. >> alfonsi: petermann glacier in greenland is one of the largest glaciers in the arctic circle and one that's experienced dramatic melting. although it is a harsh and dangerous environment, it has drawn some of the world's leading climate scientists to study its it's sheath and look at its effects on the ocean. we watched as they attempted a first-ever look at what's happening 300 feet below the ice. >> i'm steve kroft. >> i'm lesley stahl. >> i'm bill whitaker. >> i'm sharyn alfonsi. >> i'm scott pelley. only miralax hydrates, eases and softens to unblock naturally, so you have peace of mind from start to finish. love your laxative. miralax. make delicious recipes that are lighter in calories and added sugar when you use splenda no calorie sweetener. think sugar, use splenda see me. see me. don't stare at me. see me. see me. see me to know that psoriasis is just something that i have. i'm not contagious. see me to know that i won't stop. until i find what works. discover cosentyx, a different kind of medicine for moderate to severe plaque psoriasis. proven to help the majority of

seen the changes in greenland? >> peter demenocal: the changes that are happening right now as a result of human activities are remarkable. and they're happening incredibly fast and they're-- it's not only happening fast but it's accelerating. and it's important to really get our mind around what we're saying there. we're not just saying that climate in the arctic is changing. it's changing at an accelerating rate. so basically it means it's starting to melt but it's melting at a faster and faster clip. so anyone who knows what it's like to fall off a cliff, that's what it's doing. >> for our crews photos of the alien landscape plus for more on walter cronkite goes to greenland -- >> the very top of the world. >> -- go to 60minutesovertime.com helps ease fibromyalgia pain. he also prescribed lyrica. for some patients, lyrica significantly relieves fibromyalgia pain and improves physical function. with less pain, i feel better. lyrica may cause serious allergjc reactions or suicidal thoughts or actions.s. tell your

it's on the northwest coast of greenland, just a few hundredsole. to get there in a helicopter severe and serene.ee was qaanaaq, with 700 residents and more huskies than people.ce nine months of the year, villagers have always hunted seal and narwhal to survive.imes the size of texas, and 80% of it is covered in ice, but it now losesns in snowfall every year. we saw evidence of the imbalance everywhere-- blue gashes acrossushing melt water, and the occasional thunderous crack of icebergsa. we still had 300 miles to go, and stopped twice to refuel along the way.were left behind for us by the scientists who glacier three weeks earlier. service gas station in the middle of nowhere. this will keep us going for how much longer? >> malik jensen: yeah, we canrs. >> alfonsi: our pilots, native greenlanders, kept a rifle nearby at each stop to protect have you seen polar bears out here? >> jensen: yeah, a lot. so now, it's ready, always safe. we arrived at petermann glacier. >> ah, there's the camp. >> alfonsi: and spotted the ice camp below.you. >> alfonsi:

it's on the northwest coast of greenland, just a few hundreds miles south of the north pole. to get there in a helicopter took us four hours over a rarely seen landscape that is both severe and serene. qaanaaq, with 700 residents and more huskies than people. locked in by ice nine months of the year, villagers have always hunted seal and narwhal to survive. greenland is three times the size of texas, and 80% of it is covered in ice, but it now loses more ice than it gains in snowfall every year. we saw evidence of the imbalance everywhere-- blue gashes across the ice, rivers of rushing melt water, and the occasional thunderous crack of icebergs dropping into the sea. we still had 300 miles to go, and stopped twice to refuel along the way. these barrels were left behind for us by the scientists who made the trip to petermann glacier three weeks earlier. this is the ultimate self- middle of nowhere. this will keep us going for how much longer? >> malik jensen: yeah, we can fly two and a half hours. >> alfonsi: our pilots, native greenlanders, kept a rifle nearby at each stop to

he says the cores collected in greenland are like a black box of the earth's inner workings. this one he collected just south of greenland. >> peter demenocal: so this is today's climate and we've had about 10,000 years of relatively warm climate. and then we go ten thousand years in the past - boom, there's the last ice age. this is when long island was formed and cape cod was formed. >> peter demoncal: and you can go on, and you can just find this color. it's filled with these rocks, what we call ice rafted detritus, until this period when - whoa, there's another warm phase. and then another cold phase, and a short cold phase, a longer warm phase and then - boom, another ice age. and so you've had cold, warm, cold, warm, cold, warm, today. >> alfonsi: how do we know that the warming we're seeing now, how do we not know it's part of this warm, cold, warm, cold? >> peter demenocal: that's a great question. these transitions are gradual. and kind of almost like a tide wave or something. and this transition, when you get to today, goes boom. suddenly very warm. >> alfonsi: deme

this one he collected south of greenland. >> this is today's climate. we have had 10,000 years of roll tiffly warm climate. then we go, 10,000 years in the past. boom. there is the last ice age. this is when long island was formed. cape cod was formed. go on. this is filled with these rocks. ice rafted treditis. this period. whoa, a warm phase. cold phase. then another warm phase. short cold phase. longer warm phase. boom, another ice age. so you have had, cold, warm, cold, warm, cold -- warm. today. >>> you can see the full report on our website. cbsnews.com. the overnight news will be right back. no wait time. this is great. it's very soft. can i keep it? (laughs) all the care of dove... ...now in a dry antiperspirant spray. hi, anne. how are you doing? hi, evelyn. i know it's been a difficult time since your mom passed away. yeah. i miss her a lot, but i'm okay. wow. that was fast. this is the check i've been waiting for. mom had a guaranteed acceptance through the colonial penn program, and this will really help of her final expenses. is it affordab

