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00:00Nearly four billion years ago, life began in the roiling seas of planet Earth.
00:28Eons later, primitive single-celled organisms would give rise to life of stunning complexity,
00:43and the simple creature from which humans descended.
00:53As the global environment gradually changed, animals from sea and river ventured boldly onto land.
01:05If the entire history of life on Earth were condensed to a one-year time span, our human ancestors would have arrived in the final thirteen minutes.
01:21And yet, mankind is already looking toward the new frontiers of our solar system.
01:33Reshaping all the powers of science and technology within our reach, humans have even dreamed of terraforming Mars.
01:45Reshaping a distant planet to meet the future needs of our own species.
01:55Human beings are the first in Earth's evolutionary chain with the power to intentionally and profoundly alter the global ecology, and perhaps that of worlds beyond.
02:09...
02:14...
02:16...
02:18...
02:22ORGAN PLAYS
02:52ORGAN PLAYS
03:22ORGAN PLAYS
03:24It is widely believed that the first creature to walk upright lived four million years ago,
03:30a man-like ape from the vast forests of Africa.
03:35We may be its descendants.
03:38Earth's first hominids were ape-like in physique and behavior.
03:50But they would eventually acquire larger brains, a skeletal structure better adapted to their habitat,
04:01and the skills and intelligence to go with them.
04:04Hunter-gatherer societies made their way across land and water to every continent across the globe.
04:2118,000 years ago, they had even reached Siberia and other parts of the Arctic Circle.
04:36At the time, the Earth was in the midst of an ice age.
04:47On the frozen plains of the Arctic, hunters followed the migrations of reindeer and other mammals.
04:58With global waters suspended as ice, the planet's tropical zones became drier,
05:08rainforests were reduced to islands,
05:10and some species were driven to the edge of extinction by the climate,
05:16unlike their northern cousins.
05:17These are ancient spear tips.
05:27The design of these stone tools indicates that hunting techniques were already quite advanced.
05:37The world's oldest needle dates back 20,000 years.
05:41It was made of deer horn and was used for sewing skins to make clothing.
05:47By that time, man had acquired the know-how to survive the Arctic winters.
06:01Journeying across Eurasia, nomadic tribes made their way to its east coast
06:06and found a bridge to the New World.
06:17Glaciers formed during the ice age had absorbed huge amounts of water,
06:23causing sea levels to drop.
06:27A corridor between Siberia and Alaska was revealed,
06:31connecting the two continents.
06:37Little by little, global temperatures began to rise,
06:41and the glaciers blanketing the continent to melt.
06:53Some 12,000 years ago,
06:56the naked landscape left in their wake
06:58was covered with grassland
07:00and broadleaf and conifer forests.
07:03The Arizona State Museum exhibits artifacts from that period of North American history.
07:18Evidence shows that the continent was probably a temperate zone
07:23with an abundance of wildlife.
07:25These are the bones of a mammoth felled by a hunter.
07:35Still lodged in the animal's remains
07:37are the instruments of its demise,
07:41spearheads,
07:42and a number of other tools of stone.
07:44Proof that a group of hunters
07:52had risked their lives
07:54to fight this ancient behemoth.
07:57Dr. Paul Martin is a geologist
08:16with the University of Arizona.
08:19He believes that hunting
08:20almost completely wiped out North America's mammoths.
08:24It's possible to envision
08:27a small number of people
08:29coming into Canada,
08:31Western Canada,
08:33some 11,500 years ago,
08:38and within a few hundred years only,
08:41spreading across most of North America,
08:44and another few hundred years,
08:47spreading into South America.
08:49Now, this is a dramatic account.
08:51It may or may not be true,
08:53but it fits our chronology.
08:55The extinction of the large animals,
08:57the arrival of early people,
08:59and an event around 11,000 years ago,
09:02as dated by Radio Carbon.
09:06Wild animals like the mammoth,
09:09bison,
09:10and saber-toothed cat
09:11had once been plentiful
09:12on the North American continent.
09:14But by the end of the Ice Age,
09:17almost three-quarters of these large mammals
09:19had gone extinct,
09:21some the quarry of ancient hunters.
