Fateful Planet (2024) Season 1 Episode 5 Human Planet
Fateful Planet (2024) Season 1 Episode 5 Human Planet
Just a short time after their appearance, humans become the dominant species on Earth. But despite their success they have to face threats from above and below. Like a super-volcano eruption with devastating consequences for life all around the globe. Or an asteroid coming down over a forest, with a force capable of killing millions of people. With latest technology scientists around the world are working on groundbreaking missions to develop ways to mitigate future catastrophes.
#documentary
Just a short time after their appearance, humans become the dominant species on Earth. But despite their success they have to face threats from above and below. Like a super-volcano eruption with devastating consequences for life all around the globe. Or an asteroid coming down over a forest, with a force capable of killing millions of people. With latest technology scientists around the world are working on groundbreaking missions to develop ways to mitigate future catastrophes.
#documentary
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TVTranscript
00:00Earth is born out of chaos and catastrophe.
00:07Despite such hostile conditions, life emerges on our planet.
00:14But it must withstand deadly disasters again and again.
00:20Planet Earth is a wild world, shaken by unimaginable impacts.
00:29Volcanic eruptions that flood the landscape.
00:34And drastic climate changes that lead to ice ages that freeze the world from pole to pole.
00:43Yet each assault creates a path for something new.
00:48Life always finds a way, despite being constantly put to the test.
00:56Without these catastrophes, life as we know it would not exist on our fateful planet.
01:1366 million years ago, when an asteroid impacted Earth, 75% of all species became extinct.
01:22Including all the non-alien dinosaurs.
01:27The tenacious life that re-emerged in the Cenozoic would ultimately lead to humankind today.
01:35But violent Earth forces and extreme climate changes continue to threaten our path forward.
01:41So scientists must investigate the past to prevent our extinction in the future.
01:49And while we have survived thus far, more dire calamities loom on the horizon that may again threaten all life as we know it.
01:58Including us.
02:04Morocco.
02:06Just two hours west of Marrakech, archaeologists have uncovered the oldest remains of Homo sapiens.
02:13Modern humans.
02:16Professor Abderjali Bouzougar, from the National Institute of Archaeological Sciences and Heritage in Morocco,
02:24hopes that the ancient bones will reveal new information about the development of humankind.
02:30The extinction of the non-alien dinosaurs 66 million years ago,
02:35paved the way to the development of other mammals.
02:39This leads to the development of hominids, including Homo sapiens.
02:45Humankind has had a long evolutionary journey.
02:50Fossil records combined with DNA studies reveal the last common ancestor of both humans and chimpanzees,
02:58lived between 5 and 6 million years ago.
03:02After that, the species diverged.
03:06The hominids developed an upright posture.
03:09This was a critical point in human evolution, because it freed our hands to handle objects.
03:15An upright posture is shared by all hominid species that would appear throughout Earth's history.
03:22Today, only one remains.
03:25Homo sapiens.
03:27To learn more about our early ancestors, Abderjali meets with Professor Abderwahed Ben Nasser,
03:33at the excavation site of Jebel Ihud.
03:36The professor discovered remnants of an ancient human shelter
03:39that also yields groundbreaking information about human evolution.
03:44This is an exact replica of a skull found here by Ben Nasser.
03:49It has rewritten the beginning of our human history.
03:54It's exciting. I'm holding now the oldest example of the Homo sapiens in the world,
03:59because the date is around 315,000 years ago.
04:04We thought that Homo sapiens existed in Africa around 200,000 years ago.
04:09With this new discovery in Jebel Ihud, the scientists pushed back the age of more than 100,000 years ago.
04:17Ben Nasser also found sophisticated tools and weapons from the Middle Paleolithic,
04:23between 250,000 and 25,000 years ago.
04:28They represent a significant step in human evolution.
04:33Proof of the growing intelligence that sets us apart from all other animals on Earth.
04:40In this place there are a lot of fireplaces, and fire was used for many reasons.
04:47One of them was to cook the meat.
04:49It means that we will increase the protein in this food,
04:52which was really very necessary and helpful for the body, but especially for the brain,
04:57which was really something, a huge step in the human evolution in this part of the world.
05:04A larger, more organized brain was key to the next stages of our evolution.
05:12A day's drive from Jebel Ihud,
05:14Professor Bouzougar has found more evidence of increasingly refined evolution in our early ancestors.
05:22Grotte du Pigeon is a cave that was discovered by scientists over a century ago.
05:29This is a treasure trove.
05:31It's helping us to better understand Homo sapiens,
05:34not only from a biological perspective, but also from a social and cultural perspective.
05:43Hi, Miriam. How are you?
05:45I'm good, thank you.
05:47How are you?
