♪ NARRATOR: THIS YEAR, THE WORLD'S BEST-KNOWN CLIMATE ACTIVIST, GRETA THUNBERG, TURNED 18.

GRETA, VOICE-OVER: PEOPLE SAY A LOT OF THINGS ABOUT ME.

DONALD TRUMP: GRETA-- YOU KNOW GRETA?

[CROWD JEERING AND BOOING] GRETA, VOICE-OVER: PEOPLE CALL ME A BRAT, AN IDIOT... AND YET, FOR REASONS I DON'T UNDERSTAND, PEOPLE LISTEN WHEN I TALK.

[CROWD CHEERING] YOU ARE LISTENING TO ME RIGHT NOW... [CROWD CHANTING "GRETA"] BUT I DON'T WANT THAT.

I DON'T WANT YOU TO LISTEN TO ME.

I WANT YOU TO LISTEN TO THE SCIENCE.

MAN: WE ARE SEEING A HUGE CHANGE IN THE TEMPERATURE OF THE PLANET.

THE SCIENCE IS VERY CLEAR.

WOMAN: THIS IS NOT SOMEONE ELSE'S PROBLEM.

WE ALL NEED TO ACT NOW.

NARRATOR: THIS SERIES FOLLOWS GRETA ON AN EXTRAORDINARY YEAR IN HER MISSION TO FIGHT CLIMATE CHANGE.

GRETA: I'VE BEEN GOING THE WHOLE WAY AROUND THE WORLD THE WRONG WAY.

NARRATOR: IN 2019, SHE TOOK A YEAR OFF SCHOOL AND SET OUT TO WITNESS FIRSTHAND THE IMPACT OF GLOBAL WARMING WITH THE WORLD'S LEADING CLIMATE EXPERTS... MAN: THIS YEAR, WE HAD THE FASTEST MELT RATE WE'VE EVER MEASURED-- 6 METERS OF ICE DOWN.

NARRATOR: AND DISCOVER WHETHER TECHNOLOGY CAN HELP PROTECT OUR FUTURE.

MAN: WE COULD STORE ALL THE EMISSIONS WE COULD POTENTIALLY IMAGINE.

GRETA, VOICE-OVER: WE SHOULD BE HOPEFUL, BUT HOPE DOESN'T COME FROM WORDS.

HOPE ONLY COMES FROM ACTION.

ANNOUNCER: GRETA'S TAKEN HER PROTEST TO THE GLOBAL STAGE... GRETA: WORLD LEADERS ARE BEHAVING LIKE CHILDREN, SO IT FALLS ON US TO BE THE ADULTS IN THE ROOM.

NARRATOR: BUT IN A YEAR WHEN COVID-19 BROUGHT LIFE TO A STANDSTILL...

THE RISK LEVEL HAS RISEN.

THE CORONAVIRUS CONTINUES TO SPREAD.

GRETA: I HAVE CONTRACTED THE CORONAVIRUS.

NARRATOR: CAN GRETA CONVINCE A WORLD REELING FROM ONE CRISIS TO FINALLY FACE ANOTHER?

WOMAN: COVID-19 HAS REALLY GIVEN THE WORLD A TREMENDOUS OPPORTUNITY TO RESET.

MAN: WE'RE NEVER GETTING OUT OF HERE.

WOMAN: HOW WE ADDRESS THE CLIMATE CRISIS WILL DETERMINE WHAT THE FUTURE OF LIFE ON EARTH LOOKS LIKE.

GRETA: WE CAN ACT, BUT WE DON'T HAVE TIME TO WAIT.

♪ ♪ WOMAN, ON RADIO: FROM THE UNITED NATIONS TO THE U.S. CONGRESS, GRETA THUNBERG IS GAINING INTERNATIONAL ACCLAIM FOR HER FIGHT TO STOP CLIMATE CHANGE.

NARRATOR: JUST 4 WEEKS AGO AT THE START OF HER YEAR OUT OF SCHOOL, GRETA WAS IN NEW YORK ADDRESSING THE UNITED NATIONS.

AND IF YOU CHOOSE TO FAIL US, I SAY, WE WILL NEVER FORGIVE YOU.

[APPLAUSE] HOW DARE YOU?

NARRATOR: ALTHOUGH GRETA'S SPEECH HAS CATAPULTED HER TO GLOBAL PROMINENCE, SHE HAS NO ENTOURAGE.

SHE'S TRAVELING WITH JUST HER FATHER SVANTE.

THEY'RE HEADING FAR BEYOND THE GLARE OF THE WORLD'S MEDIA TO THE CANADIAN ROCKIES TO SEE FIRSTHAND EVIDENCE OF CLIMATE CHANGE...

BUT FIRST, SHE'S GOING NORTH TO EDMONTON TO ADDRESS A CLIMATE STRIKE IN THE CAPITAL OF THE OIL-RICH PROVINCE OF ALBERTA.

♪ GET DOWN ♪ ♪ KEEP FOSSIL FUELS IN THE GROUND ♪ ♪ GET UP, GET DOWN ♪ ♪ KEEP FOSSIL FUELS IN THE GROUND ♪ MAN: YOU WRITING YOUR SPEECH?

NO.

IT'S ALREADY DONE.

I'M JUST READING THROUGH IT TO MAKE SURE THAT I DON'T WANT TO MAKE ANY LAST-MINUTE CHANGES WHICH I ALWAYS DO.

SVANTE: MAYBE I SHOULD GO IN ADVANCE WITH THE BIG BAG.

WE DO EVERYTHING TOGETHER SO MUCH, BUT THIS PART WE DON'T TO TOGETHER.

GRETA: NO.

I DON'T WANT HIM AT THE MARCHES.

SVANTE, VOICE-OVER: FATHER, SUPPORTIVE FATHER.

THAT'S THE ROLE I PLAY.

YOU KNOW, FIRST TIME SHE SPOKE IN PUBLIC, YOU KNOW, I WAS TERRIFIED, YOU KNOW, BECAUSE OF HER AUTISM.

WOULD SHE RUN AWAY?

WOULD SHE START TO CRY?

WOULD SHE GO SILENT?

WOULD SHE DO SOMETHING THAT WOULD HURT HER?

MAN: OUR STREETS!

WHOSE STREETS?

OUR STREETS!

GRETA: WILL THIS BE TOO WARM?

SVANTE: YEAH.

NO.

I'D SAY NO... AND TAKE THE STAIRS BECAUSE THE LIFT TAKES FOREVER.

SEE YOU DOWN THERE.

♪ NARRATOR: IT'S BARELY A YEAR SINCE GRETA FIRST SKIPPED SCHOOL AND STARTED A LONE PROTEST OUTSIDE THE SWEDISH PARLIAMENT DEMANDING ACTION ON CLIMATE CHANGE.

MY NAME IS GRETA, AND I AM 15 YEARS OLD, AND I AM SCHOOL-STRIKING FOR THE CLIMATE.

WE WILL NOT STOP.

THIS IS OUR FUTURE, AND THIS IS OUR CHOICE.

NARRATOR: SINCE THEN, HER ACT OF DEFIANCE HAS INSPIRED THE YOUNG, CAPTURED THE ATTENTION OF WORLD LEADERS, AND SNOWBALLED INTO A MASS MOVEMENT.

GRETA, VOICE-OVER: MY FAVORITE STORY GROWING UP WAS "THE EMPEROR'S NEW CLOTHES."

THE EMPEROR IS NAKED, AND EVERYONE JUST PRETENDS HE ISN'T.

THE ONLY ONE WHO DARES TO QUESTION THIS COLLECTIVE LIE IS A CHILD.

THAT STORY REALLY IS THE STORY OF OURSELVES, OF OUR SOCIETY, OF HOW THE WORLD LOOKS NOW.

WE CLIMATE ACTIVISTS ARE ALL THAT CHILD SAYING THAT THE EMPEROR IS NAKED.

