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

2009
WeCommune: Tech Support for Communes
If people are recognizing the practical potential in post-ownership living, why aren't even more models for collaboration, sharing and product-service systems thriving? According to architect Stephanie Smith, spurring the movement may be a simple matter of providing the tech support...

2008
How Clean Coal Cooks Your Brain
Jeff Goodell dissects the logic of "clean coal." The logic is simple: America has lots of coal. We are a technologically advanced society. Ergo, we can clean up coal. What's the problem? Well, here's one: "clean coal" is not an actual invention, a physical thing – it is an advertising slogan, and one with a dangerous subtext that without coal, civilization as we know it will come to an end. That's a false assertion...

2005
The Tsunami and Climate Change
Alex Steffen notes that the tsunami was not directly the result of climate change, but was an example of the kinds of disasters we can expect to see if climate change gets as bad as is now expected. Therefore, while we weren't ready for this one, we should do much better preparing for and facing future disasters...

Other recent "look backs":
June 11
June 14
June 15