♪ JOHN: TONIGHT ON PBS NEWS WEEKEND, RUSSIA LAUNCHES DRONES INTO UKRAINE HOURS AFTER PRESIDENT TRUMP RAISES DOUBTS ABOUT PUTIN'S COMMITMENT TO PEACE.

AS PRESIDENT TRUMP'S SECOND TERM APPROACHES DAY 100, WE EXAMINE THE MOST CONTROVERSIAL AND CONSEQUENTIAL MOMENTS AND HOW GLOBAL WARMING MAY BE ENDANGERING CULTURAL ARTIFACTS IN REMOTE ALASKA.

>> THEY ARE IMPORTANT NOT JUST TO LOCAL FOLKS BUT OUR COLLECTIVE HERITAGE AS HUMANS.

♪ JOHN: GOOD EVENING.

I AM JOHN YANG.

RUSSIA CONTINUES ITS DEADLY ASSAULT ON UKRAINE WATCHING A SWEEPING DRONE ATTACK THAT KILLED AT LEAST FOUR PEOPLE A DAY AFTER PRESIDENT TRUMP MET WITH VOLODYMYR ZELENSKYY AT THE VATICAN.

BOTH DESCRIBED THE DISCUSSION IN POSITIVE TERMS.

AFTER THE MEETING, MR. TRUMP TOOK TO SOCIAL MEDIA TO CRITICIZE VLADIMIR PUTIN.

THERE WAS NO REASON FOR PUTIN TO BE SHOOTING MISSILES INTO CIVILIAN AREAS, CITIES, AND TOWNS.

IT MAKES ME THINK MAYBE HE DOES NOT WANT TO STOP THE WAR.

WILLIAM TAYLOR IS A DISTINGUISHED FELLOW AT THE LAND TO COUNSEL'S EURASIA -- ATLANTIC COUNCIL'S EURASIA CENTER AND LATER TESTIFIED IN MR. TRUMP'S IMPEACHMENT.

WHAT DO YOU THINK OF THAT STATEMENT?

>> I THINK THE PRESIDENT IS REALIZING AFTER THAT EVIDENCE OF THESE ATTACKS, AND OTHER ATTACKS ON RELIGIOUS HOLIDAYS, TWO WEEKS AGO, THREE WEEKS AGO, AND WE KNOW THE DISCUSSION PRESIDENT TRUMP HAD WITH PRESIDENT ZELENSKYY, FOR THE FIRST TIME, DIRECT, UNFILTERED CONVERSATION BETWEEN THE TWO PRESIDENTS, THAT PRESIDENT TRUMP IS REALIZING PRESIDENT PUTIN MAY NOT BE SERIOUS ABOUT THIS NEGOTIATION, ABOUT STOPPING THE WAR.

I BELIEVE PUTIN IS NOT SERIOUS ABOUT STOPPING IT BUT I THINK THE PRESIDENT MAY BE COMING TO THE SAME CONCLUSION.

JOHN: DO YOU THINK IT WAS SIGNIFICANT YESTERDAY AT THE VATICAN THE FRENCH PRESIDENT AND CARE STAR MARK WERE ALSO THERE -- KEIR STARMER WERE ALSO THERE?

>> I DO.

I THINK THOSE THREE HAVING A DIRECT CONVERSATION WITH PRESIDENT TRUMP HAS BEEN ABLE TO IMPRESS ON PRESIDENT TRUMP THE IMPORTANCE OF A FAIR AND JUST AND DURABLE PEACE AND THAT PRESIDENT PUTIN IS NOT PART OF THAT SOLUTION.

PRESIDENT PUTIN STARTED THE WAR AND HE CAN END IT BUT ONLY IF HE IS PRESSURED TO DO SO.

I IMAGINE THAT IS WHAT THE FRENCH AND BRITISH TOLD HIM AND I AM SURE THAT IS WHAT PRESIDENT ZELENSKYY TOLD HIM.

