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00:00Once, there was a world, not so very different from our own.
00:17There were occasional natural catastrophes.
00:21Massive volcanic eruptions, and every once in a while,
00:24an asteroid would come barreling out of the blue to do some damage.
00:28But for the first billion years or so, it would have seemed like a paradise.
00:36This is what we think the planet Venus might have looked like when our solar system was young.
00:43Then, things started to go horribly wrong.
00:58I don't know what we've ever seen as this is, what is our world,
01:01and the dre possibly has a ice-creamed afterlife.
01:02We thought that we don't even know what we've ever seen before.
01:05We thought that this is a scene called Earth.
01:07We thought that this would be really good.
01:09We thought that this is a scene called Earthì „ene.
01:11We thought that we were to find out that of the world that we love,
01:13the world that we have and that we give them to,
01:17the world that is one of our bodies and that we are.
02:49The planet Venus, which once may have seemed like a heaven, turned into a kind of hell.
02:55The difference between the two can be a delicate balance, far more delicate than you might imagine.
03:01Once things began to unravel, there was no way back.
03:05This is what Venus, our nearest planetary neighbor, looks like today.
03:10Venus' oceans are long gone.
03:24The surface is hotter than a broiling oven, hot enough to melt lead.
03:30Why?
03:31You might think it's because Venus is 30% closer to the sun than the Earth is, but that's not the reason.
03:37Venus is completely covered by clouds of sulfuric acid that keep almost all the sunlight from reaching the surface.
03:44That ought to make Venus much colder than the Earth.
03:47So why is Venus scorching hot?
03:50It's because the small amount of sunlight that trickles in through the clouds to reach the surface can't get back out again.
03:57The flow of energy is blocked by a dense atmosphere of carbon dioxide.
04:03That carbon dioxide gas, or CO2 for short, acts like a smothering blanket to keep the heat in.
04:09No one is burning coal or driving big gas guzzlers on Venus.
04:14Nature can destroy an environment without any help from intelligent life.
04:19Venus is in the grip of a runaway greenhouse effect.
04:24Why does it look like we're inside a bowl?
04:28It's due to the intense atmospheric pressure.
04:32That's the wreck of Venera 13.
04:35In 1982, the scientists and engineers of what was then the Soviet Union successfully landed this spacecraft on Venus.
04:44They managed to keep it refrigerated for over two hours so it could photograph its surroundings
04:49and transmit the images back to Earth before the onboard electronics were fried.
04:57Venus and Earth started out with about the same amount of carbon.
05:07But the two worlds were propelled along radically different paths.
05:11And carbon was the decisive element in both stories.
05:15On Venus, it's almost all in the form of gas, carbon dioxide, in the atmosphere.
05:22Most of the carbon on Earth has been stored for eons in solid vaults of carbonate rock, like this one.
05:33Part of a chain that forms the celebrated White Cliffs of Dover, right on the English Channel.
05:40What titan built this wonder of the world?
05:43A creature a thousand times smaller than a pinhead.
06:04Trillions of them.
06:06One-celled algae.
06:07Volcanoes supply carbon dioxide to the atmosphere, and the oceans slowly absorb it.
06:19Working over the course of millions of years, the microscopic algae harvested the carbon dioxide
06:25and turned it into these tiny shells.
06:28They accumulated in thick deposits of chalk or limestone on the ocean floor.
06:37Later, the restless Earth pushed up the seafloor and carved out these massive cliffs.
06:45Other marine creatures took in carbon dioxide to build enormous coral reefs.
06:51And the oceans converted dissolved CO2 into limestone, even without any help from life.
06:56As a result, only a trace amount was left as a gas in Earth's atmosphere.
07:02Not even three hundredths of one percent.
07:05Think of it.
07:06Fewer than three molecules out of every 10,000.
07:09And yet, it makes the critical difference between a barren wasteland and a garden of life on Earth.
07:22With no CO2 at all, the Earth would be frozen.
07:26And with twice as many, we're still talking about only six molecules out of 10,000.
07:34Things would get uncomfortably hot and cause us some serious problems.
07:39But never as hot as Venus.
07:41Not even close.
07:42That planet lost its ocean to space billions of years ago.
07:47Without an ocean, it had no way to capture CO2 from the atmosphere and store it as a mineral.
07:52The CO2 from erupting volcanoes just continued to build up.