05:48I'm good, thank you.
05:49Professor Bouzougar works with Ph.D. student Miriam Benoghadi
05:53to record any archaeological finds in the cave.
05:57Looks like there's something unusual here.
06:04Can you see?
06:06It's perforated.
06:07It's a shellbeak.
06:09The most interesting and fascinating things we found are shellbeaks.
06:14These snails, they are marines, and they came from the coast.
06:18So those people, around 82,000 years ago, they went to the sea to collect these species,
06:26which means that it is really a long distance walking in order to collect such snails.
06:33The closest coastal spot today is about 30 miles from the Grotte du Pigeon.
06:39Bouzougar is certain this is where our ancestors must have collected the shells.
06:46Here on the beach, you would have seen thousands of shells,
06:50but our ancestors collected only tiny shells, because they are only three centimeters.
06:59So they can't be brought to the cave to be consumed by these people.
07:05You had to get thousands of these tiny shells to even get half a kilo of the shells.
07:14So it can't have been a food source.
07:19So the question is, why did our ancestors bring them to the cave?
07:28When the scientists examined the shell beads,
07:31they realized stone or bone tools had been used to perforate them.
07:36This is the first time when Homo sapiens will use something which is not a tool,
07:43but something which probably was decorating their bodies or probably their clothes.
07:49This crafting of shell beads marks significant progress in our evolution.
07:55To make such things like shell beads, you need to be able to talk,
08:01to explain to other members of the group that in one or two days walking from the cave,
08:08there is a coast where these shells are available.
08:13Our ancestors didn't just travel to the coast.
08:17They would migrate out of Africa in search of new food sources,
08:21and their journey would take them to the site of a deadly catastrophe.
08:26It was an event that had potential to cause the demise of humankind.
08:34A world away from Morocco, Antarctica,
08:37holds surprising clues about a calamity our ancestors had to face.
08:43Ice can store vital details about our planet's history over millions of years.
08:50In the 1990s, scientists discovered something astonishing in ice cores,
08:55dating back to 74,000 years ago, extremely high levels of sulfur.
09:02The presence of sulfur was the first indication that something catastrophic might have happened,
09:08and the magnitude of the deposits revealed that it was possibly cataclysmic.
09:14An event of this magnitude had the potential to wipe out our early ancestors,
09:20and perhaps all life on Earth.
09:23Scientists scoured the planet for the possible origin of such a massive eruption.
09:28Their search finally drew them to one of the few features on Earth
09:32capable of producing such an event, the Pacific Ring of Fire.
09:37It's a vast chain of volcanoes that stretches more than 25,000 miles
09:42from the southern tip of South America, along the west coast of North America,
09:47across the Bering Strait, and down into Japan and New Zealand.
09:51The Ring of Fire boasts 75% of all active volcanoes on Earth.
09:57They form a horseshoe-like shape around the edge of the Pacific Ocean,
10:01due to the movement of tectonic plates.
10:05This is a geologically active region where the Pacific plate
10:09slides beneath the surrounding continental plates in a process called subduction.
10:17When the heavy Pacific plate sinks below the lighter continental plates,
10:21pressure turns the dense mantle of the Pacific plate into magma
10:25and pushes it towards Earth's surface.
10:29Over millions of years, this has created the chain of volcanoes.
10:37Sumatra. Indonesia is a country within the Ring of Fire.
10:42It has some of the highest rates of volcanic activity on the planet.
10:48So, geologist Dr. Martin Danizic has come here to search for clues
10:52about what may have happened 74,000 years ago.
10:57His investigation begins at Mount Sinabung,
11:00where a deposit near the active volcano has caught his attention.
11:08I'm using a hand lens to actually check what kind of composition we have in this particular rock.
11:13I can see it's very porous. I can see different minerals here.
11:18This rock is called ignimbrite.
11:22Ignimbrite is a volcanic rock that forms during explosive eruptions.
11:28The large size of this deposit indicates it was produced by a massive event.
11:35But although further analysis reveals that the eruption occurred 74,000 years ago,
11:41the geologist is doubtful it can be tied to the sulfur-heavy cores found in Antarctica.
11:48Danizic believes this volcano is not the culprit.
11:54Sinabung volcano is simply too small.
11:56It's not capable to produce this size of pyroclastic flow.
12:01And what that means is that there must be a gigantic volcano that produced these rocks.
12:11Danizic's search for possible sources of the eruption
12:14leads him to one of Sumatra's biggest landmarks.
12:18This is Lake Toba. It's enormous.
12:21It goes 100 kilometers this way. It's about 30 kilometers wide.
12:27Lake Toba is so vast, it contains an island the size of Singapore at its center.