09:27Humans pressed onward toward South America.
09:31According to Dr. Martin,
09:33it may have taken as few as several hundred years
09:36for man to reach Tierra del Fuego
09:38at the foot of the continent.
09:39The wind-swept landscape of Patagonia
09:48lies at the southern tip of Argentina.
09:58Sheltering themselves in these isolated caves,
10:01our ancestors left signs of their passing,
10:05paintings of animals that cover the walls.
10:08To subsist in this remote corner of the world
10:15would require acres of land and new skills.
10:22The effect of the disappearance of large animals,
10:25the effect of the decline of animal resources,
10:28requires the people who have invaded this continent
10:31to master other kinds of material,
10:36such as plants.
10:38And in that regard,
10:40eventually we get to agriculture
10:42and another population increase.
10:45But the net effect of the colonization of the New World
10:49is a boom in population
10:51and then a crash
10:53as people are obliged to turn to other resources
10:57and learn how to harvest plants.
10:59By this time,
11:05hunter-gatherer societies
11:06had established themselves across the globe.
11:12Anthropologists gauged
11:13that the total world population
11:15probably numbered at most
11:17between 5 and 10 million
11:19because of the nomadic lifestyle.
11:22But this trend was beginning to shift.
11:28On the Mediterranean coast
11:29of present-day Syria
11:31are signs of the changes underway.
11:35Scattered across the hillside
11:37are the ruins of ancient villages,
11:40some 10,000 years old or more.
11:43Since the dawn of mankind,
11:49our ancestors had been nomadic people.
11:53But evidence here tells a new story.
11:57This was a year-round settlement.
11:59These are vestiges of an ancient hearth.
12:07For cooking,
12:08or warmth against the night chill,
12:10this structure of stone
12:12was the heart and gathering place
12:14of each dwelling.
12:17At Abu Huraira,
12:19we were treading on a carpet of flints,
12:22flint tools that we picked up.
12:25We saw they dated from
12:26before the beginnings of pottery making,
12:29in that part of the world.
12:31So we had a site
12:32that really was very early indeed
12:35in the story of village life
12:37in that part of the world.
12:40Dr. Andrew Moore of Yale University says,
12:43a number of factors determined
12:45why some societies adopted
12:47sedentary lifestyles.
12:50Climate was one.
12:5220,000 years ago,
12:54temperatures were low,
12:55and in the Middle East,
12:57it was also rather dry.
12:58But there would have been snow
13:01and glaciers in the mountains.
13:03And then beginning about 15,000 years ago,
13:06the climate began to improve.
13:08The temperature rose.
13:10It seems rainfall increased.
13:13And this allowed forest and grasslands
13:16to spread over the landscape.
13:19In those circumstances,
13:21hunting and gathering became very rich.
13:24Human populations increased.
13:28And for some people,
13:30like our first villagers at Abu Huraira
13:33in the Euphrates Valley,
13:35the hunting and gathering was so good
13:37in that area,
13:38they were able to settle down
13:39and to form a village.
13:42In the wake of these climatic shifts,
13:45dry and desolate landscapes
13:47gave way to grasslands and forests.
13:50An environment where animals grazed
13:55and trees grew heavy with fruit.
13:59All year long,
14:01food was plentiful here.
14:02The lodgings were framed
14:08with poplar trees,
14:10the walls and roofs sealed with thatch.
14:14A typical village consisted
14:17of several clusters of such dwellings.
14:21In time,
14:22these villages would prosper
14:23and their inhabitants
14:25assume a new social order.
14:28When people are moving
14:32across the landscape
14:33in small bands
14:34of just two or three families,
14:3610 or 20 people,
14:37they need very little
14:38in the way of social organization
14:41to run their affairs.
14:43But once they start
14:44to settle in villages,
14:45and the early villages,
14:46like Abu Huraira,
14:47had populations
14:48of 100 or 200 people,
14:50then they needed new forms
14:51of social organization.
14:53And we see them, too,
14:55starting to make fine objects.
