Global warming: Our best guess is likely wrong
No one knows exactly how much Earth’s climate will warm due to carbon emissions, but a new study this week suggests scientists’ best predictions about global warming might be incorrect. The study, which appears in Nature Geoscience, found that climate models explain only about half of the heating that occurred during a well-documented period of rapid global warming in Earth’s ancient past. The study, which was published online today, contains an analysis of published records from a period of rapid climatic warming about 55 million years ago known as the Palaeocene-Eocene thermal maximum, or PETM.
“In a nutshell, theoretical models cannot explain what we observe in the geological record,” said oceanographer Gerald Dickens, a co-author of the study and professor of Earth science at Rice University. “There appears to be something fundamentally wrong with the way temperature and carbon are linked in climate models.”
During the PETM, for reasons that are still unknown, the amount of carbon in Earth’s atmosphere rose rapidly. For this reason, the PETM, which has been identified in hundreds of sediment core samples worldwide, is probably the best ancient climate analogue for present-day Earth.
In addition to rapidly rising levels of atmospheric carbon, global surface temperatures rose dramatically during the PETM. Average temperatures worldwide rose by about 7 degrees Celsius — about 13 degrees Fahrenheit — in the relatively short geological span of about 10,000 years.
Many of the findings come from studies of core samples drilled from the deep seafloor over the past two decades. When oceanographers study these samples, they can see changes in the carbon cycle during the PETM.
“You go along a core and everything’s the same, the same, the same, and then suddenly you pass this time line and the carbon chemistry is completely different,” Dickens said. “This has been documented time and again at sites all over the world.”
Based on findings related to oceanic acidity levels during the PETM and on calculations about the cycling of carbon among the oceans, air, plants and soil, Dickens and co-authors Richard Zeebe of the University of Hawaii and James Zachos of the University of California-Santa Cruz determined that the level of carbon dioxide in the atmosphere increased by about 70 percent during the PETM.
That’s significant because it does not represent a doubling of atmospheric carbon dioxide. Since the start of the industrial revolution, carbon dioxide levels are believed to have risen by about one-third, largely due to the burning of fossil fuels. If present rates of fossil-fuel consumption continue, the doubling of carbon dioxide from fossil fuels will occur sometime within the next century or two.
Doubling of atmospheric carbon dioxide is an oft-talked-about threshold, and today’s climate models include accepted values for the climate’s sensitivity to doubling. Using these accepted values and the PETM carbon data, the researchers found that the models could only explain about half of the warming that Earth experienced 55 million years ago.
The conclusion, Dickens said, is that something other than carbon dioxide caused much of the heating during the PETM. “Some feedback loop or other processes that aren’t accounted for in these models — the same ones used by the IPCC for current best estimates of 21st Century warming — caused a substantial portion of the warming that occurred during the PETM.”
Source: Rice University
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What else was going on 55 million years ago?
What about the extinction that occured 65 million years ago that is in a layer all over the place?
Hmm interesting day for the Warmists…
If they are missing it this badly on a scale that makes all of the multidecadal oscillations moot, they have no hope of appeasing those that expect model results to validate against any real-world current data.
Thank You Rice researchers…now if only you could get the readership of the latest Discover mag so you counter the Pelosi-approved message mailed to millions a couple of weeks ago. (I sure am canceling my subscription)
Gee, the models are wrong?
Who’d have thunk it?
So either our data on the climate millions of years ago is wrong?
Or Co2 should be causing much more warming than we are seeing and models predicting? So something unknown has been stopping the warming from happening and we don’t know whether this something may stop – making things much warmer sudenly. Or get stronger to make things cooler.
Or there was an unknown something back then that caused earth to get warmer for a given CO2 that isn’t happening now?
Which are we more likely to be wrong about? The climate millions of years ago? Or the climate between 100 years ago and 100 years in the future?
So, geologic record says…
70% increase in Atmospheric Carbon…
…with a 7 degree C temperature rise.
