# What impact would a dragon the size of Asia have on the environment?

Without going into unnecessary detail, one of the races of my world believe that the land itself is a dead god, and that by resurrecting it, it will ascend to the cosmos and carry the faithful upon its back. The form they choose to represent this great god is born out of their own image, and represented by a great winged dragon.

So this eschatological event is of course purely religious fiction, but let's say it isn't. Let's say that this would absolutely happen, and that a massive, continent-sized dragon (let's say for now the size of Asia) that could propel itself through flight wasn't out of the question. So it would be as if all of Asia was suddenly ripped up from the Earth and flung into space. What would be the environmental effects of such a creature's flight?

• Comments are not for extended discussion; this conversation has been moved to chat. – Monty Wild Jul 17 '19 at 0:38
• I would recommend a planet a billion times bigger than Earth for such a large creature, especially when you'll need to explain the origins of something that is ~30000 times taller than Godzilla Earth itself. – Cœur Jul 17 '19 at 4:39
• Does it even "fly"? We have this little convention to consider "space" anything higher than 100Km, and you don't actually "fly" in space. We can currently fly up to 25km, but only with supersonic jets, we can't fly helicopters higher than 12Km, for instance. 12Km of "air" for an as-wide-as-Asia beast? 44.5 MILLIONS km² vs 12Km of available height? Can you swim in 1mm puddle? It's an unfolded origami dragon??? ^_^ – theGarz Jul 17 '19 at 11:10
• I think the worst part would be when this continent-sized dragon poops - one bowel movement would make the Mediterranean Sea uninhabitable. – RobertF Jul 17 '19 at 18:33
• How dense is the dragon? What, exactly, do you mean when you say "dragon the size of Asia" (Asia is much much much wider than it is thick, something that probably isn't true for a dragon)? – Vikki - formerly Sean Jul 17 '19 at 21:45

A dragon with a full wingspan of 20000 km (folded to fit into a 10000 km resting area) and surface area of 44 million sqkm will have a terrible impact on the environment.

Phase I

In the first days of her awakening, as she shifts, freeing herself from the encumbrance of all the cities and forests and so forth that are littering her back, widespread but relatively shallow quakes will be felt all around the perimeter. It will be quite a ride for those residing on her back! Cities will be thrown down, forests toppled, hills broken and everything will begin a terrific slide towards the edges of the Beast. Initially, small tsunamis will race across the Indian, Pacific and Arctic Oceans and the Black and Red Seas as well, as the earth of India, Arabia, northern Siberia and Eastern Asia begins to slough off. With a coastline of 63000 km, she might slough off a 1 km wide by say 100m deep ring of rubbish. This will dump 6300 cukm of rock, earth and debris into the coastal waters. I don't know the equations to model a tsunami of this size, but can imagine that most coastal areas will be considerably dampened!

Phase II

These next weeks to months will be very exciting for everyone on the planet. As the dragon lifts herself up, the mountains and earth upon her back and wings will begin a catastrophic and precipitous slide down her flanks and the dorsal surfaces of her wings. Since she's been sleeping for, like, forever, she's got quite a bit of accretion on her back. This larger slide will be composed of about 2,199,517,610 cukm of rubble --- mountain chains, accreted bedrock, soil, destroyed infrastructure and natural debris. Perhaps a quarter or third of this volume will in fact make it to her periphery in time to rain down upon the churning ocean waters below.

At this point in time, she's lifting up the edges of her wings and beginning to raise her own voluminous body. Ocean water will begin to rush into the verges, creating a muddy slurry all around her perimeter.

As she stands, her hundred km thick body will begin to rise up, lifting and rippling the underlying 50km of continental plate beneath her, much like the way, when you get out of bed in the morning, the sheets become crumpled and rippled. Contrary forces --- the release of pressure upon the mantle will cause the crust to uplift; the increased pressure of the remaining weight of the upper 50 km of the accretion plate, plus her own weight, will press down through her legs, depressing the continental plate and the underlying mantle, thinning it and perhaps causing widespread localised vulcanism running from (what were) central India and central Siberia. Massive outgassing will blow hot volcanic plumes in all directions; inflowing oceanic water will spill down over a 100km high precipice forming a vast waterfall that will empty the ocean into a 6,600,000,000 cukm chasm. All the oceans waters only amount to about 1,400,000,000 cukm of water. This new Eosphoratic Ocean will be a deep, steamy, stormy and utterly unaccessible seafood gumbo to everyone with the possible exception of any vessels that survive, Land of the Lost style, the drop over the precipice. Elsewhere it's been said that the noise of the Gibraltar Cataract would have deafened local wildlife. This waterfall will certainly deafen anyone close by!

