in 1600 the world population and for the first time in the history of mankind and reach 1 billion people . this double in 1860 to 2 billion people . then in 1960 this double to 3 billion and then it accelerate to 4 billion in 1976. right now we be head towards 7 billion people and they all have to be feed and need school and want thing we all want . i do like warn documentary but they should tell the real problem and that be overpopulation . of course politics would not burn their hand on this problem because of the power of religion but the real problem be too many people and that be why the wild animal be leave and die out and there be not enough space . in this documentary and the same a al gore and have many fault a global warming have nothing to do with mankind . throughout the 4 . 5 billion year of history of the earth and climate have change all the time . greenland use to be green and pool have change and ice time follow by warm up be part of the earth history . and we can not stop this and we be live on a very violent planet and nothing be stable and earth quake and volcanic eruption and change of magnetic field and drifting of continental shell . pollution be something we can stop and overpopulation we can stop . climate change not . of course with global warm scam and tax can be raise without protest and try to stop population grows be dangerous for politician .