Is the Earth even more sensitive to CO2 levels than we thought?

ResearchBlogging.orgOne of the more common arguments from skeptics of anthropogenic climate change is that the Earth has experienced periods during which atmospheric carbon dioxide levels were much much higher than they are today -- as much as 10 times higher. Why worry about a mere 30% increase over pre-industrial levels?

There are several answers to that challenge. The most obvious is that while it may be true that CO2 levels have been several times higher that today's 387 parts per million, the Earth was also a very different place back then. The sea level was much higher, the temperature was much warmer and it bears noting that the biodiversity at such times was quite different. But the assumption that the atmospheric CO2 levels might have been 3,000 ppm did pose some challenges to climatologists trying to figure out how the rest of the planetary ecosystem responded to dramatic changes in CO2. Some of the things that were apparently happening during high CO2 periods didn't quite make sense.

Now, however, comes a paper in PNAS (access priviledges req'd) that reports a strong possibility that CO2 levels during one of those curious periods -- the Mesozoic, which was between 251 and 65 million years ago -- were much lower that previous estimates. If the authors are right, we may have to reconsider our predictions of what might happen over the next century if CO2 levels don't stabilize soon.

"Atmospheric CO2 concentrations during ancient greenhouse climates were similar to those predicted for A.D. 2100" by soil scientist D. O. Breecker, Z. D. Sharp, and L. D. McFadden at the University of New Mexico, posits that soil carbonate "paleobarometers" used in the past to figure out how much CO2 was in the air millions of years ago involved some inappropriate assumptions. Their new analyses, which measures the amount of calcite found in North American soils, comes up with much lower estimates. Instead of upwards of 3,000 ppm,

the most often quoted CO2 atm values, those previously determined from pedogenic carbonate, are too high,and that paleo CO2 atm values did not persist above 1,500 ppmV during the past 400 million years.

These numbers are easier to reconcile with models of carbon cycles and other CO2 proxies, the authors write. And so:

the agreement between multiple proxies strongly supports the conclusion that the warmest episodes of the Mesozoic were associated with CO2 atm equal to â¼1; 000 ppmV rather than 2,000-3,000 ppmV. The relatively low CO2 atm of 1,000 ppmV during greenhouse episodes suggest that either Mesozoic warmth was partially caused by a factor unrelated to CO2 or that the Earth's climate is much more sensitive to atmospheric CO2 than previously thought.

It is entirely possible that Breecker's approach is flawed, or that the unrelated and unknown factor is responsible for the warmth that accompanied the 1,000 ppm periods. This is, after all, just one study, and who's to say that the next one won't find that the real CO2 levels during ancient greenhouse episodes were actually higher than we thought, rather than lower? To insist this one paper is proof that we're much closer to catastrophic tipping points than generally assumed would be just as foolish as changing your diet according to the latest findings on the metabolic effects of caffeine or fiber. If you did that every time a contrary study was published you'd never be able to assemble a grocery list.

The way science works -- most of the time -- is that nailing down what really happened eons ago is a kind of zig-zaggy affair. One approach might give us a lower value, in this case for Mesozoic CO2 levels, and then the next might pump that number up a bit, and the next back down a bit. As long as the peer-review process is operating as it should, however, each subsequent estimate will be closer to the actual figure than the previous one.

So while it is possible that Breecker's conclusions might have gone too far in one direction, the next analysis is likely to generate estimates that are closer to Breecker's than they are to the previous, much higher values. Eventually, we'll settle on a number that doesn't change significantly with easy subsequent attempt to nail it down.

As one scientist told Nature's Richard A. Lovett last month, the likelihood that Breecker et al are way off the marks seems unlikely.

"It makes a major revision to one of the most popular methods for reconstructing palaeo-CO2," says Dana Royer, a palaeobotanist at Wesleyan University in Middletown, Connecticut, who was not involved in the work. "This increases our confidence that we have a decent understanding of palaeo-CO2 patterns."

Lending more weight to this new approach are the findings of James Hansen and his colleagues, who last year used entirely different methods to estimate a maximum CO2 concentration 50 million years ago of just 1,400 ppm. (See also his new book, Storms of My Grandchildren.)