07:57Today, that atmosphere is 90 times heavier than ours.
08:01Almost all of it is heat-trapping carbon dioxide.
08:05That's why Venus is such a ferocious inferno so hostile to life.
08:11The Earth, in stunning contrast, is alive.
08:17It breathes.
08:18But very slowly, a single breath takes a whole year.
08:24The forests contain most of Earth's life.
08:26Most forests are in the northern hemisphere.
08:29When spring comes to the north, the forests inhale carbon dioxide from the air and grow, turning the land green.
08:37The amount of CO2 in the atmosphere goes down.
08:39When fall comes and the plants drop their leaves, they decay, exhaling the carbon dioxide back into the atmosphere.
08:49The same thing happens in the southern hemisphere at the opposite time of the year.
08:53But the southern hemisphere is mostly ocean.
08:55So, it's the forests of the north that control the annual changes in the global CO2.
09:02The Earth has been breathing like this for tens of millions of years.
09:06But nobody noticed until 1958, when an oceanographer named Charles David Keeling devised a way to accurately measure the amount of carbon dioxide in the atmosphere.
09:16Keeling discovered the Earth's exquisite respiration.
09:24But he also discovered something shocking.
09:27A rapid rise, unprecedented in human history, in the overall level of CO2.
09:33One that has continued ever since.
09:35It's a striking departure from the CO2 levels that prevailed during the rise of agriculture and civilization.
09:48In fact, the Earth has seen nothing like it for three million years.
09:56How can we be so sure?
09:58The evidence is written in water.
10:05The Earth keeps a detailed diary written in the snows of yesteryear.
10:16Climate scientists have drilled ice cores from the depths of glaciers in Greenland and Antarctica.
10:23The ice layers have ancient air trapped inside them.
10:28We can read the unbroken record of Earth's atmosphere that extends back over the last 800,000 years.
10:35In all that time, the amount of carbon dioxide in the air never rose above three hundredths of one percent.
10:42That is, until the turn of the 20th century.
10:46And it's been going up steadily and rapidly ever since.
10:49It's now more than 40 percent higher than before the Industrial Revolution.
10:54By burning coal, oil, and gas, our civilization is exhaling carbon dioxide much faster than Earth can absorb it.
11:02So CO2 is building up in the atmosphere.
11:06The planet is heating up.
11:09Every warm object radiates a kind of light we can't see with the naked eye.
11:13Thermal infrared light.
11:16We all glow with invisible heat radiation, even in the dark.
11:20This is what the Earth looks like in the infrared.
11:23You're seeing the planet's own body heat.
11:33Incoming light from the sun hits the surface.
11:36The Earth absorbs much of that energy, which heats the planet up, and makes the surface glow in infrared light.
11:43But the carbon dioxide in the atmosphere absorbs most of that outgoing heat radiation, sending much of it right back to the surface.
11:53This makes the planet even warmer.
11:55That's all there is to the greenhouse effect.
11:58It's basic physics.
11:59Just bookkeeping of the energy flow.
12:02There's nothing controversial about it.
12:04If we didn't have any carbon dioxide in our atmosphere, the Earth would just be a great big snowball, and we wouldn't be here.
12:15So a little greenhouse effect is a good thing.
12:18But a big one can destabilize the climate and wreck our way of life.
12:22All right, but how do we know that we're the problem?
12:28Maybe the Earth itself is causing the rise in CO2.
12:31Maybe it has nothing to do with the coal and oil we burn.
12:35Maybe it's those damn volcanoes.
12:39Every few years, Mount Etna, in Sicily, blows its stack.
12:44Each big eruption sends millions of tons of CO2 into the atmosphere.
12:48Now, combine that with the output of all the other volcanic activity on the planet?
12:56Let's take the largest scientific estimate.
12:58About 500 million tons of volcanic CO2 entering the atmosphere every year.
13:05Sounds like a lot, right?
13:07But that's not even 2% of the 30 billion tons of CO2 that our civilization is cranking out every year.
13:15And, funny thing, the measured increase in CO2 in the atmosphere tallies with the known amount we're dumping there by burning coal, oil, and gas.
13:29Volcanic CO2 has a distinct signature.
13:31It's slightly heavier than the kind produced by burning fossil fuels.
13:35We can tell the difference between the two when we examine them at the atomic level.
