Nepal, July 6 -- At a coastal port in Chittagong, Bangladesh, something remarkable is underway. With support from a $850 million (£620 million) investment from the World Bank, engineers are building flood-resistant infrastructure that can survive rising seas and stronger storms. A new 3.7-mile-long barrier will protect people, homes and trade in one of the world's most climate-vulnerable regions.

Projects like this do more than save lives. They show why investing in climate adaptation is one of the smartest financial opportunities of our time. There are plenty of global conferences where leaders discuss climate change and make big promises. Yet, less than 5.5 percent of global climate finance actually reaches the countries most at r...