Climate "skepticism" is not a morally defensible position. The debate is over, and it’s been over for quite some time, especially on this blog.
We will delete comments which deny the absolutely overwhelming scientific consensus on climate change, just as we would delete comments which questioned the reality of the Holocaust or the equal mental capacities and worth of human beings of different ethnic groups. Such "debates" are merely the morally indefensible trying to cover itself in the cloth of intellectual tolerance.
Wow. It is amazing that the discussion of how trace atmospheric gasses might affect global temperature, and whether the climactic reaction to this is one of positive or negative feedback, has become a moral rather than a scientific question.
Though this may be obvious to readers, its worth repeating once in a while the chain of reasoning that must all be true for dramatic government action to be justified in reducing CO2. That chain is roughly as follows:
Can the presence of CO2 be shown in a lab to increase absorption of incoming radiation?
If so, can trace amounts (370ppm) of CO2 in the Earth’s atmosphere be enough to absorb meaningful amounts of radiation and if so, how much?
If CO2 in the atmosphere tends to provide a heating effect, do feedback effects (e.g. water vapor) tend to amplify (positive feedback) or damp (negative feedback) the resulting temperature change
What would the effect of the temperature changes be, both negative AND positive. Undoubtedly some things would be worse, while others, like longer growing seasons, would be better
How are other natural effects, such as the sun, changing the climate and global temperatures, and how large are these effects compared to man’s.
If the effects in #4 are net negative, and they are large enough even to be recognizable against the backdrop of natural variations in #5, do they outweigh the substantial costs, in terms of increased poverty, slowed development, lost wealth, etc. in substantial CO2 abatement.
The answer to #1 is yes, it is settled science.
The answer to #2 is probably yes, though the amount is in some doubt, but everyone (even the IPCC) agrees it is probably less than a degree per century.
Most of the warming in forecasts (2/3 or more in the IPCC cases) comes from positive feedback in #3, but we really know nothing here, except that most systems are driven by negative feedback. In other words, this is so unsettled we don’t even know the sign of the effect. (Video here)
#4 is the focus of a lot of really, really bad science. The funding mechanism at universities has forced many people to try to come up with a global warming angle for their area of interest, so it causes a lot of people to posit bad things without much proof. If you want to study grape growing in Monterrey County, you are much more likely to get funded if you say you want to study "the negative effects of global warming on grape growing in Monterrey County." Serious science is starting to debunk many of the most catastrophic claims, and history tells us that the world has thrived in periods of warmer climates. Even the IPCC, for example, projects only minimal sea level rise over the next century as increases in Antarctic ice offset melting in Greenland. (more here)
We are beginning to understand that natural variability is pretty high in #5. Alarmist might be call "sun variability deniers" as they refuse to admit that Mr. Sun might have substantial effects on the Earth. They are kind of in a hole, though. They are trying to simultaneously claim in #3 that the climate is dominated by positive feedback, but the same time in #5 claim the climate without man is really, really stable. These two in tandem make no sense.
And in #6, nobody knows the answer, but a few serious looks at the problem have shown that aggressive CO2 abatement programs could have catastrophic effects on world poverty. Which is ironic, since the best correlation with severe weather death rates in the world is not CO2 level but wealth and poverty reduction. No matter how many storms there are, as poverty has declined in a certain region, so have severe weather deaths, even while CO2 has been increasing. So one could easily argue that CO2 abatement programs will increase rather than decrease severe weather deaths
So this is the trick people like this blogger use. They point to good science in #1 and partially in #2 to claim the whole chain of reasoning is "settled science," when in fact there are gaping holes in our knowledge of 3-4-5-6.
As a note, I have never deleted a comment on this site (except for obvious spam), despite many that disagree strongly with my position.