13:39It's clear that the increased CO2 in the air is not from volcanoes.
13:45What's more, the observed warming is as much as predicted from the measured increase in carbon dioxide.
13:51It's a pretty tight case.
13:52Our fingerprints are all over this one.
13:56How much is 30 billion tons of CO2 per year?
13:59If you compressed it into solid form, it would occupy about the same volume as the White Cliffs of Dover.
14:06And we're adding that much CO2 to the air every year, relentlessly, year after year.
14:14Unlucky for us, the main waste product of our civilization is not just any substance.
14:20It happens to be the chief climate-regulating gas of our global thermostat, year in, year out.
14:26Too bad CO2 is an invisible gas.
14:31Maybe if we could see it.
14:33If our eyes were sensitive to CO2, and perhaps there are such beings in the cosmos,
14:39if we could see all that carbon dioxide,
14:43then we would overcome the denial and grasp the magnitude of our impact on the atmosphere.
14:56But the evidence that the world is getting warmer is all around us.
15:09For starters, let's just check the thermometers.
15:12Weather stations around the world have been keeping reliable temperature records since the 1880s.
15:17And NASA has used the data to compile a map,
15:21tracking the average temperatures around the world through time.
15:25Yellow means warmer temperatures than the average for any region in the 1880s.
15:31Orange means hot.
15:33And red means hotter.
15:39The world is warmer than it was in the 19th century.
15:46Back then, at the greatest fair the world has ever seen,
15:50a forgotten genius demonstrated the solution to this problem.
15:55Come with me.
16:03Once, there was a world that was not too hot and not too cold.
16:09It was just right.
16:12Then, there came a time when the life it sustained began to notice our lovely planet was changing.
16:21And it's not as if we didn't see it coming.
16:24As far back as 1896,
16:30the Swedish scientist, Svante Arrhenius,
16:33calculated that doubling the amount of CO2 in the atmosphere
16:36would melt the Arctic ice.
16:41In the 1930s,
16:42the American physicist E. O. Hulbert
16:45at the Naval Research Laboratory confirmed that result.
16:49So far, it was still just theoretical.
16:51But then,
16:55the English engineer Guy Callender
16:57assembled the evidence to show
16:59that both the CO2
17:00and the average global temperature
17:02were actually increasing.
17:05Even now,
17:06man may be unwittingly changing
17:08the world's climate
17:09through the waste products of his civilization.
17:12Due to our release
17:13through factories and automobiles every year
17:15of more than 6 billion tons of carbon dioxide,
17:19which helps air absorb heat from the sun,
17:21our atmosphere seems to be getting warmer.
17:24This is bad.
17:26Well, it's been calculated
17:27a few degrees rise in the Earth's temperature
17:30would melt the polar ice caps.
17:32In 1960,
17:39Carl Sagan's Ph.D. thesis
17:41included the first calculation
17:43of the runaway greenhouse effect on Venus.
17:45This was part of a career-long interest
17:47in the atmospheres of the planets,
17:50including our own.
17:51In the original Cosmos series in 1980,
17:54Carl Sagan warned,
17:55We are releasing vast quantities of carbon dioxide,
17:59increasing the greenhouse effect.
18:01It may not take much
18:02to destabilize the Earth's climate,
18:05to convert this heaven,
18:06our only home in the cosmos,
18:08into a kind of hell.
18:09Since Carl spoke those words,
18:18we've burdened the atmosphere of our world
18:19with an additional 400 billion tons
18:23of carbon dioxide.
18:25And if we don't change our ways,
18:27what will the planet be like
18:28in our children's future?
18:29Based on scientific projections,
18:33if we just keep on doing business as usual,
18:36our kids are in for a rough ride.
18:38Killer heat waves,
18:40record droughts,
18:41rising sea levels,
18:43mass extinction of species.
18:46We inherited a bountiful world
18:48made possible by a relatively stable climate.
18:51Agriculture and civilization flourished
18:53for thousands of years.
18:55And now,
18:56our carelessness and greed
18:58put all of that at risk.
19:03Okay, so if we scientists are so good
19:05at making these dire long-term predictions
19:07about the climate,
19:08how come we're so lousy
19:10about predicting the weather?
19:11Besides,
19:12this year,
19:13we had a colder winter in my town.
19:15For all the scientists know,
19:17we could be in for global cooling.