14:58Big objects,
14:59like grinding stones,
15:00that they cannot carry around
15:02with them
15:02from campsite to campsite.
15:04So there are new crafts
15:05developing
15:05in these early villages
15:07before farming begins,
15:09and there are new ways
15:11of organizing society.
15:20Dramatic changes
15:21were also afoot
15:23in the Western Hemisphere.
15:24The glaciers
15:29covering North America
15:30had been slowly retreating
15:32as temperatures rose.
15:38According to one theory,
15:40as the towering glaciers
15:41melted,
15:42once gentle rivulets
15:44became a fury of streams.
15:47Eventually,
15:48they converged
15:49into one site.
15:50The flow created
15:57a huge lake
15:58in the middle
15:59of the continent
15:59with an enormous
16:01reservoir of water
16:02until the day
16:04the glaciers
16:05that had dammed
16:06the outflow
16:06collapsed.
16:08torrents of water
16:16poured from the Great Lake,
16:18creating floods
16:19of epic proportion.
16:20The escaping waters
16:27swept across North America,
16:29eventually reaching
16:30the Atlantic Ocean.
16:33The crushing surge
16:35of fresh water
16:35covered the warm ocean current
16:37like a lid on a pot.
16:40some scientists believe
16:43that this event
16:44may have triggered
16:45a new shift
16:46in global weather patterns.
16:52Evidence of Earth's
16:54grand climatic changes
16:55lies deep within
16:56the glaciers
16:57of the far north.
17:01A group of scientists
17:03from Copenhagen University
17:05has been studying
17:06these giants
17:07for more than a decade.
17:08In Greenland,
17:16ice that formed
17:17over the past
17:18250,000 years
17:20has accumulated
17:21in blocks
17:22more than a mile
17:23and a half thick.
17:27Sealed within
17:29are meteorological records
17:31of ancient weather patterns.
17:34By analyzing them,
17:36scientists may gauge
17:37with accuracy
17:38their historical effects.
17:44Buried far below the surface
17:46is 10,000-year-old ice.
17:52It's divided into distinct layers
17:55corresponding to years
17:57like the rings of tree trunks.
17:59locked in each layer
18:06is precise information
18:07about the ancient atmosphere.
18:12We know now
18:14that the planet's
18:15rising temperature
18:16suddenly dropped
18:1711,000 years ago.
18:20It plummeted by nearly
18:2620 degrees Fahrenheit
18:28matching the coldest
18:30period of the ice age.
18:40This brief ice age
18:42affected not only Greenland
18:43but the entire world
18:46and lasted
18:471,000 years.
18:48In the fertile crescent
18:57where man first settled
18:59the thick forests
19:00and grasslands
19:01disappeared
19:02creating dire
19:04food shortages.
19:07I think
19:08had this changing climate
19:09occurred
19:10several thousand years earlier
19:11it would not have been
19:12so disruptive
19:13but by now
19:14human populations
19:15has expanded
19:16quite considerably.
19:17so they were
19:18very dependent
19:19on rich hunting
19:20and gathering
19:21and when that
19:22was no longer possible
19:23when that was
19:24damaged
19:24if you like
19:25by this climatic reversal
19:27they had to find
19:28a new way of life.
19:30So I think
19:30the beginnings of farming
19:32are the result
19:33of a climatic change
19:34but they're also linked
19:37to growth
19:38in human population.
19:44For hunter-gatherers
19:46used to seasons of plenty
19:48solving the food crisis
19:50was a matter of survival
19:51and required
19:52a new way of thinking.
19:54As farming took hold
19:56as a lifestyle
19:57communities could support
19:59more people.
20:05In the course
20:06of their research
20:07Dr. Moore
20:08and his colleagues
20:09isolated more than
20:11150 different species
20:12species of plant seeds
20:14all collected
20:15by the ancient settlers.
20:19Wild wheat
20:20and legumes
20:21had appeared
20:22hardy plants
20:24that could withstand
20:25severe climatic change.
20:27the international
20:37research center
20:38of Japanese studies.