JOHN: THE PRESIDENT ALSO WONDERED IF PUTIN HAS TO BE HANDLED DIFFERENTLY THROUGH BANKING OR SECONDARY SANCTIONS.

WHAT COULD THE ADMINISTRATION DO IN THOSE AREAS IT IS NOT ALREADY DOING?

>> THE ADMINISTRATION CAN PUT SECONDARY SANCTIONS ON THOSE NATIONS THAT BY OIL FROM RUSSIA.

RUSSIA IS HEAVILY DEPENDENT ON OIL EXPORTS.

RUSSIA SELLS A LOT OF OIL TO THE CHINESE AND INDIANS.

PUTTING SANCTIONS ON THE CHINESE AND INDIANS, IF THEY CONTINUE TO BUY THE OIL FROM RUSSIA THAT FUNDS THE WAR EFFORT, THAT COULD HAPPEN.

THAT IS NUMBER ONE.

NUMBER TWO, THERE ARE SANCTIONS, THERE ARE BANKS THAT HAVE NOT BEEN SANCTIONED YET UNDER THE EXISTING REGIME.

THERE ARE MORE SANCTIONS THAT COULD BE PUT ON.

THERE ARE WAYS TO MAKE THE EXISTING SANCTIONS MORE EFFECTIVE.

THERE IS A SHADOW FLEET THE RUSSIANS USED TO EXPORT OIL AND THERE ARE WAYS TO CRACK DOWN ON THAT SHADOW FLEET TO BE SURE THAT GOES AWAY, THAT REVENUE STOPS FLOWING INTO THE RUSSIAN TREASURY.

THAT WILL STOP THE RUSSIAN WAR MACHINE.

THAT IS ALSO A PART OF THE VULNERABILITY PRESIDENT PUTIN UNDERSTANDS HE HAS.

THIS IS A REAL VULNERABILITY THAT COULD MAKE PRESIDENT COME TO THE TABLE.

JOHN: WHAT IS YOUR SENSE OF WHERE THIS GOES FROM HERE?

>> I THINK THE ADMINISTRATION, AFTER THESE CONVERSATIONS YESTERDAY, UNDERSTANDS THIS IS HARD, THIS IS DIFFICULT.

I BELIEVE WE ARE GETTING INDICATIONS THEY RECOGNIZE IT IS NOT GOING TO BE DONE IN DAYS AND THEY OUGHT TO TAKE SOME EXTRA TIME TO LISTEN TO THE UKRAINIAN AND EUROPEAN POINT OF VIEW AND ADJUST THEIR PROPOSALS.

MANY OBSERVERS RECOGNIZE THE PROPOSAL THE AMERICANS HAVE PRESENTED TO THE EUROPEANS BUT ALSO TO THE UKRAINIANS AND RUSSIANS IS VERY FAVORABLE TO THE RUSSIANS.

PRESIDENT TRUMP, HAVING HEARD YESTERDAY FROM THE LEADERS OF BRITAIN AND FRANCE AND UKRAINE, CAN ADJUST THAT PROPOSAL WITH SOME TIME AND TAKE IT BACK TO THE RUSSIANS.

I THINK THOSE ARE THE NEXT STEPS.

JOHN: THANK YOU VERY MUCH.

>> THANK YOUOUOR HAVING ME.

JOHN: IN TONIGHT'S OTHER NEWS, VANCOUVER POLICE HAVE RULED OUT TERRORISM AND A SATURDAY NIGHT INCIDENT WHERE A MAN PLOWED HIS CAR INTO A CROWD OF PEOPLE AT A FILIPINO HERITAGE FESTIVAL.

AT LEAST 11 PEOPLE WERE KILLED AND MORE THAN 20 OTHERS INJURED AFTER THE VEHICLE CAME TO A HALT, BYSTANDER TOLD THE 30-YEAR-OLD SUSPECT UNTIL POLICE ARRIVED.

