Interesting stories, Laura.

One thing strikes me as odd regarding the premise of Global Warming. It's the false assumption that our global climate is a stable, non-changing environment. For example, these temps (rain, lack of rain, etc) are near record levels.

That may be true. But to me it appears that the pro-Global Warming side operates with the unspoken assumption that our climate is constant. Nothing could be further from the truth. The inputs to our climate system are constantly changing. Just a few inputs that change regularly:

* Solar activity
* Planetary tilt and orbit (neither are perfect and do have oscillations)
* Interstellar dust (The earth gains mass each year from this accumulated dust. How much remains airborne?)
* Natural changes to land mass configurations. Mountains grow, erosion removes land, volcanoes create more land. All of these slightly change wind and precipitation patterns.

Granted, global temperatures appear to be warmer now, on average, than they were 100 years ago. Could it be cyclical? I haven't seen enough evidence put forth to address these questions.

Excellent points Greg, but I am going to take issue with you on your comment, "global temperatures appear to be warmer now, on average, than they were 100 years ago," because we don't have global temperature records for the last 100 years. We only have them for about the last 20 years and they are limited because they don't take into account all the different temperature variations at different strata in the atmosphere. Most of them are land-level readings. What we do have for the last 100 years are a lot of local temperatures taken around the globe. Those records contain a lot of gaps and inaccuracies and are not global.

Also, we know about a couple of warming and cooling cycles in the historical record, but we don't know the exact temperatures because the technology to accurately record temperature did not exist. So stating that we are experiencing warmer temperatures now than people had back then is not possible.

There are a number of people who want to blame the current drought in the western US on global warming, but they seem to forget that at the beginning of the 20th century, the middle of this country was a dustbowl and had been in a draught for something like 20 years. Were we having global warming then? Could it just have been the climate?

The truth is we just don't know as much as the chicken littles would like us to think we know, and we sure can't predict with any accuracy what will happen even one year from now. Just remember all the hurricane predictions from last year.

There is no reason to listen to the global warming fanatics and their sky-is-falling scenarios.

Rather than build of twenty reservoirs in the Alps to provide water to make artificial snow to replace disappearing natural snowfall: just give up snow skiing and learn the adventure and excitement of extreme geology. It is an environmentally low impact sport, and it does not require the financial expense of resisting the inevitable: global warming. There will be plenty enough rock available for everybody when the obstructing glaciers get melted off all the geologable geoforms.

One can only assume that Greg has not read the literature on Global Warming.

Even a cursory Google search reveals dozens of peer-reviewed articles that present, for example, 800,000+ years of Antarctic Ice Core data, isotope data from millions of years of sedimentary rock, and a host of other independent sources.

No reputable scientist "operates with the unspoken assumption that our climate is constant." Instead, the variations in climate are compared with the changes we see today. While a healthy skepticism is surely appropriate while approaching any topic, surely one should also apply a modicum of responsibility to read the literature, follow cites, and actually LISTEN to the evidence.

Greg, if you "haven't seen enough evidence put forth to address these questions", I suggest that it is because you haven't looked hard enough -- because the evidence IS there and readily available.

Sadly, Tom, you are mistaken and your assumption is wrong.

I have read the literature and as I clearly stated, there does not appear TO ME to be enough evidence to address these questions. Especially, as related to solar variability and planetary tilt and orbital variability.

Even though I believe differently regarding GW, that does not give you license to engage in condescension and ad hominem attacks.

Greg writes:
have read the literature and as I clearly stated, there does not appear TO ME to be enough evidence to address these questions. Especially, as related to solar variability and planetary tilt and orbital variability.

I have provided cites for the Antarctic Ice Core data elsewhere on this blog. I am under the impression (though I don't have time for a search right now) that the isotope data extends this data for geological periods. The correlation between atmospheric CO2 concentration and temperature has been established through these and similar means.

I have not claimed that solar variability, planetary tilt, and orbital variability do not also affect global climate. I join the consensus of the scientific community that these factors, taken together, are overwhelmed by the evidence in support of the global warming hypothesis.

The evidence has been presented and cited on this blog. The consensus within the peer-reviewed scientific literature is that this evidence provides compelling support for the hypothesis that global warming exists and is caused by human activity.

Greg offers no rebuttal or challenge to the cited evidence. His offering of alternate mechanisms, while interesting, does not alter the mechanism proposed. If a car is slowing down because its engine has run out of gas, offering evidence of air resistance neither helps nor hinders the question of whether or not more gas is needed.

