If, as now seems likely, world leaders reach an agreement on climate change when they meet in Paris at the end of the month, they will have taken a momentous step towards protecting our planet. But it will still only be a start. To make true progress on climate change, we need new economic structures and new technology.

This will come at a price; developing countries in particular will have to balance the cost of environmental clean-up with the need for continued growth. But it will also bring benefits, creating new and more sustainable sources of prosperity. And, as so often in cases where progress depends on upfront investment, finance holds the key.

Green finance should not be another form of aid that wealthy nations will provide to poorer countries. Nor can it be state-backed project financing in disguise. Instead, the focus should be on harnessing market principles to draw in private capital so that clean technologies can be commercialised and financing shifted away from polluting industries that rely on wreaking environmental destruction without paying for it.