Today we have a 33% increase in Atmospheric Carbon…
…with a ~1 degree C temperature rise…?
This is clearly “worse/faster than expected.”
I can hear it now… the models must be re-jiggered to give more warming to account for PETM…
Maybe they will figure out that one is not causal of the other?… Nahhh..
Just wondering. Is there any chance that the elevated carbon levels in the atmosphere during PETM could have been the result of warming and not the cause?
10,000 years to rise 7C? Linearly?
Why am I not worried.
“No one knows exactly how much Earth’s climate will warm due to carbon emissions…”
This statement isn’t saying what it seems to be saying. It’s true no one knows exactly how much. But it has been narrowed it down to be a small, irrelevant amount. To find exactly what that small amount is, to measure it precisely, at this point, is basically inconsequential. The money spent studying co2’s effect on climate could be far better spent studying the sun, clouds, and ocean currents.
From the commentary on this paper by David Beerling in the same issue:
“The upshot of the study by Zeebe and colleagues is that forecasts of future warming could be severely underestimating the extent of the problem that lies in store for humanity as greenhouse gases accumulate in the atmosphere. Understanding warming feedbacks that were triggered by rising atmospheric CO2 concentrations in the past constitutes a pressing scientific challenge. However, if we are to avert irreversible long-term warming, prudence dictates that we urgently cut greenhouse-gas emissions, primarily through phasing out our dependence on coal-fired power stations, unless fitted with carbon capture and sequestration technology. But the global energy demand is rising, and there is no technological ‘magic bullet’ to solve the alternative-energy challenge. Unremitting release of CO2 into the atmosphere therefore looks set to continue in the coming decades, and evidence from Earth’s history suggests that humanity is in danger of entraining feedbacks that will accelerate the arrival of a much warmer planet.”
“Some feedback loop or other processes that aren’t accounted for in these models…”
It may be helpful to him to watch the documentary “The Cloud Mystery”.
http://www.thecloudmystery.com/Home.html
“In addition to rapidly rising levels of atmospheric carbon, global surface temperatures rose dramatically during the PETM. Average temperatures worldwide rose by about 7 degrees Celsius — about 13 degrees Fahrenheit — in the relatively short geological span of about 10,000 years.”
Maybe 55 million years ago our primitive pre-human ancestors learned about the magic of FIRE! The idea spread around the uncivilized globe over a period of about 10,000 years as fire migrated with our primitive pre-human ancestors.
At least that’s a better hypothesis than others I’ve heard.
“There appears to be something fundamentally wrong with the way temperature and carbon are linked in climate models.”
This isn’t news to most of us here – it’s what we’ve been trying to tell everyone for 20 years now.
I would like to know how they determined that temperatures went up 7 degrees C 55 million years ago. Occam’s razor would suggest that whatever proxy they are using for the temperature is wrong.
I’m also curious about what mechanism they suggest for a 70% increase in CO2.
snip – same exactly worded comment posted as:
andy stoffers
with the same exact ip address
I don’t allow people to have multiple identities here – Anthony
Well wat they are not saying is that since the temperature rise is proportional to the log of the CO2 rise, then 70% rise is not so much more than 38% rise logarithmically, so howcome they got a seven drgree rise back then, and we got almost nothing.
And of course we know the earth’s orbit was exactly the same as it is today, and the solar constant was 1366 W/m^2 just like now; so absolutley nothing has changed except the climate sensitivity.
Maybe if the modellers used a bigger clmate sensitivity they may get an answer more like the result they are looking for.
How many million years ago did they say this was ?
