[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:12.58,0:00:15.84,Default,,0000,0000,0000,,All right, let's get up\Nour picture of the earth.
Dialogue: 0,0:00:16.16,0:00:17.58,Default,,0000,0000,0000,,The earth is pretty awesome.
Dialogue: 0,0:00:17.60,0:00:20.03,Default,,0000,0000,0000,,I'm a geologist, so I get\Npretty psyched about this,
Dialogue: 0,0:00:20.05,0:00:21.42,Default,,0000,0000,0000,,but the earth is great.
Dialogue: 0,0:00:21.44,0:00:24.90,Default,,0000,0000,0000,,It's powerful, it's dynamic,\Nit's constantly changing.
Dialogue: 0,0:00:24.92,0:00:26.72,Default,,0000,0000,0000,,It's a pretty exciting place to live.
Dialogue: 0,0:00:27.78,0:00:31.48,Default,,0000,0000,0000,,But I want to share with you guys today\Nmy perspective as a geologist
Dialogue: 0,0:00:31.50,0:00:33.72,Default,,0000,0000,0000,,in how understanding earth's past
Dialogue: 0,0:00:33.74,0:00:37.24,Default,,0000,0000,0000,,can help inform and guide\Ndecisions that we make today
Dialogue: 0,0:00:37.26,0:00:40.34,Default,,0000,0000,0000,,about how to sustainably live\Non earth's surface.
Dialogue: 0,0:00:41.02,0:00:44.76,Default,,0000,0000,0000,,So there's a lot of exciting things\Nthat go on on the surface of the earth.
Dialogue: 0,0:00:44.78,0:00:46.34,Default,,0000,0000,0000,,If we zoom in here a little bit,
Dialogue: 0,0:00:46.86,0:00:50.52,Default,,0000,0000,0000,,I want to talk to you guys a little bit\Nabout one of the things that happens.
Dialogue: 0,0:00:50.54,0:00:53.29,Default,,0000,0000,0000,,Material get shuffled around\Nearth's surface all the time,
Dialogue: 0,0:00:53.31,0:00:56.55,Default,,0000,0000,0000,,and one of the big thing that happens\Nis material from high mountains
Dialogue: 0,0:00:56.56,0:00:59.04,Default,,0000,0000,0000,,gets eroded and transported\Nand deposited in the sea.
Dialogue: 0,0:00:59.06,0:01:01.02,Default,,0000,0000,0000,,And this process is ongoing all the time,
Dialogue: 0,0:01:01.05,0:01:03.44,Default,,0000,0000,0000,,and it has huge effects\Non how the landscape works.
Dialogue: 0,0:01:03.46,0:01:05.36,Default,,0000,0000,0000,,So this example here in south India --
Dialogue: 0,0:01:05.38,0:01:07.88,Default,,0000,0000,0000,,we have some of the biggest\Nmountains in the world,
Dialogue: 0,0:01:07.90,0:01:09.88,Default,,0000,0000,0000,,and you can see in this satellite photo
Dialogue: 0,0:01:09.90,0:01:14.08,Default,,0000,0000,0000,,rivers transporting material\Nfrom those mountains out to the sea.
Dialogue: 0,0:01:14.10,0:01:16.28,Default,,0000,0000,0000,,You can think of these rivers\Nlike bulldozers.
Dialogue: 0,0:01:16.30,0:01:20.02,Default,,0000,0000,0000,,They're basically taking these mountains\Nand pushing them down towards the sea.
Dialogue: 0,0:01:20.38,0:01:21.72,Default,,0000,0000,0000,,We zoom in a little bit.
Dialogue: 0,0:01:21.90,0:01:23.64,Default,,0000,0000,0000,,We can see that -
Dialogue: 0,0:01:25.47,0:01:27.20,Default,,0000,0000,0000,,I'll give you guys an example here.
Dialogue: 0,0:01:27.21,0:01:28.56,Default,,0000,0000,0000,,So we zoom in a little bit,
Dialogue: 0,0:01:28.59,0:01:31.18,Default,,0000,0000,0000,,I want to talk to you guys\Nspecifically about a river -
Dialogue: 0,0:01:31.20,0:01:33.96,Default,,0000,0000,0000,,you can see these beautiful patterns\Nthat the rivers make
Dialogue: 0,0:01:33.98,0:01:36.08,Default,,0000,0000,0000,,as they're pushing material\Ndown to the sea,
Dialogue: 0,0:01:36.10,0:01:37.72,Default,,0000,0000,0000,,but these patterns aren't static.
