There is a lot of discussion back and forth between environmentally-aware folks who disagree on how we should proceed.  James Hansen has been a consistent scientific voice warning us that change is required and he has been [1] muzzled at times.

Dr. Hansen has signed on to the idea that we have to get atmospheric carbon dioxide down to [2] 350 ppm.  [3] Climate Progress has an [4] open letter to Dr. Hansen about this idea.   Climate Progress appears to think that 450 ppm ought to be the target.

This is a hard discussion to follow for those of who do not have a phd in some related field.  I think we have to keep in mind that it is likely there is a cost benefit analysis that comes into play.  The cost on responding to droughts, famines, floods, hurricanes has to be weighed against the cost of aggressive climate action that will reduce the impact and cost of the natural disasters that attend global warming.

The human cost of death and suffering that goes along with climate change can’t even be quantified in this discussion.

I think that we might be wise to err on the side of caution and go after the problem of global warming with the kind of zeal that some folks have for going after the potential danger of “terrorists.”

[5] Change is coming.  President Obama is in the wings.  It is encouraging to be engaged in an active discussion about what level of carbon dioxide should be the target instead of listening to policy makers equivocate about the problem of global warming.

I think we have to walk some kind of tightrope to keep up pressure and enthusiasm for change without resorting to the kind of conflict that will reduce our effectiveness.  I think it will become clear in time if the magic number (if one exists, because global climate is an amazingly complex system) is 350 or 380 or 410.  If we find out the magic number is 300 and we have organized around lower cost number like 450, our cost-containment strategy just went out the window.