This is not the only new paper to conclude that that the Earth is more sensitive to CO2 levels than previously assumed. Late last year also saw the publication, in Nature Geoscience of "Earth system sensitivity inferred from Pliocene modelling and data" in which Daniel Lunt of the University of Bristol and colleagues

estimate that the response of the Earth system to elevated atmospheric carbon dioxide concentrations is 30-50% greater than the response based on those fast-adjusting components of the climate system that are used traditionally to estimate climate sensitivity

What does all this mean for the future: Breecker and colleagues wrap up their findings with this typically understated warning:

Comparison of projected future CO2 atm with results from the recalibrated CO2 paleobarometer (Fig. 2B) indicate atmospheric CO2 may reach levels similar to those prevailing during the vegetated Earth's hottest greenhouse episodes by A.D. 2100..... Given that the Early Permian CO2 increase may have caused the termination of the Late Paleozoic Ice Age (7, 8, Fig. 2D), the only known icehouse-greenhouse transition on a vegetated Earth, the effects that unmitigated CO2 increases may have on future climate warrant careful consideration.

It is entirely possible then, that keeping CO2 levels to no more than 450 ppm -- or keeping our cumulative carbon emissions to no more than a trillion tonnes -- will be insufficient to ensure the temperature increase over pre-industrial times stays below 2°C. Which only highlights the need to begin the transition to a low- or zero-carbon economy sooner rather than later.
--
Breecker, D., Sharp, Z., & McFadden, L. (2009). Atmospheric CO2 concentrations during ancient greenhouse climates were similar to those predicted for A.D. 2100 Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0902323106

More like this

A new paper by Chilingar, Khilyuk and Sorokhtin is up to their previous standard. Here's the abstract: The writers investigated the effect of CO2 emission on the temperature of atmosphere. Computations based on the adiabatic theory of greenhouse effect show that increasing CO2 concentration in the…
So a fair degree of warming is inevitable, eh? That's the conclusion of a PNAS paper making the rounds this week. (I wrote about it yesterday.) But just how "irreversible" are the coming changes? As Arthur C. Clarke said, "When he states that something is impossible, he is very probably wrong." The…
I recently noted that there are reasons to think that the effects of human caused climate change are coming on faster than previously expected. Since I wrote that (in late January) even more evidence has come along, so I thought it was time for an update. First a bit of perspective. Scientists have…
See that black box over on the left-hand side of this blog? The one with the numbers counting down? That's a little widget I assembled by rejigging one from trillionthtonne.org. The basic idea is that, if our climate can be expected to suffer severe disruption at a certain amount of global warming…

While I understand the point being made here and elsewhere, I still find myself stuck at a simple sentence/ thought: The most obvious is that while it may be true that CO2 levels have been several times higher that today's 387 parts per million, the Earth was also a very different place back then. Why is it we can look back and say "the earth was a very different place back then"", in argument, yet never allow the Earth WILL be a very different place right now, next century, etc? I believe we can do better, of course, but why this steadfast belief the Earth is now as it will always be from here until the sun dies- and it's our responsibility to maintain it as such? Perhaps the Earth during the Mesozoic is the benchmark, and we are trying to correct one of the corrective swings- the one that happens to be nearly perfect for human life. 4.5 billion years is a very long time to take just a sliver and call it our starting point...

Just considering...

raebird, the Earth will certainly be a very different place at some point in the future. At some point it will be so different that humans will not be able to survive. I would rather that time come later rather than sooner, personally.

BC, I wholeheartedly agree... However, my question remains: Are we correcting an issue we humans caused, or are we doing a "Niagara Falls" and trying to artificially, and unnaturally, head off the inevitable? And will it be something we find out 20 generations from now, when they realize it truly was "not nice to fool (with) Mother Nature", and we've actually doomed humanity to an earlier extinction by messing with a very limited data set and truly, in the grand scheme, a lack of greater knowledge? Or are we actually behind the curve, and the sky really IS falling as we speak due to our lack of care and foresight- and who do we go to for an accurate assessment?

