However there is a positive feedback loop (as well as other more complex feedbacks, not all of which are fully understood): more CO2 means warming, which in turn results in melting of decayed matter (eg peat bogs of siberia) releasing more CO2.

There are of course other factors (radiation from the sun, earth orbit cycles) which also force the climate. But analysis and modelling is showing that the current rate of warming (10 x greater than any other time in the past 1 million years) cannot be explained by natural forcing. It can however be explained by CO2 (and other GHG) emissions.

2. What is the *biggest* driver of climate change is not relevant to the question: are we forcing the climate system out of equilibrium. There can be many forces in play in the climate, but if you really throw one out of whack (say by doubling the atmospheric concentrations of CO2) you will throw the whole system out of equilibrium.

Is it worth the risk?

Can you post irrefutable evidence (or cite sources) in two areas:

1) If correlation does not imply causation, did the temperature rises precede or follow the increase in CO2 concs in the atmosphere over the past millions of years ? This is along the lines of: What were the relative contributions of the other drivers that may have led to an increase in global temperatures and CO2 ? On a related note, if likely this is an autocatalytic process, i.e. higher temperatures leading to higher CO2 concs further promoting higher temps, then what set it off each time ?

2) I’m especially curious about the anthropogenic component of the CO2 conc. While conceding that pos-industrial revolution we have been dumping tons of CO2 into the atmosphere, does it matter if simultaneously the biggest driver for increasing CO2 concs is something else ?

So, you don;t have to rely solely on the Vostock charts. There are many other bits of evidence you can look at. Read this: WSJ vs Scientific Consensus.

But to answer directly: the scientific consensus happens to be that human activities (CO2 and other emissions) are forcing the climate system. So I’m not going on *my* opinion, I am taking the mainstream scientific opinion.

In the long run, of course we can’t stop climate change. The world has seen and will continue to see huge fluctuations in global climate (20k years ago most of the world was under a kilometer of ice). But if we like human civilization then we’ll want to avoid doing anything to upset the equilibrium we are in (in fact, maybe, when knowledge is more advanced, we’ll take action to countervail natural cycles). Again, scientific consensus is that human CO2 and otehr emissions ARE forcing the climate system beyond what is expected due solely to natural causes.

As for sweeping claims, again I will say: I’ll put my faith in what the majority opinion within the scientific community. If research begins to show something differen then we can talk again of course.

Finally, the other types of (mostly) local pollution are a totally different issue. I don’t really expect that we’ll see human civilization collapse in the next 50 years, or 100 years. But I’d like to make my political decisons to help make sure we don’t collapse. The local issues are important, but their impacts are smaller and controlled. The worst-case climate risk is totally uncontrolled. That’s pretty scary.

“Still, it’s irrelevant that there are other (possibly more worrisome) climate forcers, the worry is that climate is getting forced at all, and what impacts that might have.”

The real question is whether our current activity is really any sort of dominant force (within any meaningful cycle) on the current climate change apparently-cyclical pattern. If we refer solely to your Vostok chart, I’m not so sure; while we are on an upswing of atmospheric CO2 and global temperature, I’m not sure that the dominant driving force is human behavior. It’s an apparently cyclical pattern; we’re not helping the upswing, but then it’s not completely obvious that we can prevent it by lowering CO2 emissions, even significantly.

Like I said though, I don’t disagree with fighting pollution through government-imposed means (sometimes), but I do think that it’s important to not make sweeping claims with respect to the causality of climate change (and the systems that govern it); most importantly because doing so undermines the anti-pollution argument itself — and there are many other reasons besides for just global climate change that deserve attention. Immediate health issues for example (increase of asthma cases in newborns, smog-related health issues, the destruction of wildlife, etc. — ironically some of these may end up forcing climate change in the longer run, but by then we’ll be too dead to care about our failing agricultural system).

1. 1970 cooling, see here for an analysis. Two important points there: 1940-1970 did see cooling; and the science has advanced since 1970 to much better understand the climate system. That is, even if there was some worry in the scientific community (overblown in the press) about a coming Ice Age, it was acknowledged at the time that the scientific evidence was uncertain. 30 years, and much more research has passed. So one would hope the conclusions and predictions now would be different.

2. The Mann Hockey Stick, see here for an analysis. Main points: The hockey stick is one piece of evidence, not the only piece. Science works that way: you don’t get consensus based on one study. It takes many different types of corroborating evidence to make a scientific theory stick, so to speak. You can lose one data set, and still have a robust theory. Further, the main conclusions of the Mann study in fact are corroborated elsewhere. So though the Hockey Stick had some problems, other studies confirm its conclusions.

3. Sources of Information. I would not agree that Friends of Science is “as valid as any other.” I prefer to put my vote with more credible sources, such as the National Academies of Science (pdf) of: Brazil, Canada, China, France, Germany, India, Italy, Japan, Russia, UK and the USA. I think they carry more weight than a website run by a couple/few/tens of climate skeptics.

4. Benny Peiser/Oreskes. Peiser has withdrawn most of his criticisms of Oreskes study. And now says: “I do not think anyone is questioning that we are in a period of global warming. Neither do I doubt that the overwhelming majority of climatologists is agreed that the current warming period is mostly due to human impact.” For more see here (pdf).

5. Oregon…I think you’ve done enough yourself to remove that from serious debate.

6. Consensus/leftists/statists. Perhaps you are right. But more importantly, we have an overwhelming consensus of scientists. As reflected best, I think, by the statements of the National Academies of Science of the eleven most powerful countries in the world. That’s the group I’ll go with, over the Oregon folks.

When I read these kind of nonsensical, laughable, conspiracy theories which have nothing to do with the science I question the motivations of those making them. They are just a parrotting of ideological rants of the likes of Suzuki and Gore, neither of whom are climatologists, but who are famously known for their political science activities.

Actually I was just surfing to learn more about this issue, since I lived through the early 1970’s when scares of the new ice age where being flung around by doomsayers who of course always get the attention of media. As for your examples, I can copy boiler plate equally as well as you can if I were so inclined. Or I could just rely on the example of the discredited and fraudulent “hockey stick”graph by Michael Mann, the poster boy for the doomsayers a few years back who forecast rapid increases in global temperatures in the early 1990’s, which was the basis of ICCP and still used by Al Gore in “An Inconvenient Truth”. In 2006, both the National Academy of Sciences (NAS) and an independent researcher refuted the basis of the “hockey stick.”

Obviously neither of us is a climatologist or expert in a related field so we are forced to rely on others. Friends of Science is one site authored by skeptical climatologists which is as valid as any other but whose authors seem to be the object of personal attacks from leftists and a rag tag miscellany of world statists, including the elitists at the CBC.

As for Orseskes’ claims, they’ve already been refuted. According to British social scientist Benny Peiser, less than 2% of the climate studies in the survey actually endorsed the so-called “consensus view” that human activity is driving global warming.

Sure no doubt the Oregon petition had bogus names on it. Which petition doesn’t? And what would you expect from 19,000 names? So deduct a few. Deduct 5,000. Deduct 90%, it would still leave 2,000.

So much for scientific consensus.

All we have is consensus among leftists and statists who have seized another cause now the Soviet empire has imploded.

That threat (aslo: threat of losing oil supplies, threat of china’s power in middle east etc) was worth some $450 billion per year of military spending.

So: is the climate risk as big ? bigger ? smaller?

I would say much bigger, and so I would think an equivalent logistical and political seriousness should be applied to the problem.