Ten kilometers northeast from the Place de la Bourse, the historic epicenter of France’s financial system, lies the airport of Le Bourget. It was here on December 12, 2015 that the Paris Agreement on Climate Change was gaveled to conclusion with a striking green hammer by France’s foreign minister Laurent Fabius. From the beginning, money has loomed large in global climate negotiations, focusing on two tightly interlinked questions: first, how to raise the capital needed to decarbonize the global economy, one that is also protected from the impacts of a disrupted climate; and second, who should pay for this transition both within and between nations.