I've been watching many documentaries on global warming these days. One of them said that: It was a BBC channel documentary. Global warming is causing the temperature of the earth to rise. Global warming is due to increased CO2 levels in the atmosphere. This CO2 is attributed to human activities like increased emissions and all that. Well another one is opposed to this idea of blaming the humans for all this phenomenon. The Documentary was named "Global Warming Swindle". They attributed this phenomenon to the Sun and said that it was normal and had happened before also. Sunspots reflected the activity and the temperature trends on earth followed them closely. And also due to the clouds. They are deadly opposed to the idea that human activities are causing all this and that out of all the green house gases CO2 is a very small fraction. Water Vapours comprise of a very large fraction of green house gases. And the amount of CO2 that humans put into the atmosphere is much less than what is being poured in by nature itself. Then Mr. Al Gore also blames this rise in temperature to human activities in his famous documentary presentation "An Inconvenient Truth". Then yet in another documentary from BBC again....called "Global Warming-The Big Chill", they say that the global warming may be leading us to dropping temperatures. It was mainly focused on UK and mentioned about the conveyor convection belt of the Ocean. But it was predicted that UK might be heading towards very cold and frequent winters like somewhat of the past(I dont remember the year but it was not very distant). This stopping of the belt was due to addition of fresh water from fast melting greenland. They also attributed it to the sun but not sunspots in particular and also the cosmic rays. So this thought is whirling inside me like a hurricane and I need explanation. All Documentaries seem pretty convincing and have there own set of experts. So tell me : What basically is global warming? Though I know this but still these all theories have confused me. How far is the increasing CO2 level to blame for this effect? What role is the sun playing in it? And if anybody has seen these documentaries please do comment on their acceptibility. Are these proven facts or just material for the media to sell?