Again, just pondering...

mpatter,

It's not news that high CO2 levels would be required to kick the Earth out of a "snowball" phase. During "snowball Earth" phases, the Earth's albedo was very high. High albedo means strong negative temperature forcing. So to get the Earth's temperature high enough to melt the ice, a lot of positive temperature forcing would be required to overcome the negative forcing due to ice/snow reflectivity. That would require a lot of CO2.

Once enough ice/snow melted, then enough of the Earth's surface would be exposed to the atmosphere to allow chemical "weathering" to remove CO2 from the atmosphere and restore the CO2 levels to their "pre-snowball" ranges.

Evidence for this is supported not just by modeling, but by actual physical evidence from sediment cores, etc.

By caerbannog (not verified) on 07 Jan 2010 #permalink

I'm not surprised. It all fits nicely together, especially considering the evidence from stomata counts of Metasequoia and Ginkgo for comparably low CO2 levels during the last 60 million years.

these people have proposed that even higher CO2 levels (10-30%) would have been required to end the snowball earth periods, if they were truly global

That's why they write "vegetated Earth" ( = Devonian and later).

Are we correcting an issue we humans caused, or are we doing a "Niagara Falls" and trying to artificially, and unnaturally, head off the inevitable?

What we're doing right now is pumping insane amounts of CO2, unprecedented for 55 million years, into the atmosphere. That wouldn't, indeed couldn't, have happened on its own.

By David MarjanoviÄ (not verified) on 07 Jan 2010 #permalink

We have carbon dioxide and temperature data going back at least 420,000 years (thanks, Lake Vostok!). The "baseline" for temperature and CO2 is derived from that data. I find it unlikely that the past half a million years were a persistent downward fluctuation.

At any rate, we are not trying to terraform the Earth by slowing CO2 emissions; we are trying to stop the active damage we are currently doing and let the Earth do its thing. Beyond halting our own emissions, there's not much we can do anyway.

@raebird: I don't know anyone (other than creationists) who believe the planet will remain unchanged into the distant future. However, very large changes do not usually occur in a mere few hundred years (with the obvious exception of events such as volcanic eruptions and meteorite impacts). Any attempts to mitigate a rapid temperature increase are not intended to keep things just the way they are, but to avoid a hypothetical catastrophic ecological upset. That's the unselfish reason. Humans have much more to fear and much more certain problems to face; for example a gradual change over a few decades may render enormous expanses of agricultural areas pretty much useless. At this point in history we are absolutely dependent on oil and aggressive agricultural practices to feed the human population. A need to relocate farms (where to - what large ecosystems need to be destroyed to move the farms) will at the very least result in a severe disruption to the food supply of an already overpopulated planet.

By MadScientist (not verified) on 07 Jan 2010 #permalink

Why does it seem that, every time climatologists revise their predictions, they always change in the direction nobody wants?

We have carbon dioxide and temperature data going back at least 420,000 years (thanks, Lake Vostok!). The "baseline" for temperature and CO2 is derived from that data. I find it unlikely that the past half a million years were a persistent downward fluctuation.

Actually, if the latest research holds up (and it looks pretty solid according to AGU fellow and NAS member Dr. Richard Alley), we may be able to push that 420K years back to 15 million years or more!

Check out his UCLA press-release for details:http://www.sustain.ucla.edu/news/article.asp?parentid=4676

By caerbannog (not verified) on 07 Jan 2010 #permalink

Why does it seem that, every time climatologists revise their predictions, they always change in the direction nobody wants?

Because, contrary to the denialists, climatologists have been extremely conservative in their warnings. Those horrifying predictions are actually biased towards the best-case scenarios.

By D. C. Sessions (not verified) on 07 Jan 2010 #permalink

And we mustn't forget that solar radiation was lower at these time scales. The Sun's output increases by about 10% every billion years. So, for example, 300 million years ago, 3% less solar radiation arrives at the Earth. A very different energy budget indeed.

As noted by our host the authors say,

"The relatively low CO2 atm of 1,000 ppmV during greenhouse episodes suggest that either Mesozoic warmth was partially caused by a factor unrelated to CO2 or that the Earth's climate is much more sensitive to atmospheric CO2 than previously thought."

I notice none of you have focused on the first part of that statement. The part that says something other than CO2 may have caused the warming. This assuming that their conclusion, which is at odds with, wait for it, the CONSENSUS is even correct.

