A well written argument for moving forward with CO2 abatement. It contains at least one inconsistency. And it omits consideration of the most important alternative conclusion.
The inconsistent argument arises when it is stated
The scale of the effect must be demonstrated to be large enough to have impact. Once this is shown, and it has been, the burden of proof of absence of harm is on those who would deny it..
The author is drawing on the models when he states parathetically "and it has been." This is after he has just convinced some of us that even if the models are all wrong we should not roll the dice when the conseqences of our not acting are dire. He has failed to recognize that a conclusion that the "scale of the effect must be large enough to have impact..." Is dependent on models.
This is disconcerting when we know that no model has been as yet shown to be correct. All models that have existed long enough to test their predictive quality have been shown to be wrong, drastically in many cases.
What is happening in reality then? It's this: the IPCC is adjusting the parameters in their currently favored models every few years. This brings the models predictions into acceptable agreement with the last few years of data! Sadly, we prefer a model that correctly predicts the future rather than the past! (See Nir Shaviv).
So what if the models are all wrong. If there are some guesses coming from competent climate scientists that rising CO2 may lead to catrastrophic temperature rise wouldn't it make sense to be cautious and stop releasing so much anthro CO2 into the only atmosphere we have? That's how the argument goes, and it seems to be a good one when the consequences of doing nothing about CO2 emission could wreck our planet's human habitat.
Unfortunately the author of this otherwise fine article has not recognized that there is already scientific findings that have not yet been shown to be incorrect and are fully suported by data that are dispositive of the Hanson Hypothesis. This is the hypothesis that anthropomorphic CO2 will result in catastrophic temperature rise.
Many sound arguments exist for development of non-fossil energy sources, and many strong arguments can be made for the US participation in international climate accords. An argument based on fear of catastrophic warming due to anthropomorphic CO2 is not one of them however.
This is not to suggest that our Earth is not warming. But if it is, it is not measurably due to rising anthropomorphic CO2.
We can be absolutely certain of one thing, however, the climate will continue to change as it always has. If we find it rapidly changing in a way that is inhospitable to human life, we had better get busy and find out why. Perhaps it is due to human thermal pollution or some other anthropomorphic cause. If the cause is anthropomorphic in nature, then we should be able to do something about it.
