The Earth's magnetic field is failing. That was the theme of the PBS show Nova that I watched the other evening. They put forth the hypothesis that at worse, this would lead to the earth becoing a barren wasteland like Mars. At best, it would lead to an upsurge in human cancer deaths. But on the plus side, the aurora displays would be fantastic! The reason for the failure of the magnetic field was related to movement of molten iron in the earth's core. This is one problem not caused by human activities. Unlike the destruction of the rain forests, the hole in the ozone layer, global warming, the demise of coral reefs, species extinctions, ect., we don't need a global summit to decide how to deal with this. It's beyond human control. The show concluded with the cheerful statement that no one watching would be alive when the magnetic field failed. That makes me feel much better. I was already bummed out about the fact that Count Chocula cereal has disappeared from my local grocery store shelf.