19:19Here's the difference
19:20between weather and climate.
19:22Weather is what the atmosphere does
19:24in the short term.
19:25Hour to hour,
19:26day to day.
19:27Weather is chaotic,
19:29which means that even
19:30a microscopic disturbance
19:31can lead to large-scale changes.
19:34That's why those 10-day weather forecasts
19:36are useless.
19:37A butterfly flaps its wings in Bali,
19:39and six weeks later,
19:40your outdoor wedding in Maine is ruined.
19:43Climate is the long-term average
19:45of the weather over a number of years.
19:47It's shaped by global forces
19:48that alter the energy balance
19:50in the atmosphere,
19:51such as changes in the sun,
19:53tilt of the Earth's axis,
19:54the amount of sunlight the Earth
19:56reflects back to space,
19:57and the concentration of greenhouse gases
20:00in the air.
20:01A change in any of them
20:02affects the climate
20:03in ways that are broadly predictable.
20:06My friend's meandering
20:07represents the short-term fluctuations.
20:10That's weather.
20:12It's almost impossible to predict
20:14what will attract his interest next,
20:15but not hard to know
20:17what the range of his meandering will be,
20:19because I'm holding him on a leash.
20:23We can't observe climate directly.
20:26All we see is the weather.
20:27The average weather over the course of years
20:29reveals a pattern.
20:31I represent that long-term trend,
20:34which is climate.
20:36Keep your eye on the man,
20:38not the dog.
20:39Weather is hard to predict,
20:43like my friend here,
20:45but climate is predictable.
20:47Climate has changed many times
20:49in the long history of the Earth,
20:50but always in response
20:51to a global force.
20:53The strongest force
20:54driving climate change right now
20:56is the increasing CO2
20:58from the burning of fossil fuels,
20:59which is trapping more heat
21:01from the sun.
21:02All that additional energy
21:03has to go somewhere.
21:05Some of it warms the air.
21:06Most of it ends up in the oceans.
21:09All over the world,
21:10the oceans are getting warmer.
21:13It's most obvious in the Arctic Ocean
21:15and the lands that surround it.
21:21Okay, so we're losing the summer sea ice
21:23in a place where hardly anyone ever goes.
21:27What do I care
21:28if there's no ice around the North Pole?
21:36Ice is the brightest natural surface
21:42on the Earth,
21:43and open ocean water is the darkest.
21:46Ice reflects incoming sunlight
21:48back to space.
21:50Water absorbs sunlight
21:51and gets warmer,
21:53which melts even more ice,
21:55which exposes still more ocean surface
21:58to absorb even more sunlight.
22:00This is what we call
22:01a positive feedback loop.
22:04It's one of many natural mechanisms
22:06that magnify any warming
22:08caused by CO2 alone.
22:10We're at Drew Point, Alaska,
22:13on the edge of the Arctic Ocean.
22:16When I was born,
22:29the shoreline was a mile farther out,
22:32and it was breaking off
22:33at a rate of about 20 feet per year.
22:36Now,
22:37it's being eaten away
22:39at about 50 feet per year.
22:42The Arctic Ocean is warming
22:43and at an increasing rate.
22:46So it's ice-free
22:47during more of the year.
22:49That leaves the shore here
22:51more exposed to erosion from storms,
22:54which are also getting more powerful.
22:56Another effect of climate change.
22:59The northern reaches of Alaska,
23:01Siberia, and Canada
23:02are mostly permafrost.
23:04Ground that has been frozen
23:06year-round for millennia.
23:08It contains lots of organic matter.
23:10Old leaves and roots from plants
23:12that grew thousands of years ago.
23:15Because the Arctic regions
23:16are warming faster
23:17than anywhere else on Earth,
23:19the permafrost is thawing,
23:21and its contents are rotting,
23:24just like when you unplug the freezer.
23:30The thawing permafrost
23:32is releasing carbon dioxide
23:33and methane,
23:35an even more potent greenhouse gas,
23:37into the atmosphere.
23:39This is making things even warmer.
23:41Another example
23:42of a positive feedback mechanism.
23:45The world's permafrost
23:46stores enough carbon
23:47to more than double
23:49the CO2 in the atmosphere.
23:51At the rate we're going,
23:52global warming could release most of it
23:54by the end of the century.
23:56We might be tipping the climate
23:58past a point of no return
23:59into an unpredictable slide.
