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

2009
Does City Living Trim Greenhouse Gas Emissions?
A study published in The Journal of Urban Planning and Development, quantified the emissions from building materials and construction, home heating and power demands, and transportation energy, in both urban suburban neighborhoods in the Toronto metro area. And they found that downtown residents use radically less energy, and consequently emit about two-thirds less climate-warming CO2 than their suburban counterparts. Take a look...

2008
Al Gore on Optimism
(OK, this was technically posted on the 18th, but since there was nothing on the 16th, and this is worth revisiting, we hope you'll forgive this flexible version of "today")

Watch Al Gore talk up the politics of optimism in this half hour video...

2005
Food Force
James Cascio reviews Food Force, a video game produced by the UN World Food Program...

Other recent "look backs":
April 13
April 14
April 15