Dialogue: 0,0:01:37.74,0:01:40.43,Default,,0000,0000,0000,,These rivers are wiggling\Nand jumping around quite a bit,
Dialogue: 0,0:01:40.45,0:01:42.42,Default,,0000,0000,0000,,and it can have big impacts on our lives.
Dialogue: 0,0:01:42.44,0:01:44.84,Default,,0000,0000,0000,,So an example of this\Nis this is the Kosi River.
Dialogue: 0,0:01:44.86,0:01:47.52,Default,,0000,0000,0000,,So the Kosi River\Nhas this nice c-shaped pathway,
Dialogue: 0,0:01:47.54,0:01:49.100,Default,,0000,0000,0000,,and it exits the big mountains of Nepal
Dialogue: 0,0:01:50.02,0:01:52.16,Default,,0000,0000,0000,,carrying with it a ton of material,
Dialogue: 0,0:01:52.18,0:01:55.15,Default,,0000,0000,0000,,a lot of sediments that's being\Neroded from the high mountains,
Dialogue: 0,0:01:55.17,0:01:57.03,Default,,0000,0000,0000,,and it spreads out across India
Dialogue: 0,0:01:57.05,0:01:58.37,Default,,0000,0000,0000,,and moves this material.
Dialogue: 0,0:01:58.66,0:02:00.96,Default,,0000,0000,0000,,So we're going to zoom in to this area
Dialogue: 0,0:02:00.98,0:02:04.41,Default,,0000,0000,0000,,and I'm going to tell you a little bit\Nabout what happened with the Kosi.
Dialogue: 0,0:02:04.43,0:02:06.100,Default,,0000,0000,0000,,It's an example of how dynamic\Nthese systems can be.
Dialogue: 0,0:02:07.02,0:02:10.60,Default,,0000,0000,0000,,So this is a satellite image\Nfrom August of 2008,
Dialogue: 0,0:02:10.62,0:02:12.32,Default,,0000,0000,0000,,and this satellite image is colored
Dialogue: 0,0:02:12.34,0:02:14.52,Default,,0000,0000,0000,,so that vegetations or plants\Nshow up as green
Dialogue: 0,0:02:14.54,0:02:16.20,Default,,0000,0000,0000,,and water shows up as blue.
Dialogue: 0,0:02:16.22,0:02:19.76,Default,,0000,0000,0000,,So here again you can see\Nthat c-shaped pathway
Dialogue: 0,0:02:19.78,0:02:21.70,Default,,0000,0000,0000,,that this river takes as it exits Nepal.
Dialogue: 0,0:02:22.22,0:02:24.24,Default,,0000,0000,0000,,And now this is monsoon season.
Dialogue: 0,0:02:24.26,0:02:26.76,Default,,0000,0000,0000,,August is monsoon season\Nin this region of the world,
Dialogue: 0,0:02:26.78,0:02:29.68,Default,,0000,0000,0000,,and anyone that lives near a river\Nis no stranger to flooding
Dialogue: 0,0:02:29.70,0:02:33.27,Default,,0000,0000,0000,,and the hazards and inconveniences\Nat minimum that are associated with that.
Dialogue: 0,0:02:33.54,0:02:35.80,Default,,0000,0000,0000,,But something interesting\Nhappened in 2008,
Dialogue: 0,0:02:35.82,0:02:38.72,Default,,0000,0000,0000,,and this river moved in a way\Nthat's very different.
Dialogue: 0,0:02:38.74,0:02:41.74,Default,,0000,0000,0000,,It flooded in a way that's very\Ndifferent than it normally does.
Dialogue: 0,0:02:41.76,0:02:44.52,Default,,0000,0000,0000,,So the Kosi River is flowing down here,
Dialogue: 0,0:02:44.54,0:02:47.12,Default,,0000,0000,0000,,but sometimes as these rivers\Nare bulldozing sediment,
Dialogue: 0,0:02:47.14,0:02:48.40,Default,,0000,0000,0000,,they kind of get clogged,
Dialogue: 0,0:02:48.42,0:02:50.56,Default,,0000,0000,0000,,and these clogs can\Nactually cause the rivers
Dialogue: 0,0:02:50.58,0:02:52.28,Default,,0000,0000,0000,,to shift their course dramatically.
