Scaling up

The concept of serving the world's poorest four billion or so people has been popular since CK Prahalad introduced the idea a decade ago. But so far, profits remain elusive

Equipped with funding from UBS, a New York non-profit aims to reduce tuberculosis and malaria with home improvements

2013's most popular pieces asked questions about alternative economic models, explored eco-houses and took a stroll down Copenhagen's convex streets

Urbanisation makes cities a main focus for environmental policy. Digital technology and innovation will enable a better quality of life and reduced energy consumption

The vice president of the Pacific nation at risk of being submerged says displacement is a lingering threat but new opportunities lie ahead

Predicted sea-level rises threaten many of the world's most important cities, write Alison Kemper and Roger Martin

The German city is planning a green network that will cover 40% of the city area, contributing to resilience and allowing biking, swimming and nature watching in the city

Mike Scott: Wherever there is traction there is power is the theory behind piezo technology which is why scientists are tapping energy from roads, railways and dancefloors

Elisabeth Braw: Global warming poses a real threat to cities but planners in the Danish capital are taking visionary steps to ensure its resilience – and success – as far ahead as 2100

Water is the essential ingredient for all kinds of products made in developing countries, yet assessing its value raises issues

Cities are where the greatest climate change challenges and greatest opportunities lie, and where mayors are pioneering initiatives, writes Mike Scott