Phase III

Having stablised her stance on the shifting surface of the underlying continental plate, the areas surrounding what was Asia will suffer massive earth quakes, as her movements cause the plate to depress and rise. Broad chasms will evolve at the plate boundaries, allowing for magma to rise; and as plates catastrophically collide, vast earthquake swarms will overwhelm even the most distant lands. The heat generated from these motions may raise the overall temperature by many degrees, a process called Dragon-Made Global Warming. During this phase, the remaining unstable crust materials on her back will continue to slide off. Much, of course, will land relatively harmlessly in the mud surrounding the Eosphoratic Ocean, but quite a bit will rain down into the Ocean itself. As mountains with weights of up to 161,932,476,090,000 kg rain down into the water from a height of about 250 km, great fountains of water and rock will be cast up into the atmosphere. Other geological features will be cast high into the atmosphere, even into space, as she shakes out her wings and seeks to rid her body of all irritants. These low velocity meteors, hundreds of which will be mountain sized or larger, and many millions of which will be smaller, will eventually be stopped by Earth's gravity and return to the surface causing widespread chaos as the meteor shower ensues.

Phase IV

If anyone is left on the surface of the planet, after all the teratsunamis, petaquakes and Global Warming, two catastrophes will ensue. The first is the gradual collapse of the Eosphoratic Precipice itself. All the weight of the damaged and unstable continental crust surrounding the Ocean will cause a massive weakening. Gravity will begin the process of destroying the newly formed Ocean by causing the 200 km high walls of the chasm to collapse inward.

But that's not even the worst of it! The second and final catastrophe to befall Earth's climate will be the flight of the Dragon. Every dragon wants to fly. Tis instinct. If you've ever been privileged to watch a dragon take off, as I have, or at least have watched a bird take off, say from a branch, you know there are two components to achieving flight: one is the wing lift & body crouch; two is the leap with the legs and downthrust with the wings.

Our dragon will now crouch down, settling like a great duck in the boiling waters of the Eosphoratic Ocean, tensing her body to prepare for her leap. Furthermore, she will rapidly raise her nearly 44 million sqkm wingspread well above the height of the atmosphere. It's only about 500 km thick --- each of her wings is about 10000 km long, a 20000 km wingspread all unfurled! She's a big girl. Raising those wings will create a vacuum generating updraft over the Ocean, causing hurricane force winds to blow towards her. This will cause destruction of any remaining structures through hypercane force derechos ripping across the surface of the planet at all levels of the atmosphere. The result will be a massive accumulation of air and water vapour over the Ocean and a severe partial vacuum area over the antipodes. The storms surrounding her body will be amazing!

And then - - - she flies!

Her powerful legs will spring into action. Causing her 16 146 000 000 000 kg weight to gracefully leap into the air, she'll punch the full strength of her legs down onto the already stressed, cracked, and heaving continental plate. The exertion will be too much for the solid crust to handle. Her 10000 km long body will simply press the crust down into the mantle below. The mantle is only about 2700 km deep, and she's gonna be using all that in order to take off. She's going to cause localised solidification of the mantle as incredible pressures compress crust into all layers of mantle. Her toes may even touch the outer core!

At the same time, she'll bring her wings down. Anyone left alive on the planet will be able to see as the outer edges enter the atmosphere and light up infrared as the friction interactions with all that piled up air cause her wings to heat up.

Her rapidly descending wings will now cause all the pent up air to be explosively expelled from around her body. If Smaug's wings were a hurricane, this girl's wings simply blow much of the remaining atmosphere out into space. The relatively gentle hypercane force winds that were generated by their lift will now be increased by orders of magnitude as she forces them downward.

