We suggest that mentorship is particularly important for scientists from the developing world (see Nature 515, 453–454; 2014). It can address the problem of science inequality while helping to resolve global issues.

Academics in developing countries are rarely able to take advantage of cutting-edge knowledge from leading universities, more than 90% of which are in high-income nations (see go.nature.com/wffbfi). Expenditure on research and development is typically less than 1% of gross domestic product — one-third of the amount spent by most developed nations (see go.nature.com/gio8pu).

Scientists from wealthy countries could be encouraged to mentor young scientists from developing nations by including mentorship requirements in grant awards, for example.

Also, allocating resettlement funding can help to counter the 'brain drain' of researchers leaving low-income countries. It encourages them to return to share experience and knowledge and build local capacity.