Three young teachers - one British, two Zimbabwean - decided to tackle the problem of contaminated drinking water after three children at their remote school in Zimbabwe died. They designed the Elephant Pump - based on an ancient Chinese technology, using a rope and recycled plastic discs and costing less than a tenth of the more sophisticated pumps installed by aid efforts. It provides each child with clean water for life for less than a dollar. Almost all of those installed so far are still working, while developing countries are littered with broken conventional ones. There are now over 1,200 in Zimbabwe alone - and they are to be spread throughout Africa, with the help of the prize-winner's cheque from the prestigious St Andrews Prize for the Environment.

Log on to e-commerce websites and you can help indigenous peoples in some of the world's remotest corners earn a decent income. You can browse among such delights as silver jewellery from the Karen hill tribe in Thailand, baskets from the weavers of the Kikuthuko Women's Group in Kenya and contemporary indigenous designs from Australian Aboriginal artist Lynne Jordan, without glancing away from your screen. Usually helped by Northern groups - such as People Tree, The Virtual Souk, Global Exchange and Ten Thousand Villages - artisans and farmers from distant villages and rainforests are putting their products online and accessing a growing market for high-quality, fairly traded goods.

Twin with a hippo? In a way that is what the staff of the Calgary Zoo in Canada did when they made a small grant to local chiefs in Ghana to set up the Wechiau Community Hippo Sanctuary, beginning a long-standing relationship between the two institutions. The hippo sanctuary protects the environment, gives jobs to local young people and provides income for local artisans. It began with a small grant from the zoo to local chiefs to start the sanctuary. The relationship is just one example of a host of partnerships in practical cooperation between North and South, between schools, hospitals, churches, local councils and even entire villages, cities and counties in the developed and developing world.

Former busker and concert violinist Aubrey Meyer worked out a plan for North-South cooperation that is increasingly being hailed as a way forward in tackling climate change. Contraction and Convergence, as it is called, envisages allocating every person on Earth the right to emit an equal - but diminishing - amount of carbon dioxide, the main cause of global warming. Gradually, over decades, the amounts emitted by people in rich and poor countries would converge, while the total amount of the pollution would contract to an agreed safe amount. The idea is being taken up by scientists, economists, religious leaders, political parties and even governments all over the world as a just solution.

'They are', says Kofi Annan, the United Nations Secretary-General, 'the ultimate expression of what the UN is all about'. There are over 30,000 UN volunteers - 70 per cent from developing countries, 30 per cent from rich ones - who have worked for peace and development in more than 140 developing and Eastern European countries. Their myriad projects have ranged from running vocational training for women in Palestine to implementing a national geographic information system in Bhutan and staffing a health clinic in Timor-Leste. Many continue to work for development even after their period of service is up: Dean Mulozi spent more than two years in the Maldives developing communications systems for island micro-entrepreneurs before returning to his home country, Zambia, to begin a similar project.

Developing countries often destroy their wild areas and species to try to pay crippling international debts. But debt-for-nature swaps reverse the process. Thought up 20 years ago by Dr Tom Lovejoy, then the deputy chair of WWF-US, debt-for-nature swaps involve conservation organizations buying up part of a country's commercial debt at a large discount and redeeming it for local projects to protect forests and other important ecosystems. Since the first swap - between Conservation International and Bolivia - more than 20 countries have taken part in these deals. In all, $3.75 billion of debt has been cancelled in this way, providing $1.25 billion to be devoted to protecting the environment.

It is renaming itself Practical Action, and that just about describes it. For the past 40 years - under its old name, the Intermediate Technology Development Group - it has worked with local people at the grassroots in developing countries to introduce 'appropriate technologies' that are more productive than traditional ones, but less expensive than those used in industrialized countries. Founded by E. F. Schumacher, the author of Small is Beautiful, Practical Action encourages people to find their own solutions, including installing gravity ropeway systems for mountain transport in Nepal; training metalworkers to forge wheels for animal carts in Sudan; introducing an online agricultural information database in Peru; and building micro-hydroelectricity generators to power villages in Sri Lanka.