:07
Speaker 2: clearly an era when life really took off. It's when
29:10
Speaker 2: sense organs came to the fore. It's when brains came
29:14
Speaker 2: to the fore. And it's when predation got going, it's
29:16
Speaker 2: when things learn to eat one another. So, which is
29:18
Speaker 2: quite cool.
29:19
Speaker 1: And I mean, even though, you know, I've sort of
29:21
Speaker 1: been in and around biologists now for a long time
29:25
Speaker 1: as a trained chemist, it's still hard for me to
29:28
Speaker 1: get my head around some of these concepts and especially
29:32
Speaker 1: so many species that are now extinct, right? And the
29:35
Speaker 1: diversity of life that changes, although it's not fast in
29:39
Speaker 1: the grand scheme of things on our level it is
29:42
Speaker 1: fast and it is i think he explained it all
29:45
Speaker 1: really well no.
29:46
Speaker 2: He did he did i mean the scale that as
29:48
Speaker 2: you say the time scales that you're working at when
29:50
Speaker 2: individual um reactions are going you know which is in
29:53
Speaker 2: microsecond you know mini mini mini microseconds or whatever they're
29:56
Speaker 2: called versus billions of years, and then going from the,
30:01
Speaker 2: you know, from individual atoms and, you know, electrons interacting
30:04
Speaker 2: with one another, well, interacting right the way through to,
30:08
Speaker 2: you know, the planet and the solar system. I mean,
30:11
Speaker 2: it's just astonishing how much science has kind of learned
30:14
Speaker 2: and uncovered, I think.
30:15
Speaker 1: It is. Yeah, I think we could give ourselves a
30:17
Speaker 1: pat on the back as a, you know, generally as
30:20
Speaker 1: a species. I mean, we've unearthed quite a lot, right?
30:24
Speaker 2: We have, but we've also, you know, we're changing the
30:27
Speaker 2: planet and not necessarily a good way for us. You know,
30:30
Speaker 2: life will survive, but we, you know, if we do
30:34
Speaker 2: decide we want to kind of try and clean up
30:36
Speaker 2: the planet, we will do it because we realize that
30:39
Speaker 2: we're hurting ourselves rather than hurting anything else.
30:42
Speaker 1: Yes, that's right. It'll be a dire need to get
30:45
Speaker 1: on with it and hurry up and do it, right?
30:46
Speaker 3: Yeah.
30:47
Speaker 2: Well, I think that next time and probably the last
30:51
Speaker 2: one before Christmas, we're going to do a science of Christmas.
30:53
Speaker 2: Just you and me, right? Yeah.
30:55
Speaker 1: Yeah.
30:55
Speaker 2: Let's do that. OK, so you're going to ask me
30:58
Speaker 2: about Christmas animals and I might ask you about the
31:02
Speaker 2: the biochemical reactions that go on after a huge Christmas
31:07
Speaker 2: lunch with a little bit too much pork.
31:09
Speaker 1: Yeah, absolutely.
31:10
Speaker 2: I think that'll be fun.
31:11
Speaker 1: Let's see how we go.
31:12
Speaker 2: Let's do that. Great. Well, great to see you, Simon,
31:16
Speaker 2: and talk to you soon.
31:18
Speaker 1: Yeah, safe travels, Tim.