A financial official from an island that’s among the world’s most vulnerable to global warming has a plan to quickly increase the amount spent on climate solutions in developing nations. And his plan requires little additional spending by rich countries.

"If you focus only on grants, only on people transferring money to you, you’re never gonna get the scale we need to save the planet," says Avinash Persaud, a Barbados-born, U.K.-raised development economist who was previously a banker in the City of London. His target for spending on emissions-reducing projects alone by developing countries is about $1.5 trillion per year — or seven times the sum rich countries currently give in overseas development aid for all causes, including health and poverty reduction.

In a recent interview, the impatient 56-year-old who serves as the financial adviser to Barbados Prime Minister Mia Mottley explained that the obstacle is better understood not as the lack of money but how to adjust the rules of global capitalism to end the prevailing climate-finance deadlock.