12:34The island itself is also peculiar,
12:37with sheer cliffs rising unusually high above Lake Toba's surface.
12:45This is Samosir Island. Its highest point is over 1,600 meters.
12:50Now we are at 900 meters.
12:53This can give you an idea of how high the island rises above this lake.
13:00Dr. Danizic is able to access the island's subsurface at a local quarry.
13:06And an outcrop reveals a surprising layer of sediment.
13:10It's actually sediments that form in a lake.
13:13Now, we are probably 400 meters above the current lake level,
13:18so the lake can be seen over here.
13:21But these sediments formed below water, if that makes sense.
13:29The scientist sees only one explanation for this.
13:34The answer is that Samosir Island is a huge block
13:38that used to be below water, and then it was pushed up,
13:43was uplifted by a leftover magma in a magma chamber.
13:47Essentially, we are standing in the middle of a giant volcano.
13:52The extinct volcano is so large,
13:55it's difficult to even recognize it from the ground.
13:58And Lake Toba is the caldera.
14:01And approximately 74,000 years ago,
14:04this volcano produced a gigantic eruption.
14:08We call it supereruption.
14:12Toba exploded in a cataclysmic eruption
14:15that released gas, ash, and magma on an unprecedented scale.
14:21The supervolcano shot more than 1,000 cubic miles of volcanic matter into the sky.
14:27The billowing clouds, heated to over 1,000 degrees Fahrenheit,
14:31spelled death for any vegetation in their path.
14:37When the plume collapsed, it sent more than 8 trillion tons of volcanic material
14:42hurtling towards the ground at over 250 miles an hour.
14:48The lethal pyroclastic flow devastated everything,
14:53The lethal pyroclastic flow devastated everything in its path.
15:01Probably everything within a radius of 100 kilometers
15:05was obliterated by pyroclastic flows.
15:09Volcanic debris spread across the Indian Ocean and into Asia,
15:14covering several million square miles of the planet's surface.
15:19But long-term consequences of the mega-eruption
15:23would be even deadlier than the immediate aftermath.
15:28Sulfur dioxide emitted from the volcano formed a veil around the globe,
15:33blocking out sunlight.
15:35Some scientists believe Earth's temperature dropped by up to 16 degrees Fahrenheit.
15:42On a global scale, it's been proposed that this super-eruption
15:48could have caused a bottleneck in human population,
15:52meaning that the number of individuals living on this planet
15:56would reduce to 3,000 to 10,000 individuals.
16:00If true, humankind came close to extinction 74,000 years ago,
16:05and the theory assumes Africa and Asia sheltered the few survivors.
16:12Back in Morocco, Professor Bouzougar has been investigating
16:16how our ancestors reacted to the super-eruption.
16:21He isn't convinced of the bottleneck theory.
16:26We only found 82,000 years old shell beads,
16:30but we found others which are much younger,
16:33like this one, which is dated to around 70,000 years ago.
16:38This means that the Toba eruption didn't act as a bottleneck for Homo sapiens,
16:43because here what we can see is an evolution of Homo sapiens without the disruption.
16:48While the Toba eruption may not have endangered humankind's survival,
16:53Earth still posed challenges for Homo sapiens.
16:56Evidence of an environmental shift can be found within the cave.
17:01Our ancestors apparently needed to keep warm.
17:05This edge was probably used in order to cut, you know, branches of the trees.
17:12And this is something very new. This is a new technology in this context.
17:17And this shift could be related to a climate change.
17:22To understand how the environment changed,
17:25Professor Bouzougar and his student search for hidden clues.
17:29The researchers want to understand how eruptions can affect the environment,
17:34because during the millennia that followed the Toba super-eruption,
17:38Earth posed new challenges for Homo sapiens.
17:44When analyzing these charcoals,
17:46we understand that in this part of the world, in Africa, the climate was dry.
17:54And if we compare it with Europe during the Ice Age, it's slightly different.
18:03The climate had changed due to the shifting of Earth's position to the Sun.
18:11In the north, glaciers grew.
18:1350,000 years after the Toba eruption, they reached their maximum.
18:20Our early ancestors forged their way through the frozen wilderness of an Ice Age,
18:27sharing the challenges with colossal creatures.
18:31Somehow, humans adapted and thrived.
18:35This Ice Age boasted a surprising array of megafauna.
18:41Majestic mammoths roamed the plains, and saber-toothed cats prowled for prey.
18:49Humans coexisted with these magnificent animals.
18:53Pleistocene cave art reveals the hour ancestors had for these creatures,
18:58as they immortalized their encounters on the stone walls.
19:05As the Ice Age drew to a close, the changing climate altered habitats and transformed landscapes.
