"This is our planet, the Earth." "It's unique in the solar system, perhaps even in the universe." "My name's Iain Stewart and I want to show you how our planet works." "In this series, I'm exploring the four powerful forces that have worked together to create our world." "Wow!" "Volcanoes, the oceans, ice." "But this week it's the atmosphere, the most finely balanced of all the forces," "but the one that has the greatest power over our lives." "It's easy to take the air we breathe for granted." "It's invisible, but we depend on it completely." "The atmosphere creates our climate and protects us against the cold hostility of space, and it provides oxygen to fuel our bodies." "But now our atmosphere is changing..." "My God!" "...with potentially devastating consequences." "Our atmosphere is full of contradictions." "It's immensely powerful and yet it's incredibly sensitive." "It's destructive and at the same time it protects us." "It's essential for all life and yet it was created by life." "Without it the planet would be utterly uninhabitable." "I've come to South Africa for something very special," "a personal tour of the atmosphere." "The air above us is made up of many layers and this is my chance to see what they do." "I'm going to take a ride on a jet, but not just any jet." "This one is one of the fastest planes on the planet." "And, more importantly, it flies high, very high." "This plane is an English Electric Lightning, a legend from the 1 960s, and South Africa is one of the few places where they're still flying." "My pilot today is Dave Stock." "You're going to feel like you're strapped onto the front of a missile." "I don't know if I like that or not." "Part of me likes it and part of it terrifies me." "Look at that!" "STOCK:" "The last of the great Cold War fighters." ""If the canopy does not open..."" "Things like that you really don't want to read, really." "How's the helmet?" "It feels nice, yeah." "We humans are perfectly adapted to survive at ground level, where the air has all the right conditions for life." "It's the right temperature, right pressure and it's got the right mix of gases." "Down here, there's plenty of oxygen about, but after about three kilometres, the air's so thin that there's not enough oxygen to breathe." "So if you didn't have this mask, you'd slip into unconsciousness." "I'd better put it on." "MAN ON RADIO: 1 2 1, continue your approach." "Flight information..." "(STEWART YELLING)" "(EXCLAIMS)" "STOCK:" "Heading 1 50." "STEWART:" "The atmosphere that surrounds our planet is made up of four key layers, each very different." "Although I'm above the clouds, I'm still at the very bottom in a layer called the troposphere." "It's a narrow band, usually little more than 1 0 kilometres thick." "The troposphere is a rich soup of warm moist oxygen-rich air." "It's unstable, chaotic and unpredictable but life depends upon it." "And in just a couple of minutes, I'll be leaving it behind." "Yeah." "STEWART:" "Wow!" "I'm now at 40,000 feet above the Earth." "That's about 1 2 kilometres." "STEWART:" "We're approaching 45,000 feet and we're about to cross an invisible boundary in the atmosphere." "We're leaving behind the first layer, the troposphere, and entering the stratosphere." "A very different place." "Here the air is stable and exceptionally dry, so there's virtually no weather." "The stratosphere is home to the ozone layer which reduces the amount of lethal solar radiation reaching the Earth." "We've reached 50,000 feet, or 1 5 kilometres." "Nearly 90% of the gases that make up the atmosphere are below me." "But the atmosphere stretches on high above me." "It gradually fades away into space which is another 85 kilometres above my head." "This is as high as this plane can take me." "The return to Earth is even quicker than the journey up." "Although my return to reality takes a little longer." "Ah..." "Terra firma, eh?" "Fantastic." "It looks different from here." "My ears!" "But almost 50 years ago, one man went much, much higher than me, and he experienced the atmosphere in a completely different way." "On August 1 6th, 1 960, long before man had set foot on the Moon, military pilot Joe Kittinger took a solo journey to the edge of space." "Not in a rocket, but in a giant helium balloon." "He reached 3 1 kilometres, high into the stratosphere." "That's twice the height that I reached." "Then Kittinger did something astonishing." "He jumped!" "This is the actual moment." "He fell to Earth reaching a speed of almost 1,000 kilometres an hour, and yet he could feel absolutely nothing." "KITTINGER:" "I had no ripple of the fabric on my pressure suit and it was a very weird sensation." "I had no visual reference of anything so I thought I was really suspended in space." "STEWART:" "Only when he re-entered the troposphere, the lower atmosphere, did he experience the deafening but reassuring roar of air rushing past him." "(AIR ROARING)" "Finally, he opened his parachute." "His jump