this is "world news." tonight, showdown. iran threatens to hurl a body blow at the u.s. economy, closing off the world's gateway to oil, to gas. the u.s. warns, "no way." free fall. newt gingrich plummets 20 points in 20 days as mitt romney surges. bird versus plane. a way too close encounter in the sky and what we learned about today air safety. mystery solved. the puzzle at the heart of the alfred hitchcock classic. what really made those birds attack? and superstar. the young who refused to be sidelined. hear him soar. >> touchdown!

good evening. tonight, the u.s. is engaged in a global showdown with iran. the iranians leveling a threat at the heart of the american economy. tonight, vowing to shut down a key gateway for the world's oil supply. this comes at the end of a year in which americans have paid more for gasoline than ever before. and the u.s. response to iran is tough. don't even try it. so, how real is the threat? and could it harm the fragile economic recovery? abc's cecilia vega covering the showdown from washington for us tonight. cecilia? >> reporter: good evening, diane. iran, upset the u.s. is about to impose sanctions over the country's nuclear program is now telling the world that it could easily shut down this vital artery, leading to the oil rich persian gulf. any attempt by the iranians to shut down the strategic strait of hormuz could send oil and gas prices skyrocketing in this country.

an astounding 20% of the world's oil travels through that vital waterway, just 20 miles wide and right in iran's backyard. their navy chief said on iranian tv today closing the strait of hormuz will be "easier than drinking a glass of water." and if they follow through on that threat, experts predict higher prices at the pump. >> depending on how long this goes on and how much is really going to be affected, by summertime we could be looking at upwards of $5. >> reporter: and that could have a profound effect on this nation's already fragile economy. economists say if prices rose from today's $3.26 a gallon average to $5, it would zap $218 billion in consumer spending over a year. money for things like restaurants, vacations and trips to the mall would instead go straight to the gas tank. >> what i might have to do is stay home a little bit more often and work from the phone. >> reporter: while president obama is on vacation in hawaii,

purposefully keeping quite on iran's provocations, the u.s. is responding forcefully. the u.s. navy vowing today that any disruption will not be tolerated. this eased concerns in the oil markets, but with america and iran facing off in these troubled waters, nothing is certain. >> if the iranians actually attempted to shut down that strait of hormuz, it would almost be like saying, "please attack me." you know, it would be an act of war. >> reporter: even if the strait remains open, new u.s. sanctions are about to be imposed on countries that trade with iran. those sanctions will make it difficult for other countries to buy iranian oil and possibly gas prices will increase around the world. well, oil prices did not rise today. experts are telling us that just the threat alone could be enough to raise gas prices by as much as 50 cents a gallon. diane? >> there will be a big chess game under way in the days ahead. thank you, cecilia. and we have big news tonight on the political front. your vote, your voting, begins

in just six days. and newt gingrich is in a freefall in iowa. new polls showing he has dropped from first to fourth place in less than a month. abc's jon karl is here to tell us what happened to the gingrich surge. >> reporter: diane, it has been a spectacular collapse. by my count, gingrich has lost nearly 20 points in 20 days. in a campaign of ups and downs, gingrich looks like he is in danger of being the shortest-lived front-runner of all. gingrich visited a little chocolate factory in iowa today to poke fun of mitt romney who compared his campaign to lucille ball's failed effort on a chocolate assembly line. >> report to governor romney, we've taken his thought so seriously, and we're here in the chocolate factory. >> reporter: but gingrich, who less than a month ago confidently predicted victory now trails not just romney in iowa but also ron paul and even rick santorum, with perry and bachmann not far behind. gingrich now looks like he's in a four-way race for third place.

