GZERO World Clips

As many as one million plant and animal species are being threatened with extinction as a result of human activity. That is the conclusion of a sweeping 1,500 page United Nations assessment, according to an early summary of the report released Monday. The report forecasts a staggering loss of biodiversity brought on by pollution, loss of habitat, invasive species and climate change. It also projects "grave impacts on people around the world (as a result of the change) are now likely." Ian Bremmer spoke with a man who says the consequences are actually far more dire than most people realize. And yet David Wallace-Wells, author of "The Uninhabitable Earth," also offers a bit of hope.