Dialogue: 0,0:02:52.30,0:02:55.16,Default,,0000,0000,0000,,So this satellite image\Nis from just two weeks later.
Dialogue: 0,0:02:55.18,0:02:57.12,Default,,0000,0000,0000,,Here's the previous pathway,
Dialogue: 0,0:02:57.14,0:02:58.76,Default,,0000,0000,0000,,that c-shaped pathway,
Dialogue: 0,0:02:58.78,0:03:00.88,Default,,0000,0000,0000,,and you notice it's not blue anymore.
Dialogue: 0,0:03:00.90,0:03:02.88,Default,,0000,0000,0000,,But now what we have is this blue pathway
Dialogue: 0,0:03:02.90,0:03:05.36,Default,,0000,0000,0000,,that cuts down the middle\Nof the field of view here.
Dialogue: 0,0:03:05.38,0:03:07.72,Default,,0000,0000,0000,,What happened is\Nthe Kosi River jumped its banks,
Dialogue: 0,0:03:07.74,0:03:10.44,Default,,0000,0000,0000,,and for reference,\Nthe scale bar here is 40 miles.
Dialogue: 0,0:03:10.46,0:03:13.98,Default,,0000,0000,0000,,This river moved\Nover 30 miles very abruptly.
Dialogue: 0,0:03:14.66,0:03:17.84,Default,,0000,0000,0000,,So this river got clogged\Nand it jumped its banks.
Dialogue: 0,0:03:17.86,0:03:19.96,Default,,0000,0000,0000,,Here's an image from about a week later,
Dialogue: 0,0:03:19.98,0:03:22.24,Default,,0000,0000,0000,,and you can see\Nthese are the previous pathways,
Dialogue: 0,0:03:22.26,0:03:24.92,Default,,0000,0000,0000,,and you can see this process\Nof river-jumping continues
Dialogue: 0,0:03:24.94,0:03:27.51,Default,,0000,0000,0000,,as this river moves farther away\Nfrom its major course.
Dialogue: 0,0:03:28.02,0:03:30.08,Default,,0000,0000,0000,,So you can imagine\Nin landscapes like this,
Dialogue: 0,0:03:30.10,0:03:32.72,Default,,0000,0000,0000,,where rivers move around frequently,
Dialogue: 0,0:03:32.74,0:03:37.24,Default,,0000,0000,0000,,it's really important to understand when,\Nwhere and how they're going to jump.
Dialogue: 0,0:03:37.26,0:03:41.14,Default,,0000,0000,0000,,But these kinds of processes\Nalso happen a lot closer to home as well.
Dialogue: 0,0:03:41.74,0:03:43.56,Default,,0000,0000,0000,,So in the United States,
Dialogue: 0,0:03:43.58,0:03:47.64,Default,,0000,0000,0000,,we have the Mississippi River\Nthat drains most of the continental US.
Dialogue: 0,0:03:47.66,0:03:50.04,Default,,0000,0000,0000,,It pushes material\Nfrom the Rocky Mountains
Dialogue: 0,0:03:50.06,0:03:51.60,Default,,0000,0000,0000,,and from the Great Plains.
Dialogue: 0,0:03:51.62,0:03:54.84,Default,,0000,0000,0000,,It drains it and moves it\Nall the way across America
Dialogue: 0,0:03:54.86,0:03:56.78,Default,,0000,0000,0000,,and dumps it out in the Gulf of Mexico.
Dialogue: 0,0:03:57.42,0:04:00.88,Default,,0000,0000,0000,,So this is the course of the Mississippi\Nthat we're familiar with today,
Dialogue: 0,0:04:00.90,0:04:02.100,Default,,0000,0000,0000,,but it didn't always flow\Nin this direction.
Dialogue: 0,0:04:03.02,0:04:04.68,Default,,0000,0000,0000,,If we use the geologic record,
Dialogue: 0,0:04:04.70,0:04:07.42,Default,,0000,0000,0000,,we can reconstruct\Nwhere it went in the past.