MAN: THE ENVOY WITH GRETA IS ON ITS WAY.

GRETA, VOICE-OVER: WHEN SOMEONE DARES TO SAY THAT OUT LOUD, THAT CHANGES SOMETHING.

GRETA: TODAY IS FRIDAY, AND, AS ALWAYS, WE ARE ON CLIMATE STRIKE... [CHEERING] AND WE TEENAGERS ARE NOT SCIENTISTS, NOR ARE WE POLITICIANS, BUT IT SEEMS MANY OF US UNDERSTAND THE SCIENCE BECAUSE WE HAVE DONE OUR HOMEWORK.

[CHEERING] GRETA, VOICE-OVER: PEOPLE THINK THAT I'M AN ANGRY TEENAGER WHO SCREAMS AT WORLD LEADERS.

THAT'S, LIKE, THE PICTURE PEOPLE HAVE OF ME.

THAT'S NOT WHO I AM.

GRETA: WE ARE DOING THIS BECAUSE OUR FUTURE IS AT STAKE AND WE WANT THE PEOPLE IN POWER TO UNITE BEHIND THE SCIENCE.

[CHEERING] GRETA, VOICE-OVER: WE SAY, YEAH, WE'RE GONNA LIMIT THE GLOBAL AVERAGE TEMPERATURE RISE TO 1.5-- THAT'S WHAT IT SAYS IN THE PARIS AGREEMENT-- BUT THEN WE JUST CONTINUE LIKE BEFORE, WHICH WILL BE CATASTROPHIC.

THAT IS WHAT I'M TRYING TO HIGHLIGHT.

GRETA: SO THANK YOU, AND CONTINUE.

NEVER GIVE UP.

WE STAND TOGETHER.

[CROWD CHEERING] NARRATOR: IN 2015, 196 STATES SIGNED UP TO THE PARIS AGREEMENT TO LIMIT GLOBAL TEMPERATURE RISE TO WELL BELOW 2 DEGREES CELSIUS AND PURSUE EFFORTS TO KEEP IT TO 1.5 DEGREES.

GRETA'S MISSION IS TO HOLD THEM TO THE AGREEMENT, BUT NOT EVERYONE HERE SUPPORTS HER MESSAGE.

WOMAN: HERE IN A PROVINCE THAT RELIES ON RESOURCE REVENUE, THE SOUND OF OPPOSITION RINGS LOUD.

[TRUCK HORN HONKS] MAN: WE WANT TO SHOW CANADA AND GRETA THAT WE'RE VERY ENVIRONMENTALLY FRIENDLY, AND IN ALBERTA WITH OUR OIL PATCH, WE'RE ENVIRONMENTAL LEADERS IN THE WHOLE WORLD.

DIFFERENT MAN: WELL, WE'RE JUST MAKING A LITTLE NOISE TO LET PEOPLE KNOW THAT ALBERTA ISN'T ABOUT TO GIVE UP ON OUR OIL SANDS OR OIL-GAS EFFORT.

WOMAN: WE NEED JOB IN ALBERTA.

MAN: DO WE NEED GRETA?

PARDON ME?

NO.

♪ NARRATOR: THE CANADIAN OIL AND GAS INDUSTRIES EMPLOY OVER 170,000 PEOPLE AND CONTRIBUTE OVER $70 BILLION A YEAR TO THE COUNTRY...

BUT IT'S ALSO THE LARGEST CONTRIBUTOR TO CANADA'S GREENHOUSE GAS EMISSIONS, A POTENTIAL TRADEOFF BETWEEN THE STRENGTH OF THE ECONOMY AND THE HEALTH OF THE PLANET.

IT'S A STORY REPEATED AROUND THE WORLD.

GRETA: THIS IS WHAT IT'S ALL ABOUT.

THIS IS THE CENTER, THE HEART OF IT, THE THING THAT DRIVES EVERYTHING AND THAT DRIVES THE ECONOMY.

PEOPLE WON'T SEE THIS.

THEY WON'T SEE HOW THIS OIL IS EXTRACTED, WHERE THEIR PETROL OR WHERE THEIR FUEL COMES FROM, AND YET IT IS DESTROYING SO MANY PEOPLE'S LIVES AND SO MUCH NATURAL HABITAT, SOMETHING DEFINITELY NEEDS TO CHANGE, SOMETHING DRASTIC, AND YET I DON'T KNOW HOW THIS INDUSTRY WILL BE ABLE TO CONTINUE IF WE TAKE THE ACTION REQUIRED, BUT IT HAS TO CHANGE.

THINGS HAVE TO CHANGE.

WOMAN, ON RADIO: AVERAGE TEMPERATURES IN CANADA HAVE RISEN BY 1.7 DEGREES CELSIUS, TWICE AS FAST AS THE REST OF THE WORLD.

NARRATOR: 1.7 DEGREES SINCE THE 1940S MIGHT NOT SEEM SIGNIFICANT...

BUT TO UNDERSTAND THE IMPACT THAT CAN HAVE, GRETA IS SPENDING THE NEXT WEEK HEADING TO 3 KEY LOCATIONS IN NORTH AMERICA.

FIRST, SHE'S OFF TO JASPER NATIONAL PARK IN CANADA'S ROCKY MOUNTAINS.

IT'S HOME TO PRISTINE PINE FORESTS, BUT HUGE TRACTS ARE DYING.

I HAVE STUDIED... NARRATOR: GRETA'S COME TO MEET BIOLOGIST BRENDA SHEPHERD TO FIND OUT WHAT'S CAUSING THIS DRASTIC CHANGE.

GRETA: WHAT KIND OF DIFFERENT ANIMALS ARE THERE HERE USUALLY?

WHEN I WALKED DOWN HERE ON FRIDAY, I SAW A FEMALE GRIZZLY BEAR WITH HER 3 CUBS ON THIS TRAIL.

NARRATOR: SCIENTISTS HAVE DISCOVERED THAT A RISE IN TEMPERATURE HAS ALLOWED A PEST TO FLOURISH AND ATTACK THESE TREES, LEAVING THEM DEFENSELESS.

AND WHAT IS THIS COLORING ON THE SIDE?

SO THIS TREE IS ALL RED AND DEAD, AND IT WAS INFESTED BY MOUNTAIN PINE BEETLE.

IT EVENTUALLY KILLS.

THE FEMALES BURROW IN UNDER THE BARK, AND THEN THEY START TO EAT THE TISSUE AND BUILD THESE GALLERIES, AND INSIDE THE GALLERIES IT ALMOST LOOKS LIKE A MAZE UNDER THE BARK, AND SHE LAYS HER EGGS.

♪ NARRATOR: WHEN THE LARVAE HATCH, THEY FEED ON THE TISSUE THAT THE TREE USES TO TRANSPORT ITS NUTRIENTS.

EFFECTIVELY, IT STARVES.

BRENDA SHEPHERD: IT'S RARE FOR A TREE TO BE ABLE TO SURVIVE A MOUNTAIN PINE BEETLE INFESTATION.

THE NEEDLES WILL START TO DROP, AND THEY WILL BECOME KIND OF LIKE SKELETON TREES.

THE BEETLES HAVE NEVER BEFORE CAUSED SUCH WIDESPREAD DESTRUCTION HERE.

FREEZING WINTER TEMPERATURES NORMALLY KILL THEM OFF.

GRETA: SO APPROXIMATELY HOW COLD DOES IT NEED TO BE TO KILL THIS BEETLE?

WE NEED AT LEAST SEVERAL DAYS OF AROUND MINUS 40, WHICH WOULD BE HISTORICALLY THE NORM FOR US, BUT OVER THE LAST DECADE, THE WINTERS HAVE NOT BEEN COLD ENOUGH ANYMORE TO KILL THE BEETLE.

THE POPULATION OF MOUNTAIN PINE BEETLE HAS BEEN GROWING AND GROWING IN THE PARK.

