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Only the stratosphere is dry enough and with a long enough residence time (a few years) for the small anthropogenic inputs to be important.

Only the stratosphere is dry enough and with a long enough residence time (a few years) for the small anthropogenic inputs to be important.

If you think we can make accurate preditions based on 100 years of data

In the 70s, scientists were absolutely convinced that they'd mastered the complex climate change models, and confidently assured us all that an Ice Age was imminent.

And not only does it appear that global warming is much greater in scope than any amount of anthropogenic factors can account for

it also appears that there's not much we can do about it anyway.

In the 70s, scientists were absolutely convinced that they'd mastered the complex climate change models, and confidently assured us all that an Ice Age was imminent.

And not only does it appear that global warming is much greater in scope than any amount of anthropogenic factors can account for

it also appears that there's not much we can do about it anyway.

what about volcanoes, cow manure and all the other natural things we can't control? They contribute far more to global warming than cars do

"> reduced air pollution and increased water evaporation appears to be
>adding to man-made global warming.

Actually, the pollution was (or 'is', in southern Asia and China) *masking* the effects of increased warming at ground level. Cleaning up the air doesn't add additional forcing; it merely keeps it elsewhere.

I don't think I can bear to read the following hundreds of ignorant "I've heard it's all due to the sun getting hotter" crap we always get on Slashdot AGW stories. If you think that, you don't know what you're talking about. Go away and read Real Climate or, for a comprehensive refutation of all the trolls we can expect to see attached to this story, please refer to this excellent debunking of so-called 'sceptic' canards, lies and deliberate mis-statements of facts.

We still don't know how much of this is because of humans or natural

• The Discovery of Global Warming
  
• Real Climate
  
• A Few Things Ill-Considered
  

"Back up your answer with facts."

Good advice...

"All of the scientific consensus in the world has yet to produce a climate model that can *predict* the climate for *any* century in the past."

I call bullshit

"hockey stick" curve anyone?

I call implied bullshit

"hydrogen enthusiasts, water vapor is a greenhouse gas too"

Water vapour lasts 10 days in the atmosphere, unless you are expecting the oceans to boil what is the point of the second experiment you propose?

"Now a "consensus scientist" starts out with a single fact."

You have the terms scientific consensus and industry shill confused. Scientific consensus means the accepted scientific view, if you can point to ANY peer-reviewed study published in the last 10yrs that goes aginst the "scientific consensus" on AGW then please give a link to the abstract. While you are looking think about where all the FUD in the popular press could be coming from and who is paying for it?

After having said all that your first experiment asks some good questions that are still the subject of much research, however there are plenty of studies that attempt to answer them. The basic conclusion is "it depends on the exact method and logistics", some proposed systems are simply political-pork, others can make significant cuts in CO2 emmisions. OTOH: A strong global market for CO2 credits would rapidly find the most efficient large scale methods.

"Back up your answer with facts."

Good advice...

"All of the scientific consensus in the world has yet to produce a climate model that can *predict* the climate for *any* century in the past."

I call bullshit

"hockey stick" curve anyone?

I call implied bullshit

"hydrogen enthusiasts, water vapor is a greenhouse gas too"

Water vapour lasts 10 days in the atmosphere, unless you are expecting the oceans to boil what is the point of the second experiment you propose?

"Now a "consensus scientist" starts out with a single fact."

You have the terms scientific consensus and industry shill confused. Scientific consensus means the accepted scientific view, if you can point to ANY peer-reviewed study published in the last 10yrs that goes aginst the "scientific consensus" on AGW then please give a link to the abstract. While you are looking think about where all the FUD in the popular press could be coming from and who is paying for it?

After having said all that your first experiment asks some good questions that are still the subject of much research, however there are plenty of studies that attempt to answer them. The basic conclusion is "it depends on the exact method and logistics", some proposed systems are simply political-pork, others can make significant cuts in CO2 emmisions. OTOH: A strong global market for CO2 credits would rapidly find the most efficient large scale methods.

"Back up your answer with facts."

Good advice...

"All of the scientific consensus in the world has yet to produce a climate model that can *predict* the climate for *any* century in the past."

I call bullshit

"hockey stick" curve anyone?