Dialogue: 0,0:04:08.22,0:04:10.52,Default,,0000,0000,0000,,So for example, this red area here
Dialogue: 0,0:04:10.54,0:04:14.08,Default,,0000,0000,0000,,is where we know the Mississippi River\Nflowed and deposited material
Dialogue: 0,0:04:14.10,0:04:15.74,Default,,0000,0000,0000,,about 4,600 years ago.
Dialogue: 0,0:04:16.34,0:04:18.44,Default,,0000,0000,0000,,Then about 3,500 years ago it moved
Dialogue: 0,0:04:18.46,0:04:20.84,Default,,0000,0000,0000,,to follow the course\Noutlined here in orange.
Dialogue: 0,0:04:20.86,0:04:22.88,Default,,0000,0000,0000,,And it kept moving and it keeps moving.
Dialogue: 0,0:04:22.90,0:04:24.80,Default,,0000,0000,0000,,So here's about 2,000 years ago,
Dialogue: 0,0:04:24.82,0:04:26.52,Default,,0000,0000,0000,,a thousand years ago,
Dialogue: 0,0:04:26.54,0:04:27.76,Default,,0000,0000,0000,,700 years ago.
Dialogue: 0,0:04:27.78,0:04:30.20,Default,,0000,0000,0000,,And it was only\Nas recently as 500 years ago
Dialogue: 0,0:04:30.22,0:04:33.06,Default,,0000,0000,0000,,that it occupied the pathway\Nthat we're familiar with today.
Dialogue: 0,0:04:34.18,0:04:36.12,Default,,0000,0000,0000,,So these processes are really important,
Dialogue: 0,0:04:36.14,0:04:38.100,Default,,0000,0000,0000,,and especially here, this delta area,
Dialogue: 0,0:04:39.02,0:04:42.84,Default,,0000,0000,0000,,where these river-jumping events\Nin the Mississippi
Dialogue: 0,0:04:42.86,0:04:45.68,Default,,0000,0000,0000,,are building land at the interface\Nof the land and the sea.
Dialogue: 0,0:04:45.70,0:04:47.44,Default,,0000,0000,0000,,This is really valuable real estate,
Dialogue: 0,0:04:47.46,0:04:52.72,Default,,0000,0000,0000,,and deltas like this are some of the most\Ndensely populated areas on our planet.
Dialogue: 0,0:04:52.74,0:04:55.20,Default,,0000,0000,0000,,So understanding the dynamics\Nof these landscapes,
Dialogue: 0,0:04:55.22,0:04:58.36,Default,,0000,0000,0000,,how they formed and how they will\Ncontinue to change in the future
Dialogue: 0,0:04:58.38,0:05:00.78,Default,,0000,0000,0000,,is really important\Nfor the people that live there.
Dialogue: 0,0:05:01.58,0:05:03.12,Default,,0000,0000,0000,,So rivers also wiggle.
Dialogue: 0,0:05:03.14,0:05:06.04,Default,,0000,0000,0000,,These are sort of bigger jumps\Nthat we've been talking about.
Dialogue: 0,0:05:06.06,0:05:08.32,Default,,0000,0000,0000,,I want to show you guys\Nsome river wiggles here.
Dialogue: 0,0:05:08.34,0:05:10.88,Default,,0000,0000,0000,,So we're going to fly down\Nto the Amazon River basin,
Dialogue: 0,0:05:10.90,0:05:12.92,Default,,0000,0000,0000,,and here again we have a big river system
Dialogue: 0,0:05:12.94,0:05:17.32,Default,,0000,0000,0000,,that is draining and moving and plowing\Nmaterial from the Andean Mountains,
Dialogue: 0,0:05:17.34,0:05:19.16,Default,,0000,0000,0000,,transporting it across South America
Dialogue: 0,0:05:19.18,0:05:21.86,Default,,0000,0000,0000,,and dumping it out\Ninto the Atlantic Ocean.
Dialogue: 0,0:05:22.66,0:05:27.36,Default,,0000,0000,0000,,So if we zoom in here, you guys\Ncan see these nice, curvy river pathways.
Dialogue: 0,0:05:27.38,0:05:30.36,Default,,0000,0000,0000,,Again, they're really beautiful,\Nbut again, they're not static.
Dialogue: 0,0:05:30.38,0:05:32.12,Default,,0000,0000,0000,,These rivers wiggle around.
