With the war in Ukraine now in its 10th month, Russian President Vladimir Putin and U.S. President Joe Biden have both expressed openness to peace talks to end the fighting, as have leaders in France, Germany and elsewhere. This comes as millions of Ukrainians brace for a winter without heat or electricity due to Russian strikes on Ukrainian civilian infrastructure. “This war needs to end because it’s a disaster for everybody, a threat to the whole world,” says economist and foreign policy scholar Jeffrey Sachs, director of the Center for Sustainable Development at Columbia University. He says four major issues need to be addressed to end the war: Ukraine’s sovereignty and security, NATO enlargement, the fate of Crimea and the future of the Donbas region.