19:13Soon, the balance between humans and animals also began to shift.
19:20During the Ice Age, Homo sapiens was hunting megafauna for meat
19:27and to use the hides for shelters or for worms.
19:33And scientists now know that Homo sapiens were sufficiently reproducing,
19:41and by having the size of the population growing, they were in need of more resources, food resources.
19:52The human population was growing, resources were dwindling,
19:57and competition for them, with us, may have caused the numbers of megafauna to decrease.
20:04The huge animals began to disappear.
20:08People hunted the once abundant Ice Age herds, and the animals weren't able to reproduce quickly enough.
20:18Homo sapiens groups survived because they have a long history,
20:23and they were adopting also some kind of hunting strategies which helped them to survive.
20:34The megafauna numbers rapidly declined over about 2,000 years.
20:40Most of the majestic creatures vanished, never to roam the landscape again.
20:48Around 10,000 years ago, ice melted,
20:52which means that Homo sapiens group, they need a new, to adopt a new behavior,
21:00and this behavior will lead to what we know now about storing,
21:06and also about domesticating plants and other animals.
21:12Crop cultivation and the keeping of livestock provided our ancestors with a stable and reliable food supply.
21:21This radical shift from a nomadic hunter-gatherer lifestyle to an agrarian one
21:27would define the Neolithic Revolution.
21:30And when you have this kind of activity, you need private property.
21:36When you got this, you need to build cities, and then you need to defend these cities.
21:46Settlements grew into towns, and then cities.
21:51Trade became vital as civilizations were created.
21:55This was the beginning of the modern world, and it happened quickly.
22:01We have reshaped our planet, and even traveled beyond it.
22:05But regardless of humankind's ingenuity, Earth's primal forces remain beyond our control.
22:19At Gooden Lake, Montana.
22:22We are a success as a species, and we continue to progress.
22:27But on our planet and in the cosmos, unexpected threats to our survival still loom.
22:35These bare trees are silent witnesses to a catastrophe that unfolded here during the summer of 1959.
22:44Seismologist Dr. Jamie Farrell is investigating an event
22:48that was triggered by the ceaseless reshaping of Earth.
22:53On the night of August 17th, there was an earthquake, magnitude 7.3,
22:58that shook the entire region.
23:00Unfortunately, there were some people in the Madison Canyon,
23:03downstream from Hebgen Lake, at a campground,
23:06and just above them, the mountain gave way due to the shaking.
23:10And there was a huge landslide, rock slide, that came down on the campground.
23:18One of America's worst series of earthquakes in this century,
23:21felt throughout the Northwest, centers its force on southwestern Montana.
23:26In Madison River Canyon, 50 million tons of earth and rock,
23:30the top of an 8,000 foot mountain,
23:32thundered across a forest campground in one of the biggest landslides.
23:36So many people were buried underneath that landslide and are still there today.
23:42The event is tragic proof of the immense amount of seismic activity that occurs in this region.
23:50Around 2,000 earthquakes occur here every year.
23:54Many are never even felt.
23:57So right here where we're standing now, we're now at the actual fault scarp here,
24:00from the Hebgen Lake earthquake in 1959.
24:02And what you see here is, you see this big break in the earth here.
24:05And prior to the earthquake, these two levels would have been on the same level.
24:09And instantaneously, as soon as the earthquake happened,
24:12this side here mostly just dropped down along the fault.
24:15So six meters of offset, like that.
24:19But something must have triggered this fatal landslide.
24:23Jamie's research leads him to a huge and famous potential threat nearby.
24:28Yellowstone, the first national park in the world.
24:33Continuous hydrothermal activity beneath the park surface creates a natural spectacle.
24:40But it also hides a potentially lethal catastrophe, much larger than the Toba eruption.
24:47So here we're looking at Grand Prismatic Spring.
24:49This is one of the iconic hot springs in Yellowstone National Park.
24:52It's one of the largest hot springs in the world.
24:54And this is one of many of the thermal features here we have in Yellowstone.
24:58We have over 10,000 thermal features here in the park.
25:03The incredible attractions draw millions of visitors every year.
25:08But while they are stunning, the hydrothermal vents and pools can quickly become dangerous.
25:16Geologic activity in Yellowstone must be closely monitored.
25:20One of Jamie's roles is to probe the source of the hydrothermal springs and geysers.
25:28So my job as a seismologist is to monitor Yellowstone for seismic activity.
25:35We have about 40 seismometers running in Yellowstone all the time.
25:40So this is a map of all the earthquakes that have been located in the Yellowstone region
25:44from the 70s to the 90s.
25:46And this is a map of all the earthquakes that have been located in the Yellowstone region
25:50from the 70s to the present.