20:42Here
20:43Dr. Yoshinori Yasuda
20:45analyzes the pollen
20:47culled by the ancient
20:48Syrian settlers.
20:49He can predict
20:54how the climate
20:54affected their environment.
21:00His samples
21:01include vast amounts
21:02of pollen
21:03from wheat,
21:04barley,
21:04and rice plants
21:05survivors of the
21:07devastating ice age
21:08that had threatened
21:09their civilization.
21:14Cereal grasses
21:15abounded in the wooded
21:17uplands of the
21:18fertile crescent.
21:20Many of the plants
21:21were wild,
21:23but other apparently
21:24domesticated varieties
21:25were also discovered
21:27there.
21:34Dr. Yasuda believes
21:36that this pollen
21:37offers proof
21:38of a new human
21:39enterprise,
21:41agriculture,
21:43the science
21:43that would turn grains
21:44into a dietary staple.
21:47When the new ice age
21:54hit 11,000 years ago,
21:55it was no longer
21:56practical for people
21:57to rely on the forest
21:59for food.
22:04I believe
22:05that people
22:05then turned
22:06to cultivation,
22:08domesticating rice plants
22:09in the wild grasslands.
22:14The cold climate
22:15caused a food crisis
22:16and humans
22:17were forced
22:18to make the shift
22:19towards agriculture.
22:24Though the relentless cold
22:26had dealt them
22:26a serious blow,
22:28generations of settlers
22:30used their ingenuity
22:31to survive.
22:38Over the years,
22:40our ancestors
22:41sowed a variety
22:42of grain,
22:43learning through trial
22:44and error
22:45and error
22:45which would take
22:46to the landscape.
22:49The cereals harvested
22:51would be husked
22:52and ground
22:53for porridge
22:54or bread.
22:56One of the most successful
22:58grains
22:58was wheat.
23:03With the domestication
23:04of plants,
23:05humans would cease
23:07to be the product
23:07of natural selection.
23:10Instead,
23:11they would be
23:12the agents
23:13of growth
23:13and change,
23:15steering the direction
23:16of other species.
23:19Small enclaves
23:20of humanity
23:21would blossom
23:22into larger ones
23:23and nomadic societies
23:25would dwindle
23:26as farming
23:27became a way of life.
23:28by cultivating
23:39the earth,
23:40humans gained
23:41more control
23:42over their food supply
23:43and relied less
23:45on the random
23:46gifts of nature.
23:48This simple act
23:50would revolutionize
23:51how society developed.
23:53Dr. George Wilcox
24:00of the Institute
24:00of Eastern Prehistory
24:02in France
24:03is studying
24:04how wild wheat
24:05becomes domesticated.
24:09The relationship
24:10between man
24:10and cereals
24:11really developed
24:12into a symbiosis
24:13in that man
24:14became completely
24:15dependent
24:16on cereal cultivation
24:17because when
24:19his population
24:19reached a certain level,
24:21he would not be able
24:21to find enough food
24:23in the environment
24:24and so he was
24:25totally dependent
24:26on this production
24:28economy of cereals.
24:29Looking at it
24:30from the other
24:30point of view,
24:31very rapidly,
24:33the cereals evolved
24:35into plants
24:37which were incapable
24:38of reproducing
24:38themselves in the wild
24:40and this is,
24:42we can see this
24:42quite simply
24:43because the ears
24:45stay intact
24:47after maturity
24:48and are left open
24:49to attack
24:49by birds and insects.
24:51whereas in the wild
24:53they will fall
24:53to the ground
24:54and this is why
24:55domesticated cereals
24:57cannot really survive
24:58in the wild
24:59and so they became
25:00completely dependent
25:01on man
25:02for their reproduction.
25:06The wild wheat
25:07in the foreground
25:08is covered
25:09with a thick husk.
25:11The domesticated
25:12variety alongside
25:13is thinner
25:14with the grain
25:15double its size.
25:18Cultivating crops
25:19for human consumption
25:20required experimentation.
25:25Dr. Wilcox believes
25:27that pre-agricultural
25:29societies already
25:30had tools
25:31conducive to farming
25:32including the stone sickle.