As her body leaps up, up and away from the ravaged Earth, first, as her forelimbs rise up from the surface, the northern half the Asiatic plate will crack due to the release of massive pressure and undulating mantle waves will, due to dvorakian forces, cause the fractured portions to roll and tilt precariously even as her full weight further depresses the southern half. The release of pressure in the north will cause the viscoelastic mantle to liquefy into gargantuan gouts of molten magma while the remaining portion of solid plate screams and groans as its relative cool is pressed deep into the liquid core. And then, her hind limbs too shall rise up from the surface: the northern half of the Asiatic plate will collapse back down onto the raging mantle and the sudden release of pressure on the core and deep mantle will cause a fountain of molten material to spew from the very centre of the planet! She will be lifted up and as she rockets peacefully into space and on to her journey, she'll leave the Greatest Show On Earth's last act and curtain call for the few survivors.

Phase V

The sudden departure of an Asia sized ettadragon will instantly remove all remaining pressure on the mantle and underlying core beneath where she was. The Eosphoratic Ocean, now long vapourised and blown away by her thunderous wingstroke won't even help hold down the final cataclysm. Now, the remainder of the planet will suffer gravitational shocks as it struggles to attain homeastasis: the planet was round(ish) and now it's not, but it wants to be again. Resulting shockwaves will pulverise and melt the crust. Whatever water remains will boil. Air will sear. The exposed core and mantle will create a wonderful geyser of gaseous iron and molten rock which will shoot up into space.

The shocks and violence of this partial core ejection will cause the remaining mantle and crust to collapse. Quite apart from the remaining mountainous meteors that are still raining down on the ravaged surface, the liquefying core and mantle matter will now begin to rain back down. Most of the surface by this time will already be molten. And what isn't will be very hot, shaken, cracked, splintered and smithereened. Atmospheric temperature might be as high as 200 degrees centigrade and winds will still be raging.

Summation

There won't be an environment left to have an impact on.

• In phase IV the logic extrapolation fails badly: how can she fly? Ok, you can streach the atmosphere's height up to 1500km (exosfere) but this doesn't change that 100Km is usually considered space and you don't "fly" in space. We can fly up to 25km, but only with supersonic jets, we can't fly helicopters higher than 12Km. 12Km of "air" for 20'000km wingspan beast? Can you (1.8m) swim in 1.08mm puddle? Beside that, nice answer! +1 – theGarz Jul 17 '19 at 7:19
• There is no environment. It's outside the environment. – TRiG Jul 17 '19 at 10:36
• @theGarz Well, since she's an interstellar dragon, she obviously needs some other way of motion than flapping wings. But even if she just jumped, without the flapping, the result would be the same. Heck, even just the displacement of her volume from her standing up would be quite enough to cause most of those effects :D – Luaan Jul 17 '19 at 10:49
• This is a beautiful answer. What would you say the largest dragon that could hypothetically take off without eradicating all life on Earth would be? – Tam Coton Jul 17 '19 at 12:11
• I hereby declare you the official Jon Skeet of WordBuilding, fantasy n stuff. Congratulations! – Kyle Vassella Jul 17 '19 at 19:20

Everyone on the Earth dies and the planet becomes a steaming molten mess circling the Sun. Eventually everything will calm down and life will restart.

But why? Fill a bucket with water. Now remove 1 cup of water. The removal of the water causes a wave across the surface of the cup while the water redistributes to fill in the hole. The same basic thing happens if you remove an entire continent. The surface of the planet shifts to fill in the hole and become a sphere again. Very little will survive this. Maybe some sea life survives, maybe some birds are lucky enough.

Finally, the axis of the planet will change, drastically changing the seasons. The planets orbit will change slightly because some of the Earth's speed was stolen by the flying away land mass.

If your dragon is just a very, very large creature then - as ably described by elemtilas - total destruction of the Earth's environment ensues. But this is religion describing a god-like entity, and you didn't slap a tag on this, so perhaps there is some wiggle room.

Of course there's no continent-sized physical entity slumbering away with insects drilling into its bones for the mineral content. That would be silly. What we have here is a spiritual force that encompasses the whole continent and will manifest itself as a huge spritual dragon that will sweep up the faithful and carry them to their reward. As the god rises through the stone and dirt, gathering the spirits of the faithful, they will transcend to become pure spirit themselves. They will spend eternity travelling with their god, who will show them all the secrets of the cosmos.

Or from a slightly more rational perspective the entity will wake up, gather some energy supplies for the trip from the life forces around it, then take off to the next available world with complex life energy. Not so much rewarding the faithful as taking them along as snacks. Oops.

(If you've ever seen Final Fantasy: The Spirits Within you'll have some nifty visuals to relate this to.)