A little research shows that throughout the hundreds of millions of years of geologic time CO2 has shown no consistent positive or negative correlation to temperature. In fact it has been very high during some ice ages (the Ordovician) and low during some warm periods (the early Carboniferous).

It is quite clear that CO2 has never caused a "run away" green house effect and the paltry levels of CO2 that humans are capable of adding from the burning of fossil fuels are certainly not going to send the earth into a period of "catastrophic" warming.

Lance -

Of course CO2 has never caused runaway warming on earth. We would not be here if it had; however, runaway warming has happened on Venus, which has roughly the same surface radiation flux as Earth thanks to the highly reflective clouds, but is several hundred degrees hotter.

One day, the increase in the Sun's radiation will cause this effect to happen on Earth.

As far as previous warming goes.. Just a few changes in ocean circulation can make a huge difference. For example, closing the gap between South America and the Antarctic peninsular would quickly cause far more heat to be transferred to Antarctica and melt most of the ice cap, lowering albedo and hence raising the temperature of the entire planet.

But there again, the idea that the climate of the Earth is a complicated system that changed by several different factors it far too hard for denialists. After all, you start admitting that and soon you'll find yourself having to follow the scientific method.

By Andrew Dodds (not verified) on 07 Jan 2010 #permalink

Andrew Dodds,

"But there again, the idea that the climate of the Earth is a complicated system that changed by several different factors it far too hard for denialists. After all, you start admitting that and soon you'll find yourself having to follow the scientific method."

Yes, the earth is a complicated system. That was my point and the level of CO2 in the atmosphere correlates poorly to temperature over geologic time scales.

If you have to invoke just so explanations over and over again to keep making excuses for that lack of correlation at some point you should consider the obvious possibility that CO2 isn't a very potent climate forcing.

Oh, but that doesn't fit your predetermined and politically motivated tautology does it.

The funniest part is that you tried to scold me about following the scientific method.

Here's a hint.

What is the step in the scientific method after analyzing the data and realizing that your theory has limited utility in explaining that data?

Then again if you work at the CRU...

"Which only highlights the need to begin the transition to a low- or zero-carbon economy sooner rather than later."

Lead from the front and I'll follow. Show me your plan to transition yourself to a zero-carbon economy and I'll put it to use reducing my own carbon footprint. It's at least a win-win: Save me money and saves the environment I live in.

This is addressed to all of you "AGW is gonna kill us all" folks, not just our host.

Clearly, James, the major flaw in your reasoning is that you're crediting peer-reviewed scientific literature over right wing think-tank publications. (Poe)

By Nils Ross (not verified) on 07 Jan 2010 #permalink

"Lead from the front and I'll follow. Show me your plan to transition yourself to a zero-carbon economy and I'll put it to use reducing my own carbon footprint."

Show me the last time any action against the interests of the individual became popularised by the choices of individuals, rather than by coercion through legislation. Emancipation, industrial relations, environmental regulations -- in every case fought for in the equivalent of a legislative arena. Likewise, viable solutions to AGW all require collective action, expressed in legislation.

So it's not what a given person does. It's what--and who--they vote for. So your sentiment doesn't seem a terribly useful one.

By Nils Ross (not verified) on 08 Jan 2010 #permalink

Lance -

Can you tell me what my 'predetermined and politically motivated tautology' is. Never knew I had one..

And, no, they are not 'just so' explanations. Try and learn something, thinking is so important..

By Andrew Dodds (not verified) on 08 Jan 2010 #permalink

Thank you, Nils, for blowing the lid off the motivations of all of you AGW cultists:

"Show me the last time any action against the interests of the individual became popularised by the choices of individuals, rather than by coercion through legislation."

You've explained in no uncertain terms that this is an issue of you and your kind coercing the rest of us into compliance. You have no interest whatsoever in convincing us to do what is right for ourselves and others.

I used to think there may be something of value hidden beneath the surface of AGW cultism. Now I know that there is not. You have freed me to fight you every step of the way until you are defeated like the other anti-humanity movements of the past.

