Can open source save the planet?

I think has huge potential as indeed nowadays tools are being design for short-life durability and I think an open source effort can turn out tools that are more useful in that aspect and that will iterate to be all that is needed.

On the other hand, how long until John Deer and Holland start sueing with infringment of "ability to plow the earth" patents?

hmm sounds nice but as some one in IT who started in mech eng I think you have a very optimistic idea of what is possible.

Also your mistaking cheap DIY tools with the ones the pro's use.

This is a perfect place to start eliminating money from the world and going to resource based system. Recylced tools with high performance and anyone can build.

You know one of Maos big ideas in the great leap forward was for villagers to make steel - it did not turn out well.

Open source definitely will not save the planet, but the ideas behind Free Software might.

possibly but this has been going on for 40+ years under the name of sustainable development.

Yes, and Steve Buscemi will proclaim, "this is GNU/RMS/Linux..I know this", right before they destroy the asteroid.