In the first story only the faithful are taken. The 'Left Behind' series, as badly written as it may be, has all sorts of ideas about what happens with a significant portion of the population simply disappear.

The second option is much more exciting because the creature wouldn't just rip the life out of the faithful, it would harvest all of the life it could. Assuming it can't live off the life force of algae, fungi and other simple forms, perhaps it only kills advanced animal life. And just the life energy, so there's a vast area covered with rotting corpses. Simple insects would become the dominant life form after a few years, to the point where they would spread to dominate the other areas of the planet.

Of course if it harvests the life from all plants too then I imagine that the only thing that would survive would be fungi and protozoa, with a vast supply of nutrients and nothing to hold them back. Fungal wasteland inside of a year, followed by massive competition for the remaining resources, then complete collapse.

Let's hope they were right about it only taking the faithful along. Still a bunch of rotting corpses to deal with, which could be an issue if the religion was followed by the vast majority of people.

Seriously?

Assuming the dragon's belly is more or less spherical, and 5,000 km thick, it should weight about 1020 tons, give or take one order of magnitude, depending on the actual density of a dragon. That's around 1023 kilograms, or ten thousand times the estimated mass of the atmosphere. So, uh, let's hope that dragon doesn't try to fly. You wouldn't like it, not just because Earth would likely be pushed away, but air might get... a tidbit thin when given such a massive thrust.

Does a dragon have a heart? I'm guessing yes. Does it beat? Let's hope not, everyone will be deaf (or dead). Oh heck. let's hope it can stand up and unfold its wings without... uh, moving.

Does the dragon breathe? Let's hope not. Let's also hope no gaseous components of sorts come out of its other end. Let's not think about the fact that dragons tend to have fiery hot breath. Does it drool? Hopefully not.

How much heat does a dragon generate just to live? Well, we don't know. But an average human with 75kg has an output of about 100W. So let's say... roughly 1W per kilogram body weight (actually... more, but let's generously round down).
Holy shit, I don't want to be near a creature that outputs 1023W. Climate change is a hoax, you know. It's all dragons.

Now let's hope that beast doesn't need to eat...

• What if we instead used the metabolism of a hibernating animal? It's not fair to use the power output of a mammal which is on the move 16 hours a day. (Not that I think it will change much, just curious) – Muuski Jul 15 '19 at 18:23
• @Muuski: Well OK, feel free to subtract 3 orders of magnitude, that's still around 100 exawatts. Huh, I had to look that one up, didn't know what came after peta... – Damon Jul 16 '19 at 9:52
• "creature that outputs 10^23W" - spread across the size of Asia. Still awfully lot though. – John Dvorak Jul 16 '19 at 18:29
• Larger animals use less energy per unit mass than small animals because of the square-cube law, and cold-blooded or hibernating animals use less energy than active warm blooded animals. – Monty Wild Jul 17 '19 at 0:34
• @MontyWild: Not sure that is true. Square-cube sure does apply, but the base metabolism to keep cells alive remains the same per cell or per unit of volume. OTOH surface is (relatively to volume) much smaller due to SQL. Much like a baby will die from cold if you leave it unprotected in "actually not so cold" environment (metabolism cannot keep up with heat loss), our dragon would probably be searing hot since it has very little surface compared to its volume. Also, the dragon is not hibernating but woke as stated in the Q. – Damon Jul 17 '19 at 13:11

In addition to what @TrevorD pointed out there would also be an unprecedented volcano-esque blast as the weight of the continent came off the underlying rocks. The gases dissolved into the mantle under the continent would be liberated. Think of what happens to a shaken bottle of carbonated beverage that's opened suddenly, now imagine that the bottle lid is Asia and the foam pouring out is made of rock and explodes into volcanic ash as soon as it leaves the ground.

• Ah, I see - providing a large thermal updraft to help our dragon take flight – Chronocidal Jul 15 '19 at 12:30
• @Chronocidal Yeah that's one way of looking at it. – Ash Jul 15 '19 at 12:30

The mythic story says "the land itself", if this can be interpreted as the entire planet you have the classic "World Echinus" theory as put forth in Sir Arthur Conan Doyle's Prof. Challenger story, "The Day the Earth Screamed".

The theory surmises that the entire world is a living creature with the surface crust of the Earth being like the "test" or shell of an echinoderm or sea urchin.