Yeah these proxies for real data, are just a joy to work with; the biggest problem is trying to convince your Professor, that is isn’t just all guess work.
snip – same exactly worded comment posted as:
alex karpath
with the same exact ip address
I don’t allow people to have multiple identities here – Anthony
E.M.Smith (17:49:58) : “I can hear it now… the models must be re-jiggered to give more warming to account for PETM…Maybe they will figure out that one is not causal of the other?… Nahhh…”
If you read it closely, the write-up is really postulating another, hitherto unknown positive feedback. [But, again, the relevant question is whether CO² led or trailed on the upswing and the downswing.] I suspect this is just another “worse than we thought” setup. The other shoe will be dropped in a month or two.
I have charted the temp vs CO2 data over this period and there is really a poor correlation between the two. This chart also shows the important continental drift timelines which are fundamental to understanding this climate period.
http://img20.imageshack.us/img20/2464/tempvsco267m.png
[I added the new CO2 data at 1700 ppm during the short PETM 55 million years ago (there are other CO2 estimates which are lower and some people prefer to talk about the Eocene Thermal Maximum as lasting 5 or 6 million years rather than the short spike that this paper is about)].
Carbon dioxide concentration was high during the PETM, true; however, it was declining since the Early Cretaceous. For the transition Paleocene-Eocene, the concentration of carbon dioxide in the atmosphere was about 340 ppmV, lower than during the Miocene, which could explain only 0.8 °C from the total effective fluctuation of 13 °C; nevertheless, the temperature was sustainably increasing since the end of the last Ice Age during the transition Middle-Late Jurassic. The dramatic rise of carbon dioxide during the transition Paleocene-Eocene could be easily explained when considering the release of this gas from the oceans and the dry sand by the increase of surface temperatures.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V61-49567JH-3&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=957579875&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=52c5af9622535b34fb667c4606561759
i’d be interested to see if they have been able to look at this occurrence at a fine enough timescale to see which came first, the warming or the CO2 rise. everyone assumed that CO2 was driving temperature in the vostok cores until they examined them on a decadal level and realized that in every glaciation, temperature started rising 6-1200 years before CO2 did.
increased CO2 is a RESULT of a warmer world. this is very well understood chemistry. heat water and it can hold less dissolved CO2. so when the world warms, oceans outgas. note that mistaking an effect for a cause can ofter look like positive feedback.
THAT is the real problem with the current models. they assume that CO2 drives climate in a meaningful way. this has NEVER been proven or even demonstrated. CO2 is a lagging variable to temperature on any reasonable timescale. the mid troposphere (where the greenhouse effect takes place) has warmed less than the surface in direct contradiction to all of the predictions of these GCM’s. the “fingerprint” that was expected has been shown to be absent by both satellites and radiosondes.
i am absolutely astounded that models that have been so thoroughly discredited and have so utterly failed to predict climate are still being used as the basis for predictions upon which to base legislation.
“Eric Naegle (17:55:24) :
Just wondering. Is there any chance that the elevated carbon levels in the atmosphere during PETM could have been the result of warming and not the cause?”
Good question….. Because as we all know, CO2 lags behind temperature rise. The Ice cores dating around 400 thousand years show at least an 800 year lag.
It would be a good assumption to say the same was true 55 million years ago.
Hansford: If what you say is true, then we can expect CO2 rising for at least the next few centuries even if the alarmists are successful in shutting down economic activity worldwide, certainly sounds like nothing can be done about the majority of CO2 emissions.
If you mean 800 years, then we may see the CO2 rising now in response to the Medieval Warm Period and then maybe a drop in a couple centuries due to the Little Ice Age.
andy stoffers (18:11:38) :
So seven degrees warming in 10,000 years produced one of the worst mass extinctions in the history of the world.
One of the five worst massive extinctions occurred in the transition Cretaceous-Tertiary (65 million years ago) and it is attributed to flood volcanic eruptions of basalt from India’s Deccan Traps which were accompanied by massive emissions of volcanic toxic gases. The fluctuation of temperature and climate change occurred 10 million years after the massive extinction occurred.
As I have said in my previous post, the rise of carbon dioxide occurred millions of years after the warming started. It seems that the volcanic activity is related in some way to warming.