ABOUT 50% OF THE FORESTED AREA OF THE PARK HAS BEEN AFFECTED.

HALF OF THE FOREST.

HALF THE FORESTED AREA, AND THE PARK IS BIG.

LIKE, IT'S 11,000 SQUARE KILOMETERS.

IT'S HARD TO THINK ABOUT, IT'S JUST SO BIG TO UNDERSTAND.

DOES THAT HAVE ANY EFFECT ON ANY OTHER SPECIES, AS WELL?

THIS TREE IS SUPPORTING THE BIRDS, THE SQUIRRELS, THE GRIZZLY BEARS, AND MANY OTHER SPECIES, AND THE ECOSYSTEM WOULD BE CHANGED DRASTICALLY IF THAT SPECIES WERE NO LONGER THERE.

YOU MIGHT NOT THINK THAT THESE SMALL, SMALL, INSIGNIFICANT CHANGES IN MEASURED TEMPERATURES WOULD LEAD TO ANYTHING, BUT WE HAVE TO UNDERSTAND THAT ECOLOGICAL SYSTEMS ARE VERY COMPLEX.

IF YOU CHANGE ONE TINY THING VERY, VERY SLIGHTLY, THAT COULD HAVE DEVASTATING CONSEQUENCES.

♪ WOMAN: WHAT WE NOW KNOW IS, NATURE IS ALL COMPLETELY INTERCONNECTED, AND SO, THEREFORE, WHEN CLIMATE CHANGE AFFECTS ONE ASPECT, IT HAS REPERCUSSIONS ON ALL OTHER ASPECTS.

MAN: WE'RE LIVING THROUGH A BIODIVERSITY CRISIS.

ONE STUDY SHOWED THAT FOR THE BEST-STUDIED SPECIES-- LAND MAMMALS, BIRDS, REPTILES, AND AMPHIBIANS-- SOME 20% TO 30% OF THOSE SPECIES WILL BE COMMITTED TO EXTINCTION BY 2050 ON CURRENT TRENDS.

IT'S A REALLY SHOCKING, WORRYING STATISTIC.

WOMAN: THERE ARE SO MANY SPECIES THAT ARE ALREADY ENDANGERED.

THEY ARE ALREADY AT THE BRINK.

WHAT CLIMATE CHANGE IS DOING TO BIODIVERSITY IS PUTTING SO MUCH OF WHAT'S LEFT AT RISK.

WILLIS: IF YOU LOOK OVER THE LAST 10 YEARS AT DROUGHT EVENTS, THESE ARE KILLING OFF THESE BEAUTIFUL TREES, THESE ABSOLUTE GIANTS OF THE RAINFOREST, AND WITH THOSE TREES, YOU'RE NOT ONLY LOSING THE BIODIVERSITY ASSOCIATED WITH THE TREES.

YOU ALSO LOSING THE ABILITY OF THAT TREE TO TAKE UP ATMOSPHERIC CARBON DIOXIDE.

THESE TREES, THEY'RE OFTEN DESCRIBED AS THE LUNGS OF THE EARTH.

TAKE THOSE TREES AWAY, YOU LOSE THE ABILITY OF NATURE TO REALLY BALANCE OUR ATMOSPHERE.

NARRATOR: GRETA'S COMMITMENT TO ACTIVISM HAS SEEN HER SPEND MUCH OF THE LAST YEAR ON THE ROAD.

♪ GRETA, VOICE-OVER: I WANT TO BE JUST A NORMAL TEENAGER, BUT THIS IS NOT A NORMAL SITUATION, AND I THINK WE MUST STEP OUT OF OUR COMFORT ZONES.

SVANTE: AS A PARENT, I SUPPORT HER IN WHAT SHE DOES, IF SHE WOULD HAVE BEEN A FOOTBALL PLAYER OR IN BALLET DANCING OR PIANO PLAYING OR WHATEVER, I WOULD HAVE SUPPORTED HER, SO THAT'S WHAT SHE WANTS TO DO, THEN SO BE IT.

YEAH.

I'LL DO THAT.

YOU PROBABLY WISH I HAD PICKED UP BALLET DANCING OR SOMETHING.

I DO.

I DO.

I DO.

YEAH.

I DO.

YOU KNOW, SHE'S SO DRIVEN, AND SHE FOUND A PURPOSE AND A MEANING AND A JOY IN DOING ALL THIS, AND IT WAS JUST LIKE SHE FELL INTO PLACE.

♪ NARRATOR: SVANTE IS NOW DRIVING GRETA FURTHER INTO THE CANADIAN ROCKIES IN AN ELECTRIC CAR LOANED BY FRIENDS.

HERE, GLACIERS COVERS HUNDREDS OF SQUARE MILES AND PROVIDE FRESH WATER FOR MILLIONS OF PEOPLE IN NORTH AMERICA.

MAN: WE'VE GOT A LONG WALK TO GET TO THE ICE NOW.

YEAH.

NARRATOR: SHE'S HERE TO FIND OUT HOW CLIMATE CHANGE IS AFFECTING THIS LANDSCAPE.

GRETA'S JOINED PROFESSOR JOHN POMEROY AND HIS TEAM OF HYDROLOGISTS, WHO'VE BEEN STUDYING THE ATHABASCA GLACIER.

POMEROY: SO IT'S ABOUT 400 YEARS FOR A SNOWFLAKE TO TURN INTO ICE AND THEN FLOW FROM THE TOP OF THE COLUMBIA ICEFIELD DOWN TO THE ATHABASCA GLACIER, SO WHEN WE GET UP TO THE TOE OF THE GLACIER, WE'LL SEE ICE THAT HAD FORMED IN THE RENAISSANCE PERIOD.

HMM.

NARRATOR: THE ATHABASCA GLACIER HAS BEEN PART OF THIS VAST ICEFIELD FOR THOUSANDS OF YEARS...

BUT IN JUST OVER A CENTURY, IT'S LOST MORE THAN HALF ITS VOLUME.

POMEROY: WHEN I FIRST CAME HERE IN 1979, THE ICE WAS RIGHT AROUND HERE.

WE DIDN'T UNDERSTAND THEN THAT THE GLACIAL RETREAT HERE WAS ALREADY ACCELERATING BECAUSE OF HUMAN-CAUSED CLIMATE CHANGE.

WHEN DID IT BECOME CLEAR?

WHY?

IT BECAME CLEAR LATER IN THE 1980S AS THE ICE MELT INCREASED, AND THIS YEAR, WE HAD THE FASTEST MELT RATE WE'VE EVER MEASURED ON THE ATHABASCA-- 6 METERS OF ICE DOWN OVER THE SUMMER, FASTER THAN OUR MODELS WERE PREDICTING.

♪ NARRATOR: PROFESSOR POMEROY HAS DISCOVERED IT'S NOT JUST RISING TEMPERATURES THAT ARE PUSHING THIS AND OTHER GLACIERS TO THE BRINK.

HOW FAR UP ARE WE GOING?

WE'LL GO UP HERE INTO THE BARE ICE.

THIS CRUNCHY ICE IS WEATHERING CRUST.

UNDERNEATH IT, YOU SHOULD HAVE THE REAL GLACIER ICE.

HERE.

TAKE A SHOT.

POMEROY: AH, LOOK AT THAT.

IT'S DUST AND SOOT FROM FIRES UNDER THIS BECAUSE OF CLIMATE CHANGE OR MORE FOREST FIRES THAT PUT ASH AND SOOT ONTO THE GLACIER, AND THEY DARKEN IT.

NARRATOR: DARK COLORS ABSORB MORE SUNLIGHT AND HEAT UP FASTER, SO THE MORE SOOT AND DUST FROM INCREASINGLY COMMON FOREST FIRES, THE LESS SUNLIGHT THE GLACIER CAN REFLECT.

