Alex Steffen: Ideas for a Sustainable Future

Worldchanging.com founder Alex Steffen offers a fast-paced round-up of radical answers to our planet’s greatest challenges, ranging from green cities and buildings, to ingenious tools for the developing world (flowers that detect landmines; straws that purify water as you drink; merry-go-rounds that pump water using the energy expended by children at play).

Watch the Video at: TED