POLICE SAY THE MAN HAS A HISTORY OF INTERACTIONS WITH LAW ENFORCEMENT AND MENTAL HEALTH PROFESSIONALS.

THEY SAY THE DEATH TOLL COULD RISE AS SOME OF THE INJURIES ARE LIFE-THREATENING.

ISRAELI JETS STRUCK BEIRUT'S SOUTHERN SUBURBS TODAY FOR THE THIRD TIME SINCE THE CEASE FIRE.

THE JETS COULD BE HEARD OVER THE CITY AND THERE WERE TWO WARNING STRIKES.

THEN ISRAEL HIT AN AREA WHERE THEY SAID HEZBOLLAH STORED PRECISION MISSILES.

HEZBOLLAH HAS LONG HAD WIDE SUPPORT AND INFLUENCE IN THE SOUTHERN SUBURBS.

PAKISTANI FORCES KILLED MILITANTS THEY SAY WERE TRYING TO SNEAK INTO THE COUNTRY.

THEY CLAIM THEY WERE PART OF THE PAKISTANI TALIBAN WHICH THEY SAY IS CARRYING OUT HIGH-PROFILE ATTACKS IN PAKISTAN FROM SAFE HAVENS INSIDE AFGHANISTAN.

MEMBERS HAVE FOUND SANCTUARY IN AFGHANISTAN SINCE THE TALIBAN'S TAKEOVER FOUR YEARS AGO.

POPE FRANCIS' TOMB OPENED TO THE PUBLIC TODAY.

THOUSANDS LINED UP EARLY TO PAY THEIR RESPECTS INSIDE THE CHURCH LOCATED IN ROME'S MOST MULTICULTURAL NEIGHBORHOOD.

HIS FINAL RESTING PLACE IS A SPARSE WHITE TOMB SIMPLE AND MARKED WITH HIS NAME IN LATIN -- SIMPLY MARKED WITH HIS NAME IN LATIN.

>> HE WAS A PERSON CLOSE TO EVERYONE SO WE RESPECT HIM FOR WHAT HE DID, EACH IN OUR OWN WAY.

JOHN: AN ESTIMATED 200,000 PEOPLE ATTENDED THE SPECIAL MASS HONORING FRANCIS IN ST. PETER'S SQUARE.

TODAY IS THE SECOND OF NINE DAYS OF OFFICIAL MOURNING BEFORE CARDINALS ME TO ELECT THE NEW POPE.

STILL TO COME, WE LOOK BACK AT PRESIDENT TRUMP'S EVENTFUL FIRST 100 DAYS IN OFFICE.

AND HOW WARMING ARCTIC TEMPERATURES MAY BE ERODING HISTORY.

JOHN: TOMORROW IS THE END OF VOTING IN CANADA TO ELECT A NEW PRIME MINISTER.

THE BIG ISSUE WITH THE CAMPAIGN HAS BEEN U.S.-CANADIAN RELATIONS, ESPECIALLY PRESIDENT TRUMP'S TARIFF SCRIPT THE TWO FRONT RUNNERS ARE THE LIBERAL READY LEADER AND CURRENT PRIME MINISTER MARK CARNEY AND THE CONSERVATIVE PARTY LEADER.

SINCE THE BEGINNING OF THE YEAR, OPINION POLLS HAVE GONE FROM SHOWING A COMMANDING CONSERVATIVE PARTY LEAD TO A NARROWER BUT CONSISTENT LIBERAL PARTY LEAD.

DAVID IS A WRITER FOR THE ATLANTIC AND HOSTS A SHOW.

HE IS A NATIVE AND PART-TIME RESIDENT OF CANADA.

MORE THAN A 20-POINT PERCENTAGE SWING.

WHAT HAPPENED?

>> LET'S TALK ABOUT WHY THE CONSERVATIVES WERE SO FAR AHEAD.

