Duncan Green: Time is right for a mature debate on overseas aid

But taking that political consensus for granted would be a mistake, and that's why Oxfam's conference on "Making the most of Scotland's Aid" today is particularly timely.

One problem is that the aid debate is so dumb, polarised between "aid is bad" and "aid is great", neither of which considers how to improve the existing system. So what does good, and better, aid look like? For a start, it needs to be liberated from rich countries' political interests and targeted at helping poor people. Partly, that means strengthening developing country governments, for example by supporting them in building up decent public and free health and education systems. It is also transparent, as developing country governments struggle to plan effectively when they don't know what aid they will receive even a year or two down the road.

Aid is also having to adapt to a changing world, nowhere more so than on climate change. The recent drought and wildfires in Russia, floods in Pakistan and the drought and floods in Niger are consistent with what the climate modellers are telling us to expect if we do not get a grip on carbon emissions.

But the challenges of development, and thus to aid, go far beyond climate change – how do we feed a world population rising to nine billion by mid-century, without destroying the planet in the process? Can we control rising consumption in the rich countries, which puts huge strain on the Earth's resources? Aid can play a part as supporting actor, rather than lead role – that will always belong to the citizens and governments of poor countries – in rising to these new challenges.

We seem to have lost the ability to simultaneously celebrate aid's many achievements and think critically about how to improve it. We need to do more of both.

• Duncan Green is head of research at Oxfam.