25:39Discovered in Jordan,
25:41this harvesting tool
25:42is 10,000 years old.
25:48The handle
25:49was made of animal bone
25:51to which a sharp stone blade
25:53was attached.
25:55Honed to perfection,
25:56it cut like a knife of steel.
26:01This is what really changed
26:02the selection pressures.
26:04During the gathering stage,
26:06they would have sickles like this
26:07but what they wouldn't do
26:09of course
26:09would be to sow
26:10and the big change
26:12comes when they start sowing
26:13and their economy
26:14becomes an economy
26:15of production.
26:16In other words,
26:17they can increase
26:19the quantity
26:21of grain needed
26:22for their population
26:24and so that
26:25as the population increased
26:26so would the production increase.
26:33Farming and shepherding
26:35would spread to areas
26:36throughout the Fertile Crescent.
26:39Among them,
26:40the Beta Site
26:41in the Jordan Rift Valley.
26:46Mortars of stone
26:48have been uncovered,
26:50tools to grind flour
26:51into wheat
26:52for bread baking.
26:53agriculture created a demand
27:07for new goods and services.
27:12The mass production of food
27:15and the establishment
27:16of property
27:16required our ancestors
27:18to move a giant step away
27:21from their hunter-gatherer pasts.
27:25The development
27:26of agricultural societies
27:28was a turning point
27:29in human civilization.
27:33Up until about
27:3410,000 years ago,
27:36the global population
27:38had leveled off
27:39but with the rise
27:40of agriculture,
27:42it skyrocketed.
27:445,000 years ago,
27:46the Earth already
27:47supported 100 million people.
27:51The Ebla Palace
27:59in northern Syria.
28:02Built about 5,000 years ago,
28:06this ancient city
28:07was a major center
28:08of commerce
28:09and home
28:10to some 200,000 people.
28:17The bazaar at Ebla
28:18offered harvests
28:20from miles around.
28:26This is the oldest
28:27known library.
28:29It belonged to the king
28:30of Ebla.
28:33From the remnants
28:34of his library,
28:3615,000 clay plates
28:38written in cuneiform
28:39were preserved.
28:43Most were business documents
28:45dealing with taxes,
28:46land ownership,
28:48and agricultural trade.
28:54This one lists wages
28:56paid in wheat.
28:59From these ancient records,
29:02it is clear that
29:03as agriculture
29:04became more productive,
29:06man was less concerned
29:07about his daily survival.
29:09ornaments of gold
29:13reflect the material wealth
29:15of the kingdom
29:16and are signs
29:17of a higher culture
29:18with well-developed
29:20artistic expression.
29:21The evolution
29:34of agricultural societies
29:36opened another chapter
29:38in Earth's book of life,
29:40the birth of civilization.
29:42along the banks
29:50of the Tigris
29:51and Euphrates
29:51in Egypt
29:52and the river basins
29:54of the Indus.
29:57And in China,
29:59the first roots
30:00of civilization
30:00sprouted in the river paddies
30:02where a new crop
30:04called rice
30:05was being farmed.
30:06in central Syria,
30:13a mill built
30:13more than a thousand
30:14years ago
30:15still functions today.
30:19Farmers depend
30:20on this ancient
30:2190-foot workhorse
30:23to help irrigate
30:24the local crops.
30:36With the introduction
30:37of irrigation
30:38and cultivation,
30:40food production grew
30:41at an astounding rate.
30:46Powering the mill
30:47was a feat of engineering
30:49in its day.
30:51The harnessing
30:51of moving water
30:52required new technology.
31:01Many hundreds of years later,
31:03in the late 18th century,
31:05mechanical innovations
31:06would initially drive
31:08the industrial revolution.
31:18With the invention
31:19of the steam engine,
31:21the power available
31:22for human enterprise
31:24was staggering
31:24and would change
31:26the very rhythms
31:27of daily life.
31:35In the centuries
31:36that followed,
31:37humans would reach
31:38for even greater control
31:40over their environment,
31:42mining fossil fuels
31:43like coal and oil
31:45to exploit their energy.