The ecological and economic debt my not-so-great generation of elders is leaving for the children to pay off is as unconscionable as it is gigantic.

It appears many too many leaders in our time are not even willing to do what could be judged as sensible by choosing to merely treat symptoms of climate destabilization. They appear to have given up hope of ever acknowledging and addressing the human-driven root causes of what ails the Earth. Such abysmal failures to exercise intellectual honesty, moral courage, common decency and bold action in the face of looming, clear and present dangers to future human wellbeing and environmental health are beyond the pale. I suppose a catastrophic outcome of an unimaginable kind can be expected to occur on Earth soon, now that unbridled selfishness and rampant greediness are everywhere extolled as virtues and allowed to rule the world. What a shame it is to see such a sham foisted upon the human family by the most arrogant and avaricious, self-proclaimed Masters of the Universe among us. What else but a colossal global shambles can result from such overshadowing perversity?

By Steven Earl Salmony (not verified) on 08 Jan 2010 #permalink

@10,000li

You didn't answer his challenge, you only attempted to undermine his credibility. Nice dodge.

So you disagree with one cult and you're going to join the other one? Just because some people ruin it for you with their zealotry doesn't make the science they're attempting to represent only junk nor does it make a valid excuse to jump in bed with zealots in the other ditch (especially those who do not stand on the issue based on science).

The Ordovician ice age was remarkably short⦠do we even have CO2 proxies from during that time? And what's the evidence for Early Carboniferous "low" values?

By David MarjanoviÄ (not verified) on 08 Jan 2010 #permalink

Of course CO2 has never caused runaway warming on earth. We would not be here if it had; however, runaway warming has happened on Venus, which has roughly the same surface radiation flux as Earth thanks to the highly reflective clouds, but is several hundred degrees hotter.

After taking into account the Bond albedos of the planets, the solar flux at Venus is in fact rather less than that of Earth: the ratio is about 0.7. Or in other words, the planet with the highest surface temperature in the solar system ranks in a mere third place in terms of the solar flux absorbed.

David Marjanovic,

"The Ordovician ice age was remarkably short⦠do we even have CO2 proxies from during that time?"

Well if you consider 300,000 to 500,000 years to be "remarkably short". I'm not sure what proxies indicate the CO2 level but it is consistently referred to as being between 8 to 20 times current levels in the literature during that "remarkably short" ice age of nearly half a million years.

"And what's the evidence for Early Carboniferous "low" values?"

CO2 levels dropped rapidly from about 1500 ppm at the beginning of the Carboniferous, an historically low value to that point, to levels very close to today by the middle of the Carboniferous. There was a period of tens of millions of years while the CO2 dropped and the temperatures remained constant and far above today's values.

A graph of CO2 and temperature across all geologic ages reveals that CO2 and temperature are poorly correlated.

10,000i #16 - I have insulated my attic properly and had cavity wall insulation put in. My new car was 10 mpg more efficient than the old one, (That is 45mpg here in the UK) and my next one will be more efficient yet, although I'll be doing my best to go carless, as many of my friends are. Hmm, what else? Ahh yes, walking to the shops, using public transport, trying to buy more local food in season, not joining the consumerist frenzies which lead people to buy new furniture and redecorate when they feel like it. Also much of my furniture is over 10 years old, in fact this desk I'm typing at is around 40 years old. Oh, and I've been using low energy lightbulbs for 9 years now and switch things off at the wall.

Not so much else I can do right now - the greater methods of reducing CO2 production rely upon replacement of coal and gas fired power stations, which Scotland seems to be on the way to doing, albeit more slowly than I would like.

So what were you complaining about exactly?

CO2 levels dropped rapidly from about 1500 ppm at the beginning of the Carboniferous, an historically low value to that point, to levels very close to today by the middle of the Carboniferous. There was a period of tens of millions of years while the CO2 dropped and the temperatures remained constant and far above today's values.

Well, no ...

Average global temperatures in the Early Carboniferous Period were hot- approximately 20° C (68° F). However, cooling during the Middle Carboniferous reduced average global temperatures to about 12° C (54° F). As shown on the chart below, this is comparable to the average global temperature on Earth today!

