Stiell and Daryl Vaz, a Jamaican minister who leads efforts to deal with climate change, also called on wealthy governments to boost contributions to the Green Climate Fund, which is helping the Caribbean island nations implement projects to adapt to a warmer world.
U.N. climate chief Espinosa said the different streams of financing for climate action around the world were "all over the place" and needed to be brought together in a unified system. In Bonn, at the June 17-27 talks, government officials should concentrate on devising a "solid" mechanism for carbon markets, which business is waiting for, she added.
This is a key area that was postponed when the "rulebook" for the Paris Agreement was hammered out last December.
The Paris pact allows countries to transfer emissions reductions among themselves using carbon credits, but they have yet to agree on how to do that to ensure the reductions are not counted twice where they are produced and purchased.
Espinosa said protests and school strikes by young people over government inaction on climate change - a movement that has gathered steam since last year - should serve as a reminder to U.N. negotiators why their work mattered.
"They (youth) have credible and solid demands that are mobilising political leadership," she said.