25:52And what you can see here, the green outline here, this is Yellowstone National Park.
25:56And each one of these dots represents one earthquake.
25:58There's over 50,000 earthquakes on this map that we've located from the 70s to now.
26:06The seismometers record even the faintest ground movement.
26:11So we can use data recorded on these instruments to find out that, you know,
26:14about five kilometers beneath our feet in Yellowstone, there's a magma reservoir.
26:17There's molten material beneath us.
26:20That's, you know, that's feeding all the things that we see in Yellowstone,
26:23the thermal features, the earthquakes, the ground deformation.
26:27That's what's the source of all that change that we can see.
26:31Yellowstone's intricate network of hot springs is fueled by magma stored below Earth's surface.
26:39The magma is also responsible for pressure changes that lead to the region's numerous earthquakes.
26:47Three miles below the landscape, the molten rock lies in a chamber nearly 55 miles long and 25 miles wide.
26:56It is the source for one of the largest volcanoes in the world, a supervolcano like Toba.
27:04We're standing right now on the north rim of the Yellowstone caldera.
27:08And down there to our south, about 40 kilometers where you can see those snow-covered mountains,
27:13that's the southern edge of the caldera.
27:15So this is a good perspective of just how massive this caldera is.
27:19And this is the reason why, you know, a lot of people don't realize, you know,
27:22they're asking where the volcano is, but they've been in it most of the time.
27:27This giant chamber holds a huge amount of magma.
27:31So with the scale you can see here, the magma reservoir is about the same size as the caldera that you can see behind me right here.
27:37And the amount of material that's down in there is kind of mind-boggling.
27:41There's enough material down there that if you took all of it, you could fill the Grand Canyon about 10 or 11 times.
27:48But where does all the magma come from?
27:51While Toba and many other volcanoes were formed from subduction at the boundary of tectonic plates,
27:58Yellowstone is different.
28:01This volcano is unusual because it formed in the middle of a plate.
28:06Underneath the plate lies an anomalous hotspot, much warmer than the surrounding mantle.
28:12Plumes of magma from the hotspot rise towards the surface to feed the reservoir beneath Yellowstone.
28:20Scientists need to know if the Yellowstone supervolcano poses a threat today.
28:26Humankind survived the aftermath of a superexplosion in the past.
28:31But what about in the future?
28:33Volcanologist Dr. Madison Myers is investigating Yellowstone's past
28:38to learn more about the destructive power this volcano might be capable of.
28:45A volcanologist's job essentially is to look at rocks, try to understand what happened in the past,
28:50and then try to figure out what could happen in the future.
28:54Yellowstone's rocks reveal that the volcano erupted multiple times over millions of years.
29:00Most eruptions were minor, but two were devastating.
29:05So by studying the deposits around Yellowstone,
29:08we're able to tell that there was actually two large supereruptions that occurred here.
29:12The oldest, at 2.1 million years ago, is the Huckleberry Ridge Tuff, erupted around 2,500 cubic kilometers.
29:19And then the younger one, at 630,000 years ago, is the Lava Creek Tuff,
29:23which formed the Yellowstone caldera, which we can see here.
29:26We're actually sitting on the caldera edge right now.
29:30Nearly 250 cubic miles of material was ejected by Yellowstone's most recent eruption.
29:37Ignobrites, ash, and quartz crystals are still found throughout the area.
29:43These remnants of the enormous event show that it dwarfed the most violent catastrophes in modern history.
29:51Well, if you think of Mount St. Helens, Mount St. Helens was this enormous, extremely impactful volcano,
29:57and you can imagine just the plume going up, the devastation that happened in the forest.
30:03That was one cubic kilometer.
30:05So if you have the ability to expand that by multiplying it by a thousand,
30:09that's what the Lava Creek Tuff eruption was like.
30:14The landscape was in upheaval because of this eruption, and eventually the entire region collapsed.
30:22Now, researchers wonder if a similar explosion could happen again.
30:29There's no reason to think that it couldn't happen again.
30:32We do have like a chain of essentially volcanic centers leading up to this
30:36that have shown that multiple large eruptions have happened.
30:39So it is very feasible that in the future you might have a super eruption.
30:44To potentially forecast how much warning time we'd have before a catastrophic eruption,
30:50Dr. Myers examines the ancient volcanic deposits for clues.
30:57So with the rocks that we take back to the lab, we're able to look into them and kind of dissect what their histories were.
31:04So we use different instrumentation to try to image it, try to get a picture of what was happening.
31:10She is focused on tiny crystals within the rocks, which are snapshots from the last major eruption.
31:16They record details, much like the rings inside a tree trunk.
31:21So in trees, you see these different zones that are representing growth of the tree's life.