remains the longest freefall in history." "Just 1 5 minutes after he jumped, Kittinger was back on the ground." "Falling from over 30 kilometres high, Kittinger had plummeted through 99% of the gases that make up the atmosphere." "KITTINGER:" "Fifteen minutes before, I had been at the edge of space and now, to me, I was in the Garden of Eden." "We really don't appreciate what a beautiful planet we have." "STEWART:" "Although Kittinger had jumped from high in the stratosphere, he still didn't reach the furthest edge of our atmosphere." "Above are two more protective layers so wispy and tenuous they barely exist, but they're both vital for our planet." "Beyond the stratosphere, at about 50 kilometres, lies the third layer, the mesosphere." "It's this layer that protects us from meteors." "When we see a shooting star, it's actually a meteor burning up high in the atmosphere." "The mesosphere is also home to a strange phenomenon called noctilucent clouds." "They're thin, wispy clouds that can only be seen at sunset when they're illuminated from beneath by the low Sun." "Finally, beginning at 85 kilometres, there's the fourth layer, the thermosphere." "The atmosphere is so thin here that beyond 1 00 kilometres is declared to be the beginnings of space." "It's in this layer that the space shuttle orbits the Earth." "It's also out here that the Sun's lethal solar wind is intercepted by Earth's magnetic field and diverted towards the poles" "creating the aurora." "But there's another way of looking at the atmosphere." "If you could unwrap the atmosphere from the surface of the Earth and put it all into a ball, this is what it would look like." "In fact, the volume of the atmosphere is just 5% of the Earth." "The layer that we spend our lives in, the troposphere, is just a narrow band." "It's that thin blue line around our planet." "It's a finely balanced mixture of different gases essential for life but it also has a physical presence." "To understand the troposphere we live in, you have to think of it not just as a gas, but also as a fluid." "In effect, we live at the bottom of an ocean of air." "Just like water, air has turbulence." "These clouds are formed as the air creates eddy currents flowing around the tips of mountains." "Tornadoes are like giant whirlpools." "And just like the ocean, the troposphere even has waves." "This cloud in Queensland, Australia, is actually the largest wave in the world." "It can reach two kilometres high." "It forms regularly when a band of moist sea air approaches a long straight coastline where it's forced to rise by the land." "As the air cools, it condenses to form a cloud which then rolls inland at 40 kilometres an hour, visible evidence of the ocean of air above us." "And just like any fluid, the atmosphere has a weight." "It presses down on each square centimetre of our bodies with a force of one kilogram." "That's like having a small car parked on your chest." "The only reason that we don't collapse in a heap is because the air inside our bodies balances the pressure outside." "We're like lobsters walking on the sea bed, oblivious to the weight of the fluid above us because we're so adjusted to it." "And if you're still in any doubt about the fluid nature of the atmosphere, some people can even surf on it." "Admittedly, it's a little trickier than traditional surfing, which is why it's best left to an expert like Troy Hartman." "Troy isn't just falling vertically through the air, he can move horizontally, too." "The sky is Troy's ocean." "Whoa!" "Once you come to terms with the idea that the atmosphere is a fluid, you realise it has some extraordinary consequences." "One of them is that Earth's atmosphere is capable of shaping the surface of the planet, even cutting through solid rock." "I'm on my way to a very special place, a place where you can really see how powerful the atmosphere can be." "Only a few people every day are granted the honour of walking the three mile path to get there." "But there's a good reason for that." "This rock formation in Arizona is one of the most precious geological sites on the planet." "Wow!" "Look at this." "It is so beautiful." "It's like being inside a giant sculpture, a geological piece of art." "These rocks are called The Wave." "You can see why." "The giant curvaceous shapes look as if they've been carved out by water." "Instead they've been sculpted by a different fluid motion, the wind." "As it buffets these sandstone rocks, the wind wears away grains of sand, picking them up and carrying them." "And that turns the wind into a giant scouring pad, scratching away at the rock surface and etching out these lines of weakness." "This place has formed over hundreds of thousands of years, which may seem a long time, but in geological terms, this is a blink of an eye, which just goes to show the raw power of the air around us." "It's amazing what the wind can do, and when you look at something like that, you realise the power of the