Similarly, atmospheric concentrations of carbon dioxide (CO2) in the Early Carboniferous Period were approximately 1500 ppm (parts per million), but by the Middle Carboniferous had declined to about 350 ppm -- comparable to average CO2 concentrations today!

Hmm, CO2 declined to about today's levels, temp declined ... to about today's level.

And this, mind you, comes from a denialist site.

Dhogaza,

This is where you would call me a "liar". I'll be more generous and assume you are just confused.

Look again. The graph at the site you visited shows just what I said, temps during the early Carboniferous remaining constant and high for tens of millions of years while CO2 dropped from approximately 1500 ppm to levels similar to today, around 300 ppm.

In fact the mid to late Carboniferous and early Permian are the only other times when CO2 levels and temps were as low as their are today. These periods represent a very small fraction of the earth's history.

We are in a period of long serial glaciations interspersed with brief interglacial warm periods. These interglacial periods typically last about 20,000 years. We are 18,000 years into this one.

We almost certainly will head back into a glacial period some time (relatively) soon. Or do you suppose that the small amount of forcing from CO2 from fossil fuels is going to prevent this?

Would that necessarily be a bad thing?

"the paltry levels of CO2 that humans are capable of adding from the burning of fossil fuels"

Burning fossil fuels has, over a geologically very short time span, raised atmospheric carbon dioxide to levels not seen in hundreds of thousands, if not millions, of years. Look it up for yourself. CO2 is at "experimental" levels for planet earth.

"You've explained in no uncertain terms that this is an issue of you and your kind coercing the rest of us into compliance. You have no interest whatsoever in convincing us to do what is right for ourselves and others."

Actually, all I've done is defend the necessity of legislation that makes people do stuff. Like, you know, laws that make people not keep slaves, that make people pay their workers a living wage, that make them not pour toxic waste into rivers.

You denialists love to throw your hands up in the air and cry about liberty. But a system of laws is a system of coercion. And it's a system of coercive laws that works. Freedom without laws is certainly just a word with no substance. No one's advocating an oppressive regime of anti-greenhouse laws. They're demanding the real costs of emissions be accounted for, and that economies adjust appropriately.

By Nils Ross (not verified) on 08 Jan 2010 #permalink

We almost certainly will head back into a glacial period some time (relatively) soon. Or do you suppose that the small amount of forcing from CO2 from fossil fuels is going to prevent this?

Would that necessarily be a bad thing?

Lance plays the "avoiding an ice age 50,000 years from now is more important than avoiding expensive, grossly dislocating, warming over the next century" card.

Just like a real BS non-scientist.

And, hey, glad I found the site you were drawing your misinformation from. As I said, it's a denialist site, and it didn't actually support your conclusions when you poached it, which was my point.

Meanwhile, if I were motivated, I might actually go dig into Real Science and put forth an even stronger case.

But, of course, in your BS mind (yes, BullShit), the only sources that count are ideological ones, not anything run by actual scientists.

I can't really be bothered with totally dishonest, half-educated, ideologically-blinded university drop-outs like Lance.

Not for the moment (I'm sure I'll get annoyed enough to feed the troll in the future, but for the moment, no).

Pick up the slack, slackers!. He's the worst. Semi-educated enough to cherry pick seemingly meaningful factoids while being as dishonest as Anthony Watts.

Regarding the Ordovician Ice Age, looks like CO2 levels did play a deciding role in the massive and rapid ice age at the end of the Ordovician:

"A large drop in seawater 87Sr/86Sr during the Middle Ordovician was among the most rapid in the entire Phanerozoic. New 87Sr/86Sr measurements from Nevada indicate that the rapid shift began in the Pygodus serra conodont zone of the upper Darriwilian Stage. We use a numerical model to explore the hypothesis that volcanic weathering provided the fl ux of nonradiogenic Sr to the oceans. A close balance between volcanic outgassing and CO2 consumption from weathering produced steady pCO2 levels and climate through the middle Katian, consistent with recent Ordovician paleotemperature estimates. In the late Katian, outgassing was reduced while volcanic weathering continued, and resulted in a cooling episode leading into the well-known end-Ordovician glaciation."

http://www.geology.ohio-state.edu/~saltzman/young_et_al_2009.pdf

IOW, in the Late Ordovician major volcanism along what would later become the Atlantic Ocean put out lots of CO2. The CO2 levels were kept in check by the concurrent heavy weathering of the volcanic rocks, which sequesters CO2. At the end of the Ordovician (the Hirnantian Stage), the volcanism suddenly stopped, but the weathering continued unabated, causing a rapid and massive drawdown of CO2. It looks like this massive Ice Age lasted less than a million years, and the double whammy of first glaciation and sealevel drop with the later return to greenhouse climate caused the second largest mass extinction event in the Phanerozoic.