I call implied bullshit

"hydrogen enthusiasts, water vapor is a greenhouse gas too"

Water vapour lasts 10 days in the atmosphere, unless you are expecting the oceans to boil what is the point of the second experiment you propose?

"Now a "consensus scientist" starts out with a single fact."

You have the terms scientific consensus and industry shill confused. Scientific consensus means the accepted scientific view, if you can point to ANY peer-reviewed study published in the last 10yrs that goes aginst the "scientific consensus" on AGW then please give a link to the abstract. While you are looking think about where all the FUD in the popular press could be coming from and who is paying for it?

After having said all that your first experiment asks some good questions that are still the subject of much research, however there are plenty of studies that attempt to answer them. The basic conclusion is "it depends on the exact method and logistics", some proposed systems are simply political-pork, others can make significant cuts in CO2 emmisions. OTOH: A strong global market for CO2 credits would rapidly find the most efficient large scale methods.

A couple of comments: It would be a stupid objection even if it were true, because computers and modeling technology have advanced enormously in 30 years. But in fact it is not. The so called "scare" was pretty much confined to this article in the popular press--nothing in the scientific literature supports the claim of a threat from global cooling. Moreover, the scientific paper that apparently inspired the Newsweek hysteria actually reported that cooling would be expected if the effects of human activities were not considered .

Woah, I knew there were a lot of global warming (or "human causation") deniers on slashdot, but I hadn't checked here in a while - didn't realize it was this bad! No wonder I don't come here much any more.

For all y'all's edification, I STRONGLY recommend:

The Discovery of Global Warming
Real Climate
A Few Things Ill-Considered

I'll come back when y'all have read those, ok?

About H2O and warming: here

...is to pontificate while ignoring the facts:

http://www.realclimate.org/

The sad fact is that since 1988, the contrarian position on global warming has been nothing more than a snow job by Republican politicians and Republican interests, especially right-wing "think tanks" paid to churn out talking points that benefit industry and politicians.

The depth of right-wing hackery is demonstrated not just by George W. Bush, but by George Will, who to this day denies that anthropogenic global warming is real. His denials read like creationists flailing their tiny fists against 150 years of consensus on evolution. "One degree might be the margin of error" -- that is quite simply false.

To see George Will, the face of modern conservatism, in full petulant splendor, you have to watch the video. All he brings to the table -- all any global-warming denier can bring to the table -- is a snow job of out-of-context quotes from the 1970s about how some scientists thought the globe was cooling, not warming. Pretty sad. But that's one of the many differences between scientists and pundits. When new facts come to light, scientists change their minds.

But there has been a Republican pattern, from 1988, when James Hansen went before the U.S. Senate to explain that he was "99 percent" certain that global warming was real and that it was to some extent caused by humans, to earlier this year when the Bush administration's appointee tried to muzzle the very same James Hansen on the very same issue. Over and over we see partisan politics as the opposition to actual science. By arguing that any action on global warming would destroy our economy (not true -- carbon emission per GDP dollar has gone down dramatically since 1970 while productivity has boomed), Republicans play the issue as a political weapon, forcing Democrats to adopt moderate positions. Remember Bush's campaign ad making fun of Kerry for even considering a gasoline tax?

And who suffers? We are already in the midst of the Sixth Extinction, and though the first effects of global warming are just beginning to be felt, it's about to slam the ecosystem like a freight train. The only hope we have is that technology will take a quantum leap soon enough to allow us to effectively change planetary climate, on a scale we can't today engineer. But that's a crap shoot, a total unknown (much like global dimming, by the way, which we also know next to nothing about, and which if part of a natural cycle may mean global warming is going to get much, much worse over the next century). We need to do something besides hope.

It seems that it's too late to halt global warming's effects, thanks largely to fifteen years of Republican dissembling, but maybe if we start now we can mitigate to some extent the horrific human death, disease and displacement that will be everyday news on our grandchildren's planet. All we can do is start now. Maybe if these poll numbers are accurate, finally, finally we may be able to help.

Realclimate weren't impressed...

What do you mean by saying that the Mann "hockey stick" was proved wrong at MIT? The MIT climate scientists I know mostly agree with the following realclimate article...

Just to be "fair and balanced", here is a review of Crichton's state of fear by some qualified and published climatoligists. Also their rebuttal of Crichton's testimony to the senate committee is worth a look.

