WASHINGTON — There’s an unexpected method governments can use to reduce poverty, improve public health and reduce greenhouse gas emissions, top world leaders said Friday.

Their idea: Make transportation in the world’s megacities more available and sustainable to reduce congestion and benefit populations – and economies – that are projected to boom in the coming decades.

Jim Yong Kim, president of the World Bank, said Friday at a global transportation conference that working on sustainable transportation is part of the bank’s moral responsibility and will be a major focus of its lending in the coming years. Lifting people out of poverty is the bank’s chief mission, Kim said. But climate change caused by global warming threatens that mission, he said, particularly for future generations.

The bank recently issued a report that outlines what the world could be like if temperatures rise by 7 degrees Fahrenheit by 2060. It’s sometimes difficult for people to understand that, Kim said, but he offered the example of his own 3-year-old-son.

“To put it very bluntly . . . when he’s my age, he’ll be living in a world where the oceans will be 150 percent more acidic, the coral reefs will have all been melted away, the fisheries would have been completely disturbed, and probably every single day, there will be food fights and water fights all over the world,” he said. “The world that I’m literally handing over to him as an adult will be one that does not exist today. For me it’s very real.”