atmosphere." "It's constantly at work, constantly shaping the land." "And this happens all over the planet." "The winds shape the Earth's surface on a massive scale." "Where the winds blow relentlessly from one direction, they can carve giant ridges." "They're called yardangs." "These are in Iran," "while these are in Northwest China." "But this scouring doesn't just shape the land." "It's only the first stage of a process that transports many vital ingredients needed for life all around the planet." "When the wind kicks up in the Sahara desert, huge volumes of sand and dust, rich in nutrients and minerals, are lifted into the air to be blown out across the Atlantic." "Here, much of it falls into the sea where the minerals fertilise the ocean, but some is carried on the wind all the way across the Atlantic" "to the Amazon rainforest of South America." "In fact, a staggering 40 million tons of dust is transported from the Sahara to the Amazon every year." "Here, the rain washes it out of the atmosphere and onto the forests below" "where it's a vital source of nutrients that keep the rainforest healthy." "In this way, the constantly swirling atmosphere plays a critical role in the cycle of life on Earth." "But this constant churning of the air around us is fundamental to how our planet works in another much more direct way." "It creates the weather." "At the heart of everything is heat." "All weather, from the gentlest breeze to the fiercest hurricane, is the result of heat moving in the atmosphere." "This is three months of weather packed into just a few seconds." "The clouds are generated by heat evaporating moisture from the oceans and the land." "The weather patterns that result are complex and unpredictable because of the way the atmosphere interacts with the land," "the sea and even the planet's ice." "To see the clash of these forces at their most extreme," "I'm heading to South America." "(PEOPLE SINGING)" "(WHISTLES BLOWING)" "This is the Festival de la Pachamama." "It's a noisy celebration by villagers here in Purmamarca in Argentina." "There's a serious business to this because this carnival is an offering." "It's a request for a good harvest, and the god that they're pleading to is Pachamama, mother earth, controller of the weather." "(BAND PLAYING UPBEAT TRADITIONAL MUSIC)" "You know, we spend a lot of time talking about the weather, but here they've really got something to talk about because in this part of Argentina they get some of the worst storms in the world." "(THUNDER CLAPPING)" "Scientists work out where the stormiest places in the world are by counting the number of lightning strikes in a year." "It might not look like it, but this region is at the top of the league tables." "It seems curious that the storms should be so bad here." "This is such a peaceful landscape right now, but when you know the clues to look for, this has got everything you need to brew a really rip-roaring storm." "This landscape is the perfect arena for two very powerful masses of air to clash," "each with their own very different qualities." "Here in Argentina, the warm moist air is particularly warm and moist because it's been swept down from one of the stickiest places in the world." "Just to the north of me here is the Amazon basin." "And the cold air is particularly cold because it's being channelled up from the South Pole down there." "This combination is a recipe for trouble." "(THUNDER RUMBLING)" "The extreme turmoil caused by the cold and warm air clashing is what drives a storm." "But there's another feature of this landscape that makes storms particularly frequent and intense in this region." "I'm in the foothills of one of the greatest mountain chains in the world," "the Andes." "These ramparts act as a kind of barrier, trapping this dangerous mixture of warm and cold air in the same place." "And that thunder that you hear is because what's happening is as the cold and warm air masses mix, it's a clash of extremes and this is a battleground." "(THUNDER RUMBLING)" "Storms are gathering in the mountains so that's where I'm heading." "I'm hoping to see some of the lightning this region is famous for." "The problem is while the mountains make this area stormy, they don't make it easy to catch up with the storm." "Right now, all I see is a black sky in front of me." "It's just a wall of dark cloud and dust." "I mean, what we haven't seen is lightning." "I haven't seen any." "Look at that!" "I think I spoke too soon." "It's quite beautiful, actually." "The lightning is just the by-product of the extreme air movements within the storm clouds." "As the moist air rises, it cools and water particles freeze." "Some become small ice crystals, others larger, slushy ice." "These two different types of ice collide and become electrically charged." "An electric field builds up until it becomes so strong" "it reaches for the Earth below." "But far higher in the atmosphere is a much more elusive, much more exotic form of