Greg's choice of words, including the emphasized "TO ME", is his own, as is the claim that "the pro-Global Warming side operates with the unspoken assumption that our climate is constant." Greg has offered no cites to support his claimed pervasive assumption of constant climate.

When someone makes an unsupported claim, it is not an "ad-hominem attack" to challenge that claim. If evidence is presented, and no rebuttal offered, it is not "condescending" to suggest that the person is unfamiliar with or has misread the evidence.

An alternative, of course, is to suggest that Greg is willfully denying or ignoring said evidence. I thought I was being more gracious by leaving open the possibility that he was simply unaware of it.

My condolences to the Euroweenies and their lack of snow. However, I just received an email from Whister-Blackcomb Ski Area in British Columbia and the poor saps up there have had to endure 13.5 feet of snow in the month of November. The headline of the email reads: "Whistler shatters November snowfall record".

Don't you just hate it when that happens?

Tom...I'm relatively new to this blog, so I haven't had time to read the wealth of cites and counter cites on all the posts yet. Therefore, it would be nonsense to expect me to provide a rebuttal or challenge to something I haven't read. True?

I've gotten into citation wars before and found that they're pretty much useless. Parties on both sides of a given topic can, and generally do, find citations that support their point.

But, to make you happy...here goes:

Regarding planetary tilt and orbital oscillation:

http://www.livescience.com/animalworld/061011_earth_wobble.html

Regarding the uncertainty surrounding the effects of solar variability:

http://www.space.com/scienceastronomy/sun_output_030320.html

Regarding both solar variability and Interstellar dust incursion:

http://arxiv.org/ftp/physics/papers/0503/0503158.pdf

Graciously submitted....

Greg, thanks for the cites.

As I wrote earlier, we have already agreed that other factors may have made a contribution to historical global warming. This does not, however, address the question of how these contributions compare to the contribution now being made by the unprecedented level and growth of atmospheric CO2 concentration.

In your second cite, the lead author of the study (Richard Willson) explicitly notes this (emphasis mine):

Further satellite observations may eventually show the trend to be short-term. But if the change has indeed persisted at the present rate through the 20th Century, "it would have provided a significant component of the global warming the Intergovernmental Panel on Climate Change reports to have occurred over the past 100 years," he said.

That does not mean industrial pollution has not been a significant factor, Willson cautioned.

Scientists, industry leaders and environmentalists have argued for years whether humans have contributed to global warming, and to what extent. The average surface temperature around the globe has risen by about 1 degree Fahrenheit since 1880. Some scientists say the increase could be part of natural climate cycles. Others argue that greenhouse gases produced by automobiles and industry are largely to blame.

Willson said the Sun's possible influence has been largely ignored because it is so difficult to quantify over long periods.

Confounding efforts to determine the Sun's role is the fact that its energy output waxes and wanes every 11 years. This solar cycle, as it is called, reached maximum in the middle of 2000 and achieved a second peak in 2002. It is now ramping down toward a solar minimum that will arrive in about three years.

My read of the literature does lead me to conclude that NO reputable scientist claims or assumes that climate is "a stable, non-changing environment." To the contrary, the reason that the confirmation of human-caused global warming has attracted such scientific interest is that it requires detecting and validating a low-level signal in the presence of background noise, much like attempting to recognize someone calling your name in a crowded party.

The point, however, is that the scientific community has reached consensus about this. I'm not sure whether the LaViolette paper has been peer-reviewed, I'm not sure where it's been published, and I've been unable to find any citations of it. I have found the website of the author. I've also found the website of the foundation he has created, the Starburst Foundation. In LaViolette's "Purpose" statement, he writes:

The peer review process, which normally is relied on to determine which ideas out of the many should become funded, is often subject to this bias. As a result, new ideas that could potentially produce scientific breakthroughs are generally refused funding. Thus most work carried out in today's research institutions tends to be traditional, rather than innovative.

The Starburst Foundation was formed to circumvent this problem. It serves as a vehicle through which donors may fund high-quality leading-edge research that otherwise would have great difficulty finding financial support. By greasing the wheels of change, the Starburst Foundation helps to create new concepts and tools necessary to mankind's survival in the new age that is now upon us.

Climatology does not seem to be a central interest or competency of LaViolette, and he seems to operate outside the mainstream of the peer-review process.

My assertion therefore remains that the scientific community has reached a consensus that human-caused global warming has been demonstrated. This consensus could be in error -- but the cite's you've graciously submitted do not, in my humble opinion, demonstrate that error.