31:27The same thing is true for crystals. They record the different kind of phases of their life.
31:32And so by looking at these different zones, we can see, oh, this eruption actually was triggered.
31:40Based on her research, Madison is certain that geologists will be able to predict an impending super eruption well in advance.
31:50Volcanic systems often have warning signs, and the more you monitor them, the more warning signs they often give.
31:56And Yellowstone is one of the best monitored volcanoes in the United States, so it's going to give off plenty of warning signs.
32:01Likely for the same kind of decades to century-long timescales that the crystals are recording,
32:06because the crystals are recording changes in pulses of magma coming in. That's an earthquake.
32:11So we would have signals that we could use to understand that unrest was happening.
32:19Seismologist Jamie Farrell is also on the lookout for these signs.
32:25The main things that we would look for, the main things that we monitor for here in Yellowstone are increased seismic activity,
32:31increased ground deformation, and then changes in the gas output in Yellowstone.
32:37So we would look for those three things.
32:39If one of those things changes, that doesn't necessarily mean anything's out of the ordinary.
32:43But if all three things happen at the same time, and they're all pointing to the same thing,
32:47then we would know, OK, maybe magma's moving up into the shallow crust. It might make it to the surface.
32:52Let's look at this deeper.
32:54The scientists know that if a super-eruption does occur, it would have catastrophic consequences.
33:01Yeah, another super-eruption would change our world completely. I mean, it would have at least decades of impact.
33:07One thing we would definitely have, we'd have a big explosion.
33:10It would eject a lot of material, a lot of ash.
33:13We would have a lot of ash fall in the surrounding areas.
33:15We would have pyroclastic flows coming out from the plume, devastating the area around here in the park.
33:22The effects of such an eruption would reach far beyond North America.
33:28These large-volume eruptions are going to have devastating consequences.
33:32They shoot these huge plumes way up into the stratosphere that likely cycle the world multiple times,
33:39leading to this global winter where vegetation's going to struggle, animals will struggle.
33:45And so it would be a completely devastating and life-altering event.
33:49I would say that it's probably one of the top things that could threaten humankind.
33:54It would be a global catastrophe, far greater than the Toba eruption, that would endanger all life on Earth once again.
34:06But life on our planet isn't just threatened by disasters created by Earth's processes.
34:13In 2013, residents of Chelyabinsk, Russia, witnessed a dramatic event.
34:19The sky blazed as an asteroid entered Earth's atmosphere.
34:24Caught on dash cams and surveillance videos, people were stunned.
34:32Foscati, Italy.
34:34The European Space Agency is one of the few organizations dedicated to monitoring space hazards.
34:42Dr. Richard Meusel, head of planetary defense, has been studying the Chelyabinsk event in detail.
34:50We know that the impactor had about a diameter of 20 meters.
34:55The asteroid approached with an estimated velocity of over 66,000 kilometers a second.
35:01The damage went into the millions.
35:03Unfortunately, many people got hurt.
35:06In total, there were more than 1,400 people injured.
35:10But we can consider this even a lucky event,
35:13because the energy deposited in the atmosphere was several times that of the Hiroshima bomb.
35:21Things could have been much worse.
35:24With a diameter of 65 feet, this asteroid is tiny compared to those that impacted Earth in the past.
35:3366 million years ago, an asteroid with a diameter of around 6 miles struck Earth.
35:40Instantly, the energy of billions of nuclear weapons was released when the impactor vaporized,
35:47melting the bedrock into molten plasma.
35:51The resulting thermal radiation, earthquakes, and tsunamis wreaked havoc around the globe on an unprecedented scale
35:59and was one of the most disastrous events in Earth's history.
36:04The impact caused a chain reaction of horrific events that caused the extinction of 75% of all species alive at the time.
36:26Asteroids remain among the biggest threats to our planet.
36:31There's a lot of stuff out there.
36:33Today, we know more than a million asteroids already, which are out there.
36:37But of these, 30,000 are especially interesting because they come close to Earth.
36:42That's what we call the near-Earth objects, and these are the ones of particular interest to us.
36:47We track them as much as we can, but we don't only determine their orbits where they are at the moment.
36:53We determine their paths up to 100 years into the future and check if they actually will become a danger to us one day.
37:01Fortunately, most of these asteroids are only a few inches to a few yards in diameter.
37:08Every day, more than 100 tons of harmless debris and dust from space bombard our planet.
37:18They usually burn up in the atmosphere as shooting stars, creating a spectacle, nothing more.
37:25But once in a while, asteroids come along, which are bigger in size and do pose a danger.
37:33This is what happened in Tunguska, a remote forested region of Siberia.
