When it comes to predicting the future of green jobs globally, the numbers look impressive. Tens of millions could be created this decade in clean energy and nature protection alone as fossil fuel industries shrink and green investment grows.

But what exactly are these new roles, where will be they be located, will they pay fairly and what skills will be required?

Workers themselves, especially those in polluting industries, have doubts about the optimistic outlook presented by international agencies, said Nick Pesta, a senior strategy associate at RMI, a U.S.-based energy transition think tank.