Tom and Gene,
I think you both miss the point. No one says that we are not warming. The 2 points of contention are: a)whether this warming is unprecedented, and b)whether this warming is anthropegenic.

Dr Mann's famous 1999 MBH98 temperature reconstruction (hockey stick graph) said both were occuring; however, since 2003, his study has come under scrutiny for his choice of proxies as well as his PCA analysis. The June 2006 NAS report essentially said there is no way we can accuratly proxy past global temperatures using the methods that Mann used. They did, however, find nothing wrong with his bristlecone proxies for the last 15 years of his study. He used this series of proxies to construct the famous blade of his hockey stick, which showed the 1990s being the hottest since AD1000. Ross McKitrick, Steve McIntyre, and Hans Von Storch found however, that using Mann's PCA algorithim, they get "hockey sticks" no matter what data they input- even random numbers show the results that Mann published. Also, a number of biologists say that the Bristlecone is a poor proxy for temps.

We do know that we arewarming, but we certainly do not know if the warming is unprecedented. As far as CO2 being THE greenhouse gas that has caused the recent warming (since 1977, temperatures worldwide have been on the upswing after a 30 year "cool" period), this is pure conjecture. Yes, CO2 has gone from 280ppm to 370ppm in the last 100 years, but it only accounts for 2-3% of ALL greenhouse gase- water vapor being the dominant greenhouse gas is 96%.

The premise should be phrased in terms of greenhouse warming as there has always been natural global warming and cooling. Atmospheric scientists have reached a consensus on greenhouse warming and given a static earth, this should lead to global warming. Only the degree of artificial warming is in doubt.

JP,

I'm guessing you were addressing me (gene?). I may not have been clear, but you and I agree. There is no doubt that temperatures have warmed slightly. Where I see disagreement is by how much and more importantly WHY. That's why I am waiting to see other variables beyond CO2 addressed.

Tom,

I didn't post those cites to unequivocally denounce GW. I posted those to show research that addresses some of the issues I don't believe have been investigated enough.

Requoting what you posted:

Scientists, industry leaders and environmentalists have argued for years whether humans have contributed to global warming, and to what extent. The average surface temperature around the globe has risen by about 1 degree Fahrenheit since 1880. Some scientists say the increase could be part of natural climate cycles. Others argue that greenhouse gases produced by automobiles and industry are largely to blame.

Willson said the Sun's possible influence has been largely ignored because it is so difficult to quantify over long periods.

I am simply pointing out uncertainty as related to these additional inputs.

Just FYI, there IS a global consensus by scientists that global warming is happening, and that it is caused by humans.

http://www.realclimate.org/index.php/archives/2004/12/just-what-is-this-consensus-anyway/

Greg, perhaps we are approaching consensus.

My claim has always been that the scientific community has, in the past few years, reached a consensus in the peer-reviewed literature that global warming is real and is, to use JP's term, anthropogenic.

That does not mean that there isn't discussion among researchers. It does mean that that discussion has not resulted in published peer-reviewed papers. It also does not mean that CO2 is claimed to be the only cause. It does mean that the causal correlation between historical temperature and CO2 concentration is generally agreed on (by the same standards).

Do various researchers have various opinions? Yes, of course. Do they discuss those opinions? Yes, of course. Will this consensus change if research compels a change? I certainly hope so.

In the meantime, I submit that the consensus IN THE PEER-REVIEWED LITERATURE is that global warming is real and probably anthropogenic (notice I've added "probably").

Why does this matter? Because IF it is anthropogenic, and IF it is real, then the cost -- in both human and economic terms -- of taking action to minimize the damage already done is compellingly less than the expected value of doing nothing.

I argue that if we multiply the likelihood of anthropogenic global warming being real by the projected cost of its impact, the resulting immediate risk to my community, my family, and myself FAR EXCEEDS the risk presented by, for example, a terrorist attack on my community. Yet my government, led by the nay-sayers, spends hundreds of billions on a "war on terrorism" while spending a pittance on ameliorating the global warming risk. This is the political aspect of this question.

At the risk of drawing the choice too starkly, if I am forced to choose between two strategies:

• Overstate the risk now, and perhaps reduce the economic prosperity of our grandchildren's culture (although even this is highly doubtful), or,


• Understate the risk now, and face the destruction of human civilization during our grandchildren's lifetime.

I'll take the first.

Perhaps this is a game-theoretical question, and this is perhaps the real issue that merits extended debate.

"caused by humans" is easier to spell!

Lorenzo

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