CONOMIC PROGRESS HAS BEEN DISAPPOINTING OVER THOSE 10 YEARS.

PRODUCTIVITY GROWTH HAS SLOWED.

INCOMES DID NOT RISE.

THE TRUDEAU STRATEGY FOR OVERCOMING THE POOR PERFORMANCE OF THE ECONOMY PRODUCTIVELY WAS TO INVITE MANY MORE IMMIGRANTS TO COME.

CANADA'S IMMIGRATION RATES WERE ALREADY HIGH.

HE EFFECTIVELY DOUBLED THEM.

CANADIANS FIND THEMSELVES WITH POOR ECONOMIC PERFORMANCE, HUGE INFLOW OF IMMIGRANTS, RISING HOUSE PRICES, MUCH DISAPPOINTMENT.

THAT PUT THE CONSERVATIVES AHEAD UNTIL TRUMP BEGAN TO OPEN HIS MOUTH.

JOHN: WHAT HAPPENED AFTER TRUMP OPENED HIS MOUTH?

>> THERE ARE ALWAYS FRICTIONS THAT HAVE TO BE RESOLVED.

TRADITIONALLY, THEY HAVE BEEN RESOLVED THROUGH NEGOTIATION AMICABLY.

IT IS ALSO ABOUT SECURITY, POLICING, ENVIRONMENTAL.

TRUMP BEGAN TO PUT DEMANDS ON CANADA.

THEY WERE IRRATIONAL DEMANDS.

THAT HAS RALLIED CANADIANS TO THE FLAG AND MADE CANADIANS LOOK AROUND TO SAY WHICH POLITICIAN LOOKS LEAST LIKE TRUMP AND THAT IS THE GUY WE ARE GOING TO BACK.

JOHN: MARK CARNEY AND THE OTHER.

>> HE IS A VERY DYNAMIC HOUSE OF COMMONS PERFORMER.

HE MADE HIS MARK ON HOUSING PRICES.

HE NEEDS TO APPEAL TO YOUNGER VOTERS WHO HAVE BEEN PRICED OUT OF HOUSING MARKETS.

THAT WAS THE CORE OF HIS MESSAGE, ECONOMIC CHANGE, BRING DOWN HOUSING PRICES SO YOU CAN START A FAMILY.

THERE IS ALSO A MINORITY IN THE CONSERVATIVE PARTY THAT HAS RESPONDED TO SOME TRUMP LIKE THEMES.

THEY SENSED CANADIANS WERE NOT AS ANTI-TRUMP AS CANADIAN VOTERS AT A TIME WHEN TRUMP WAS SAYING I WANT TO DESTROY CANADA.

THE BANKER STEPPED IN AS THE CLEAN FACE TO REPLACE JUSTIN TRUDEAU AND A I WILL STAND UP TO TRUMP AND DELIVER -- SAYING I WILL STAND UP TO TRUMP AND SAY NO TO TRUMP.

I AM NOT SURE THE CANADIANS WILL SAY NO TO EVERYTHING.

JOHN: WHEN AMERICANS HEAR LIBERAL AND CONSERVATIVE, THEY THINK THEY ARE ANALOGOUS TO THE DEMOCRATS AND REPUBLICANS.

IS THAT RIGHT?

>> NOT AT ALL.

THE LIBERAL PARTY'S MOST EFFECTIVE IN THE DEMOCRATIC WORLD.

THEY ARE ALL ABOUT WINNING.

THEY ARE VERY UNLIKE THE DEMOCRATS.

THERE IS NOT A THING THEY STAND FOR THAT THEY WOULD NOT TURN UPSIDE DOWN TO HELP WIN VOTES.

THE CONSERVATIVE PARTY IS MUCH MORE REGIONALLY BASED AND FRACTIOUS.

IT HAS A HIGHER FLOOR OF SUPPORTERS BUT A LOWER CEILING.