He may write best-selling sci-fi books but his opinion on climate change is just as fictional as his books and no amount of willfull ignorance by senators and fiction writers will make climate change go away.

Just to be "fair and balanced", here is a review of Crichton's state of fear by some qualified and published climatoligists. Also their rebuttal of Crichton's testimony to the senate committee is worth a look.

He may write best-selling sci-fi books but his opinion on climate change is just as fictional as his books and no amount of willfull ignorance by senators and fiction writers will make climate change go away.

Statistical models (used by climatologists) are bound to increase in accuracy as they deal with average temperature of the entire globe over larger time scales.

This is not about determining whether it will snow or rain in Peoria on Dec. 11, 2006.

Some links that may interest you:
http://www.guardian.co.uk/climatechange/story/0,,1 517946,00.html
http://www.begbroke.ox.ac.uk/climatebasics/?style= plain
http://www.realclimate.org/index.php?p=270

Warming due to CO2 will also lead to more water vapor in the atmosphere in a positive feedback.

3) I have no idea where you are getting your numbers. Please cite some sources? Again, realclimate has reprinted a figure showing 6 different temperature reconstructions of the past 1000 years. None of them have medieval warm periods that are even as warm as today's temperatures, much less your absolutely ridiculous 2 degree C number.

Finally: Yes, historically CO2 has not been the prime mover in Ice Age oscillations - that would be orbital variations (Milankovitch cycles). However, given that the forcing changes due to orbital wobbling are small, most paleoclimatologists believe that there was a nice positive feedback loop: slight warming leads to CO2 outgassing leads to more warming leads to ice sheet retreat leads to more warming leads to more CO2 leads to... you get the picture. And our evidence for the CO2-warming link is not just "mere correlation" - there is significant science that goes into measuring all sorts of forcing agents from volcanoes to aerosols to GHGs to solar variations - and studies using these forcings find it very, very hard to explain the last 40 years of warming without taking into account anthropogenic GHG changes.

Warming due to CO2 will also lead to more water vapor in the atmosphere in a positive feedback.

3) I have no idea where you are getting your numbers. Please cite some sources? Again, realclimate has reprinted a figure showing 6 different temperature reconstructions of the past 1000 years. None of them have medieval warm periods that are even as warm as today's temperatures, much less your absolutely ridiculous 2 degree C number.

Finally: Yes, historically CO2 has not been the prime mover in Ice Age oscillations - that would be orbital variations (Milankovitch cycles). However, given that the forcing changes due to orbital wobbling are small, most paleoclimatologists believe that there was a nice positive feedback loop: slight warming leads to CO2 outgassing leads to more warming leads to ice sheet retreat leads to more warming leads to more CO2 leads to... you get the picture. And our evidence for the CO2-warming link is not just "mere correlation" - there is significant science that goes into measuring all sorts of forcing agents from volcanoes to aerosols to GHGs to solar variations - and studies using these forcings find it very, very hard to explain the last 40 years of warming without taking into account anthropogenic GHG changes.

Pfft, observation/Finite Element Anaylisis/comparison. What is there not to understand, similar techniques are used in engineering every day? Point out some contrary facts/maths/studies rather than vague philosophical notions of what is and is not predictable. You may want to start your reasearch on climate models by checking out a small fraction of the scientic effort behind them. I doubt if you will, my guess is you don't understand much past the "unpredictability" talking point currently being fed to you.

OTOH: Public discussion is about risk assesment not absolute certainty, until very recently ALL of the planets "leaders" have grossly underestimated the risks a changing climate presents. Many people such as yourself are still unaware that the greatest risk is not a rise in ocean levels, it is a direct and currently visable threat to our food chain.

Mars is seeing global warming.

Mars is experiencing local warming. Ay the southern pole. Because it is summer there. Given the combination of mars tilt and the eccentricity of its orbit the seasonal cycle can be complicated and have patterns over a much longer time scale than earth. For more try here.

Jedidiah.

Hmmm. Real Climate says no on Mars. (Real Climate is a website set up by actual climatologists to counter the lies spread by libertarians and republicans in the American media.)

The last 5 yaers are the hottest in recorded history. I'm sorry, but how far back do our climate records go? Not that far in the grand scheme of things.