POMEROY: ITS REFLECTANCE WE MEASURED THIS SUMMER WAS ONLY 18%.

NORMALLY FOR CLEAN GLACIER ICE, WE'D EXPECT AROUND 30%.

AND THAT MAKES THE GLACIER MELT FASTER.

IT DOES.

IT MAKES IT MELT MUCH FASTER, AND IT'S NOT JUST HERE.

IT'S GREENLAND.

IT'S THE ANDES.

IT'S THE HIMALAYAS.

IT'S ALL OVER WITH THE SOOT AND THE DUST DARKENING THEM, SO IT'S SOMETHING THAT WE DIDN'T EXPECT, AND IT'S PUSHING THESE GLACIERS PAST THEIR TIPPING POINT.

♪ NARRATOR: AS GLOBAL TEMPERATURES RISE, THE ATHABASCA GLACIER WILL PASS ITS TIPPING POINT AND, LIKE MANY OTHERS AROUND THE WORLD, WILL EVENTUALLY DISAPPEAR.

POMEROY: WE THINK OF GLACIERS AS GREAT AND POWERFUL THINGS, BUT, IN FACT, THEY'RE VERY FRAGILE, AND WE KNOW WE'RE NOT BRINGING THIS GLACIER BACK.

GRETA: I KNEW THINGS WERE BAD, AND I HAVE READ ABOUT THESE KINDS OF THINGS A LOT, BUT TO REALLY BE HERE AND TO STAND ON THE GLACIER AND TO HEAR FROM YOU WHO HAVE SO MUCH EXPERIENCE IN THIS IS JUST-- IT MAKES YOU REALIZE IT'S FOR REAL.

WOMAN: THE GLACIERS OF THE WORLD ARE ONE OF THE CANARIES IN THE COAL MINE, IF YOU LIKE.

EVEN IF WE PAUSE CLIMATE CHANGE NOW, IT'S PREDICTED THAT 30% TO 40% OF THE VOLUME OF TOTAL GLACIERS WOULD BE LOST.

MAN: PEOPLE DEPEND HEAVILY UPON THE SOURCE OF FRESH WATER THAT'S STORED IN GLACIERS FOR IRRIGATION AND FOR DRINKING.

EDWARDS: IT'S BEEN ESTIMATED THAT CLIMATE CHANGES THAT AFFECT GLACIERS COULD AFFECT NEARLY TWO BILLION PEOPLE.

MAN: SINCE THE EARLY 1990S, EARTH HAS LOST 28 TRILLION TONS OF ICE, AND THAT'S A HUGE NUMBER, SO THAT'S ARISING FROM MELTING MOUNTAIN GLACIERS, THE POLAR ICE SHEETS, AND SEA ICE IN BOTH POLAR OCEANS.

WHEN THE WATER ENDS UP IN THE SEA, AS IT ULTIMATELY WILL DO, THAT'LL CAUSE SEA LEVELS TO RISE.

SOME CLIMATE MODELS PREDICT AN ACTUAL METER OF SEA LEVEL RISE BY THE END OF THIS CENTURY.

THIS IS A REAL CONSEQUENCE FOR LARGE NUMBERS OF PEOPLE AROUND THE PLANET.

MAN: SEA LEVEL RISE HAS HAD A SIGNIFICANT IMPACT ON THE LIFE WITHIN THE CARIBBEAN REGION.

THERE'S ALWAYS A PLACE WHERE SOMEBODY CAN POINT TO A LOCATION IN THE SEA AND SAY, "I CAN REMEMBER WHEN THAT LOCATION USED TO BE ON THE LAND."

ANDREW SHEPHERD: ALMOST EVERY COASTLINE IN THE WORLD IS SUSCEPTIBLE TO CHANGING SEA LEVELS.

♪ GRETA, VOICE-OVER: EVERYTHING IS GOING TO CHANGE.

THE QUESTION IS JUST, WILL THE CHANGES BE ON OUR TERMS OR ON NATURE'S TERMS?

WE'LL JUST HAVE TO CHOOSE, BUT THE MORE TIME GOES BY, THE MORE THAT OPPORTUNITY DECREASES.

NARRATOR: IN 6 WEEKS' TIME, GRETA IS DUE TO ADDRESS A U.N.

CLIMATE CONFERENCE IN SOUTH AMERICA, SO SHE AND SVANTE ARE HEADING SOUTH THROUGH CALIFORNIA...

IN A COUNTRY WHERE CLIMATE CHANGE IS A VERY DIVISIVE ISSUE.

WOMAN, ON RADIO: GRETA, LISTEN VERY CLOSELY.

CLIMATE CHANGE IS NOT GOING TO KILL YOU.

THE WORLD IS NOT GOING TO END IN 12 YEARS.

YOU CAN HAVE BABIES, AND YOU WILL HAVE A FUTURE.

GRETA, VOICE-OVER: PEOPLE DON'T WANT TO TALK ABOUT THE CLIMATE, SO THEY MAKE IT ABOUT ME.

TRUMP: GRETA-- YOU KNOW GRETA?

[CROWD JEERS AND BOOS] GRETA, VOICE-OVER: I'M SUCH A PUBLIC FIGURE, AND EVERYTHING I DO GETS COMPLETELY TWISTED.

TODAY I AM PROUD TO INTRODUCE TO YOU GRETA THUNBERG.

[CROWD CHEERING] GRETA, VOICE-OVER: PEOPLE SPEND ALL THEIR TIME ONLINE SPREADING CONSPIRACY THEORIES AND SEND DEATH THREATS TO ME AND MY FAMILY.

SVANTE, VOICE-OVER: THERE'S BEEN SOME, YOU KNOW, DARK MOMENTS.

IN THOSE MOMENTS, I'VE TOLD HER, YOU KNOW, "EITHER, YOU-- YOU KNOW, YOU WANT TO DO THIS, "THEN YOU DO IT.

IF YOU DON'T WANT TO DO IT, WE GO HOME NOW."

WE ARE LIVING IN THE BEGINNING OF A CLIMATE AND ECOLOGICAL BREAKDOWN, AND WE CANNOT CONTINUE TO LOOK AWAY FROM THIS CRISIS ANYMORE.

[CROWD CHEERING] GRETA, VOICE-OVER: I DON'T MIND THE HATE.

I DON'T CARE WHAT PEOPLE SAY ABOUT ME, BUT IT'S JUST WHEN IT BECOMES, LIKE, PHYSICAL AND WHEN IT AFFECTS YOUR FAMILY, THAT'S A WHOLE OTHER DIFFERENT STORY.

THANK YOU.

[CHEERING AND APPLAUSE] GRETA, VOICE-OVER: NOT MANY HAVE EXPERIENCED SOMETHING LIKE THIS AT SUCH A YOUNG AGE, SO, YEAH.

[CHEERING AND APPLAUSE] ♪ NARRATOR: FOR THE LAST FEW YEARS, CALIFORNIA HAS BEEN RAVAGED BY WILDFIRES.

MAN: THERE ARE OVER 8,000 FIREFIGHTERS CURRENTLY FIGHTING FIRES THROUGHOUT THE STATE.

TO DATE, OVER 209,000 ACRES HAVE BURNED.

CLOSE TO A QUARTER OF A MILLION CALIFORNIANS HAVE BEEN EVACUATED.

NARRATOR: IN 2018, THE TOWN OF PARADISE WAS ALMOST COMPLETELY DESTROYED.

THIS LOOKS KIND OF BAD...

THIS ROW OF HOUSES.

GOD, IT'S DEAD TREES ALL OVER THE SYSTEM.

HI.

GOOD TO MEET YOU.

YOU, TOO.

NARRATOR: GRETA IS MEETING LOCAL RESIDENT JULIAN MARTINEZ, WHO ONLY JUST ESCAPED THE WILDFIRE WITH HIS LIFE.