IT IS A MUCH LESS IDEOLOGICAL PARTY.

THE LIBERALS MUCH MORE RUTHLESS THAN DEMOCRATS.

THAT IS WHY YOU CAN HAVE SUCH A BIG MOVEMENT BECAUSE IT IS NOT THAT POLARIZED A COUNTRY.

JOHN: WE HAVE HAD RECORD EARLY VOTING IN CANADA.

DOES THAT REFLECT VOTER INTEREST?

>> IT REFLECTS TWO THINGS.

THE TURNOUT IS GOING TO BE HIGH.

THERE HAS ALSO BEEN A TREND FOR THE VOTE TO SPLINTER INTO SMALLER PARTIES.

THIS ELECTION LOOKS TO BE A RECONCENTRATION OF THE TWO BIG PARTIES IN A WAY CANADA HAS NOT SEEN SINCE THE 1980'S, MAYBE NOT SINCE THE 1950'S.

JOHN: THANK YOU VERY MUCH.

>> THANK YOU.

♪ JOHN TUESDAY MARKS THE END OF THE FIRST 100 DAYS OF THE SECOND TRUMPET PRESIDENCY.

IT HAS BEEN A TRADITIONAL TIME TO TAKE STOCK OF A NEW ADMINISTRATION.

THE POLITICAL HISTORIAN AND PROFESSOR AT GEORGE WASHINGTON UNIVERSITY.

HOW WOULD YOU ASSESS THE FIRST 100 DAYS?

>> IT HAS BEEN AN HISTORIC 100 DAYS.

THE AMOUNT OF EXECUTIVE ACTION HAPPENING, THE TARGET OF THE TRUMPET ADMINISTRATION HAS BEEN THE CORE OF MODERN LIBERALISM.

THE ACTIONS ARE ROOTED IN AN OLDER FORM OF CONSERVATIVISM.

TARIFFS, PROTECTIONISM, ANTI-IMMIGRANT POLICY.

THE ATTACKS ON SCIENCE AND PUBLIC HEALTH, IDEAS THAT WERE POPULAR IN THE 1920'S AND 1930'S.

THE FIRST 100 DAYS ALSO HAVE CRYSTALLIZED THE INADEQUACIES OF THE POST-WATERGATE REFORMS TO CURB THE ABUSES OF EXECUTIVE POWER.

I THINK I AGREE WITH THOSE WHO SAY WE HAVE GOTTEN A TASTE OF WHAT IT IS LIKE TO LIVE IN AN AMERICAN AUTHORITARIAN STATE.

JOHN: SHOULD ANY OF THIS SURPRISE US?

DID HE NOT RUN ON A LOT OF THESE THINGS?

>> HE DID RUN ON A LOT OF THESE THINGS.

THE PARTICULAR FORM AND HAS TAKEN IS NOT SURPRISING BUT THERE IS A LEVEL OF SHOCK.

THINK ABOUT DOGE, THE DEPARTMENT OF GOVERNMENT EFFICIENCY.

ELON MUSK AND HIS TEAM HAVE GONE INTO FEDERAL AGENCIES AND CLOSED THEM DOWN, CUT STAFF, GUIDED SOME AGENCIES.

AND ALL WITHOUT CONGRESS.

UPENDED THE IDEAS AND THE LAWS OF CONGRESS HAVING THE POWER OF THE PURSE.

JOHN: NOT ONLY CONGRESS BUT ALSO THE COURTS.

WHAT DOES THIS SAY ABOUT HOW THEY VIEW OR ADDRESS THE OTHER BRANCHES OF GOVERNMENT?

>> THIS HAVE BEEN ONE OF THE MOST STRIKING THINGS OF THE FIRST 100 DAYS.

THEY HAVE HAD VERY LITTLE USE FOR THE OTHER TWO BRANCHES.

WITH A REPUBLICAN CONGRESS, THEY HAVE NOT ENACTED ANY MAJOR LEGISLATION.

