Looking back one, two and five years ago today on Worldchanging:

2009
Harnessing Both Sun and Cell Phone to Close Gaps in Local Health Care
Nancy Scola reports on two projects led by US students and their international allies that are helping to fill gaps in health care in the Global South. Though one project involves cell phone text messaging and the other equipment sterilizers powered by the sun, both have the same inspiration: using simple technology to build on the value of existing social capital...

2008
Walking: Still Better Than Driving
Walking is 12 times better for the climate than driving. Clark Williams-Derry crunches the numbers...

2005
GaiaSelene -- Space Opera Documentary
James Cascio reviews the film "GaiaSelene" and is quite critical of the people in the film who dismiss the utility of renewable energy in favor of space technologies that technologies are not quite ready yet...

Other recent "look backs":
June 15
June 16
June 17