37:39A monster explosion caused one of the most devastating impacts in human history.
37:45On the morning of June 30, 1908, a massive event shook the landscape.
37:51Brilliant lights illuminated the sky and were seen as far away as the UK.
37:58The first scientific expedition to examine the resulting damage didn't occur until 1927.
38:07Footage taken at the location shows widespread destruction.
38:13Over 80 million trees were flattened and a 1,250 square mile area of forest was destroyed.
38:23But despite the devastation, there was no sign of an impact crater.
38:28And scientists could not determine where the asteroid struck.
38:36So there has been no conclusive answer to what caused the Tunguska event to date.
38:40But the most probable explanation still remains to date.
38:45An impact of a very porous body with low density that caused an airburst of the magnitude that we observe here.
38:55When an asteroid enters Earth's atmosphere, it creates an airburst.
39:01Because the impactor travels at high velocity, pressure builds in front of it
39:06until the asteroid bounces off its target or breaks apart.
39:11When this happens, energy is released in a huge burst of light and heat,
39:17which causes immense destruction on the ground surface.
39:22Luckily, this event didn't cause any confirmed casualties.
39:27But it would be a completely different story if something like this were to happen over a densely populated area or a big city.
39:34At the European Space Agency, the planetary defense team regularly simulates emergency scenarios,
39:40so they will be prepared if an asteroid threat becomes a reality.
39:46We've taken the data from the Tunguska simulations and projected them right over Manhattan.
39:52The software now shows us the impact effects at the location.
39:57A Tunguska-sized asteroid about 160 feet wide would demolish the metropolis.
40:03Even after it broke apart 20 miles above Earth.
40:10The blast wave would shatter all windows, would damage all buildings,
40:14not build out of reinforced concrete to a considerable degree.
40:18Many people would die and millions would be affected and injured.
40:24The blazing heat would destroy block after block, affecting most of New York City.
40:31An asteroid strike like this would be a tremendous catastrophe for humankind.
40:38These things are the reason why we have developed early warning systems,
40:43so that we can notify the authorities ahead of time, so that in turn they can step in
40:48and evacuate the affected areas, thereby saving up to millions of lives.
40:53Once an asteroid is spotted, it is ranked and added to the asteroid risk list.
40:58The more Richard and his team can learn about the asteroid's potential path,
41:03the better they can determine if it will strike our planet.
41:07But is there anything that can be done if a dangerous asteroid is heading straight for Earth?
41:14In 2021, the European Space Agency teamed with NASA
41:19to launch what became known as the DART mission, or the Double Asteroid Redirection Test.
41:26The goal was to prevent asteroids that might pose imminent threats from hitting Earth.
41:32The DART probe mission planned to rendezvous with a double system,
41:37consisting of the asteroid Didymos and its moon Demorphis.
41:41This was the first attempt in space exploration to change the course of an astronomical body.
41:48The plan was to send a probe that would deliberately collide with the asteroid.
41:54During its final approach, DART transmitted a live stream of images
41:59while it was homing in on the double asteroid system.
42:03This is footage that has never seen the likes before.
42:06We first see how DART is closing in on the double asteroid system,
42:11then passing by the primary, the big one, zooming in ever closer on the small one, on Demorphos.
42:17Finally, the small one fitting the field of view until, bam, DART hits the asteroid and the transmission ends.
42:26The test was successful.
42:29But would the technology be sufficient to save us?
42:33The course of the asteroid was indeed changed for the first time in human history.
42:38At first, it would only move by a fraction of a millimeter.
42:42But in time, if an asteroid is hit early enough, when it still has billions of kilometers to go to reach its target Earth,
42:51a tiny distance can grow in time to be thousands of kilometers,
42:56turning a potential impact of a killer asteroid into a harmless flyby.
43:02Emergency strategies developed by the planetary defense team, combined with ever-advancing technology,
43:08could potentially divert a rogue asteroid to prevent the extinction of humankind.
43:16But even if we can avert threats from space and from within the Earth itself,
43:22humans pose a growing menace to our own survival.
43:27Rhone Glacier, Switzerland.
43:30The Swiss Alps are a relic from the last glacial period.
43:33As the head of the Swiss Glacial Monitoring Network,
43:37Dr. Matthias Huss from the Swiss Federal Institute of Technology in Zurich
43:42regularly checks on the conditions of the glacier.
43:46This glacier, like all glaciers in the Alps and worldwide, has receded considerably.
43:52Twelve years ago, it extended all the way to the end of the lake here, which didn't exist at the time.
43:58Now the glacier has retreated.
44:00Its thickness has decreased dramatically.
44:04Dr. Huss is worried about the extent of the changes,
44:08so he has set up a monitoring system to record the rate of the glacial melt.
