The advocacy group Tax Justice Network said that even a modest wealth tax on the world’s richest could easily raise $2 trillion each year, more than enough to help poorer nations become climate-resilient and transition to clean energy. The group cited Spain’s “solidarity surcharge,” implemented less than two years ago, which raised hundreds of millions of euros last year simply by imposing a small, progressive tax on the net worth of the 0.5% richest households. The Tax Justice Network released its proposal for a global tax on the ultra-rich ahead of November’s U.N. Climate Change Conference.