As a major global investor, I carefully watched how the United Nations General Assembly presidential speeches by Brazil’s President Jair Bolsonaro and then US President Donald Trump were suddenly upstaged by Chinese President Xi Jinping’s contrasting tone of hope as he pledged to cut carbon emissions.Faced with our greatest single global threat, man-made climate change, Xi has much more power to change the future than Trump, who claimed China invented global warming and promised to bring back…