THIS TREE STUMP RIGHT HERE USED TO BE MAYBE A 120-FOOT-TALL PINE TREE, AND THAT WAS MY FRONT PORCH.

WHEN DID THE FIRE OCCUR?

NOVEMBER 8, 2018.

THAT MORNING, I WOKE UP AT 7:00, AND I COULD HEAR THE WIND OUTSIDE, WHICH WAS REALLY STRONG, AND OVER IN ABOUT THAT DIRECTION RIGHT THERE, YOU COULD SEE A PLUME OF SMOKE, AND SO ABOUT 8:00, WE SAID, "OK. WE GOT TO START PACKING UP TO GET OUT OF HERE."

RIGHT WHEN WE WERE ABOUT TO PULL OUT, THE SKY JUST BLACKED OUT, AND IT LOOKED LIKE NIGHTTIME ALL OF A SUDDEN, AND WE WERE ABLE TO GET OUT BEFORE THE TOWN GRIDLOCKED.

[KEYS JINGLING] UH!

MAN, ON RADIO: ORDERING AN EVACUATION ORDER NOW DUE TO THE FIRE.

NARRATOR: AS THE WILDFIRE ENGULFED PARADISE, ITS 27,000 RESIDENTS TRIED TO FLEE, MANY RECORDING THEIR ESCAPE.

MAN: THERE'S NOWHERE TO GO.

OH, MY GOD, OH, MY GOD, OH, MY GOD, I DON'T WANT TO GET CAUGHT THERE.

WOMAN: IT'S STARTING TO BURN ALL AROUND ME.

MAN: OH, MY GOD.

OH, MY GOD.

WE'RE BURNING RIGHT HERE.

COME ON, PEOPLE.

GO.

THE FLAMES MOVED SO INTENSELY, YOU KNOW, IT WENT FROM A MINOR THING TO THE WHOLE TOWN WAS GONE WITHIN A COUPLE HOURS, AND THE ROADS KIND OF ACTED LIKE A FUNNEL FOR THE FLAMES.

MAN: THERE'S STUFF LITERALLY BURNING ON ALL SIDES.

WOMAN: HEAVENLY FATHER, PLEASE HELP US.

WE'RE NEVER GETTING OUT OF HERE.

CHILD: COME ON!

COMING TOWARD US.

COME ON.

WATCH OUT!

WATCH OUT!

DAD!

DEAR GOD, HELP ME GET OUT OF THIS.

PLEASE HELP ME.

MARTINEZ: I THINK 86 PEOPLE DIED IN THE FIRE.

THERE'S A SENSE OF GUILT THAT I HAVE FOR LEAVING TOWN SO QUICKLY... YOU KNOW, KNOWING THAT THERE WERE-- SORRY.

I COMPLETELY UNDERSTAND.

IT MUST BE VERY HARD.

THERE WERE A LOT OF PEOPLE THAT NEEDED HELP...

SO, YOU KNOW, KNOWING THAT THOSE OTHER PEOPLE WERE LEFT BEHIND IS SOMETHING THAT HAS STUCK WITH ME.

I FEEL IT'S JUST SO INCREDIBLY SAD.

I CAN'T IMAGINE WHAT YOU HAVE BEEN GOING THROUGH.

THERE'S BEEN PEOPLE WHO HAVE COMMITTED SUICIDE AFTER THE FIRE JUST BECAUSE THEY'VE HAD THEIR LIVES TAKEN AWAY FROM THEM.

I MEAN, EVEN RIGHT NOW AS WE'RE SPEAKING, THERE'S FIRES THAT ARE POPPING UP ALL OVER CALIFORNIA.

GRETA, VOICE-OVER: WHEN YOU HEAR ABOUT THESE STORIES AND ESPECIALLY WHEN YOU MEET THESE PEOPLE, YOU TRY TO IMAGINE YOURSELF IN THAT SITUATION... HOW DIFFICULT IT MUST HAVE BEEN TO LOSE EVERYTHING AND JUST LEAVE EVERYTHING BEHIND.

WE SEE ALL OF THESE THINGS REPEATING THEMSELVES OVER AND OVER AGAIN.

PEOPLE DIE, AND PEOPLE SUFFER FROM IT, BUT WE COMPLETELY FAIL TO CONNECT THE DOTS.

♪ NARRATOR: HERE IN CALIFORNIA, WARMER TEMPERATURES ARE DRYING OUT THE LAND, CREATING MORE FUEL FOR THE FIRES...

BUT CLIMATE CHANGE IS ALSO ALTERING THE WEATHER PATTERNS, MAKING THE FALL RAINS ARRIVE LATER AND MEANING FIRES ARE MORE LIKELY TO BE FANNED BY HIGH WINDS.

MAN: 5 OF THE 10 WORST WILDFIRES ON RECORD IN CALIFORNIA BURNED DURING SUMMER 2020-- THOUSANDS OF BUILDINGS AND STRUCTURES DESTROYED, DOZENS OF LIVES LOST... A TRAGEDY BY ANY MEASURE.

CLIMATE CHANGE IS INCREASING FOREST FIRES IN MANY PARTS OF THE WORLD-- IN SIBERIA, IN RUSSIA, IN ALASKA, AND THEN YOU HAVE ALSO SEEN THAT IN AUSTRALIA WITH THE BUSH FIRES.

MANN: SO THESE WILDFIRES, THEN, ARE PART OF A LARGER CLIMATE FEEDBACK LOOP.

YOU WARM UP IN THE HIGHER LATITUDES, THE PINE BARK BEETLE MOVES INTO THOSE FORESTS, WEAKENS THOSE FORESTS SO THERE'S MORE DRY AND DEAD WOOD TO COME TOGETHER WITH THAT DROUGHT AND HEAT TO GIVE US THOSE MASSIVE WILDFIRES, AND THEY PUT MORE CARBON POLLUTION INTO THE ATMOSPHERE, CAUSING MORE WARMING.

NARRATOR: GRETA AND SVANTE HAVE JUST OVER A MONTH TO REACH THE U.N.

CLIMATE CHANGE CONFERENCE IN CHILE...

BUT ANTIGOVERNMENT RIOTS HAVE BROKEN OUT IN THE CAPITAL SANTIAGO.

WOMAN: THE AUTHORITIES HAVE USED WATER CANNON TO DISBURSE THE CROWDS WITHOUT SUCCESS.

NARRATOR: THE UNITED NATIONS HAS DECIDED TO RELOCATE THE CLIMATE CONFERENCE TO SPAIN ON THE OTHER SIDE OF THE ATLANTIC.

[SIREN] GRETA: I'VE BEEN GOING PRETTY MUCH THE WHOLE WAY AROUND THE WORLD THE WRONG WAY, SO NOW WE ARE HEADED EAST, AND HOPEFULLY, I WILL FIND TRANSPORT THAT CAN TAKE ME TO THE OTHER SIDE OF THE ATLANTIC OCEAN.

♪ NARRATOR: FOR ALMOST ANYONE ELSE, THIS JOURNEY OF OVER 3,500 MILES WOULD MEAN HOPPING ON A PLANE FOR 7 1/2 HOURS, BUT NOT FOR GRETA.

SVANTE: FLYING OR GETTING ON A PLANE, SHE WOULD JUST REFUSE.

SHE WOULDN'T DO IT.

I DON'T WANT TO BE THE PERSON WHO SAYS, "YES.

CLIMATE CHANGE IS VERY IMPORTANT," AND THEN THE NEXT SECOND STEPS ONTO A PLANE.

♪ MAN: AVIATION BURNS THROUGH A LOT OF FOSSIL FUEL.

IF A BOEING 747 FLIES FROM LONDON TO HONG KONG, IT BURNS THROUGH SOMETHING LIKE A HUNDRED TONS OF FOSSIL FUEL.

