Towards the end of nineteenth century, Europe suddenly woke up to the riches that lay in the vast unexplored continent to its south, and the ‘scramble for Africa’ began. By the start of the First World War, almost all of the continent had been taken by European powers. The rights of Africa's own people, who lost land and many lives during this process, drew scant attention.

Why recall this episode today? Fleetingly, last summer, Africa was big news, when it became the central topic at a meeting in Scotland of the leaders of the G8 group of top industrialized nations, chaired by British prime minister Tony Blair. Yet the real action is being taken by a donor nation that isn't even a member of the G8: China.

The G8 nations — correctly, if belatedly — are considering how best to invest in Africa, so that the previous misappropriation and mismanagement can be avoided. China seems to have no such qualms. Across the continent, from Zimbabwe to Sudan, China is winning friends by lending money to Africa's most unsavoury regimes without asking awkward questions.

As a News story on page 393 of this issue illustrates, scientists and engineers are sometimes complicit with this process. Sudan's Merowe dam on the Nile could be set to repeat the mistakes that have characterized previous large-scale hydropower projects in poor countries. Studies of how to resettle 50,000 people whose land will be flooded, and assessments of the project's environmental impact, were finished late in the day, and undertaken with insufficient rigour. They would have stopped the project going ahead if the World Bank, for example, was funding it.

Lahmeyer International, the German company that is coordinating the project, is disarmingly open about why this is so. It says that funders such as the World Bank make things too complicated. Thorough environmental and social impact assessments take years; Sudan wants power now. China is willing to invest, in part to cement closer ties with an important oil producer. And the Sudanese government lacks the political infrastructure — and probably the political will — to enforce proper safeguards. So, once again, thousands of poor people look set to suffer so that a big dam project can go ahead.

People's rights and needs are once again being sidelined in the stampede for wealth.

The project's backers have sought to portray Merowe as a necessary trade-off between the competing needs of development and the rights of local people. But there is no reason why both needs can't be met. Hydropower certainly has a role to play in Africa's development. Most of the continent's available hydropower resources are untapped and could, if properly harnessed, provide a valuable and renewable source of energy. But that doesn't mean that large dams need to be built. Successful projects in Asia and South America have shown that small hydropower projects can supply a few thousand local people without the need for big resettlement projects. Smaller projects can be run with more input from local people and are easier to combine with other renewable sources, such as solar power.

Unless the lessons of the past are thoroughly learned, large dam projects will sink over time in a morass of corruption, haphazard displacement of local people, lack of political accountability, and failure to plan properly for maintenance.

South Africa has, to its credit, tried to incorporate some of these lessons into a hydropower and water-supply project in Lesotho. The project is imperfect, but at least its administrators have sought to consult with local people and to run independent assessments of its environmental impact. But South Africa, with its wealth and its relatively sophisticated political system, is an exception.

In many other African nations, there is little chance of proper safeguards being implemented. Chinese firms and government agencies will operate with few checks or balances. The same goes for the European companies involved in Merowe and elsewhere. They know that rigorous political consultation and environmental assessment are needed if big dam projects are to succeed. Yet they have been happy to engage in such projects in the absence of any such safeguards. The staff and shareholders of these firms are part of another scramble for Africa, in which local peoples' rights and needs are once again being sidelined in the stampede for wealth.