The World Bank has done a recent report estimating there will be more than 200 million climate refugees. The costs are difficult to predict as there are both direct and indirect consequences e.g., civil conflict, border tensions, etc. https://www.weforum.org/agenda/2021/09/climate-change-could-soon-force-216-million-people-to-leave-their-homes-according-to-a-new-report/

And there are billions going to early stage innovations for climate technologies from venture capitalists like Breakthrough Ventures, started by Bill Gates