lightning." "They're called sprites." "This is a type of lightning that doesn't strike down towards the ground but instead reaches upwards, sometimes as far as 75 kilometres, high into the mesosphere." "This part of Argentina is a place where storms are particularly intense, but around the globe the atmosphere is constantly in turmoil." "It's constantly churning with the clashes of cold and warm air masses." "We've seen the power of the atmosphere to shape the planet and create the weather," "but it's the relationship between the atmosphere and life that has made our planet unique in the solar system." "To understand how this vital relationship evolved, you have to go back to the very beginning of Earth's long history." "The planet's atmosphere was created shortly after the Earth was formed four and a half billion years ago." "The early Earth was highly volcanic." "And for millions of years, these volcanoes spewed out huge quantities of gas." "Slowly these gases built up and created an atmosphere." "But it was nothing like the atmosphere we know today." "This was a witches' brew of carbon dioxide, methane and steam laced with poisonous hydrogen sulphide." "There was no sign of the gas we humans depend upon, oxygen." "This lethal mix was to endure for something like two billion years" "until something unexpected began to transform the atmosphere.' primitive life." "To see how primitive life changed the atmosphere," "I'm on my way to one of the very few places on Earth where these early life forms can still be found." "Just desert scrub and empty road, welcome to the Australian outback." "It's stifling hot out there." "It must be, I don't know, mid 40s, but the journey is going to be worth it because I'm on my way to see one of the most bizarre sights in the world." "Hey, hey!" "A car." "That's the first car I've seen in about two hours now." "The sea here is full of life, but these creatures aren't what I've come for." "It's these curious lumps I'm interested in." "They're important because every single plant and animal, in fact, every single person on the planet, owes their existence to them." "These bizarre blobs look like boulders washed up on the foreshore but they're not." "They're actually alive." "These lumps are one of the earliest forms of life on Earth." "They're called stromatolites." "For all their importance, they're actually the simplest of life forms, nothing more than bacteria." "When you get up close you can see that it's only the outer part that's alive." "It's a layer of bacteria that secretes a thin film of slime which builds up layer upon layer." "It might not look like it, but these are the most successful life forms on the planet." "You know, us humans have been around for a few million years." "The dinosaurs came and went in two hundred million years." "These stromatolites have been around for 3,500 million years." "That's three-quarters of the age of the planet." "And yet when they first evolved, more than three billion years ago, these simple life forms began the most important transformation the planet has ever seen." "These stromatolites are special because they did something that was quite extraordinary." "As they took in the sunlight and photosynthesised, they broke down the chemical bonds in water releasing something that would completely change the planet." "They released oxygen." "Stromatolites were the first life to photosynthesise and release oxygen into our world." "This led to one of the most profound changes in the history of the Earth." "Ultimately, the planet would have an atmosphere rich in oxygen, but before that could happen, something got in the way." "To see what stopped the oxygen reaching the atmosphere," "I'm heading deep into the Australian outback." "Although this area is dry and dusty now, two and a half billion years ago these rocks were formed beneath the sea" "and they hold the key to what happened to the oxygen." "Back then, the seas were rich in iron that was dissolved in the water." "When the oxygen given off by the stromatolites met the iron, they bonded together." "The result, huge amounts of iron oxide formed, or as we usually know it, rust." "It was this reaction that stopped the oxygen leaving the sea." "The rust fell to the bottom of the sea and it built up as layers." "And you can..." "Oh!" "This is so hot." "You can see these layers right here." "I mean, this is metal, that's why it's so hot." "You can see the layers in the fine colourful banding on this rock." "Here it's on a tiny scale, but on this cliff, it's on a massive scale." "The layers of rust were laid down all across the world, eventually turning into seams of iron ore." "All this iron ore, in fact most of the iron ore mined across the world, only exists because very early life, stromatolites, started filling the seas with oxygen more than two billion years ago." "But that was just the very beginning of how oxygen changed our planet." "The rusting of the oceans could not go on forever." "Eventually, the