The thing that bugs me is that there's all this "it's CO2 stupid!!!" and a lot less "what if it were something else?"

Has the planet gotten warmer in the last 150 years? Yes.

Does that correlate with increasing CO2 concentration? Yes.

Does that prove the causal link? No.

There are about a million confounding factors that could disprove that causality. I mean there are enough man-made refrigerants in the atmosphere to literally blow a hole in the ozone layer. That's a real, proven, nobody-argues-about-it thing.

But if you look at the wikipedia refrigerants page you can see their Global Warming Potential (GWP). http://en.wikipedia.org/wiki/List_of_refrigerants Many of them are quite high, such that even at tiny concentrations they can have a significant impact.

The wikipedia page on CO2 emissions has this picture, which shows that tropospheric ozone, methane, nitrogen dioxide and the refrigerants combine to have as much impact as CO2 does. http://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth's_atmos...

That to me says that things are pretty complicated. The idea that our understanding of something that's complicated like that MIGHT not be complete isn't unreasonable.

Furthermore a lot of people say "climate change is settled, we need to do something about CO2" and I don't buy that argument. MAYBE climate change is settled, but even if it is there's a lot that can be done without even touching CO2 and all the economic pain and/or non-compliance to agreements that'll happen.

What I mean is that it might well be easier to deal with methane, NO2, and refrigerants than CO2. If it doesn't require the entire world giving up on developed country standards of living in the near future that's going to be a much easier sell. Mandating efficiency doesn't work re: jevons; http://en.wikipedia.org/wiki/Jevons_paradox Putting hard limits on emissions in the developed world is doable but nearly impossible in the developing world.

And even if we could get all the countries in the world to agree to hard limits on emissions, it's got to be population based, not history-based (i.e. the developed countries get larger quotas because they're already developed) or else you're basically making the undeveloped world slaves to the developed world. But even if you could somehow get the entire world to agree to such a thing, it's still terrible for one of two reasons:

1. if individuals can sell their quota on the open market fraud will be rampant since verification is impossible

2. if they can't, their governments will do so for them and we'll continue to prop up dictators all around the world

Neither is a very defensible moral position to take.

So while I'm less skeptical of climate change today than I was 10 years ago I am not 100% convinced as of yet (since complex things are complex). And all the "obvious" solutions to the problems even if I were to say "sure, it's a big enough problem we gotta do whatever we can!" end up with neutered, bad or horrible outcomes for the world. Possibly even in a worse way than if climate change continues.

EDIT: The other thing I'll mention is that we already have proven success on the trace gas emissions problem. The ozone hole should eventually close now that the problem has been solved. Rather than attacking energy (which is a multi-trillion dollar industry and affects every person on the planet) perhaps going after other sources would be more fruitful. http://earthobservatory.nasa.gov/Features/WorldOfChange/ozon...