24:01OK, the air, the water,
24:04and the land
24:05are all getting warmer.
24:07So, global warming
24:08is really happening.
24:10But maybe it's not our fault.
24:12Maybe it's just nature.
24:14Maybe it's the sun.
24:17No, it's not the sun.
24:19We've been monitoring the sun
24:23very closely for decades,
24:25and the solar energy output
24:27hasn't changed.
24:29What's more,
24:30the Earth is warming
24:30more at night
24:31than in daytime,
24:33and more in winter
24:35than in summer.
24:37That's exactly what we expect
24:38from greenhouse warming,
24:40but the opposite
24:40of what increased solar output
24:42would cause.
24:43It's now clear
24:45beyond any reasonable doubt
24:46that we are changing
24:48the climate.
24:50The sun isn't the problem,
24:52but it is the solution,
24:53and we've known this
24:54for a long time.
24:57Much longer
24:57than you might think.
25:03Paris, September 1878.
25:07The Eiffel Tower
25:08won't be built
25:09for years to come.
25:13Witness one of the most
25:17glorious spectacles
25:19the world has ever seen.
25:21The magnificent head
25:23of the Statue of Liberty
25:24has just been completed.
25:33Thousands of exhibitors
25:35from around the planet
25:36covered 66 acres of Paris
25:38with their inventions and goods.
25:41Edison's first public demonstration
25:43of the light bulb
25:44will not take place
25:45for another year.
25:47There's no such thing
25:47as electrical appliances.
25:50People don't flick switches
25:51and press buttons.
25:53It's a hand-cranked,
25:54horse-drawn world.
25:58That's the guy
25:59we came to see.
26:00The one with the crazy mustache.
26:03He's a math teacher
26:04named Augustin Mouchel.
26:06Remember, it's 1878.
26:09This is a world
26:10lit mostly by gaslight.
26:12The automobile
26:13is still years away.
26:15But Mouchel here
26:16is dazzling the crowd
26:18with his solar power concentrator.
26:22The sun belongs
26:24to all of us.
26:25Even though it is
26:26150 million kilometers
26:28away from us.
26:30Feel its awesome power.
26:32My invention
26:33concentrates the free energy
26:35of the sun
26:35and converts it
26:37into mechanical motion.
26:39It can power
26:40any kind of machine.
26:42It can produce electricity
26:44or run a printing press
26:45or make ice
26:47on a hot day.
26:48And voila!
26:52Think of it!
27:05Sunlight converted
27:06into ice.
27:07You see, my friends,
27:09what wonders
27:10we can work
27:11if we harness
27:11the bounteous energy
27:12of the sun.
27:13The world
27:15will someday
27:15run out of coal.
27:17But the magnificent sun
27:18will always be there
27:19for us.
27:23Mucho took home
27:37the gold medal
27:37from the fair.
27:39But the price of coal
27:40tumbled,
27:40becoming so cheap
27:41that there was no interest
27:43in solar energy.
27:44Besides,
27:45no one understood
27:46back then
27:46what the true cost was
27:48of burning fossil fuel.
27:50Mucho's research funding
27:51was cut off.
27:53Thirty-five years later,
27:55in the early years
27:55of the 20th century,
27:57another door opened
27:58to an alternative future.
28:00It happened in Egypt
28:01on the banks of the Nile.
28:13Memo to future time travelers.
28:16This would be
28:17an excellent entry point
28:18for averting climate change.
28:20Egypt,
28:231913.
28:25That's Frank Schumann
28:26of Philadelphia.
28:29He's only had
28:30three years
28:31of schooling,
28:32but his genius
28:33for innovation
28:34more than makes up
28:35for that.
28:37Before he was 30,
28:39Schumann had invented
28:39safety glass.
28:42Its use in automobiles
28:43and skylights
28:44saved countless lives
28:45and made him
28:46a very rich man.
28:49Rich enough
28:50to pursue
28:50his real passion,
28:53solar energy.
28:54Schumann led the team
28:56that designed
28:56and built
28:57an array
28:57of solar energy
28:58concentrators.
29:00It could power
29:01a steam engine.
29:04Schumann is hoping
29:05to use the sun's power
29:06to irrigate the desert
29:08and turn it green.
29:09The official inauguration
29:12of Schumann's
29:13solar power plant
29:13in 1913
29:14was a dazzling success.