WHEN YOU BURN THE FOSSIL FUELS, YOU GET A LOT OF OTHER POLLUTANTS THAT COME OUT OF THE BACK OF THE EXHAUST OF THE PLANE.

OF COURSE, THE CHEMICALS ARE EMITTED AT ALTITUDE.

IT HAS AN IMPACT CHEMICALLY IN THE ATMOSPHERE, APPROXIMATELY SOMETHING LIKE DOUBLING THE AMOUNT OF WARMING THAT YOU WOULD OTHERWISE GET.

BERNERS-LEE: IN LOTS OF COUNTRIES, ONLY A VERY SMALL PROPORTION OF THE POPULATION EVER FLIES, BUT, OF COURSE, SOME PEOPLE FLY A LOT.

MAN: GLOBALLY, IT'S ONLY 1% OF THE POPULATION THAT ACCOUNT FOR ABOUT HALF OF ALL AVIATION-RELATED EMISSIONS.

OF COURSE, THE CORONAVIRUS PANDEMIC'S HAD A HUGE IMPACT ON THE AVIATION INDUSTRY, AND THE KEY QUESTION IS WHETHER PEOPLE JUST GO BACK TO FLYING TO THE EXTENT THAT THEY WERE BEFORE OR WHETHER THEY SEEK ALTERNATIVES.

BERNERS-LEE: WE DON'T HAVE TO HAVE A NO-FLYING WORLD, BUT THERE'S NO ESCAPING THE NEED TO REDUCE THE AMOUNT OF FLYING THAT GOES ON.

♪ NARRATOR: GRETA AND SVANTE HAVE BEEN OFFERED A LIFT BACK TO EUROPE ON A 48-FOOT CATAMARAN CALLED LA VAGABONDE.

GRETA'S ALREADY SAILED ACROSS THE ATLANTIC ONCE THIS YEAR TO GET TO THE USA, BUT THAT WAS IN AUGUST, WHEN THE WEATHER TENDS TO BE CALMER.

MAN: IT'S NOT THE PERFECT TIME TO BE LEAVING.

YOU GOT A GULF STREAM TO CROSS, AND THERE'S JUST CONSISTENT LOWS, ONE LOW AFTER ANOTHER AFTER ANOTHER.

THERE'S NO DENYING THAT IT'S GONNA BE A TOUGH TRIP.

WOMAN: WE'RE READY, AS READY AS WE CAN BE.

SVANTE: TODAY IS PROBABLY THE MOST STRESSFUL DAY OF MY LIFE.

IT'S NOVEMBER, AND IT'S THE ATLANTIC OCEAN.

IT'S GONNA BE PRETTY ROUGH, I THINK, JUST SORT OF SILENTLY PANICKING INSIDE.

HA HA!

THE JOYS OF PARENTING.

HA HA HA!

HA HA HA!

AH... WOMAN: THE VOYAGE PROBABLY WILL TAKE TWO TO 3 WEEKS, ALL GOING WELL, BUT WE ARE AT THE MERCY OF MOTHER NATURE, SO WHATEVER SHE DECIDES TO THROW AT US, WE WILL HAVE TO MANAGE.

[CAMERA SHUTTERS CLICKING] SVANTE, VOICE-OVER: THE WEATHER SYSTEM'S VERY BAD, AND THIS TIME OF YEAR, YOU DON'T SAIL ACROSS THE NORTH ATLANTIC IN NOVEMBER OR DECEMBER.

GRETA, VOICE-OVER: IT IS VERY SYMBOLIC THAT I SAIL BECAUSE IT SENDS A STRONG MESSAGE.

WHITELUM: ALL RIGHT, READY WHEN YOU ARE.

WOMAN: GRETA THUNBERG IS BACK ON THE OPEN SEAS.

THE 16-YEAR-OLD CLIMATE ACTIVIST SET SAIL FROM VIRGINIA FOR A TRANSATLANTIC JOURNEY TO MADRID.

YAY.

WE'RE FINALLY ON OUR WAY.

WOMAN: WE HAVE TROPICAL DEPRESSION IN THE CENTRAL ATLANTIC, COULD BECOME A TROPICAL STORM SOMETIME TODAY OR TOMORROW.

I'M CURVING OUT THE SEA STAYING AWAY FROM THE U.S. WHITELUM: [SHOUTS] GRETA, VOICE-OVER: IT IS DAY ONE.

I HAVE NOT BEEN FEELING VERY WELL TODAY.

IT'S-- IT'S COLD, AND I'M A BIT SEASICK...

SO, YEAH, HOPEFULLY, THINGS WILL GET BETTER.

MAN: YES.

IT IS EXPECTED TO BECOME A TROPICAL STORM INTO THE CENTRAL ATLANTIC NOW.

♪ [THUNDER] WE ARE IN JUST THE BIGGEST ELECTRICAL STORM, FLYING 40 KNOTS, AND NIKKI'S AT THE HELM.

[WAVE CRASHES] GRETA: IT IS DAY 6.

IT'S THE MIDDLE OF THE NIGHT, AND THE LIGHTNING WAS COOL.

I'VE NEVER SEEN SUCH LIGHTNING.

IT STRUCK, LIKE, EVERY TWO SECONDS, AND THE WHOLE SKY JUST LIT UP.

SVANTE: WE HAD LIGHTNING STRIKING THE WATER EVERYWHERE.

IT'S JUST, "PSH!

PSH!"

YOU COULD HEAR THE WATER GO, "PHSS!"

AND IT JUST WENT ON, NEVER STOPPED.

GRETA, VOICE-OVER: THE STORMS ARE SO ENORMOUS, IT WAS JUST A CONSTANT GAME OF AVOIDING THE NEXT BIG STORM.

[THUNDER] MANN: IN THE ATLANTIC, WE JUST SAW THE BUSIEST SEASON FOR STORMS, AND IT COINCIDED WITH THE YEAR THAT HAD VERY WARM OCEAN TEMPERATURES IN THE TROPICAL ATLANTIC.

THE GLOBAL OCEAN'S SURFACE WARMED UP CLOSE TO ABOUT A DEGREE CELSIUS, SO WHEN YOU PROVIDE MORE WARMTH, THOSE WINDS CAN GET STRONGER.

THEY BECOME MORE INTENSE.

THEY DO MORE DAMAGE.

SOME ARGUE WE NEED TO INVENT A CATEGORY 6 TO DESCRIBE THESE 200-MILE-PER-HOUR MONSTER STORMS THAT WE'RE NOW SEEING.

EDWARDS: THERE IS ANOTHER IMPACT.

THE OCEANS ABSORB A LOT OF THE CARBON DIOXIDE THAT WE PUT INTO THE ATMOSPHERE.

WHEN CO2 DISSOLVES INTO THE WATER, IT FORMS A WEAK ACID, AND THAT AFFECTS THE CHEMISTRY OF THE OCEAN IN A WAY THAT CAN BE BAD FOR SOME ECOSYSTEMS.

♪ JOHNSON: ONE OF THE TYPES OF MARINE LIFE THAT IS MOST DRAMATICALLY IMPACTED BY OCEAN ACIDIFICATION IS CORAL REEFS.

CORAL REEFS ARE THE HOME TO A LARGE PORTION OF THE WORLD'S BIODIVERSITY, BUT SCIENTISTS ARE PREDICTING THAT WITH 1 1/2 DEGREES CELSIUS OF GLOBAL TEMPERATURE INCREASE, WE'LL LOSE AROUND 90% OF OUR TROPICAL CORAL REEFS, AND WITH 2 DEGREES CELSIUS OF WARMING, WE'LL LOSE 99% OF CORAL REEFS.

WOMAN: THERE ARE SOME THINGS WE CAN DO TO REDUCE CO2 EMISSIONS.

SHIPPING'S REALLY INTERESTING.