We have a number of temperature reconstructions going back about 2000 years. They do vary because they use http://en.wikipedia.org/wiki/Image:2000_Year_Tempe rature_Comparison.pnga variety of different sources, from glaciers, to ice cores, to tree rings, but there is pretty good general agreement. That latest such study, putting together data from a wide variety of difference sources to cross reference temperatures for the last 1200 years showed the previous century was the warmest. For records going further back there are the Greenland ice cores with detailed data going back 120,000 years. Further back than that we have the Antarctic Vostok and DomeC ice cores which provide data going back 650,000 years. That gives a pretty good general picture of temperature historically at least over a large chunk of human history, and in the end its human history that counts: whether the planet continues on its merry way matters little to us - what matters is the impact any warming has on humans.

Change is the natural way of things. I think it's pretty presumptious of us to think we're causing it.

Well there are the remarkable correlations between atmospheric carbon dioxide and temperature, even over the 650,000 years spanned by Antarctic ice cores. Combine that with the present spike in carbon dioxide, which is verifiably anthropogenic, and the absorption spectra of carbon dioxide which makes it an effective greenhouse gas, together with the close correlation between the recent spike in atmospheric carbon dioxide and temperature, and you have some good reasons to start thinking we may be causing it. Is that conclusive? No. But then there's plenty more evidence than what I can pack into a quick paragraph.

Volcanoes put out far more greenhouse gasses than anything humans do.

This one is just a bizarre bit of disinformation that keeps getting circulated. It is quite false. Volcanoes put out around 130 to 230 teragrams of carbon dioxide a year. The US alone puts out around
5844 teragrams. Atmospheric carbon dioxide from volcanoes is less than 1% of the amount from human activities. Please, put this particular myth to bed.

Jedidiah.

Hmmmm. Let's see, a major amount of ice melts from Antarctica. Freed from this weight, the continent rises (maybe). Wouldn't that displace more water, thus causing water levels to rise in other places like the ones people live in? As far as water vapor is concerned see this article at RealClimate.

But why it is dangerous is that we DO NOT KNOW WHY THIS IS HAPPENING.

If we were to "accept" the opinions of a few climatologists...

the changes in behaviour we would have to make to try not to warm the atmosphere would be very damaging to the economy.

Or a meter every 2500 years? Wow.... better shore up the levees, Waterworld is coming soon!

0.4mm per year just from the Antarctic ice sheet, and 2500 years for a meter presuming a constant rate. On the other hand there are other factors at play such as the Greenland glaciers, which are accelerating their slide into the sea, which means it might be worth considering the possibility of acceleration of the loss of Antarctic ice. There's also thermal expansion as another factor causing sea levels to rise.

It's also worth noting that, in the grand scheme of things, 0.4mm per year is quite a lot: sea level change over the last 3000 years averages to about 0.1mm to 0.2mm per year.

Is this a clear indication of catastrophic distaster? Far from it. Nor is it the least bit implicit of any sort of bizarre Waterworld scenario. However, even a 1 meter change in sea will have signficant impact given the large numbers of cities very close to sea level - even a small rise makes them far more susceptible to flooding from, say, storm swell or similar. In practice even a small change is going to displace an awful lot of people, costing an awful lot of money, and having a significant economic impact. It may not be a disaster of biblical proportions, but it is most definitely something to be concerned about and to keep an eye on.

Jedidiah.

Global warming has finally been explained: the Earth is getting hotter because the Sun is burning more brightly than at any time during the past 1,000 years, according to new research.

Climatologists have addressed this before:

At the same time, estimates of solar output in the past are extremely uncertain, and so there is a great deal of scope in blaming any unexplained phenomena on solar changes without fear of contradiction.

It is us monkeys, who have been actively measuring temperatures for two hundred years at best and are reconstructing climate history with very limited devices and methology that are getting overtly excited when we still have no idea whatsoever as what is "normal" on this planet in this part of the galaxy.

The other thing to take home is that there are a lot of people on this planet all too happy to abuse doomsday predictions to further their agendas both socially and economically.

"because all of the points used to generate that graph are averages"

Yes that is to be expected, climate is not weather it is the long term statistics of weather. Here is a much more indepth look at the hockey stick.