29:19He had invented
29:20a practical way
29:21to tap the sun's energy
29:23on an industrial scale,
29:26making solar energy
29:28even cheaper than coal.
29:29The British
29:33and German governments
29:34both offered Schumann
29:35generous funding
29:36to develop his invention.
29:39It was the ideal source
29:40of abundant power
29:41in tropical regions
29:42where imported coal
29:44was prohibitively expensive.
29:47But Schumann
29:48was dreaming
29:49even bigger.
29:51In a letter
29:51to Scientific American,
29:53he calculated
29:54that his solar power plants,
29:56if deployed
29:57in an area
29:57of the Sahara Desert
29:58only 150 miles,
29:59on a side,
30:01could supply
30:01as much power
30:02as consumed
30:03by all the industries
30:05of the world.
30:06But it was not to be.
30:08The market
30:08for a liquid fossil fuel,
30:10petroleum,
30:11was exploding
30:12for shipping,
30:13home heating,
30:14cars and trucks.
30:15Oil was abundant,
30:16cheaper even than coal,
30:18and much easier
30:19to get out of the ground
30:20and process.
30:21It took 100 men a week
30:23to fuel a ship
30:24with coal.
30:25But with oil,
30:26one man could do the job
30:28in a single day.
30:29A year after Schumann's
30:31triumph in the desert,
30:33World War I broke out.
30:35His solar collectors
30:36were recycled
30:37into weapons.
30:39Frank Schumann's dream
30:40of a solar-powered civilization
30:42would have to wait
30:43another century
30:44before it was reborn.
30:48There's another
30:49inexhaustible source
30:51of clean energy
30:51for the world.
30:52The winds themselves
30:55are solar-powered
30:56because our star
30:58drives the winds
30:59and the waves.
31:02Unlike solar collectors,
31:04wind farms
31:04take up very little land
31:06and none at all
31:07if offshore,
31:08where the winds
31:09are strongest.
31:10if we could tap
31:13even 1%
31:14of their power,
31:15we'd have enough energy
31:16to run our civilization.
31:18And more solar energy
31:32falls on Earth
31:33in one hour
31:34than all the energy
31:35our civilization consumes
31:37in an entire year.
31:38If we could harness
31:39a tiny fraction
31:40of the available solar
31:41and wind power,
31:42we could supply
31:43all our energy needs
31:44forever
31:45and without adding
31:46any carbon
31:47to the atmosphere.
31:57It's not too late.
31:59There's a future
32:00worth fighting for.
32:02How do I know?
32:03Every one of us
32:04comes from a long line
32:06of survivals.
32:07Our species is nothing
32:08if not adaptive.
32:10It was only because
32:11our ancestors learned
32:12to think long-term
32:13and act accordingly
32:14that we're here at all.
32:16We've had our backs
32:17to the wall before
32:18and we came through
32:19to scale new heights.
32:22In fact,
32:22the most mythic
32:23human accomplishments
32:24of all
32:25came out
32:26of our darkest hour.
32:27Once there was a world
32:39rigged with 60,000
32:41hair-triggered
32:42nuclear weapons,
32:44the combatants
32:44were the two
32:45most powerful countries
32:46on Earth
32:47and they were locked
32:49in a deadly embrace,
32:50each vowing
32:51that they would rather
32:52see everything we love
32:54destroy
32:54than submit
32:55to the will
32:56of the other.
32:57When I was
32:58three years old,
32:59the largest man-made
33:00explosion of all time
33:01was detonated
33:02by the Soviet Union.
33:08That terror
33:09has subsided
33:09to be replaced
33:10by new fears.
33:12The danger
33:12that the 2,000
33:13largest cities
33:14on Earth
33:14would be reduced
33:15to rubble
33:16in the space
33:17of an afternoon
33:17is no longer
33:19one of them.
33:19The nuclear rivalry
33:22between the United States
33:23and the Soviet Union
33:24had another by-product.
33:28The Apollo missions
33:30to the moon
33:30were an extension
33:31of the arms race
33:32that raged between them.
33:36Sending people
33:37to orbit the Earth
33:38or go to the moon
33:38requires big,
33:40reliable,
33:41powerful rockets,
33:42precisely the same
33:43technology you need
33:44to carry a nuclear warhead
33:46halfway around the planet
33:48to destroy
33:49your enemy's
33:50largest cities.