gingrich is trying to get things back on track with the biggest advertising blitz of his campaign. two new ads in two days, all positive. >> we can create millions of jobs right now. >> reporter: his campaign has been down before. his decision to take a ten-day greek cruise in the spring led to the mass resignation of his campaign staff. today, gingrich said that luxury cruise ship helped him understand the financial crisis. >> ironically, being in greece during the greek crisis was very helpful and gave me a much deeper perspective. >> reporter: gingrich has been hit with a one-two punch of self-inflicted mistakes and blistering attacks by his opponents. a new ad today hitting both gingrich and romney. >> serial hypocrites and flip-floppers can't clean up the mess. >> reporter: gingrich's fall has been rick santorum's gain. the former pennsylvania senator has been firelessly campaigning in iowa for almost a year he's in third place now but he's also the fastest rising candidate in the state.

it's been a topsy turvy campaign. michele bachmann has been the front-runner, rick perry, herman cain. and right now, the man who may be peaking at just the right time is mitt romney. >> and you talked to the gingrich team today what do they have to say? >> reporter: first of all, they say it's not a surprise, given all the negative ads in iowa against gingrich, that he would be down. they're now saying, diane, that he doesn't need to win in iowa. he doesn't need to come in second or third. he's strong nationally. he's going on. i have to tell you this, they are out of money, the gingrich campaign says. they will end december in the red, in debt. and it doesn't get easier after iowa. in new hampshire, mitt romney today, new poll, nearly 30-point lead. >> that's a big win. and if they want to go negative, then, in the gingrich campaign, any sign of that? >> we >> reporter: well, he certainly isn't afraid to hit back, but so far his ads have been all positive. >> but no money tonight for new hampshire. thank you, jonathan karl.

and we do have news tonight about the cancer drug avastin. today, two new studies found avastin does not significantly extend the lives of patients battling 0 vaovarian cancer. it also increases serious side effects. the studies say, at best, avastin extends life by four months in advanced cases of the disease. in november, the fda revoked avastin's approval for breast cancer, as well. doctors can still prescribe it, though insurers may not pay and a year's worth of avastin can cost $100,000 a year. we head overseas now to north korea, and the remarkable pictures of the wachling residents of the most secretive nation on the planet. the funeral of kim jong-il is under way. his son, a 28-year-old enigma, unknown and untested. and now, at the helm of a nuclear power. one america is catching closely tonight. abc's global affairs an con christiane amanpour is tracking

the clues about what this new young leader will do. >> reporter: foreign dell cases were not invited to the funeral, but state television broadcast the highly choreographed display of grief around the nation. the chief mourner, kim's 28-year-old son and heir, walking with his hand on the hearse during the 2 1/2 hour procession through the freezing capital. his older brothers, who were passed over, were nowhere in sight. once again, public displays of grief which seem over the top to outsiders. but in this closed society, where people learn from birth to revere their great leader, conformity is required. dissent is dangerous. it's not just the men and women of the military, the world's fifth largest, who march in lockstep. citizens train for years to

participate in synchronized ceremonies like this one which introduced kim jong-un to his people last year. in the capital, human beings conduct a robotic ballet to keep the traffic flowing. sweepers keep the streets immaculate. what outsiders don't see are the hundreds of thousands of people in the prison camps, or the quarter of the population that is estimated by the united nations to be starvinstarving. because of malnutrition, north koreans are now on average two inches shorter than their counterparts in the south. this nuclear-armed regime is now in the hands of this still unknown young man. while today's funeral is intended to show an orderly transition to kim jong-un, the funeral lineup shows the powerful old guard, still right up there with him. the united states will be watching very closely to see what happens in pyongyang over the next days and weeks. a u.s. administration source

tells me that nuclear negotiations could resume, where they left off. but that will depend on the first move kim jong-un decides to make as the new leader. diane? >> christiane amanpour reporting from london. and now we turn to news about something missing tonight. look at this ski resort. grass where snow ought to be. a scene repeated around the country. what's going on with the snow? we asked abc's clayton sandell to find out. >> reporter: remember the blizzards of 2010? they're a distant memory. in boston last year, they had so much snow, they blew their snow removal budget by $9 million. this year they've hardly touched a penny. no snow may be good for city budgets, but businesses that rely on it are feeling the pain. in spokane, washington, private snow plow companies are losing money. >> it's been pretty light. we haven't been doing much. >> reporter: across the west, ski resorts are suffering. snow pack in utah is down 50%.