this one he collected south of greenland. >> this is today's climate. we have had 10,000 years of relatively warm climate. then we go, 10,000 years in the past. boom. there is the last ice age. this is when long island was formed. cape cod was formed. go on. just find this color. this is filled with these rocks. ice rafted treditis. this period. whoa, a warm phase. cold phase. then another warm phase. short cold phase. longer warm phase. boom, another ice age. so you have had, cold, warm, today. >>> you can see the full report on our website. cbsnews.com. the overnight news will be right back.'re new liquid gels. and you're coming with me... you realize i have gold status? mucinex sinus-max liquid gels. dissolves fast to unleash max strength medicine. let's end this. dry spray? that's fun. it's already dry! no wait time. this is great. it's very soft. can i keep it? (laughs) all the care of dove... ...now in a dry antiperspirant spray. living well your immune system works hard to keep you on top of your game. you can support it by eating healthy, drinki

this one he collected south of greenland. >> this is today's climate. we have had 10,000 years of relatively warm climate. then we go, 10,000 years in the past. boom. there is the last ice age. this is when long island was formed. go on. just find this color. this is filled with these rocks. ice rafted treditis. this period. whoa, a warm phase. cold phase. then another warm phase. short cold phase. longer warm phase. boom, another ice age. so you have had, cold, warm, cold, warm, cold -- warm. today. >>> you can see the full report on our website. cbsnews.com. the overnight news will be right back.'re new liquid gels. and you're coming g th me... you realize i i ve gold status? mucinex sinus-max liquid gels. dissolves fast to unleash max strength medicine. let's end this. dry spray? that's fun. it's already dry! no wait time. this is great. it's very soft. can i keept? (laughs) all the care of dove... ...now in a dry antiperspirant spray. your immune system works hard to keep you on top of your game. you can support it by eating healthy, drinking fluids

this one he collected south of greenland. >> this is today's climate. we have had 10,000 years of roll tiffly warm climate. then we go, 10,000 years in the past. boom. there is the last ice age. this is when long island was formed. cape cod was formed. go on. just find this color. this is filled with these rocks. ice rafted treditis. this period. whoa, a warm phase. cold phase. then another warm phase. short cold phase. longer warm phase. boom, another ice age. so you have had, cold, warm, cold, warm, cold -- warm. today. >>> you can see the full report on our website. cbsnews.com. the overnight news will be right back. it's already dry! it's very soft. can i keep it? (laughs) all the care of dove... ...now in a dry antiperspirant spray. hi, anne. how are you doing? hi, evelyn. i know it's been a difficult time since your mom passed away. yeah. i miss her a lot, but i'm okay. wow. that was fast. this is the check i've been waiting for. mom had a guaranteed acceptance life insurance policy through the colonial penn program, and this will really help with

. >> alfonsi: petermann glacier in greenland is one of the largest glaciers in the arctic experienced dramatic melting. although it is a harsh and dangerous environment, it has drawn some of the world's leading climate scientists to study its it's sheath and look at its effects on the ocean. we watched as they attempted a first-ever look at what's happening 300 feet below the ice. >> i'm steve kroft. >> i'm lesley stahl. >> i'm bill whitaker. >> i'm sharyn alfonsi. >> i'm scott pelley. minutes." it's easy e yoative when that lax loves your body back. whense senno c sweetener. thgar, use spa don'are at e me. see knowg that i have. i'm not contagious. me t wonp. until i find what works. discover cosentyx, a different kind of medicine for te t learallear 8 ou0 peaw 7skinancemont while the rity 90% nce.dose iare lergcosent foreing,houlbe ttefor ulos of and lowered ability to th occ ll yctorif you an inf or ms.. uch er,ts, , le ar coor ihavevedvacc plan ifn's di ll yr ctorsyto cans allergic ons cur. e me e me find ski r paward diff f medicine,as dergistt cosentyx. hey,e goto do t. >> kroft

. >> so lester, the beginning of this cold air is way up in greenland. we're talking temperatures of 60 below across the greenland ice sheath. you've got low pressure over quebec and this strong low pressure system with the clockwise, counterclockwise flow around it it brings that cold air, brutally cold air into the continental united states, so low temperatures tomorrow morning, burlington minus 12, 5 in cleveland and 10 chicago and 17 in charlotte and 21 in atlanta. highs tomorrow, 19 in new york, 13 cleveland and 14 chicago but as ron mentioned those windchills are brutal. minus 6 in new york and minus 4 in cincinnati and minus 13 in chicago, and then we bottom out on sunday morning, but the good news, lester, by tuesday temperatures rebound into the 50s and 30s. everybody either at or above normal. >> all right. >>> true to predictions it's getting nasty on the campaign trail in south carolina as another so-called birther attack today threatening to sue ted cruz for, quote, not citizen. if cruz doesn't as trump clean up his act and that battle is fr

>> there were 18 mills within less than three miles of ville.wn greenland the obvious reason, cotton. there was plenty of cotton everywhere. these men who decided to go into the textile business had no experience whatsoever in the textile business. they just decided to invest in these gigantic mills. these men got together as a partnership, and that is so unlike anywhere in those world, because they competed with each other yet they partnered with each other. they served on each other's boards. these men got together and decided to build an empire together. they also decided to build greenville. the history museum is a wonderful place. it is a wonderful place because it pays homage to where greenville really started. especially the textile industry. the exhibit behind appear to for people to understand our heritage, and where we originally came from. the first mill was started in 1873. the son, alexander, is the one who started the weaving process, the spinning process in the mill. they built a larger mill across the river. that was the beginning. the huguenot mill, there were two mil