If the world is to achieve net-zero emissions without hamstringing the economic prospects of billions of people, the rich world must help developing countries decarbonise as they grow. At the Copenhagen climate summit in 2009, rich countries duly pledged to provide $100bn a year of public and private finance to poorer countries by 2020 to help them mitigate and adapt to climate change. The target is vaguely defined but is clearly being missed. Meeting it is not just a diplomatic challenge, but a technical one, given the difficulty of promoting investment in poor countries in which property rights can be insecure.
Which one of the following can be properly inferred from the passage?