iron in the sea ran out but the oxygen was still going strong." "It wasn't finished yet." "There was only one place for the oxygen to go." "It left the oceans and filled the atmosphere." "No event has been more important to the story of life on our planet." "The first thing oxygen did was give the planet a vital protective shield, the ozone layer." "It shielded the planet from lethal ultraviolet radiation coming from the Sun, allowing complex life to flourish on the surface of our planet." "The concentration of ozone in the atmosphere is revealed in this colour-coded image." "It shows the massive hole over Antarctica created by our recent pollution." "Fortunately, the hole is shrinking." "But oxygen didn't only protect the planet." "About 600 million years ago, it ended the long reign of the stromatolites and caused a revolution in the development of life." "This is because oxygen is highly reactive and can support far more energetic forms of life than bacteria." "Blessed with an oxygen-rich atmosphere, Earth became home to an extraordinary diversity of complex life." "And, ultimately, to us." "You get an idea of how dependent we are on oxygen when you see how it affects something as basic as human reproduction." "Perched between the peaks of the Andes here in Argentina are some of the highest villages in the world." "Many are over 4,000 metres." "Andean peoples have settled in these high villages for over 1 ,000 years because there's money in those mountains, precious metals like copper, silver and gold." "But when the Spanish arrived in the 1 6th century to cash in on these treasures, they had real problems." "For one thing, they couldn't have children." "Baby after baby was miscarried." "In fact, records show that in the highest Andean town it was 53 years before any of the immigrant Spanish women successfully gave birth." "The problem was the altitude." "Up here, the atmosphere is much thinner." "Oxygen levels are about half what they are at sea level, and you can really feel it." "I've got a splitting headache, keep having to take these deep breaths." "And it was this lack of oxygen that stopped the Spanish from having children." "There just wasn't enough of it getting to the unborn child and so they either died in the womb or shortly after birth." "The newly arrived Spanish, like most people, were used to breathing air at sea level which is 2 1 % oxygen, and the human body has evolved to function at this level." "But in these high-altitude villages, the lower pressure means that oxygen levels are effectively halved." "Over countless generations, the Andeans had adapted to deal with this but the Spanish immigrants struggled." "Quite how this problem was overcome after 53 years is a bit of a mystery, but I reckon it's no more complicated than the Spanish getting it together with some of those local Andean people." "That way the Spanish would get the benefit of the genetic adaptations that the locals had evolved over countless generations to cope with the altitude." "Even Andean peoples wouldn't be able to live permanently above 5,000 metres." "Higher than this and human reproduction is impossible." "In other words, oxygen sets a limit on the very existence of our species." "So life created oxygen and, in turn, oxygen has dramatically extended the possibilities for life." "And you might think that for us there's no more important gas in the atmosphere." "But you'd be wrong." "There are other gases that are every bit as important for our survival on the planet." "These are the greenhouse gases, like carbon dioxide, that, as we've seen, are pumped out from volcanoes." "Without these gases, the average temperature of the planet would fall to 1 5 degrees below freezing." "But now we're releasing extra carbon dioxide into the atmosphere by burning carbon-based fossil fuels like coal and oil and gas." "Throughout Earth's history as carbon dioxide levels in the atmosphere have changed, so has the temperature of the whole planet." "In fact, it's now becoming clear that even relatively small changes in carbon dioxide could begin a chain reaction." "And this would lead to unexpectedly large changes in our climate." "To find out what this might mean for our future, I'm off to Siberia." "I've been travelling for three days, a time difference of 11 hours ahead of London, and out there, for me, is one of the most alien landscapes in the world." "This is one of the remotest and coldest regions on the planet, and yet hidden in this frozen ground is the potential for a climate disaster." "It's called methane, and it's a far more powerful greenhouse gas than carbon dioxide." "And that's what I'm looking for." "In a few places, like along riverbanks and cliffs, where the land slips away it exposes this, the permafrost." "It's nice to get my hands on it." "It's just soil stuffed full of plants, stuffed full of carbon and frozen in ice." "And although it might not look very interesting, this stuff is really important