What if all of our bright climate scientists are stuck in group-think mode and cannot see the possibility that a rise in atmospheric CO2 is correlated with climate change, but not the most important causal factor?
What if the real story is deforestation? What if the complicated climate models underestimated the impact of trees on cloud cover because of cloud-forming factors that they weren't aware of? Scientists recently discovered such a factor.
As a low risk hedge, it would be wise to push for greater global reforestation and afforestation efforts. They will act as carbon sinks, soil stabilizers, sources of revenue, and all sorts of other good things, so little harm can possibly be done by pro-tree policies.