>> i thought, this looks a lot like it does during the summer. >> reporter: and with less of the white stuff, there's less of the green stuff. here at california's mt. baldie, the slopes are bare. >> we employ 150 in full operation. >> reporter: and in minnesota -- >> beautiful weather out here. first time golfing in minnesota in december. >> reporter: winter enthusiasts can take heart. it's nose extreme weather events that can quickly turn your winter from conditions like this -- into something a lot more like this. >> the winter is young. and we certainly think that the cold and the snow is going to return for a good part of the country. >> reporter: that's either good news or bad news. all depends on whether more snow makes you money or costs you money. clayton sandell, abc news, los angeles. and a puzzling note in the news today from the waters off the coast of california.

this week. the gray whales have arrived in record numbers. spotters out of redondo beach have reported 134 sightings already this month. that's very early. that's a 28-year record. and watchers hope it's a sign that the gray whales are finally thriving. and still ahead on "world news," five dramatic airline mishaps in just 24 hours? one of them, a direct hit with a bird. what we learned about air safety today. and breastfeeding moms protest target. what provoked their brigade? and triumph. a young boy's touch illness proves no match for his will to celebrate life. is this your normal? jamie lee curtis?? oh, hi, yes...wow, you really went all out on the decorations, huh?! yeah, but i'm so slow taking them down after all the fatty holiday food.

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[ male announcer ] yes, it is. that's the cold truth! with so many of us traveling this holiday week, we heard the news today of five airline mishaps, in just 24 hours. one of them, a direct hit from a bird. but these events happened at the end of a year that could be the safest for worldwide air travel ever. and abc's lisa stark tells us what we learned about air safety today. >> reporter: five mishaps in the air in the last 24 hours, but no injuries. a southwest jet, whose tires blew on takeoff. >> heard a loud pop and shaking, plane started shaking and they set the nose back down, said we blew a tire. >> reporter: another southwest plane hit a bird. a smoke alert on a united jet. a strange noise forced a delta emergency landing. and another delta flight also blew a tire. but the last major fatal commercial air crash in the u.s. was nearly three years ago. the skies in the u.s. and, in

fact, most of the world, are as safe as they have ever been. this year, so far, planes most commonly flown by americans worldwide had just one major crash for every 3 million flights. 49% better than last year. >> they've gotten very good at making the system very safe. >> reporter: years of effort, including new safety technology and better pilot training have paid off. but there's another reason the skies may be safer now, as well. believe it or not, it's the slow economy. that's when airlines keep their most experienced workers. during boom times, safety can slip. >> during periods of growth, you see airlines are usually pressed to try to put new people in service, to bring in new aircraft. and all of that actually puts a little bit more risk in the system. >> reporter: and there's another risk. even now. >> we have to be careful not to assume that the battle is over for aviation safety. it's not. >> reporter: accidents happen in

an instant. it happens work to ensure safe skies stay that way. lisa stark, abc news, washington. and coming up next, how one mom, attempting to breast feed her baby at target, spurred a nationwide protest movement. d, . and i quit smoking with chantix. knowing that i could smoke during the first week was really important to me. [ male announcer ] along with support, chantix is proven to help people quit smoking. chantix reduced my urge to smoke -- and personally that's what i knew i needed. [ male announcer ] some people had changes in behavior, thinking or mood, hostility, agitation, depressed mood and suicidal thoughts or actions while taking or after stopping chantix. if you notice any of these, stop taking chantix and call your doctor right away. tell your doctor about any history of depression or other mental health problems, which could get worse while taking chantix. don't take chantix if you've had a serious allergic or skin reaction to it. if you develop these, stop taking chantix and see your doctor right away as some can be life-threatening. if you have a history of heart or blood vessel problems, tell your doctor if you have new or worse symptoms.