33:53I believe that this nation
33:55should commit itself
33:56to achieving the goal
33:58before this decade
34:00is out
34:00of landing a man
34:02on the moon
34:02and returning him
34:03safely to the Earth.
34:06President Kennedy's
34:071961 speech
34:08electrified the nation
34:10and it contained
34:12much that was
34:12remarkably prophetic
34:14but not a word
34:16about a scientific objective
34:17for going to the moon.
34:19No questions
34:20about the moon's origin
34:21or the hope
34:22of bringing back samples
34:23to analyze.
34:24No,
34:25the Apollo missions
34:26were conceived
34:27as a demonstration
34:28of the superior power
34:30and precision
34:30of our strategic missiles.
34:32But a funny thing
34:34happened to us
34:35on our way
34:35to the moon.
34:38We looked homeward
34:40and discovered
34:41another world,
34:43our own.
34:44For the first time,
34:46we inhabitants
34:46of Earth
34:47could step back
34:48and see it
34:49as it really is.
34:51One world,
34:52indivisible
34:53and kind of small
34:54in the cosmic context.
34:57Whatever the reason
34:59we first mustered
35:00the enormous resources
35:01required for the
35:02Apollo program,
35:03however mired it was
35:05in Cold War nationalism
35:06and the instruments
35:07of death,
35:08the inescapable recognition
35:10of the unity
35:11and fragility
35:12of the Earth
35:13is its clear
35:14and luminous dividend.
35:16The unexpected gift
35:17of Apollo,
35:18a project conceived
35:19in deadly competition,
35:21made us recognize
35:23our community.
35:32what Titan built
35:36this wonder
35:37of the world?
35:39It was the
35:40Ifugao people
35:41of the Philippines
35:42working with
35:43not much more
35:44than their hands.
35:46About 10,000 years ago,
35:48our ancestors
35:49all over the world
35:50took advantage
35:51of another form
35:52of climate change,
35:54the gentler climate
35:55of the intermission
35:56in the ice age.
35:57They invented
36:00agriculture.
36:02They gave up
36:03the ceaseless wandering,
36:04hunting,
36:05and gathering
36:05that had been
36:06their way of life
36:07for a million years
36:08or so
36:09to settle down
36:10and produce food.
36:13They found a way
36:14to harvest
36:1510 to 100 times
36:17more solar energy
36:18than the environment
36:20naturally provided
36:21for their ancestors.
36:23People all over the world
36:25made the difficult transition
36:26from nomadic cultures
36:28to agricultural ones
36:30that used solar energy
36:32more efficiently.
36:33It gave rise
36:35to civilization.
36:38We stand on the shoulders
36:39of those
36:39who did the hard work
36:41that such a fundamental
36:42transformation required.
36:44Now,
36:45it's our turn.
36:47once there was a world.
37:00If life ever existed
37:01on Venus,
37:03it would have had
37:03no chance
37:04to avert
37:04the hellish destiny
37:06of this world.
37:09This runaway greenhouse effect
37:11was unstoppable.
37:12once there was a world.
37:28Ours.
37:30And that world is now.
37:33There are no scientific
37:34or technological obstacles
37:35to protecting our world
37:37and the precious life
37:38that it supports.
37:39It all depends
37:42on what we truly value.
37:45And if we can summon
37:46the will
37:47to act.
37:48the world is now.
37:51The world is now.
37:52The world is now.
37:52The world is now.
37:53The world is now.
37:53The world is now.
37:54The world is now.
37:54The world is now.
37:54The world is now.
37:55The world is now.
37:55The world is now.
37:55The world is now.
37:56The world is now.
37:56The world is now.
37:56The world is now.
37:56The world is now.
37:57The world is now.
37:57The world is now.
37:58The world is now.
37:58The world is now.
37:58The world is now.
37:59The world is now.
38:00The world is now.
38:00The world is now.
38:01The world is now.
38:01The world is now.
38:02The world is now.
38:02The world is now.
38:03The world is now.
38:04The world is now.
38:05The world is now.
38:36But why some say the moon? Why choose this as our goal? And they may well ask, why climb the highest mountain? We choose to go to the moon. We choose to go to the moon in this decade and do the other things. Not because they are easy, but because they are hard.
39:06We choose to go to the moon.
39:36We choose to go to the moon.