"My point is not that the temperature is not changing"

If you follow the leads in the link you will come across an article entitled "what if the hockey stick were wrong", it explains that the IPCC conclusion that the earth is warming can stand without the graph.

I also think you may be confused as to how "heat" radiates away from the Earth.

"the alarmest models invariably can't get history right"

Really?

http://www.realclimate.org/index.php?p=221

http://www.uni-leipzig.de/~meteo/MUDELSEE/publ/pdf /EPICA-challenge.pdf

"First of all, the results demonstrate clearly that the relationship between climate and CO2 that had been deduced from the Vostok core appears remarkably robust. This is despite a significant change in the patterns of glacial-interglacial changes prior to 400,000 years ago. The 'EPICA challenge' was laid down a few months ago for people working on carbon cycle models to predict whether this would be the case, and mostly the predictions were right on the mark. (Who says climate predictions can't be verified?). It should also go almost without saying that lingering doubts about the reproducibility of the ice core gas records should now be completely dispelled. That a number of different labs, looking at ice from different locations, extracted with different methods all give very similar answers, is a powerful indication that what they are measuring is real. Where there are problems (for instance in N2O in very dusty ice), those problems are clearly found and that data discarded."

Equilibrium processes?

We WERE at equilibrium. We have added a new substantial source of CO2, and we are now moving to a new higher equilibrium concentration. Tehjabsolute levels of
BTW, your volcanic CO2 numbers are very, very wrong. Anthropogenic CO2 emissins are more than two orders of magnitde heigher than volcanic emissinons. Total natural emissions of CO2 are about a norderof magnitude higher than anthropogenic inputs. Adnanthropogenic inputs are changing the equilibrium.

http://www.realclimate.org/index.php?p=160
http://www.radix.net/~bobg/faqs/scq.CO2rise.html

This folloing info is from the second URL

>From its preindustrial level of about 280 ppmv (parts per million
by volume) around the year 1800, atmospheric carbon dioxide rose to
315 ppmv in 1958 and to about 358 ppmv in 1994 [Battle] [C.Keeling]
[Schimel 94, p 43-44]. All the signs are that the CO2 rise is
human-made:

* Ice cores show that during the past 1000 years until about the year
1800, atmospheric CO2 was fairly stable at levels between 270 and
290 ppmv. The 1994 value of 358 ppmv is higher than any CO2 level
observed over the past 220,000 years. In the Vostok and Byrd ice
cores, CO2 does not exceed 300 ppmv. A more detailed record from
peat suggests a temporary peak of ~315 ppmv about 4,700 years ago,
but this needs further confirmation. [Figge, figure 3] [Schimel 94,
p 44-45] [White]

* The rise of atmospheric CO2 closely parallels the emissions history
from fossil fuels and land use changes [Schimel 94, p 46-47].

* The rise of airborne CO2 falls short of the human-made CO2 emissions.
Taken together, the ocean and the terrestrial vegetation and soils
must currently be a net sink of CO2 rather than a source [Melillo,
p 454] [Schimel 94, p 47, 55] [Schimel 95, p 79] [Siegenthaler].

* Most "new" CO2 comes from the Northern Hemisphere. Measurements
in Antarctica show that Southern Hemisphere CO2 level lags behind
by 1 to 2 years, which reflects the interhemispheric mixing time.
The ppmv-amount of the lag at a given time has increased according
to increasing anthropogenic CO2 emissions. [Schimel 94, p 43]
[Siegenthaler]

* Fossil fuels contain practically no carbon 14 (14C) and less carbon
13 (13C) than air. CO2 coming from fossil fuels should show up in
the trends of 13C and 14C. Indeed, the observed isotopic trends
fit CO2 emissions from fossil fuels. The trends are not compatible
with a dominant CO2 source in the terrestrial biosphere or in the
ocean. If you shun details, please skip the next two paragraphs.

* The unstable carbon isotope 14C or radiocarbon makes up for roughly
1 in 10**12 carbon atoms in earth's atmosphere. 14C has a half-life
of about 5700 years. The stock is replenished in the upper atmosphere
by a nuclear reaction involving cosmic rays and 14N [Butcher,
p 240-241]. Fossil fuels contain no 14C, as it decayed long ago.
Burning fossil fuels should lower the atmospheric 14C fraction (the
`Suess effect'). Indeed, atmospheric 14C, measured on tree rings,
dropped by 2 to 2.5 % from about 1850 to 1954, when nuclear bomb
tests started to inject 14C into the atmosphere [Butcher, p 256-257]

What about the Little Ice-Age?