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michelle hickman said she was trying to be discreet when workers stared at her and then asked her to move into a fitting room or restroom. today, women came out at dozens of stores, some of them nursing their children, others just in support. but today, a spokesperson from target said, "shoppers are welcome to breast feed even in public in their stores." a scientist with a passion for film says she has solved the mystery behind one of the most frightening movies of all time. what would make whole flocks of birds attack and kill? it was a real event that inspired alfred hitchcock to make his classic movie and abc's dan harris has the answer. >> reporter: what we've known all along about these psychotic winged killers with their malignant screeching and flapping, dive bombing poor tip by head ron in the movie "the birds, kws" is they were based in ale event, in 1961, when thousands of deranged sea birds

descended upon california, hurling themselves into the sides of houses, making headlines and catching the attention of a guy named alfred hitchcock, who had a mansion nearby. what has been a mystery all these years is what caused the real life birds to freak out? enter this woman, a researcher at louisiana state university, whose parents wouldn't let her watch the movie as a kid. >> it was so scary for me but when i grow up, i'm going to watch this movie again and again, and i did. >> reporter: recently the professor went back and examined samples of the plankton in the area the birds were eating back in 1961, and found strong evidence of a naturally occurring toxin that creates confusion, disor jenation and even death among birds. >> i'm so thrilled to make the connection. this is so cool. >> reporter: it's not quite as sexy as, say, demonic possession. dan harris, abc news, new york. and coming up, a young boy

who will not let his medical history determine his joy. just one phillips' colon health probiotic cap a day helps defends against occasional constipation, diarrhea, gas and bloating. with three strains of good bacteria to help balance your colon. you had me at "probiotic." [ female announcer ] phillips' colon health. i have a great fit with my dentures. i love kiwis. i've always had that issue with the seeds getting under my denture. super poligrip free -- it creates a seal of the dentures in my mouth.

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and finally, we bring you the story oaf a young boy whose body has given him big hurdles but his spirit simply will not quit. hear his joy and celebration of every day. we learned about him from our partners at espn and here's tom rinaldi. >> why do i like sports? that is a good question. >> reporter: like most 15-year-olds, lyndon baty loves sports. but not for the usual reasons. >> it's an outlet for me, to, you know, kind of escape all my medical history. >> reporter: born with a rare kidney disease, lyndon has spent half his life in hospital rooms. >> he has dialysis from 9 at night until 7 in the morning. he takes about 26 pills throughout the day, he has five

injections a week. >> reporter: he can no longer be around other kids. >> you know, when the doctor told me that, i mean, that really just, you know, sucked the life out of me. >> reporter: lyndon's parents were determined to find a way to connect lyndon at home to a life in high school. his eyes and ears? a four-wheel robot who walks the halls for him. all they need is a laptop and a wifi connection. >> came up with the baty-bot. >> what can you say about this? >> reporter: but while the robot connected lyndon, it could not heal him. he can't be exposed to classes filled with other children. and he can't play sports. but one place he can go is the safety of a small booth at the top of the bleachers. where he sits, mostly by himself, but where his voice certainly carries. >> bulldogs! i just really like to make as much noise as possible. i just really just want to be, you know, part of it, you know?

just to be part of a sports team. picked up by sheldon baty. he could go all the way. ! touchdown! i walk "monday night football" a lot so, i got some ideas from there. oh, wow, what a -- nice! oh! come on, man! >> i think his attitude with that sports announcing, it gives him a desire to keep going. >> yes, i have this kidney disease, but yet i am happy. i want people to look at me and say, "he can be happy with that, you know, why i can't be happy?" >> reporter: for abc news, tom rinaldi, espn. >> and we think lyndon is a world class champion, too. and we sure thank you for watching. we're always on at abcnews.com. don't forget, "nightline" will be along later. and, of course, we will see you right back here again for "world

news" tomorrow night. good night.