"If we spend $50 trillion ... how much will that lower world temperatures?" Kennedy asked, with Holtz-Eakin saying he doesn't know because it would be contingent on China. Holtz-Eakin: "Depends on how it's done. If we do it all in the federal budget with directed things, Kennedy: it's ultimately private dollars anyway. "You're going to look at 50 trillion dollars." Kennedy: "If we make the United States of America carbon neutral by 2050 by spending 50 trillion dollars, which you're advocating, gather." "No, if you're going to do something, do something smart. That's what I advocated." Kennedy: "If we spend 50 trillion dollars to make the United States of America carbon neutral by 2050, how much will that lower World temperatures?" "I can't expect because we don't know what China and India and the rest of the globe have done." Kennedy then asked Litterman who provided a similar answer, saying it's about working with other countries, but Kennedy again pressed about the possibility of China and India not cooperating. Kennedy: "Dr. Litterman, if we spend 50 trillion dollars or however much it takes to make the United States carbon neutral by 2050, how much will it lower World temperatures?" Dr. Litterman: "Senator, that depends on the rest of the world. We have to work with the rest of the world. We're in this together." Senator: "What if we spend 50 trillion dollars, Europe cooperates, most western democracies cooperate, but India and China don't... Founding partner at Kepos Capital and chair of the Climate-Related Market Risk subcommittee Dr. Robert Litterman testified during a hearing to consider "climate-related economic risks and their costs to the Federal Budget and the Global Economy." Kennedy also asked another witness, President of the American Action Forum Dr. Douglas Holtz-Eakin.