For those of you interested, I recently found this video. It's an hour and a half long, but it is much more in-depth than these discussions usually are on the internet.
For those of you not willing to spend an hour and a half watching this, here's the spark-notes:
The pro-warming case is almost entirely built on scientific models and projections. The only observed phenomena are 1) that CO2 levels are rising, 2) greenhouse effect at CO2 frequencies has increased, and 3) Earth has warmed something less than a degree over since we started taking measurements. As far as models go this is a pretty compelling, but
The con-warming case is largely built on anecdotal evidence and poking holes in the models, either in terms of their modeling assumptions or their accuracy.
I hope it's clear from just my spark-notes how flimsy both cases are, and this is one of the more organized and thought out debates on this which I've seen. The pro-case is built almost entirely on a post hoc fallacy. CO2 emissions are indeed higher than they ever have been, but the actual changes to Earth's climate track within the bounds we would expect natural variation to have, not proportionately to CO2 drastically changing the humidity of Earth's atmosphere. There's even a place where the con-warming presenter showed the projections from the 20 IPCC models of some years back and then compared them to the actual temperature. For a solid case you would expect the temperature to track within one or two standard deviations of the mean of all the models. The actual measurement is so low in comparison it isn't even within the spread. At best these models are incomplete, and that's assuming they are partially correct in the first place. Chaos theory says that if you're missing just one variable it is doubtful your model is anywhere near correct. Weather models are literally how the butterfly effect got its name.
The con-case is almost as bad, as it relies so heavily on anecdotal evidence. There's really not much I can say beyond "one P-38 buried under 200 feet of ice and one 5,000 year old tree stump 100 miles north of the tree line does not a compelling case make. It makes a suggestive one at best. There's also an unwillingness on both sides to address--or even mention--confounding variables. That 5,000 year old tree stump? I wonder if anyone has adjusted its location for the procession of the equinoxes. With a matter as complicated as climate that's absolutely inexcusable.
During the Q&A the con-warming speaker made a point I did think was worth bringing up; it's not likely for a model saying "Earth's warming is entirely natural" to get university grant funding. I am not in a position to comment on how accurate that observation is, but if the way academic grant applicants are selected has a structural bias, it is practically certain all the models would say a particular thing whether or not that is accurate--it is how their creators get funding--and that they would continue to espouse their models even when there is significant evidence against it because funding is on the line. This bias would then effect the community as a whole because there is not enough healthy dissent to foster proper scientific discussion. (That sounds like a fantastic S&H topic.)
On to my opinion.
There's pretty much no way to stop our carbon emissions, and it essentially doesn't matter what we do in the developed world, either.
A host of world leaders gathered last month to discuss the topic of global warming at the UN Climate Change Summit.
US President Barack Obama said it was an issue "that will define the contours of this century more dramatically than any other" - but Dr Peiser could not help but notice there were a few faces missing from the meeting.
A handful of countries - including China, India and Canada - did not attend the summit, something that did not surprise Dr Peiser.
He explained that for him, the summit reaffirmed that there is no international agreement about what to do regarding climate change.
He also suspects that the lack of attendance is due to some of the countries' growing need to continue using fossil fuels.
"That is a clear indication that reality is sinking in and the reality is that both China, India and other emerging nations have huge energy demands," he said.
"They have huge growing economies, growing populations - their energy is going to double within the next 20 years and they cannot afford to give up on conventional fossil fuels.
"That’s basically what they have told the world."
So essentially, India and China are not interested in any climate curbing discussion whether or not it is happening. This means that unless we invent--or redeploy--a power source which is economically more efficient than fossil fuels, carbon emissions will continue to rise. Incentives to use renewable energy in developed nations will have minimal impact because we're talking about whole economies ignoring whatever the IPCC says. Big economies.
Even if we were to invent such an energy source today, because of the way R&D works it would likely take 10-15 years to get to market. If the CO2-warming models are accurate, we are all screwed and there is essentially nothing anybody can do about it. Well, short of start World War IV, but that's likely to make climate matters worse, not better.
Now, after reviewing the information I have, I don't think the "pro-warming" argument does a sufficient job of separating the current warming from background noise. What it has is a solid word-model, an observation that we're making the CO2 level go up, and a weak temperature measurement. Everyone has had to admit we're on a twenty-year hiatus (their word) without knowing why, and those twenty years have seen about as many carbon emissions than the forty years before that which saw all the warming. The correlation in the actual universe is much weaker than the models suggest, and that's being generous. That, and the Kyoto Protocol and renewable energy has had very little actual influence on our carbon emissions.
So we have a shaky real-world correlation and can't do much about it, anyway. CO2 has taken such a central stage when it comes to environmental policy people have forgotten that there are other issues to discuss. At this point we need to turn our environmental policy to things we can actually have a positive influence on, such as plastics in the ocean or land overdevelopment.