44:19We have had so-called glacial selfie sticks on this glacier for several years now.
44:25They take a picture of the glacier every hour,
44:27which allows us to see how much it melts from day to day.
44:33The stick is firmly embedded in the ice.
44:36As the ice melts and the camera sits on the surface,
44:40it looks as if the stick is growing out of the ice.
44:46High-resolution cameras capture the rate at which the ice is receding.
44:52The glacier surface decreases a lot throughout the year.
44:55We lose around 20 to 26 feet of ice annually in this area.
45:01The Rhône glacier is only one glacier that is melting.
45:05At the current rate, around two-thirds of the continent's current glacial cover
45:10will be lost by the end of the century.
45:15Natural variation in ice volume is to be expected.
45:19Since the beginning of the last ice age,
45:21this glacier has grown and shrunk.
45:24Normal for such an immense body of ice.
45:27But what we are seeing now is different.
45:33The warming we had until a few hundred years ago was natural,
45:37due to solar radiation and other factors.
45:40But what we are witnessing now is man-made climate change.
45:43Human actions like burning fossil fuels, industrialization,
45:48deforestation and intensive agriculture
45:52have all created a tremendous increase in greenhouse gases.
45:57The massive amount of CO2 we relentlessly pump into the atmosphere
46:02is warming our planet at an alarming rate.
46:05The climate is changing.
46:07Glaciers are primary indicators of climate change.
46:11They clearly demonstrate the consequences of rising temperatures
46:15as ice melts with warmer weather.
46:18Everyone understands that.
46:21You don't have to be a scientist to realize that.
46:24But what we are seeing now is a huge increase in global warming.
46:28And this is not just due to climate change.
46:31It is also due to global warming.
46:33Everyone understands that.
46:36You don't have to be a scientist to realize that.
46:39The changes seen here are impressive.
46:42Within a single generation, the alpine landscape has completely changed.
46:47Globally, the melting of this glacier in the Alps may seem insignificant.
46:52However, if all glaciers worldwide,
46:55along with the large polar ice caps melt,
46:58sea levels will rise.
47:00This poses one of the greatest long-term threats to life on Earth
47:05and to the way we currently live.
47:09Since industrialization began,
47:12global warming has caused sea levels to rise by nearly 8 inches.
47:16By the end of this century, they could rise over 3 feet.
47:21Mega cities like Jakarta, Indonesia, could be swallowed by the sea.
47:26Coastal settlements would be lost,
47:28and even further inland, the severe effects would be felt.
47:35We're talking about heavy rainfall, floods.
47:38We're talking about droughts and heat waves
47:41that will become much more frequent in the future.
47:44All of this renders regions uninhabitable.
47:47We will witness climate refugees and perhaps wars over water in the future
47:52as a result of very, very significant consequences.
47:56Far-reaching consequences that humanity must somehow get control of.
48:03Global warming will cause natural disasters
48:07like hurricanes, floods and droughts to increase.
48:11Fresh water is becoming increasingly scarce,
48:14and famine is on the rise.
48:18Forced migration and unrest leading to wars could result.
48:23Between 3.3 and 3.6 billion people on Earth
48:27are extremely vulnerable to the negative consequences
48:31brought about by climate change.
48:36The problem lies primarily in the extreme velocity
48:40at which we can now observe man-made climate change.
48:43We are transitioning from one dimension
48:46to a completely different one within a generation or two.
48:49Adapting to this is incredibly difficult
48:52and represents the greatest challenge humanity will be facing in the coming decades.
49:00Yet Dr. Huss remains optimistic.
49:04While humans are the cause of this problem,
49:07we also have the tools to create the solution, if we act soon.
49:14We actually have a choice now.
49:17We still have it in our hands to set the direction
49:19in which our planet is moving and whether it will remain habitable in the future.
49:26We still have a few decades to make this course correction,
49:31and I hope that we can achieve this as a global community.
49:37Earth now has more than 8 billion people,
49:41and collectively our existence has caused the demise of many other species.
49:46The current rate of extinction is higher
49:49than any of those seen during the last five major mass extinctions.
49:55If Earth continues to grow warmer, this rate will accelerate.
50:00Some scientists believe that we are already experiencing a sixth mass extinction,
50:06and it is one that might eventually include humankind.
50:11But as Earth stewards, we can learn from the past.
50:15While using technology now and in the future
50:19to protect our planetary home for ourselves and other species.
50:26The future of life on our fateful planet now rests in our hands.
50:32It's up to us whether we are a part of it.
50:45NASA Jet Propulsion Laboratory, California Institute of Technology
51:15NASA Jet Propulsion Laboratory, California Institute of Technology