31:49Within only a few generations,
31:52they would ransack
31:53a wealth of natural resources
31:55that had been accumulating
31:57for eons.
31:58and they would multiply
32:02in such great numbers
32:04to outpace
32:05every other species
32:07in history.
32:10Today,
32:11planet Earth
32:12supports about
32:13five and a half billion
32:14Homo sapiens.
32:15Here in the peaceful
32:23New England countryside,
32:24the pressures
32:25of the human population
32:26explosion
32:27seem very remote.
32:31At the University
32:32of New Hampshire,
32:33Dr. Dennis Meadows
32:34runs a think tank
32:35that predicts future trends.
32:38His prognosis
32:39for humanity
32:40is bleak.
32:41We see that
32:44the planet
32:45rather quickly
32:47loses the ability
32:49to feed everybody.
32:51Then,
32:53with the
32:54deterioration
32:55of the agricultural system,
32:57it becomes
32:58more and more difficult
32:59to sustain
32:59industrial growth.
33:02And finally,
33:03maybe in the period
33:042030
33:05or 2050,
33:07the global population
33:08actually peaks
33:09and the death rate
33:10starts to go up
33:11and the population
33:12comes back down again
33:13to levels
33:14which can be fed.
33:20Humans
33:20are now facing
33:21our limits
33:22to growth.
33:24Do we have
33:25the wisdom
33:26and the luck
33:27to overcome
33:28this crisis?
33:29Or will we fade
33:30to extinction
33:31like so many
33:33creatures before us?
33:41While we contemplate
33:43our future
33:44here on Earth,
33:45some futurists
33:46look to space
33:47as our next frontier.
33:49They dream
33:50of altering
33:51the ecology
33:52of Mars
33:52to sustain
33:53human life.
33:56It's possible.
33:57It's scientifically possible.
33:59It's no longer
33:59in the realm
34:00of science fiction.
34:02But the question then
34:04is,
34:04should we restore Mars
34:05to have a condition?
34:07I mean,
34:07we can,
34:07but should we?
34:08In some sense,
34:10human beings
34:10are the seeds
34:11that can take life
34:13from one planet
34:14to another planet
34:15and beyond
34:15throughout the whole galaxy
34:17because we are
34:19the only species
34:20that has the intelligence
34:22required
34:22to build the machines,
34:25to develop the technology,
34:26to spread life
34:27from beyond
34:28the Earth.
34:30And so one can view
34:31in some sense
34:32human beings
34:33as having a unique role
34:35and a unique charter
34:36among the organisms
34:39of Earth
34:39which is to spread
34:40that life.
34:43The average temperature
34:45on Mars
34:46is minus 80 degrees Fahrenheit
34:48and its atmosphere
34:50very thin.
34:56Vast oceans of water
34:58lie buried
34:58under layers
34:59of polar ice.
35:01releasing them
35:08is at the core
35:09of the plan
35:10to terraform Mars.
35:18Satellites equipped
35:19with huge reflecting mirrors
35:22would channel solar heat.
35:24as the ice caps
35:40began to melt
35:41they would release
35:43vapor
35:43into the Martian
35:44atmosphere.
35:45an arsenal of technology
36:03would be deployed
36:04to terraform the planet.
36:06to speed the thaw
36:13factories constructed there
36:16would emit
36:17greenhouse gases.
36:22The vapor
36:23would condense
36:24into rain
36:25and shower
36:26the Martian surface.
36:27rivers would form
36:40and the oceans
36:42of Mars
36:43would come to life.
36:51The plan
36:52optimistically estimates
36:54100 years
36:55to create
36:56those oceans
36:58and another
36:58100,000 years
37:00to make Mars
37:01fit for human habitation.
37:09Replicating the steps
37:11of Earth's development
37:12photosynthesizing bacteria
37:14would be released
37:15on the Martian surface
37:17and then plants
37:19to produce oxygen.
37:26In time
37:28the atmosphere
37:29on Mars
37:30might resemble
37:31our own.
37:36Eventually
37:37this future world
37:38would support
37:39a Martian metropolis
37:41full of human colonists.