for our atmosphere." "That's because sealed in the permafrost are all the ingredients needed to create methane." "The danger is if the permafrost was to melt as a result of global warming, it could release methane on a massive scale." "This would dramatically accelerate global warming far beyond current predictions." "Worryingly, here in Siberia, there are signs the permafrost is already starting to melt." "Temperatures are rising faster here than anywhere else on the planet." "Three degrees in the last 1 0 years, although you'd never know it." "The best place to see what effect global warming is having on the permafrost is the many lakes found in this region." "And that's what's brought ecologist Katey Walter to this frozen wasteland." "She believes she's already detected the first signs that methane is being released from the permafrost." "Inside the permafrost is a very large volume of dead plants." "And what's happening is that the permafrost is melting and thawing and slumping into the bottoms of the lakes." "Those dead plants thaw out, and they ferment at the bottom of the lake and methane is the by-product." "Methane comes out." "If Katey's right, then we should be able to find methane almost everywhere." "Ah, this is the ice." "I've got to the ice." "Look at that, that's beautiful!" "Oh, there's bubbles." "STEWART:" "The ice is over a metre thick and it's obvious that it's full of bubbles trapped inside it." "The trouble is it won't stay trapped in these bubbles for long." "When the ice thaws in spring, the gas will escape." "Methane is a greenhouse gas that's 2 3 times stronger than carbon dioxide, so we're very interested in understanding how much methane is coming out of these lakes." "STEWART:" "There's one sure way to check just how much methane is in these bubbles because it's highly flammable." "Wow!" "My God!" "Whoo!" "I can't believe it's a fire coming out of ice." "Isn't this amazing?" "It's a bit surreal." "We're on a lake in Siberia..." "Cut into a lake." "...and the lake is burning." "It's pretty amazing, huh?" "It never ceases to surprise me." "STEWART:" "Alarmingly, these bubbles can be found all over the place which means there must be enormous amounts of methane trapped here." "STEWART:" "Okay." "Go." "(BOTH EXCLAIMING)" "You all right?" "You okay?" "Yeah." "You ready?" "Yeah." "That's nice, isn't it?" "This place is just full of these." "(WHOOPING)" "STEWART:" "Fire coming out of ice is one of the most bizarre things I've ever seen, but it has very serious implications." "Methane like that is coming out of lakes right across the area, but that's the problem." "When you add them all together it comes to a huge volume of greenhouse gas entering the atmosphere." "The effects of all that gas could be very dramatic and very fast because it will lead to a chain reaction." "Global warming causes the permafrost to melt." "The more the permafrost melts, the more fermentation happens in the bottoms of the lakes, the more methane comes out which enhances global warming." "And it feeds back onto itself." "And just goes on" "and on and on and on." "That's right." "So, melting, methane, melting, methane." "Right." "It's almost like there's a time bomb waiting to go off." "And it's potentially a very big time bomb." "This great frozen expanse covers an area well over nine and a half million square kilometres, which means, in terms of size, it's bigger than the entire USA." "If the permafrost was to melt, it would multiply the amount of methane in the atmosphere by a factor of 1 0." "That would be certain to speed up global warming, but by how much and with exactly what consequences, no one can really say yet." "It all comes down to the fickle nature of the atmosphere." "A change in one ingredient, like the level of methane, can mean a dramatic shift in climate." "After my experience on the frozen lakes," "I'm heading for the nearest town, Cherskiy." "It's a Soviet-era settlement that's locked in ice for six months of the year." "The people who live here are a reminder that the human race can adapt to cope with an extraordinary range of conditions." "But what we've not had to deal with is a climate that's changing at incredible speed." "It has taken billions of years to create the atmosphere that we have today, and during that time an interdependence between life and the atmosphere has emerged." "But now we are threatening the delicate balance between life and the air that surrounds us." "We're the first species ever consciously to be changing the atmosphere, knowingly warming it on a grand scale." "For Earth, a warmer atmosphere will be nothing new, but for us humans, this is uncharted territory," "because now we're in the vulnerable position of having placed ourselves at the mercy of the most fickle of all forces, the atmosphere." "Next time, the power of ice." "Dynamic..." "STEWART:" "It's beautiful!" "...and destructive." "It has shaped our world, and has even driven the course of human evolution."