See also this summary: http://thedragonstales.blogspot.com/2009/10/ordovician-extinction-cause…

Oh and by the way Lance, I'm not sure what's worse: you relying on the overly simplistic Scotese graph for CO2 and Temp history, or thinking you can eyeball conclusions like yours from it.

RE dhogaza

And, hey, glad I found the site you were drawing your misinformation from.

Somehow, I just knew it would be Monte Hieb. I think I just blocked off another Bingo square or must now consume a glass of some beverage.

Somehow, I just knew it would be Monte Hieb.

It was my first introduction to the site ... and hopefully my last visit.

Oh now C.R. Scotese and R.A. Bremer are denialists huh?

It's funny that whenever scientific evidence is presented that contradicts your preconceived ideas it is dismissed as "denialism".

Gincko (great another anonymous douche bag)the study you present says.

"We use a numerical model to explore the hypothesis that volcanic weathering provided the flux of nonradiogenic Sr to the oceans."

Nice hypothesis but using a numerical model proves absolutely nothing. The Ordovician ice age occurred and persisted for nearly a half a million years with atmospheric CO2 level at approximately 4400 ppm, more than ten times today's levels.

dhogaza,

Just when I thought we might have a rational conversation you return to your usual ill-mannered behavior of ignoring the evidence and of attacking me personally.

The truth is that you, and most of the other shrill AGW sycophants that populate the internet, don't want to engage in a rational discussion.

Pity.

@Lance: I think gincko was quite clear: it is an overly simplistic CO2 vs temperature graph. It's one useful for showing general principles, just like the model of the atom with electrons flying around the nucleus at a fixed distance.

Saltzmann has shown that CO2 levels were actually much lower when the Ordovician ice age began (although not necessarily the only forcing). Formation of the Appalachian mountains just provides a mechanism of CO2 removal.

we haven't had run away warming because there is a God! She might be call Gaia who knows.

So we are witness to a mass extinction.
Exciting and depressing all at once.

Correlating negligible CO2 plant food levels to a potential manmade global warming disaster still remains no more than tilting at windmills. Why do the agw religion nutjobs so desperately NEED this presudo-science hoax to be true at the expense of all rational thought? Lots of obvious answers to that one.....

By Der Hog Hoze boi (not verified) on 10 Jan 2010 #permalink

@raebird: You are "stuck at a simple sentence / thought" namely the thought that the "Earth was a different place back then." My take on this as a layman is derived from the statements which I have heard from credible scientists, such as Richard Alley, that a prominent factor in what was different about the earth back then was the sun. The sun was fainter, and this had a profound effect on climate. This is sometimes refered to as the faint sun paradox or problem. Our understanding of the sun's behavior is informed by our understanding of nuclear fusion and fission and by the spectroscopic evidence which is in accord with our knowledge of stellar evolution. The general point being that higher levels of GHGs in the past were consistent with the behavior of the planet's climate.

The curiosity about how and why the Earth has had periods of glaciation in the past is the question that prompted the growth of our understanding of how our planet's climate has varied through time.

By Patrick R (not verified) on 10 Jan 2010 #permalink

Lance, Great Wall (of Denial), and Hozehead:

If you're going to challenge the science, FFS learn some! It may take you awhile, but it's really not that hard. Start here. Until you do, you're all conspicuous examples of the Dunning-Kruger effect and nobody on this or any other ScienceBlog will take you seriously. Of course, if you're really not up to it...

Just sayin'!

By Mal Adapted (not verified) on 10 Jan 2010 #permalink

Mal Adapted,

Nice data free rebuke. Do you feel better now?

