"This is our planet, the Earth." "It's unique in the solar system, perhaps even in the universe." "My name is Iain Stewart and I want to show you how our planet works." "I'm exploring the atmosphere." "The atmosphere creates our climate and protects us against the cold hostility of space." "And it provides oxygen to fuel our bodies." "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." "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 1960s, 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 kilometers the air's so thin, if you didn't have this mask, you' d slip into unconsciousness." "I' d better put it on." "MAN ON RADIO: 121, continue your approach." "Flight information..." "(STEWART YELLING)" "(EXCLAIMS)" "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 more than six miles thick." "The troposphere is a rich soup of 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." "And now I'm 40,000 feet above the Earth." "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." "Nearly 80% of the mass of gases that make up the atmosphere are below me." "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 16th, 1960, long before man had set foot on the Moon, military pilot Joe Kittinger took a solo journey to explore the heavens." "Not in a rocket, but in a giant helium balloon, to determine the risks of high-altitude bailouts from air or spacecraft." "The balloon took Kittinger over 19 miles 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 620 miles an hour" "and yet he had no sense of speed." "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:" "Kittinger had fallen at great speed as he plunged toward the troposphere, thick with clouds, floating over a New Mexico desert." "(AIR ROARING)" "Finally, he opened his parachute." "His jump remains the longest freefall in history." "Just 15 minutes after he jumped, Kittinger was back on the ground." "Falling from the upper reaches of the stratosphere," "Kittinger had plummeted through 99% of the atmosphere's mass." "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 the stratosphere are more protective layers so wispy and tenuous that they barely exist, but are vital for our planet." "About 30 miles beyond the stratosphere lies the third layer the mesosphere." "It's this layer that helps protect 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 in the summer at high latitudes." "Beginning at nearly 50 miles high, there's the fourth layer the thermosphere." "Here, the atmosphere is so thin that beyond 50 miles we approach the beginnings of space." "The space shuttle orbits the Earth in the thermosphere." "It's also where nitrogen and oxygen interact with the Sun's lethal solar wind," "creating the aurora around the Earth's poles." "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." "Its weight is equal to a layer of water 34 feet deep, covering the Earth." "The layer that we spend our lives in, the troposphere, is just a narrow band." "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 gases, 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 one of the largest waves in the world." "It can reach to over a mile high." "It's a solitary tropospheric wave that combined with the humidity in the region takes the form of a visible cloud." "As the air cools, it condenses to form a cloud that rolls inland at 2 5 miles 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 of our bodies with a force of over 1 4 pounds per square inch." "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 realize 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 honor 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 in Arizona are known as The Wave." "And it's easy to see why." "These 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 the sandstone rocks, the wind picks up grains of sand, and becomes a giant scouring pad, ." "scratching away at the rock surface and etching out these lines." "The Wave has formed over hundreds of thousands of years." "It may seem a long time, but in geological terms, that's the blink of an eye." "Which just goes to show the raw power of the air." "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 dust, rich in minerals, are lifted into the air to be blown out across the Atlantic." "Here, much of it falls into the sea." "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 minerals that keep the rainforest healthy." "In this way, the constantly swirling atmosphere plays a critical role in the cycle of life on Earth." "It creates the weather." "At the heart of all weather is heat." "This is three months of weather packed into just a few seconds." "The clouds are generated by 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 Argentina." "(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)" "This part of Argentina they get some of the worst storms in the world." "(THUNDER CLAPPING)" "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 channeled 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." "Look at that!" "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" "that's been caught on film." "They're called sprites." "This is a type of lightning that doesn't strike down towards the ground but instead reaches upwards within the mesosphere," "30-50 miles high." "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 probably highly volcanic." "And for millions of years, these volcanoes spewed out huge quantities of gas." "Slowly these gases built up and created the 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 primitive life began to transform the atmosphere." "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." "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 almost three billion years ago, these simple life forms began one of the most important transformations the planet has ever seen." "These stromatolites are special because they did something that was quite extraordinary." "As they took in the sunlight and photosynthesized, they broke down the chemical bonds in water releasing something that would completely change the planet." "They released oxygen." "The bacteria forming the stromatolites were the first life to photosynthesize and release oxygen into our world." "This led to one of the most profound changes in the history of 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 colorful 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, much 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 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 color-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 stromatolite 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 some idea how dependent we are on oxygen when you see how it affects something as basic as human reproduction." "This is the village of Aruya, perched high in the Andes." "It's one of a string of villages in this area that are some of the highest in the world." "Many are close to 10,000 feet above sea level." "Andean peoples have lived here for generations." "But when the first Spanish colonists arrived, they faced a problem, they couldn't have children." "Baby after baby miscarried." "It took almost 50 years before any of the immigrant Spanish women gave birth." "The problem may have been a lack of oxygen." "The newly arrived Spanish, like most people, were used to breathing air at sea level, which is 21 % oxygen." "But up here, the oxygen levels are effectively almost halved." "The Andeans had adapted to deal with this but the Spanish struggled." "Nobody knows quite how the Spanish overcame this problem but it's probably no more complicated than having children with the locals." "Even Andean peoples wouldn't be able to live permanently above 5,000 meters." "H igher 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 nearly 27 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." "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 is 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." "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." "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." "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 three feet thick and 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." "Alarmingly, these bubbles can be found all over the place which means there must be enormous amounts of methane trapped here." "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." "If the permafrost was to melt, it would significantly increase the amount of methane in the atmosphere." "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." "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." "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." "Now we` re in the vulnerable position of having placed ourselves at the mercy of the most unpredictable of forces, the atmosphere."