causing global warming with dire effects. tina krause is in london with the details. >> reporter: good morning. it's not easy to get nearly 200 countries to agree on anything, especially something with such an economic impact. the summit opens this morning and it's expected to last for two weeks. negotiators will try to come to terms on a deal that will slow and reduce greenhouse gas emissions. and at least slow down the effect of global warming. president obama will be in paris two days. he arrived last night and went directly to the concert hall, the bataclan, where the most people were killed during the terrorist attacks two weeks ago. also last night, protesters clashed with police. french forces used tear gas to stop demonstrators who defied a government ban on protests. french authorities did not want large crowds gathering after the terrorist attacks. this is the kind of pollution the summit wants to stop. smog in shanghai reached hazardous levels this morning and two previous summits did nothing on change the way developing economies like china and india operate. that is the bi

still grieving the city is slowly coming back to life. teen a krause, cbs news -- tina kraus, cbs news, paris. >>> to campaign 2016 where there's been a big shift in the polls. donald trump has surged ahead of ben carson in a pair of new polls. an air force base news washington post survey puts donald trump ahead by 10 points. trump continued to stir emotion on the campaign trail today with his approach to muslims. he said he'd bring back waterboarding, create a data business for syrian refugees and monitor mosques. >> i think waterboarding is peanuts compared to what they do to us. >> trump claimed he witnessed arab americans in new jersey celebrating the fall of the twin towers after the 9/11 attacks. the jersey city mayor responded by saying the republican frontrunner is just plain wrong. >>> coming up it could be an uncomfortable subject for a man, but tonight a simple new test could save many of them from a painful procedure and save a plot of money in -- lot of money in the process. >> plus new evidence el nino could be a huge hit this winter. >> and carlos santana like you've ne

tina krause says the company is defending its aircraft and its crew. >> reporter: u.s. intelligence sources tell cbs news the russian jetliner that crashed in egypt was likely not shot document while some sources are not ruling out a possible bomb on board, the u.s. director of national intelligence said there is no proof terrorists are to blame. >> we don't have any direct evidence of any terrorists involvement yet. >> reporter: russian airline officials contradicted egyptian reports that the pilot requested to land at the nearest airport because of technical issues. metro jet bosses say there was no mechanical issue or pilot error and some catastrophic event caused the plane to dive into the des certificate, killing all on board. the bodies were brought back to st. petersburg upon. the jet laner broke apart in mid-air about 23 minutes into the flight. investigators hope the black box flight recorders hold the clues they need to solve the worst air disaster in russian history. tina krause, cbs news. >>> claims from islamic militants who say they shot down the plane have been dismis