Nations rich and poor must invest now to protect against the effects of climate change or pay an even heavier price later, a global commission warned Tuesday.

Spending $1.8 trillion across five key areas over the next decade would not only help buffer the worst impacts of global warming but could generate more than $7 trillion in net benefits, the report from the Global Commission on Adaptation argued.

"We are the last generation that can change the course of climate change, and we are the first generation that then has to live with the consequences," former UN chief Ban Ki-moon, who chairs the commission, said at the report's launch in Beijing.

"Delay and pay, or plan and prosper," he said, sharing a catchphrase from the commission, which is co-chaired by Microsoft founder Bill Gates and World Bank CEO Kristalina Georgieva.

Investing now in early warning systems, climate-resistant infrastructure, mangrove protection, better agriculture and improving fresh water resources would pay for itself several times over, the report said.

Mangroves - tropical tidal water forests - protect, for example, against storm surges and act as nurseries for commercial fisheries, but at least a third of them globally have been uprooted for tourism or aquaculture.