Picking the precise moment when the world’s leaders had unmissable evidence of climate change is a matter for unsolvable debate, but there’s a strong case to be made for 1990. That year the elite researchers who serve as the volunteer scientists on the United Nations Intergovernmental Panel on Climate Change published their first report on the state of global warming science. Based on the report’s findings, more than 150 countries were able to agree on two key things: Burning fossil fuels increases the concentration of greenhouse gas in the atmosphere, and additional emissions would result in a hotter planet. Five years later, political leaders from more than a hundred countries gathered in Berlin for the first Conference of the Parties (COP). There have since been 24 more COP meetings, all of which have demonstrated that agreeing on scientific evidence isn’t the same thing as building a consensus on what […]