Dialogue: 0,0:05:32.14,0:05:35.76,Default,,0000,0000,0000,,We can use satellite imagery\Nover the last 30 or so years
Dialogue: 0,0:05:35.78,0:05:37.92,Default,,0000,0000,0000,,to actually monitor how these change.
Dialogue: 0,0:05:37.94,0:05:42.12,Default,,0000,0000,0000,,So take a minute and just watch\Nany bend or curve in this river,
Dialogue: 0,0:05:42.14,0:05:45.12,Default,,0000,0000,0000,,and you'll see it doesn't stay\Nin the same place for very long.
Dialogue: 0,0:05:45.14,0:05:47.42,Default,,0000,0000,0000,,It changes and evolves\Nand warps its pattern.
Dialogue: 0,0:05:48.94,0:05:51.32,Default,,0000,0000,0000,,If you look in this area in particular,
Dialogue: 0,0:05:51.34,0:05:54.32,Default,,0000,0000,0000,,I want you guys to notice\Nthere's a sort of a loop in the river
Dialogue: 0,0:05:54.34,0:05:55.76,Default,,0000,0000,0000,,that gets completely cut off.
Dialogue: 0,0:05:55.78,0:05:57.36,Default,,0000,0000,0000,,It's almost like a whip cracking
Dialogue: 0,0:05:57.38,0:06:00.06,Default,,0000,0000,0000,,and snaps off the pathway\Nof the river at a certain spot.
Dialogue: 0,0:06:00.46,0:06:02.08,Default,,0000,0000,0000,,So just for reference, again,
Dialogue: 0,0:06:02.10,0:06:07.04,Default,,0000,0000,0000,,in this location, that river\Nchanged its course over four miles
Dialogue: 0,0:06:07.06,0:06:08.74,Default,,0000,0000,0000,,over the course of a season or two.
Dialogue: 0,0:06:09.18,0:06:12.08,Default,,0000,0000,0000,,So the landscapes\Nthat we live in on earth,
Dialogue: 0,0:06:12.10,0:06:14.52,Default,,0000,0000,0000,,as this material\Nis being eroded from the mountains
Dialogue: 0,0:06:14.54,0:06:15.88,Default,,0000,0000,0000,,and transported to the sea,
Dialogue: 0,0:06:15.90,0:06:17.52,Default,,0000,0000,0000,,are wiggling around all the time.
Dialogue: 0,0:06:17.54,0:06:18.100,Default,,0000,0000,0000,,They're changing all the time,
Dialogue: 0,0:06:19.02,0:06:21.48,Default,,0000,0000,0000,,and we need to be able\Nto understand these processes
Dialogue: 0,0:06:21.50,0:06:24.24,Default,,0000,0000,0000,,so we can manage and live\Nsustainably on these landscapes.
Dialogue: 0,0:06:24.26,0:06:27.32,Default,,0000,0000,0000,,But it's hard to do\Nif the only information we have
Dialogue: 0,0:06:27.34,0:06:29.68,Default,,0000,0000,0000,,is what's going on today\Nat earth's surface.
Dialogue: 0,0:06:29.70,0:06:31.76,Default,,0000,0000,0000,,Right? We don't have\Na lot of observations.
Dialogue: 0,0:06:31.78,0:06:36.60,Default,,0000,0000,0000,,We only have 30 years' worth\Nof satellite photos, for example.
Dialogue: 0,0:06:36.62,0:06:39.52,Default,,0000,0000,0000,,We need more observations\Nto understand these processes more.
Dialogue: 0,0:06:39.54,0:06:41.16,Default,,0000,0000,0000,,And additionally, we need to know
Dialogue: 0,0:06:41.18,0:06:44.40,Default,,0000,0000,0000,,how these landscapes are going\Nto respond to changing climate
Dialogue: 0,0:06:44.42,0:06:45.68,Default,,0000,0000,0000,,and to changing land use
Dialogue: 0,0:06:45.70,0:06:48.54,Default,,0000,0000,0000,,as we continue to occupy\Nand modify earth's surface.
Dialogue: 0,0:06:49.26,0:06:51.80,Default,,0000,0000,0000,,So this is where the rocks come in.