SO IF YOU HALF THE SPEED WITH WHICH SHIPS GO, YOU MORE THAN HALF THE CO2 EMISSIONS THAT COME FROM THEM, AND WE SAW THIS DURING THE GLOBAL FINANCIAL CRISIS, WHERE WE SAW A BIG DROP IN CO2 EMISSIONS, SO THINKING HARD ABOUT HOW WE MOVE FREIGHT AND PEOPLE AROUND THE WORLD IS REALLY IMPORTANT.

♪ GRETA, VOICE-OVER: WE ARE APPROXIMATELY HALFWAY.

THE WEATHER FORECAST LOOKS GOOD.

IT'S JUST AN AMAZING EXPERIENCE TO BE ABLE TO JUST BE OUT HERE IN THIS WILDERNESS AND TO LOOK AT THE OCEAN, AND TIME SORT OF DOESN'T EXIST OUT HERE.

YOU JUST LIVE IN THE MOMENTS.

YOU FEEL CALM.

♪ GRETA, VOICE-OVER: I THINK THAT WAS SOMETHING I NEEDED BECAUSE IT CAN GET VERY OVERWHELMING TO CONSTANTLY BE IN THE CENTER OF ATTENTION.

THAT WAS VERY ENJOYABLE TO JUST BE INVISIBLE, TO JUST BECOME MYSELF.

SVANTE, VOICE-OVER: THE OCEAN WAS A VERY PLEASANT PLACE TO BE.

YOU'RE COMPLETELY SHUT OFF FROM THE WORLD.

IT CHANGES YOU IN A WAY.

GRETA, VOICE-OVER: YOU JUST SIT THERE FOR HOURS AND HOURS...

COMPLETELY SURROUNDED BY THIS WILDERNESS.

YOU SEE HOW BIG THE WORLD ACTUALLY IS AND THESE VAST OCEANS THAT COVER MOST OF THE GLOBE AND HOW IMPORTANT THEY ARE TO ALL OF US.

NARRATOR: 20 DAYS AFTER LEAVING THE USA, GRETA AND LA VAGABONDE ARE APPROACHING THE PORTUGUESE CAPITAL LISBON.

GRETA, VOICE-OVER: YOU COME FROM NOTHING AND JUST YOU AND THE OCEAN AND THEN SUDDENLY LAND... MAN: THE TEENAGE ACTIVIST GRETA THUNBERG HAS RECROSSED THE ATLANTIC ON HER WAY TO A CONFERENCE WHERE GOVERNMENTS ARE DEBATING WHAT TO DO TO STOP THE PLANET OVERHEATING.

GRETA, VOICE-OVER: AND ALL THAT COMES WITH IT-- POLLUTION, ALL THE NOISES... ♪ STARTS TODAY ♪ GRETA, VOICE-OVER: AND THEN YOU HAVE ALL THESE CAMERAS IN YOUR FACE.

[CHEERING AND APPLAUSE] GRETA, VOICE-OVER: SOMETIMES IT GETS TOO OVERWHELMING, AND ALSO IF YOU'RE AUTISTIC, IT'S BECOME EVEN MORE.

♪ NARRATOR: FROM LISBON, GRETA'S TAKING THE TRAIN TO THE U.N.

CLIMATE CHANGE CONFERENCE IN MADRID.

IT'S A CHANCE TO PREPARE THE SPEECH SHE'S BEEN ASKED TO GIVE.

SVANTE, VOICE-OVER: SHE'S VERY, VERY DRIVEN, AND SHE DOESN'T WANT TO WASTE ANY TIME.

SHE READS A LOT OF BOOKS, A LOT OF ARTICLES ABOUT SCIENCE.

GRETA, VOICE-OVER: I KNOW THERE HAVE BEEN MANY NEW REPORTS COMING OUT AND MANY NEW FIGURES TO LOOK AT.

THIS MORNING, I SAW THAT THE GLOBAL EMISSIONS OF GREENHOUSE GASES FROM 2019 WILL INCREASE, AND ALSO 2010 TO 2019 WILL MOST LIKELY BE THE HOTTEST DECADE EVER RECORDED.

WHEN I WAS YOUNGER, I PICTURED MY FUTURE BEING SOME KIND OF SCIENTIST WORKING IN A LAB, NEVER SEEING THE DAYLIGHT.

THAT'S WHAT I THOUGHT I WAS GONNA BE LIKE WHEN I GREW UP, BUT IT DIDN'T REALLY TURN OUT LIKE THAT.

[CAMERA SHUTTERS CLICKING] WOMAN: [SPEAKS SPANISH] BUENO.

MAN: IT IS INCREDIBLE TO WITNESS THE PHENOMENON OF GRETA THUNBERG, WHO, IN THE SPACE OF A YEAR, HAS GONE FROM SOLO PROTESTS OUTSIDE THE SWEDISH PARLIAMENT TO GALVANIZING MILLIONS OF PEOPLE IN THE FIGHT AGAINST CLIMATE CHANGE.

[PEOPLE CLAMORING] GRETA, VOICE-OVER: IF I'M GONNA REACH OUT TO THIS MANY PEOPLE AND BRING ATTENTION TO THE CLIMATE CRISIS, THEN THIS IS SOMETHING THAT I HAVE TO ACCEPT BECAUSE WITH THAT BIG OF A PLATFORM COMES MUCH ATTENTION AND RESPONSIBILITY.

♪ NARRATOR: THE UNITED NATIONS' ANNUAL CLIMATE CONFERENCE, KNOWN AS COP, GIVES THE WORLD'S GOVERNMENTS AN OPPORTUNITY TO MEET AND NEGOTIATE A WAY TO KEEP TO AN AGREED LEVEL OF GLOBAL AVERAGE TEMPERATURE RISE.

MAN: COP25 JUST THE LATEST INSTALLMENT IN A QUARTER-CENTURY OF DIPLOMACY THAT'S SO FAR FAILED TO CURB CLIMATE CHANGE.

GAMBHIR, VOICE-OVER: IN TERMS OF THE TIME SCALE IN WHICH WE NEED TO STOP EMITTING CARBON DIOXIDE INTO THE ATMOSPHERE, WE HAVE THIS CONCEPT CALLED THE CARBON BUDGET... MANN: THE CARBON BUDGET, SIMPLY PUT, IS HOW MUCH CARBON WE CAN BURN AND KEEP GLOBAL TEMPERATURES BELOW SOME LEVEL, AND WE KNOW, FOR EXAMPLE, THAT WE CAN STILL KEEP THEM BELOW 1 1/2 DEGREES CELSIUS.

GAMBHIR: SO THAT BUDGET IS SOMEWHERE BETWEEN ABOUT 200 BILLION TO 300 BILLION TONS OF CARBON DIOXIDE.

THAT MAY SOUND LIKE A LOT, BUT WE'RE EMITTING ABOUT 40 BILLION TONS OF CARBON DIOXIDE PER YEAR.

WOMAN: IF YOU DO THE MATH, WHAT THAT MEANS IS THAT IF WE CONTINUE TO EMIT CARBON AT OUR CURRENT PACE, WE'RE GONNA RUN THROUGH AND DEPLETE THAT BUDGET BY 2030.

NARRATOR: WITH ALMOST ALL THE WORLD'S NATIONS SET TO OVERSHOOT THEIR CARBON BUDGETS, GRETA IS PLANNING TO USE HER SPEECH TO DEMAND THAT GOVERNMENTS HONOR THE PROMISES THEY'VE MADE ON CLIMATE CHANGE.

SVANTE: BUT MAYBE IT'S-- YEAH.

YEAH.

THERE IT WAS.

YEAH, BUT IT WAS ON THE DOCUMENTS.

[INDISTINCT CONVERSATION] GRETA, VOICE-OVER: PEOPLE ARE ONLY LISTENING TO THE EMOTIONAL BITS, LIKE "HOW DARE YOU?"

AND "I WANT YOU TO PANIC" AND SO ON.