Just sayin'!

You've provided us with ample data, Lance.

By Mal Adapted (not verified) on 10 Jan 2010 #permalink

dhogaza, I've had Monte Hieb's site (and the Scotese chart) cited by opponents in the past.

Lance, the temperature chart that Scotese shows is out of date. Might want to check out this paper.

Deech56,

Yes, I am aware of that paper. It isn't new after all it was published in 2007.

Their use of carbonate isotopes disagrees with the many studies using oxygen isotopes.

As I'm sure you know, one paper doesn't change the "consensus".

Of course you are eager to believe the results of an outlying, novel study when its results support your conclusions.

A bit inconsistent don't you think?

Lance, what consensus? Scotese's chart is based on Veizer's 2000 Nature paper. Are there more studies that confirm Veizer's work? Royer, et al.also note that the original Veizer analysis is problematic and propose a pH-corrected temperature record.

The Phanerozoic sea surface temperature record as inferred from shallow marine carbonate δ18O values has been used to quantitatively test the importance of potential climate forcings, but it fails several first-order tests relative to more well-established paleoclimatic indicators: both the early Paleozoic and Mesozoic are calculated to have been too cold for too long. We explore the possible influence of seawater pH on the δ18O record and find that a pH-corrected record matches the glacial record much better.

So it seems that Came's work is not the outlier here.

As long as big interests (carbon trading, ludicrous taxes...) have their hands deep in pockets of everyone, I will be very skeptical about everything related to human caused global warming (recently changed to climate change). It's like asking a wolf how to keep a meadow. It will of course recommend many more sheep to keep it bio-eco healthy clean and organic.

Romunov: can you explain to me why you do not have the same skepticism towards the big interests in maintaining the 'status quo'? That is, oil and coal companies?

First of all, forgive my bad english.

I'm worried about those studies about the climate in the past. The way every parameters was measure is always changing, even the 14c method was revised because of a higher 14c level in the atmosphere a few times in the past. From a distant past estimation, you cannot conclude anything.

Here's something better I guess.

"According to current best estimates of climate sensitivity, the amount of CO2 and other heat-trapping gases added to Earth's atmosphere since humanity began burning fossil fuels on a significant scale during the industrial period would be expected to result in a mean global temperature rise of 3.8°F -- well more than the 1.4°F increase that has been observed for this time span."

http://www.sciencedaily.com/releases/2010/01/100119112050.htm

And there is explanation of this here

http://www.sciencebits.com/OnClimateSensitivity

http://motls.blogspot.com/2006/05/climate-sensitivity-and-editorial.html

And it's not the haze because there is a global brightening

http://folk.uio.no/jegill/papers/Stjern_etal_2009_IJClim.pdf

romunov, you are right about the carbon market, if an international treaty about carbon emission is signed, it will worth many trillions dollars.

First of all, forgive my bad english.

I'm worried about those studies about the climate in the past. The way every parameters was measure is always changing, even the 14c method was revised because of a higher 14c level in the atmosphere a few times in the past. From a distant past estimation, you cannot conclude anything.

Here's something better I guess.

"According to current best estimates of climate sensitivity, the amount of CO2 and other heat-trapping gases added to Earth's atmosphere since humanity began burning fossil fuels on a significant scale during the industrial period would be expected to result in a mean global temperature rise of 3.8°F -- well more than the 1.4°F increase that has been observed for this time span."

http://www.sciencedaily.com/releases/2010/01/100119112050.htm

And there is explanation of this here

http://www.sciencebits.com/OnClimateSensitivity

http://motls.blogspot.com/2006/05/climate-sensitivity-and-editorial.html

And it's not the haze because there is a global brightening

http://folk.uio.no/jegill/papers/Stjern_etal_2009_IJClim.pdf

romunov, you are right about the carbon market, if an international treaty about carbon emission is signed, it will worth many trillions dollars.

Lance, it's that douchbag again, hi.

"Nice hypothesis but using a numerical model proves absolutely nothing. "

Talk about selective reading: They used a model to test their hypothesis, and see if the model's predictions matches the data that they had collected. And it did, so while all you heard was "numerical models", you failed to see how they were utilised.