In this April 3, 2014, file photo, giant machines dig for brown coal at the open-cast mining Garzweiler in front of a smoking power plant near the city of Grevenbroich in western Germany. Despite uncertainties about whether the United States will remain committed to the Paris climate accord under President Donald Trump, diplomats convened talks in Bonn, Germany, on May 8, 2017, on implementing the details of the global deal to combat global warming.

(Martin Meissner / AP)