Dialogue: 0,0:06:51.82,0:06:54.32,Default,,0000,0000,0000,,So as rivers flow,
Dialogue: 0,0:06:54.34,0:06:57.24,Default,,0000,0000,0000,,as they're bulldozing material\Nfrom the mountains to the sea,
Dialogue: 0,0:06:57.26,0:07:00.72,Default,,0000,0000,0000,,sometimes bits of sand and clay\Nand rock get stuck in the ground.
Dialogue: 0,0:07:00.74,0:07:03.44,Default,,0000,0000,0000,,And that stuff that gets stuck\Nin the ground gets buried,
Dialogue: 0,0:07:03.46,0:07:07.20,Default,,0000,0000,0000,,and through time, we get\Nbig, thick accumulations of sediments
Dialogue: 0,0:07:07.22,0:07:09.24,Default,,0000,0000,0000,,that eventually turn into rocks.
Dialogue: 0,0:07:09.26,0:07:11.84,Default,,0000,0000,0000,,What this means is that we can\Ngo to places like this,
Dialogue: 0,0:07:11.86,0:07:14.56,Default,,0000,0000,0000,,where we see big, thick stacks\Nof sedimentary rocks,
Dialogue: 0,0:07:14.58,0:07:16.08,Default,,0000,0000,0000,,and go back in time
Dialogue: 0,0:07:16.10,0:07:18.84,Default,,0000,0000,0000,,and see what the landscapes\Nlooked like in the past.
Dialogue: 0,0:07:18.86,0:07:20.100,Default,,0000,0000,0000,,We can do this to help reconstruct
Dialogue: 0,0:07:21.02,0:07:25.34,Default,,0000,0000,0000,,and understand\Nhow earth landscapes evolve.
Dialogue: 0,0:07:26.26,0:07:27.88,Default,,0000,0000,0000,,This is pretty convenient, too,
Dialogue: 0,0:07:27.90,0:07:30.88,Default,,0000,0000,0000,,because the earth has had\Nsort of an epic history. Right?
Dialogue: 0,0:07:30.90,0:07:35.72,Default,,0000,0000,0000,,So this video here\Nis a reconstruction of paleogeography
Dialogue: 0,0:07:35.74,0:07:39.36,Default,,0000,0000,0000,,for just the first\N600 million years of earth's history.
Dialogue: 0,0:07:39.38,0:07:41.36,Default,,0000,0000,0000,,So just a little bit of time here.
Dialogue: 0,0:07:41.38,0:07:44.12,Default,,0000,0000,0000,,So as the plates move around,
Dialogue: 0,0:07:44.14,0:07:47.28,Default,,0000,0000,0000,,we know climate has changed,\Nsea level has changed,
Dialogue: 0,0:07:47.30,0:07:50.96,Default,,0000,0000,0000,,we have a lot of different\Ntypes of landscapes
Dialogue: 0,0:07:50.98,0:07:53.72,Default,,0000,0000,0000,,and different types of environments\Nthat we can go back --
Dialogue: 0,0:07:53.74,0:07:55.12,Default,,0000,0000,0000,,if we have a time machine --
Dialogue: 0,0:07:55.14,0:07:56.48,Default,,0000,0000,0000,,we can go back and look at,
Dialogue: 0,0:07:56.50,0:07:58.24,Default,,0000,0000,0000,,and we do indeed have a time machine
Dialogue: 0,0:07:58.26,0:08:01.60,Default,,0000,0000,0000,,because we can look at the rocks\Nthat were deposited at these times.
Dialogue: 0,0:08:01.62,0:08:03.64,Default,,0000,0000,0000,,So I'm going to give you\Nan example of this
Dialogue: 0,0:08:03.66,0:08:05.88,Default,,0000,0000,0000,,and take you to a special\Ntime in earth's past.
Dialogue: 0,0:08:05.90,0:08:09.12,Default,,0000,0000,0000,,About 55 million years ago,\Nthere was a really abrupt warming event,
Dialogue: 0,0:08:09.14,0:08:11.64,Default,,0000,0000,0000,,and what happened was\Na whole bunch of carbon dioxide
Dialogue: 0,0:08:11.66,0:08:13.48,Default,,0000,0000,0000,,was released into earth's atmosphere,
Dialogue: 0,0:08:13.50,0:08:17.36,Default,,0000,0000,0000,,and it caused a rapid\Nand pretty extreme global warming event.