Fact is, we're looking at a ~2000 year snapshot of an incredibly comlex system that's a few billion years old.

But what I'm saying is that we don't know how we are affecting it.

What about the Little Ice-Age?

Fact is, we're looking at a ~2000 year snapshot of an incredibly comlex system that's a few billion years old.

But what I'm saying is that we don't know how we are affecting it.

mars is not undergoing global warming.

http://www.realclimate.org/index.php?p=192

mars warming seems to be mainly caused by a decrease in the huge dust storms it has. These storms typically reflect sunlight. If you have a year with few storms the temp can increase by a great deal.

You can certainly find "some credible scientists" (for certain values of "some", "credible", and "scientists") who believe that the consensus on climate change is wrong, the same way you can find some who believe that the consensus on /the Big Bang/Evolution/the Ozone Hole/name your pet theory/ is wrong too.

Why don't you go to an AGU meeting and attend a sampling of climate talks and see what the real state of the science is? You'll see a lot of acknowledgment of uncertainty, but basically, if you interview 100 attendees at the conference, I would guess that 98 would be willing to place money down that next century will be warmer than this one due to anthropogenic causes, and maybe 90 of them would say that it was something to worry about. The basic science behind this has been understood for more than a century (see Svante Arrhenius), and the evidence just keeps mounting.

And please don't trot out the global cooling canard: Realclimate (among other sources) debunks that nicely.

And I love that the article that YOU linked to states "Most of the prominent organisations making the case against mainstream climate science have an avowed agenda of promoting free markets and minimal government. They often accept funding from the fossil-fuel industry. Few employ climate scientists."

Oh, PLEASE.

Michael Crichton is out to make money. He gets money for giving his "daring" speech on the rubber chicken circuit. He gets money on sales of his latest shlock thriller, which has evil grant-hungry climate scientists running weather control machines to terrorize the populace.

Here is what actual climate scientists have to say about the claims in his novel:

http://www.realclimate.org/index.php?p=74

At CISCOP, Chris Mooney reviews State of Fear:

http://www.csicop.org/doubtandabout/crichton/

A look at the politics behind Crichton's crusade:

http://www.grist.org/advice/books/2005/02/01/rober ts-fear/

Who are your going trust, Crichton or scientists?

http://gristmill.grist.org/story/2005/1/20/234126/ 976

OK. Maybe you can't trust scientists. How about the opinions of another author? Here is what Gregory Benford has to say:

http://www.signonsandiego.com/uniontrib/20050121/n ews_lz1e21benford.html

For example, simulations of iron fertilization of the oceans in the Southern Hemisphere initially showed that almost 8 billion tons of carbon would be absorbed by the ocean each year. Yet, after 500 years of continuous fertilization, the net increase in absorption would be less than 1 billion tons of carbon per year.

First, the previously sequestered carbon dioxide does eventually leak back out of the ocean, although the leakage rate is most rapid in the first years.

However, at best, it's only a partial solution to the problem, and it would involve ecosystem management on an unprecedented scale.

This kind of large-scale

And on solar radiation increases:

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

Oh, and as far as "solar forcing" goes, you may wish to have a look at what RealClimate have to say. To sum up, there's very little good historical data on the topic, which makes it an easy copout for people seeking alternative explanations for warming.

I also notice that the rise in temperature precedes the rise in CO2 for the most part of that graph.

It does, and the interesting thing is that that is actually to be expected. Without some other reason for CO2 to rise (like, for example, creatures burning fossil fuels) something else is required to raise CO2 levels and produce the natural cycles. As it happens warming can often cause an increase in CO2 - warmer oceans hold less CO2. Once a natural warming fluctuation (from, say, solar variation) has become sufficient to introduce enough atmospheric CO2 for it to be a driver the temperature continues to rise as a result. You'll note that the lag of CO2 to temperature is quite small in comparison to the size of the total warm period that results. More detail about this phenomenon can be found here.