37:47If curiosity
37:49is a measure
37:50of intelligence
37:51it is natural
37:52for humans
37:53to look beyond
37:54our horizon.
37:59Before we dare
38:00to design
38:01a new world
38:02we would be wise
38:03to understand
38:04our own.
38:08We will never
38:09fully understand
38:10ourselves
38:10or our Earth
38:11only by looking in.
38:13There is a certain
38:14requirement to look out
38:15to compare ourselves
38:17to other worlds
38:17and to other futures.
38:19and I think
38:20Mars plays a key role
38:21there
38:21in that it is
38:22the planet
38:23that's the most
38:23like Earth.
38:24And the technology
38:25that we've developed
38:26allows us
38:28to contemplate
38:29going to Mars
38:30studying it
38:31taking life
38:32there with us
38:33and maybe even
38:34constructing a biosphere
38:35terraforming Mars.
38:40What exactly
38:42does it take
38:42to support
38:43life on Earth?
38:44To answer
38:48that question
38:49scientists
38:50built a model
38:51here in the dusty
38:52Arizona desert.
38:58Called
38:59Biosphere 2
39:00it was the first
39:02serious attempt
39:03to build
39:04an entirely
39:04closed
39:05and self-sustainable
39:07ecosystem.
39:07The Noah's Ark
39:15of the desert
39:16biosphere housed
39:183,800 different
39:19animal and plant
39:21species.
39:24The atmosphere
39:25inside
39:26was isolated
39:27from the world
39:28beyond its
39:29huge glass dome
39:31by airlocks.
39:34Plants
39:35would provide
39:36all necessary oxygen
39:38and the habitat
39:39would be
39:40self-sufficient
39:41requiring no
39:42supplies
39:43from the outside.
39:52Its bold design
39:54would be put
39:54to the test
39:55in September
39:561991
39:57by eight volunteers.
39:59They would live
40:00in the facility
40:01as part of an
40:02experiment
40:02studying the
40:03viability
40:04of the artificial
40:06ecosystem.
40:08For the next
40:09two years
40:09they would be
40:10cut off
40:11from all
40:11physical contact
40:13with the outside
40:13world.
40:15They would have
40:15to survive
40:16on the crops
40:17they grew
40:18within the
40:18biosphere.
40:20At first
40:21the experiment
40:22appeared to be
40:23running smoothly
40:24but all too soon
40:26there was
40:26emergency
40:27one of many
40:28that would
40:29plague the project.
40:30Linda Lay was
40:36in charge of
40:37the plans
40:38they depended
40:38on for food.
40:42Our oxygen
40:43started to decline
40:44and it declined
40:45to a point
40:46where it was
40:46difficult for us
40:47to breathe.
40:48We would take
40:49a few steps
40:50up a staircase
40:51and have to take
40:52a big breath
40:53because we would
40:54be out of breath.
40:55It was very difficult
40:56to live under
40:57those conditions,
40:57very difficult
40:58to do all
40:59of the work
40:59that we had
41:00to do in here
41:01to grow
41:01our own food
41:02and to maintain
41:03our systems
41:03with the shortage
41:04of oxygen.
41:08The oxygen levels
41:10continued to fall
41:11eventually registering
41:13dangerously low.
41:16Just where the gas
41:17was going
41:18within the sealed
41:18habitat
41:19puzzled scientists.
41:22To resolve
41:23the immediate
41:24crisis
41:24they decided
41:25to boost
41:26the oxygen level
41:27pumping it in
41:29from the outside.
41:31In so doing
41:32the parameters
41:33of the original
41:34experiment
41:34a self-sustainable
41:36biosphere
41:37were breached.
41:40But without
41:40the additional oxygen
41:42the volunteers
41:43would not be able
41:45to survive.
41:49The source
41:51of the oxygen
41:51depletion
41:52continued to
41:53elude scientists
41:54scientists
41:55until at last
41:56they analyzed
41:57the composition
41:58of biosphere's
41:59soil.