ROOSEVELT, IF YOU GO BACK TO THE ORIGINAL 100 DAYS, IT WAS 100 DAYS BECAUSE HE STARTED TO USHER IN THE NEW DEAL.

THESE WERE THINGS HE DID THROUGH CONGRESS.

TRUMP HAS A FRIENDLY REPUBLICAN CONGRESS TO WORK WITH BUT HE HAS SHOWN LITTLE INTEREST IN HIM.

WITH THE COURTS FOR THE MOST PART, THEY HAVE IGNORED THE PORTS.

THERE IS A CON OF LITIGATION HAPPENING.

I THINK A LOT MORE THAN EVEN IN THE FIRST TERM.

I THINK THE ADMINISTRATION'S ATTITUDE AND ARGUMENTS HAVE BEEN THAT THE COURT SHOULD NOT CONTROL WHAT THEY SEE AS LEGITIMATE EXECUTIVE AUTHORITY.

JOHN: ARE WE HEADING FOR A SHOWDOWN BETWEEN THE PRESIDENT AND THE COURTS?

>> THERE HAS ALREADY BEEN A SHOWDOWN.

WE HAVE FEDERAL JUDGES WHO HAVE THREATENED TO HOLD MEMBERS OF THE ADMINISTRATION IN CONTEMPT FOR NOT FACILITATING THE RETURN OF ABREGO GARCIA.

THE SUPREME COURT HAS ISSUED A MIDNIGHT RULING STOPPING DEPORTATION TO THE TERRORISM JAIL IN EL SALVADOR.

THIS CERTAINLY SEEMS LIKE A MOMENTOUS TIME IN TERMS OF THE BALANCE OF POWERS.

JOHN: IN THESE FIRST 100 DAYS, WE HAVE SEEN PRESIDENT TRUMP'S APPROVAL RATINGS ALMOST FLIP.

IN THE NEW YORK TIMES AVERAGE OF PUBLIC POLLS, A WEEK AFTER THE INAUGURATION, 52% APPROVE, 43% DISAPPROVE.

THIS PAST WEEK, IT WAS JUST THE OPPOSITE.

44% APPROVE, 52% DISAPPROVE.

WHAT DO YOU MAKE OF THAT?

>> HISTORICALLY, IT IS A LITTLE SURPRISING.

THE FIRST 100 DAYS, IT IS A HONEYMOON PERIOD.

THERE IS A REAL HOPE BECAUSE THEY JUST WON REELECTION OR ELECTION.

THEY BELIEVE THEY HAVE A MANDATE.

SUALLY PRESIDENTS ARE REALLY POPULAR.

IT IS ONE OF THEIR MOST POPULAR MOMENTS OFTENTIMES.

TRUMP IS HISTORICALLY LOW, THE LOWEST APPROVAL RATINGS OF ANY MODERN PRESIDENT IN HIS FIRST 100 DAYS.

I THINK THE WORRYING THING POLITICALLY FOR THE ADMINISTRATION IS HIS NUMBERS ON THE ECONOMY HAVE REALLY GONE DOWN.

JOHN: THE ORIGINAL 100 DAYS, FRANKLIN ROOSEVELT LAID THE GROUNDWORK FOR THE NEW DEAL.

IS THERE ANY SENSE OF WHAT TONE THIS PRESIDENT HAS SET IN THE FIRST 100 DAYS, WHETHER THIS WILL CARRY ON OR HAVE A LONG-TERM EFFECT ON THE UNITED STATES?

>> IT IS HARD TO KNOW.

I DON'T REMEMBER THAT MUCH FROM TRUMP'S FIRST 100 DAYS.

THE SO-CALLED MUSLIM BAN, THE CHAOS AT THE AIRPORTS IS ONE MEMORY.

THIS FEELS MUCH MORE MOMENTOUS.