Dialogue: 0,0:08:17.38,0:08:20.04,Default,,0000,0000,0000,,And when I say warm, I mean pretty warm,
Dialogue: 0,0:08:20.06,0:08:23.04,Default,,0000,0000,0000,,that there were things\Nlike crocodiles and palm trees
Dialogue: 0,0:08:23.06,0:08:26.08,Default,,0000,0000,0000,,as far north as Canada\Nand as far south as Patagonia.
Dialogue: 0,0:08:26.10,0:08:29.28,Default,,0000,0000,0000,,So this was a pretty warm time\Nand it happened really abruptly.
Dialogue: 0,0:08:29.30,0:08:30.52,Default,,0000,0000,0000,,So what we can do
Dialogue: 0,0:08:30.54,0:08:33.60,Default,,0000,0000,0000,,is we can go back and find rocks\Nthat were deposited at this time
Dialogue: 0,0:08:33.62,0:08:37.22,Default,,0000,0000,0000,,and reconstruct how the landscape changed\Nin response to this warming event.
Dialogue: 0,0:08:37.66,0:08:39.56,Default,,0000,0000,0000,,So here, yay, rocks.
Dialogue: 0,0:08:39.58,0:08:41.92,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:08:41.94,0:08:43.68,Default,,0000,0000,0000,,Here's a pile of rocks.
Dialogue: 0,0:08:43.70,0:08:45.32,Default,,0000,0000,0000,,This yellow blob here,
Dialogue: 0,0:08:45.34,0:08:47.08,Default,,0000,0000,0000,,this is actually a fossil river,
Dialogue: 0,0:08:47.10,0:08:48.77,Default,,0000,0000,0000,,so just like this cartoon I showed,
Dialogue: 0,0:08:48.79,0:08:52.08,Default,,0000,0000,0000,,these are deposits that were\Nlaid down 55 million years ago.
Dialogue: 0,0:08:52.10,0:08:55.20,Default,,0000,0000,0000,,As geologists, we can go\Nand look at these up close
Dialogue: 0,0:08:55.22,0:08:56.65,Default,,0000,0000,0000,,and reconstruct the landscape.
Dialogue: 0,0:08:57.34,0:08:58.84,Default,,0000,0000,0000,,So here's another example.
Dialogue: 0,0:08:58.86,0:09:01.32,Default,,0000,0000,0000,,The yellow blob here is a fossil river.
Dialogue: 0,0:09:01.34,0:09:02.88,Default,,0000,0000,0000,,Here's another one above it.
Dialogue: 0,0:09:02.90,0:09:06.20,Default,,0000,0000,0000,,We can go and look in detail\Nand make measurements and observations,
Dialogue: 0,0:09:06.22,0:09:07.60,Default,,0000,0000,0000,,and we can measure features.
Dialogue: 0,0:09:07.62,0:09:09.100,Default,,0000,0000,0000,,For example, the features\NI just highlighted there
Dialogue: 0,0:09:10.02,0:09:13.48,Default,,0000,0000,0000,,tell us that this particular river\Nwas probably about three feet deep.
Dialogue: 0,0:09:13.50,0:09:15.60,Default,,0000,0000,0000,,You could wade\Nacross this cute little stream
Dialogue: 0,0:09:15.62,0:09:17.86,Default,,0000,0000,0000,,if you were walking around\N55 million years ago.
Dialogue: 0,0:09:18.58,0:09:21.48,Default,,0000,0000,0000,,The reddish stuff that's above\Nand below those channels,
Dialogue: 0,0:09:21.50,0:09:23.28,Default,,0000,0000,0000,,those are ancient soil deposits.
Dialogue: 0,0:09:23.30,0:09:27.16,Default,,0000,0000,0000,,So we can look at those to tell us\Nwhat lived and grew on the landscape
Dialogue: 0,0:09:27.18,0:09:30.74,Default,,0000,0000,0000,,and to understand how these rivers\Nwere interacting with their floodplains.
Dialogue: 0,0:09:31.78,0:09:36.16,Default,,0000,0000,0000,,So we can look in detail\Nand reconstruct with some specificity
Dialogue: 0,0:09:36.18,0:09:39.04,Default,,0000,0000,0000,,how these rivers flowed\Nand what the landscapes looked like.