What the lag really tells us is that in the natural cycle CO2 is often not the initial trigger for a warm period - that's not surprising as there are many factors affecting climate and generally the carbon cycle keeps CO2 relatively stable. Once CO2 has been pushed out of balance it can certainly act as a forcing and shift the global climate for significant time spans. Instead of a natural climate event causing the most recent significant change in atmospheric CO2 humans have caused it. Unsurprisingly there is, this time, no lag of CO2 behind temperature, instead temperature is lagging behind CO2. What the global climate will do in response and where the new equilibrium will be remains a somewhat open question.

Jedidiah.

"Just because someone received .... doesn't mean they're smart."

No, but there is an extremely high probability he is not stupid.

OT: The fixation on foam is odd, I would have thought the story most concerning NASA's chief at the moment would be Hansen and the policy police.

Do a whois on them and you will see thier physical address is the exact same as the address Fenton.com which is a left wing PR firm that represents liberal organizations including moveon.org.

They addressed that almost a year ago. Why they wouldn't be more cognizant of the appearance of conflict of interest, I don't know.

There have been times in the planet's past (within the last 100,000) years where the climate was MUCH warmer with much higher concentrations of C02.

Carbon dioxide levels are at their highest from the last twenty million years. That's 20,000,000 years. You know, 200 times longer than your 100,000 number.

Here's a chart for the last 400,000 years. See the gigantic spike on the left? That's us.

The IPCC relevant quote for the 20 Myr number.

but to attribute current climate conditions over the last 20 years or even 40 with human activity

Carbon dioxide levels in the atmosphere are absolutely from human activity. That's proven - really, proven - by isotopic abundances.

Why is it politics to assume that if we can change - significantly - the atmospheric composition of the planet, we can change the climate?

But to be equally fair, realscience.org's [sic] main contributors seem to be Mann et el. so I wouldn't expect objective criticisms of MBH98.

You appear to think that science is a political party or cult, which has an orthodoxy and sticks to it. Nothing could be further from the truth. Scientists tear each other's theories apart mercilessly, beginning in the peer-review process. The only restriction is that criticism as well as theories must have a foundation in fact. Research is often funded and conducted with the goal of determining which out of a set of conflicting theories is actually correct.

Theories which have already been proven incorrect by the existing data need not apply. That already includes "our activities aren't doing anything".

I started out believing there was a link between warming and anthro CO2. But after I started digging a little I found it wasn't as easy to establish as I thought it would be.

Two reseachers from Canada, Stephen McIntyre and Ross McKitrick

One of whom is an economist, and the other works in the mining industry. Not exactly "...errors according to climatologists. There's been plenty of picking apart of McIntyre and McKitrick so I won't get into that, you can read the links if you're interested. Instead I'll point you to this chart of historical temperature showing 10 different, largely indepedent, historical reconstructions all using different proxy data sets, from glaciers, to ice cores, to tree rings, and various combinations. Sure there isn't perfect agreement, but I think the trend is very clear. The point is that it is not a case of everything resting on Mann's original report. Since that time a great deal more work has been done, by a wide variety of different people, and hile results have varied they have all come to essentially the same basic conclusion.

Jedidiah.

Two reseachers from Canada, Stephen McIntyre and Ross McKitrick

One of whom is an economist, and the other works in the mining industry. Not exactly "...errors according to climatologists. There's been plenty of picking apart of McIntyre and McKitrick so I won't get into that, you can read the links if you're interested. Instead I'll point you to this chart of historical temperature showing 10 different, largely indepedent, historical reconstructions all using different proxy data sets, from glaciers, to ice cores, to tree rings, and various combinations. Sure there isn't perfect agreement, but I think the trend is very clear. The point is that it is not a case of everything resting on Mann's original report. Since that time a great deal more work has been done, by a wide variety of different people, and hile results have varied they have all come to essentially the same basic conclusion.

Jedidiah.

More info and details here.

We're not denying it, we're just questioning wether it's linked to CO2.

PR firms are noted for producing bovine excrement. They are really good at polishing it to make it look good, but it doesn't change its essence. If you want to know where climate scientists stand, you should read stuff written by climate scientists.

The cornerstone to the IPCC Report is the Michael Mann (et el) "hockey stick" graph