42:02To their surprise
42:04the earth
42:05inside the facility
42:06was absorbing
42:07the limited supply.
42:11Fresh, nutrient-rich
42:12soil had been spread
42:14throughout biosphere
42:15providing an ideal
42:16environment
42:17for bacteria
42:17to grow.
42:20Bacteria
42:20also breathe
42:21oxygen.
42:23The scientists
42:24in charge
42:24had not accounted
42:25for this
42:26unexpected variable.
42:27On biosphere 1
42:31on the earth
42:32we have a balance
42:33between the amount
42:34of oxygen
42:35that's produced
42:36by the plants
42:36and the amount
42:37of oxygen
42:37that's consumed
42:38by the microbes
42:39in the soils.
42:40And this is fairly
42:41stable on the earth.
42:43Well in biosphere 2
42:43it's not stable.
42:45And in fact
42:45there is more
42:46consumption of oxygen
42:47by the microbes
42:48in the soil
42:48than there is
42:49production of oxygen
42:50by the plants.
42:52Our oxygen
42:52was going
42:53into the soils.
42:54Well another part
42:55of that which is
42:55not a biological
42:56process is that
42:58when oxygen
42:59is consumed
43:00by the soils
43:00the soil produces
43:01carbon dioxide.
43:03And were we
43:04to see that
43:05in our atmosphere
43:05we would have known
43:06that it was a soil
43:07problem but we did
43:08not see this buildup
43:09of carbon dioxide
43:10because the concrete
43:11was absorbing
43:12the carbon dioxide.
43:14So we had first
43:14of all a biological
43:15process which was
43:16an imbalance
43:17of production
43:18and consumption
43:19of oxygen
43:19and then a
43:21sequestering
43:22of carbon dioxide
43:22by the concrete.
43:25So seamless
43:28is the order
43:29of the natural world
43:31that we underestimate
43:32its complexity.
43:34Perhaps this is
43:35a lesson
43:36of Biosphere 2.
43:40Shaped over
43:41billions of years
43:42Earth's changing
43:43ecosystems
43:44determine
43:44what will grow here.
43:47Grasping the nuances
43:48of their fragile balance
43:49could take many
43:51human lifetimes.
43:56Until we understand
43:57this planet of life
43:58dare we contemplate
44:01the shaping
44:01of distant worlds?
44:06By considering
44:07how to build
44:08a Biosphere on Mars
44:09we will learn a lot
44:10about how our Biosphere
44:12works
44:12and about how to
44:13take care of
44:13our Biosphere
44:14and how to prevent
44:15it from failure
44:17which would be
44:17a real disaster
44:19if we don't
44:20manage it properly.
44:21And whether we like
44:22it or not
44:22human beings
44:24have to become
44:24the managers
44:25of the Biosphere.
44:26We have such
44:27an impact
44:28on the Biosphere
44:29that we can no longer
44:30allow it to take
44:31care of itself.
44:32We have to start
44:33deciding what we're
44:34going to do
44:34and how we're going
44:35to manage it.
44:36And so we have to learn
44:37a lot more
44:38about Biospheres
44:39than we know
44:39right now.
44:46In the 20th century
44:48man first ventured
44:50into outer space.
44:55From his vantage point
44:56on high
44:57the Earth
44:58was a breathtaking sight.
45:05Brilliant blue skies
45:06framed islands
45:07of life below.
45:09And for one
45:11unparalleled moment
45:12all humankind
45:14marveled with gratitude
45:15at the extraordinary
45:17place we call home.
45:23If we are to continue
45:24our journey on Earth
45:26we must find the wisdom
45:28to change
45:29or perhaps
45:30cede our place
45:32to the next
45:33in the evolutionary line.
45:39the future
45:40of life below.
45:41And for one
45:42to be able to
45:43to the future
45:44to the future
45:44and to the future
45:45and to the future
45:45we must find the wisdom
45:45of the future.
45:45And for one
45:45of the future
45:46who is the
45:46true
45:46of the future
45:47and the future
45:47and the future
45:47of the future
45:49we must find the truth.
45:51So we will be able to do this
45:52in our lives.
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