Dialogue: 0,0:09:39.06,0:09:41.54,Default,,0000,0000,0000,,So when we do this\Nfor this particular place
Dialogue: 0,0:09:42.26,0:09:43.48,Default,,0000,0000,0000,,at this time,
Dialogue: 0,0:09:43.50,0:09:46.24,Default,,0000,0000,0000,,if we look what happened\Nbefore this abrupt warming event,
Dialogue: 0,0:09:46.26,0:09:49.88,Default,,0000,0000,0000,,the rivers kind of carved their way\Ndown from the mountains to the sea,
Dialogue: 0,0:09:49.90,0:09:55.04,Default,,0000,0000,0000,,and they looked maybe similar to what\NI showed you in the Amazon River basin.
Dialogue: 0,0:09:55.06,0:09:57.52,Default,,0000,0000,0000,,But right at the onset\Nof this climate change event,
Dialogue: 0,0:09:57.54,0:09:59.02,Default,,0000,0000,0000,,the rivers change dramatically.
Dialogue: 0,0:09:59.58,0:10:01.44,Default,,0000,0000,0000,,All of a sudden they got much broader,
Dialogue: 0,0:10:01.46,0:10:05.02,Default,,0000,0000,0000,,and they started to slide back and forth\Nacross the landscape more readily.
Dialogue: 0,0:10:05.98,0:10:09.88,Default,,0000,0000,0000,,Eventually, the rivers reverted\Nback to a state that was more similar
Dialogue: 0,0:10:09.90,0:10:13.72,Default,,0000,0000,0000,,to what they would have looked like\Nbefore this climate event,
Dialogue: 0,0:10:13.74,0:10:15.38,Default,,0000,0000,0000,,but it took a long, long time.
Dialogue: 0,0:10:16.34,0:10:20.20,Default,,0000,0000,0000,,So we can go back in earth's time\Nand do these kinds of reconstructions
Dialogue: 0,0:10:20.22,0:10:22.84,Default,,0000,0000,0000,,and understand how\Nearth's landscape has changed
Dialogue: 0,0:10:22.86,0:10:26.64,Default,,0000,0000,0000,,in response to a climate event like this\Nor a land use event.
Dialogue: 0,0:10:26.66,0:10:28.76,Default,,0000,0000,0000,,So some of the ways that rivers change
Dialogue: 0,0:10:28.78,0:10:33.56,Default,,0000,0000,0000,,or the reasons that rivers change\Ntheir pattern and their movements
Dialogue: 0,0:10:33.58,0:10:37.52,Default,,0000,0000,0000,,is because of things like with extra water\Nfalling on the land's surface
Dialogue: 0,0:10:37.54,0:10:39.48,Default,,0000,0000,0000,,when climate is hotter,
Dialogue: 0,0:10:39.50,0:10:42.04,Default,,0000,0000,0000,,we can move more sediment\Nand erode more sediment,
Dialogue: 0,0:10:42.06,0:10:43.90,Default,,0000,0000,0000,,and that changes how rivers behave.
Dialogue: 0,0:10:44.78,0:10:46.88,Default,,0000,0000,0000,,So ultimately,
Dialogue: 0,0:10:46.90,0:10:49.52,Default,,0000,0000,0000,,as long as earth's surface is our home,
Dialogue: 0,0:10:49.54,0:10:52.92,Default,,0000,0000,0000,,we need to carefully manage\Nthe resources and risks
Dialogue: 0,0:10:52.94,0:10:55.92,Default,,0000,0000,0000,,associated with living\Nin dynamic environments.
Dialogue: 0,0:10:55.94,0:10:59.88,Default,,0000,0000,0000,,And I think the only way\Nwe can really do that sustainably
Dialogue: 0,0:10:59.90,0:11:02.12,Default,,0000,0000,0000,,is if we include information
Dialogue: 0,0:11:02.14,0:11:06.24,Default,,0000,0000,0000,,about how landscapes evolved\Nand behaved in earth's past.
Dialogue: 0,0:11:06.26,0:11:07.48,Default,,0000,0000,0000,,Thank you.
Dialogue: 0,0:11:07.50,0:11:11.94,Default,,0000,0000,0000,,(Applause)