IT IS MOMENTOUS FOR THE EFFORTS TO HARVEST POWER, TO WIELD POWER, TO TAKE POWER FROM CONGRESS, SPENDING POWER, IGNORING THE COURTS, THE EFFORTS TO DRAMATICALLY SCALE BACK THE SIZE OF GOVERNMENT, BUT TO DO IT IN A SLASH AND BURN WAY.

IT FEELS LIKE AN HISTORIC MOMENT.

THE STAKES FEEL QUITE HIGH RELATIVE TO OTHER RECENT 100-DAY PRESIDENCIES.

JOHN: THANK YOU VERY MUCH.

>> THANK YOU FOR HAVING ME.

♪ JOHN: FINALLY TONIGHT, A JOURNEY TO REMOTE ALASKA WHERE GLOBAL WARMING IS BEING BLAMED FOR ENDANGERING A TREASURE TROVE OF INDIGENOUS ARTIFACTS.

HE NONPROFIT MEDIA ORGANIZATION VISIT ONE SITE WHERE ARCHAEOLOGISTS SAY THEY ARE IN A RACE AGAINST TIME.

> CAN YOU SEE IT?

IT LOOKS LIKE A MOSAIC OF DAILY LIFE PRESSED DOWN INTO THE DIRT.

>> HOW MANY PEOPLE LIVED HERE?

>> THIS WAS A SETTLEMENT.

ABOUT 200 PEOPLE LIVED HERE STARTING AS EARLY AS 1450A.D THIS IS ALL WOOD FROM SHAKESPEARE'S TIME.

>> IT IS PRESERVED SO WELL.

>> THE AVERAGE DIGGER WILL FIND ONE OR TWO JAW-DROPPING MUSEUM PIECES PER DAY.

>> LET'S KEEP DIGGING.

>> AT THE EDGE OF THE WORLD, THE ARCHAEOLOGIST AND HIS TEAM ARE DIGGING DOWN, PIECING TOGETHER THE STORY OF AN HISTORICAL COMMUNITY THAT CAME TO AN END MORE THAN 300 YEARS AGO.

>> THE OBJECTS WE ARE FINDING ARE IMPORTANT NOT JUST TO LOCAL FOLKS AND THEIR HERITAGE BUT TO OUR COLLECTIVE HERITAGE AS HUMANS.

WHAT IS SCARY IS THAT WITH CLIMATE CHANGE, THIS RECORD IS UNDER THREAT.

IT IS A RACE AGAINST TIME, BOTH AGAINST EROSION AND THE FACT THE PERMAFROST HAS MELTED AND THESE THINGS ARE SLOWLY ROCKING.

WHEN THE PERMAFROST IS GONE, THE SITES ARE EXPOSED TO THE U.K. -- TO DECAY.

THIS AMAZING RECORD IS BEING LOST VERY QUICKLY.

>> THE MELTING PERMAFROST AND COASTAL EROSION HELPED UNVEIL THE SITE FOR ARCHAEOLOGISTS.

BUT THOSE FORCES ALSO THREATENED TO DESTROY AND WASH AWAY THESE ARTIFACTS.

THAT IS WHY ARCHAEOLOGISTS SAY THAT THEIR WORK IS INEXTRICABLY WINKED TO CLIMATE CHANGE.

NOW, SCIENTISTS IN BOTH FIELDS ARE SOUNDING THE ALARM AS THE WORLD CONTINUES TO WARM.

SCIENTIFIC STUDIES SHOW MELTING GLACIERS IN PLACES LIKE ALASKA WILL IMPACT FAR OFF OCEANS, LANDS, AND THE PEOPLE, AND CULTURAL SITES ON IT.

THOSE LOOMING CHANGES POSE A DANGER TO NATURAL AND CULTURAL HERITAGE ALL OVER THE WORLD.

IN FACT, UNESCO SAYS THERE IS NO GREATER THREAT RIGHT NOW TO WORLD HERITAGE SITES THAN A WARMING PLANET.

