We get so little news about the developing world that we often forget that there are literally millions of people out there struggling to change things to be fairer, freer, more democratic, less corrupt.

Optimism is a political act. Those who benefit from the status quo are perfectly happy for us to think nothing is going to get any better. In fact, these days, cynicism is obedience.

The denser places get, the lower the amount of energy people use to get around it.

By looking at climate change as a clean energy generation problem, we're setting ourselves up not to solve it.

At its very heart, Worldchanging is about using the best of people's new ideas, bringing them together and applying them to the massive problems that we all face.

Copenhagen has done a remarkable job creating streets that are focused on bicycles and pedestrians.

In almost all city governments in America, the small group of people who don't want change are able to block change.