In this model the god is already carrying the faithful. They just may not appreciate their god's true intent. (misinterpreted hermeneutics)

I feel this premise is more believable than a dragon-like creature the size of a continent who will one day separate from the planet, not only destroying the planet it leaves behind, but also killing any creatures residing on its back, when it flies off into space.

• As much as I am loath to reference it, this mirrors the rather appalling Doctor Who episode "Kill the Moon" – Chronocidal Jul 15 '19 at 12:35
• @Chronocidal In retrospective it wasn't that bad. The bar has been lowered. – Trevor Jul 15 '19 at 18:49

Frame challenge: the dragon that was "as big as the world" is actually much smaller than we now understand the world to be. Ten billion people could sit comfortably in an area 100 KM square. If the dragon turned out to be real, the environmental consequences would be far less than if it were actually the size of a continent.

The Earth's crust is super thin. Environmentally, it would mean ripping a continent out if the ground and deforming the whole surface. If the dragon is meant to have depth where it would leave the a massive cavern, and by massive I mean taking a bite out of a cookie, not licking an ice cream cone, then the the Earth would first have it's molten center rebalance around the center of mass, the crust of the rest of the Earth collapse around it having magma seap through and cover everything. Then it would cool again after a long time.

There just wouldn't be environment left.

A number of answers and comments have suggested that this would affect the axial tilt or orbit of Earth, so let's first work out the likely mass of the dragon to see how plausible those scenarios are.

The land area of Asia is $$44.58 \cdot 10^{12} m^2$$. (1) The continental crust is $$30-50 km$$ thick.(2) Density of the crust ranges from $$2.2$$ to $$2.9\;g/cm^3$$.(3) This suggests that Asia has a mass of about $$2.94 \cdot 10^{21} kg$$ to $$6.46 \cdot 10^{21} kg$$, which is between 1/1000 and 1/2000 of Earth's total mass. We'll take the larger number as a worst case scenario (although in practice, dragons are probably less dense than rock).

Now let's have the dragon fly up to the edge of the atmosphere, 100 km up (4). The total mass of the Earth-Dragon system is, of course, unchanged, so we just need to see how much the center of mass moves. Taking the old center of mass as our zero point, the dragon is a point mass of $$M_{earth}/1000$$ at 100 km + the earth's radius, or 6,456 km. The earth is a point mass of $$999 \cdot M_{earth}/1000$$ at -25km, since the Asia-shaped part we removed was all on one side. Which gives us a center of mass 18.5 km away from where it used to be. The orbit won't care; even if the dragon flies away entirely, the orbital radius will change by less than 1 in 30 million; we can just add another leap day once every billion years or so and everything works out.

The center of mass of the remaining Earth has only moved by $$0.1\%$$, but it's no longer on the axis of rotation, so there will be a small but measurable change in axial tilt. Of course, when dealing with this much mass, small-but-measurable probably still means enough torque to cause the worst earthquakes in human history, but I'm afraid we've reached the limit of what I can calculate exactly.

The more immediate problem is that if the crust flies away, we now have an area of exposed mantle the size of Asia. The closest event in history to that would be the eruption that formed the Siberian Traps. Those are 7 times smaller than the exposed area (and the actual area that erupted would be smaller still), and that event is one of the more likely causes of the Permian-Triassic mass extinction, which wiped out 95% of all life, but arguably cleared the way for the rise of the dinosaurs. It's somewhat appropriate that this time, it's the rise of a giant reptile that leads to the extinction event, instead of the other way around.

• if moving a part of Earth by 100km moves the center of mass by 43km, the dragon would be too heavy. Your calculation seems to be more akin to moving the dragon to 6456km height, so the effect on the orbit will be much lower. I love how the dragon is basically two-dimensional, at something like 10000km*10000km*50km, just a big piece of the crust. – Chieron Jul 16 '19 at 19:17
• @Chieron 6456 km from the original center of mass. But it starts on the surface, which is already 6356 km away from the CoM. And it's the Earth's CoM that's 6456 km away from the dragon's CoM; the dragon is still close to the surface. Most of the movement of the CoM of just the Earth part comes from the fact that we removed a 50km thick slice from one side, rather than where that slice moved to. (I did have an extra factor of 2 in there, now corrected. It didn't change much; 43 is now 18.5) And it is worth noting that the dragon actually moves 125 km in order to put its center at +100 km. – Ray Jul 16 '19 at 20:47