I SAY THESE THINGS BECAUSE THEY GET PEOPLE'S ATTENTION, AND NOW I HAVE PEOPLE'S ATTENTION, I DON'T NEED TO MAKE A SPEECH LIKE THAT.

I WANT THEM TO LISTEN TO THE ACTUAL CONTENT AND THE SCIENCE.

CAN I GET A PICTURE?

YEAH.

CAN YOU DO IT QUICK?

BECAUSE I'M LATE.

♪ GRETA, VOICE-OVER: I DON'T KNOW IF THIS WILL SHIFT THE FOCUS.

IT PROBABLY WON'T.

THE HEADLINE WILL BE "GRETA THUNBERG MAKES EMOTIONAL SPEECH."

I KNOW THAT THAT'S GONNA BE THE REACTION, BUT I'M DOING EVERYTHING I CAN, AT LEAST, TO MAKE SURE THAT THAT'S NOT THE CASE.

MAN: THERE ARE 29,000 DELEGATES AT THIS CLIMATE SUMMIT BUT ONLY ONE RECEIVING THIS MUCH ATTENTION.

MAN: NOW I WOULD LIKE TO INVITE TO STAGE TO TAKE THE LECTURE TO MRS. GRETA THUNBERG.

[APPLAUSE] [CAMERA SHUTTERS CLICKING] HI.

I'VE GIVEN MANY SPEECHES AND LEARNED THAT WHEN YOU TALK IN PUBLIC, YOU SHOULD START WITH SOMETHING PERSONAL OR EMOTIONAL TO GET EVERYONE'S ATTENTION, BUT TODAY I WILL NOT DO THAT BECAUSE THEN THOSE PHRASES ARE ALL THAT PEOPLE FOCUS ON.

THEY DON'T REMEMBER THE FACTS, THE VERY REASON WHY I SAY THOSE THINGS IN THE FIRST PLACE.

WE NO LONGER HAVE TIME TO LEAVE OUT THE SCIENCE.

IF WE ARE TO HAVE A 6% TO 7% CHANCE OF LIMITING THE GLOBAL TEMPERATURE RISE TO BELOW 1.5 DEGREES CELSIUS, WE HAD ON JANUARY 1, 2018, 420 GIGATONS OF CO2 LEFT TO EMIT.

WITH TODAY'S EMISSIONS LEVELS, THAT REMAINING BUDGET WILL BE GONE WITHIN ABOUT 8 YEARS.

THESE NUMBERS AREN'T ANYONE'S OPINIONS OR POLITICAL VIEWS.

THIS IS THE CURRENT BEST AVAILABLE SCIENCE.

[APPLAUSE] THESE NUMBERS DON'T INCLUDE NONLINEAR TIPPING POINTS, SUCH AS MELTING GLACIERS.

POMEROY: WE KNOW WE'RE NOT BRINGING THIS GLACIER BACK, THAT IT'S ALL BEING DRIVEN BY CLIMATE CHANGE THAT'S CAUSED BY GREENHOUSE GASES.

GRETA: TO STAY BELOW 1.5 DEGREES, WE NEED TO KEEP THE CARBON IN THE GROUND BECAUSE EVEN AT ONE DEGREE, PEOPLE ARE DYING FROM THE CLIMATE CRISIS.

WOMAN: STARTING TO BURN ALL AROUND ME.

I HAVE BEEN FORTUNATE ENOUGH TO TRAVEL AROUND THE WORLD, AND I STILL BELIEVE POLITICIANS AND CEOS ARE MAKING IT LOOK LIKE REAL ACTION IS HAPPENING WHEN, IN FACT, ALMOST NOTHING IS BEING DONE APART FROM CLEVER ACCOUNTING AND CREATIVE PR.

[APPLAUSE] THIS IS MY MESSAGE.

THIS IS WHAT I WANT YOU TO FOCUS ON.

RIGHT NOW, WE ARE DESPERATE FOR ANY SIGN OF HOPE.

PEOPLE ARE READY FOR CHANGE.

THANK YOU.

[APPLAUSE] MAN: THE 16-YEAR-OLD CLIMATE ACTIVIST GRETA THUNBERG ACCUSED RICHER COUNTRIES OF BEING MORE INTERESTED IN FINDING LOOPHOLES IN ENVIRONMENTAL LAWS THAN TACKLING CLIMATE CHANGE.

WOMAN: GRETA THUNBERG HAS ACCUSED GOVERNMENTS AND CORPORATIONS OF FAILING TO TACKLE CLIMATE CHANGE.

GRETA, VOICE-OVER: THE PEOPLE WHO HOST THE EVENT WERE VERY HAPPY AFTERWARDS BECAUSE I WASN'T ANGRY BECAUSE I THINK EVERYONE EXPECTED ME TO GO UP AND SHOUT.

I AT LEAST TRIED TO GET THE INFORMATION OUT THERE AND MAKE SURE THAT THE GAP BETWEEN WHAT POLITICIANS ARE DOING AND WHAT THE SCIENCE SAYS IS SO CLEAR THAT NO ONE CAN AVOID SEEING IT.

♪ NARRATOR: 2019 IS COMING TO A CLOSE, BUT ALREADY GRETA HAS A BUSY YEAR OF ACTIVISM PLANNED FOR 2020.

FIRST, AFTER 134 DAYS ON THE ROAD, SHE'S TAKING A CHRISTMAS BREAK.

WE'RE IN COPENHAGEN RIGHT NOW, AND WE ARE GOING TO THE CENTRAL STATION, WHERE WE WILL TAKE A TRAIN, A DIRECT TRAIN FROM COPENHAGEN TO STOCKHOLM, SO RIGHT NOW, WE'RE GOING HOME.

♪ THANK YOU SO MUCH.

THANK YOU.

THANK YOU SO MUCH.

THANK YOU.

YOU, TOO.

YOU'RE REALLY COOL.

BYE.

BYE.

SVANTE: WELL, A PENINSULA [INDISTINCT].

THERE'S SWEDEN.

I CAN SEE IT NOW.

AT LEAST IT WAS SOMETHING BETTER.

YEAH.

MANY PEOPLE OFTEN ASK ME WHETHER I'M AN OPTIMIST OR A PESSIMIST.

WOMAN: ♪ STILLA NATT ♪ I DON'T THINK THAT WE NEED TO FEEL HOPEFUL IN ORDER TO ACT.

WOMAN: ♪ HELIGA NATT ♪ ♪ ALLT AR FRID ♪ THE ONLY THING THAT CREATES HOPE IS ACTION, AND IF THERE IS NO ACTION, THERE IS NO HOPE.

WOMAN: ♪ SKINER PA BARNET ♪ ♪ I STALLETS STRA ♪ ♪ OCH DE VAKANDE ♪ ♪ FROMMA TVA ♪ ♪ KRISTUS TILL JORDEN ♪ ♪ AR KOMMEN ♪ ♪ OSS AR ♪ ♪ EN FRALSARE FODD ♪ ♪ THE LAST YEAR HAS BEEN, HAS BEEN VERY VERY CHAOTIC.

I'VE BEEN GOING HALFWAY AROUND THE WORLD THE WRONG WAY.

WE NO LONGER HAVE TIME TO LEAVE OUT THE SCIENCE.

SO IT FALLS ON US TO BE THE ADULTS IN THE ROOM.

THEY PROBABLY SEE ME AS SOME KIND OF ANGRY TEENAGER, BUT UM, I THINK IT IS IMPORTANT TO, TO LISTEN TO, TO THESE PEOPLE AND SEE WHAT THEY HAVE TO SAY.

I CAN'T BE RUDE, BUT ON THE OTHER HAND I CAN'T BE TOO NICE.

WORLD LEADERS ARE STILL TRYING TO RUN AWAY FROM THEIR RESPONSIBILITIES.

WE HAVE TO MAKE SURE THAT THEY CANNOT DO THAT.

[CHEERS]