Terra's Big Neighbor

[iancampbell]

There is very little correlation between magnetic pole changes and extinctions, so whatever happens during a change it doesn't seem to affect the biosphere much.

Indeed. As I said, slow enough to adapt. A similar thing can be said about the effect of the ice age cycle (which is approximately 30k years) on the survival of various plant species. Trees can move between geographic areas, if given enough time; what's actually happening, of course, is that areas that wouldn't support a particular species before become marginal and then ideal, as the climate zones change.

One of the potential problems with AGW is that the changes would be too fast for tree species to cope.