Barack Obama unveils tougher climate change plan - video

Barack Obama formally unveiled his administration's ramped-up plan to cut carbon emissions from power plants and declared climate change the greatest threat facing the world. Speaking to a friendly crowd at the White House a few months before international climate talks in Paris, Obama said the world may not be able to reverse global warming if aggressive action to stop it is not taken. 'There is such a thing as being too late when it comes to climate change,' he said. Continue reading...