AT RICK'S SUGGESTION, WE CAME HERE TO ALASKA TO BETTER UNDERSTAND THE IMPACTS A WARMING PLANET IS HAVING ON THE ONGOING EFFORT TO UNVEIL KEY ARTIFACTS.

HEY ARE IN CHARGE OF THE LAB AND WHAT HAPPENS TO THE OBJECTS AFTERWARDS.

HI.

I AM OBVIOUSLY WITH THE RIGHT PERSON.

WHAT HAVE YOU GOT?

>> THIS IS A LITTLE VESSEL OR MIGHT HAVE BEEN A DIPPER.

IF YOU IMAGINE THESE ATTACHED AND A LONG HANDLE, DIP IT TO GET WATER OUT.

DIGGING HERE ABSOLUTELY SPOILED YOU FOR DOING ARCHAEOLOGY ANYWHERE ELSE.

THE FACT THAT WE ARE FINDING WOOD, BASKETRY, NO ONE ELSE HAS FOUND 400-YEAR-OLD BASKETRY AND ROPES BEFORE SO THAT IS INCREDIBLE.

>> SHE IS THE SITE MANAGER.

AFTER THE OBJECTS ARE DUG UP IN THE FIELD, THEY ARE PROCESSED AND LOGGED.

WITH EVERY OBJECT THEY CLEAN, SORT, AND DOCUMENT, SHE ADDS TO THE STORY OF THESE PEOPLE.

BUT IN THE LAST COUPLE OF YEARS, THEY TOLD US THE THREADS OF THE STORY ARE FRAYING.

>> THERE IS A LOT OF KNOWLEDGE ABOUT WAYS OF LIFE, CULTURE, THE PEOPLE WHO LIVED.

LOSING THAT KNOWLEDGE, WE ALSO LOSE THE OPPORTUNITY FOR NATIVE PEOPLE, YOUNG PEOPLE TODAY TO RECONNECT WITH THAT HERITAGE AND RELEARN SOME OF THE SKILLS AND STAY CONNECTED TO THOSE WAYS OF LIVING.

WHEN EVERYTHING IS WASHED AND DRIED AND LABELED AND CATALOGED, IT ENDS UP IN HERE IN THE MUSEUM.

>> OH, WOW!

EVERYTHING YOU SAID IN THE OTHER ROOM -- WE WOULD HAVE LOST THIS ENTIRE STORY.

>> THERE ARE HUNDREDS IF NOT THOUSANDS OF SITES LIKE THIS ACROSS ALASKA.

GIVE IT FIVE OR 10 MORE YEARS, AND ALL OF THIS WOULD BE GONE.

ALL OF THIS WOULD BE LOST.

>> BEYOND ALASKA, IT IS ESTIMATED SOME 20,000 ARCHAEOLOGICAL SITES GLOBALLY ARE UNDER THREAT FROM CLIMATE CHANGE.

WITH RISING SEAS AND COASTAL EROSION, RICK SAYS HIS MISSION NOW IS TO SAVE AS MANY OF THESE ARTIFACTS AS HE CAN BEFORE THEY WASH AWAY FOR GOOD.

IT IS KIND OF SHOCKING TO HEAR THAT THIS IS A RACE, A RACE AGAINST TIME FOR THE PRESERVATION OF OUR STORY.

>> ALL WE CAN DO IS RESCUE WHAT WE CAN AS FAST AS WE CAN.

IT IS LIKE A MUSEUM IS ON FIRE.

JOHN: THE FULL DOCUMENTARY WHICH IS CALLED "MUSEUM ON FIRE" IS ON YOUTUBE.

♪ OHN: THAT IS PBS NEWS WEEKEND FOR THIS SUNDAY.

I AM JOHN YANG.

FOR ALL OF MY COLLEAGUES, THANKS FOR JOINING US.

HAVE A GOOD WEEK!

♪