It's possible extra CO2 is good. It's possible warming is good.
OK, you are asserting two hypotheses, yes? If your hypotheses were true, then we should accept or even encourage increased CO2 emission and other GHG which raised the temperature.
It would behoove society for scientists to weigh the scientific evidence supporting and contradicticting those hypotheses before taking or avoiding actions based on that hypothesis. On the other hand, if your hypotheses are false, it would be folly to act or fail to act based on them.
Q: What level of scientific consensus in favor or your hypotheses should be required before they can be the basis for decisions about action or inaction?
The most blatent dysfunction I see in the debates of global warming is staggering differences in the level of evidence or "consensus" expected. On one hand, those who doubt AGW tend to discount any degree of scientific consensus short of unanimity as "nothing is scientifically settled well enough to guide prudent decision making" - a nearly impossible standard to meet. But on the other side, these doubters make frequent assertions like:
It's probable GW is not as bad, at its worst, as slowing the economy through government intervention would be, if you measure actual quality and length of life, and technological advancement rates.
Statements of this sort are generally taken by AGW doubters to be so obviously true that no give and take of weighing scientific evidence pro and con is needed, much less applying a standard of "skepticism" towards that statement until 100% of the scientific community agrees with it.
We all have "confirmation bias", and in fact there is good evolutionary reason for that to be part of our psyche (it would be a waste of time to every day revisit afresh without bias the question of whether the sun will rise in the East or West). However the disparity of applied standards of evidence on the part of AGW doubters appears to be strikingly massive and ubiquitous.
And this is not symmetric. I have never seen AGW supporters claim explicitly or implicitly that AGW should be believed if even a few papers or a few atmospheric scientists support it while the bulk do not; they have accepted and met high levels of evidence (compared to most scientific debates). Nor have AGW supporters demanded that the assertions and hypotheses (such as quoted above) be subject to far stricter standards of evidence than AGW.
Picture an AGW supporter saying "while we will accept the judgement of merely 90%+ of atmospheric scientists as sufficient propensity of evidence upon which to base practical decision making, we demand that doubters achieve the agreement of 98%+ of relevant scientists before accepting that "more CO2 or higher temperatures are more beneficial than harmful" is relevant to practical decision making.
In fact, if you could get 90+ percent of relevant scientists and their publications to agree that after measuring, analyzing, weighing and debating all evidence, "increased CO2 and/or elevated temperatures would have a net positive effect for humans and life on earth" - I believe that a majority of AGW supporters would actually greatly rethink their positions. I know that I would.
But AGW doubters have shown near zero interest in submitting their hypotheses and beliefs to serious scientific scrutiny, much less in applying any fraction of the same standards of evidence they demand of the the other side, to their own assertions.
I think that some of this comes from a profoundly unscientific mindset that grants huge advantages of "high ground" to the perceived "status quo". That is, reducing future emission is considered a "change" which needs complete certainty, consensus and agreement before implementation, while emitting additional scores of gigatonnes of GHG is considered "no change" to our environment and "safe until absolutely proven otherwise" because it's an extension of how things have been done until now.
There might be some psychological or even legal basis of such a bias, but there is no scientific or rational support for it. The bias against "changes in government policy" in favor of "business as usual" is a kind of inertia which has no basis in atmospheric science. Scientifically, adding additional gigatonnes of GHG to the atmosphere *IS* a change, and it would at this stage be more rational policy to make the emitters prove that it's safe.
Imagine if it were different. Society has been built on low emission energy sources for hundreds of years, but there is now a proposal to for the first time burn massive amounts of fossil fuels and release many gigatonnes of carbon dioxide into the atmosphere. Humanity would be rational to ask for some pretty good evidence that this would not upset the natural systems before committing to such a change in course.
The thing is - these two scenarios may invert the societal inertia of "which direction is a change in course", but that's an artifact of social policy; the scientific question of "what's the most likely effect of adding X gigatonnes of GHG in the next century" still remains similar in both scenarios.
I believe that a rational skeptical society would at this stage demand the equivalent of an "environment impact statement" (in US terminology) before approving the addition of large quantities of GHG. The burden of proof should probably be on the emitters if anything, not hugely tilted towards "business as usual".
Even if one doesn't think the question of AGW is "completely settled scientifically", the massive preponderence of scientific judgement and published scientific studies supporting AGW makes it far more than a credible hypothesis or a wild speculation.
That is, the concept that "emitting additional gigatonnes of GHG to the atmostphere will very likely have major and often seriously deleterious effects on the natural and human environment" is not a marginal speculation like "tomorrow the sun will rise in the west" which the functional basis of confirmation bias should protect of from wasting time on. It represents the considered judgement of a very large predonderance of the worlds best scientists after extensive study. Even if some people don't think it's "proven" beyond what they think is reasonable doubt, in a rational and skeptical society that assertion should by now have the high ground and those favoring uncurbed emissions should a bear the burden of evidence at least as high as AGW, rather than incredibly lower.
> That the GW is being used as a rationale for massive government
> intervention in the economy, with all the attendant back-room deals
> and political "donations" to get back out of the way, as per every
> other issue through human history, is not.
Again, the scientific truth of which scenario (more or less emission) is most likely to be beneficial or harmful is not affected by whether a scenario involves government action or inaction, only by what's emitted and the effects thereof. Bringing "massive government intervention" to the discussion is to confuse and confound science with ideology.
Look at it this way - suppose a large asteroid were to be discovered to be on a collision course with the Earth, and 90%+ of astronomers agreed with that conclusion. Would the asteroid's chance of hitting or not hitting the earth depend on whether "massive governmental intervention" was implied in forming a response? Would people whose primary deciding factor regarding actions or inactions was based on their political ideology be the best architects of a rational response to the asteroid, or would evidence based scientists be a better choice?