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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Tom P (00:26:12) :
You missed my correction (11.11.12). This paper did NOT model the PETM climate.
So that takes care of the criticism that ‘the models don’t work’.
Leif Svalgaard (21:24:38) :
So, all in all, there is no good evidence for the myth that all planets change their climate in sync because of changing solar activity.
Leif… You could have an individual explanation for a climatic change in one planet alone if there were not other bodies undergoing the same process. Something is happening in the whole solar system. I am not saying it is something “atypical”, but it is something cyclical… normal, natural.
Regarding the recent stabilization of the atmospheric temperature (cooling), I am not adhered to the hypothesis of a next ice age or another little ice age. As I have said before, the earth is entering into a warmhouse after a prolonged icehouse. That a cooling has happened, yes, it has happened in the last 10 years; however, we cannot unlink the climate from the bigger modifier of climate, the ocean. Ocean is a thermoregulator which amplifies or moderates the effect of solar radiation. We have observed this through centuries.
Please, remember that Mars has not oceans of water, so the effect could not be well modified by a mere conveyor of heat (the carbon dioxide).
Nasif Nahle (06:47:46) :
You could have an individual explanation for a climatic change in one planet alone if there were not other bodies undergoing the same process. Something is happening in the whole solar system.
You have provided no evidence for that. Seasonal variations and ‘weather’ over a few years [e.g. Titan], do not constitute Climate. If anything, solar activity has been decreasing the past few decades, and if you want to ascribe climate change to solar activity, one would expect a cooling in the whole solar system, but the observations are not there to support such a claim either way.
Leif Svalgaard (07:05:59) :
You have provided no evidence for that. Seasonal variations and ‘weather’ over a few years [e.g. Titan], do not constitute Climate. If anything, solar activity has been decreasing the past few decades, and if you want to ascribe climate change to solar activity, one would expect a cooling in the whole solar system, but the observations are not there to support such a claim either way.
Mars, Titan and Earth are melting. I cannot provide evidence from the other bodies because our observations are not too close as for the cases of Earth, Mars and Titan.
It is a matter of time. Some gullies on Mars are recovering their ice sheets, for example.
I hope NASA soon releases updated data on the climatic conditions on those bodies. Perhaps they are cooling already in the same way it is happening on Earth as the solar activity is diminishing?
@Leif…
I don’t know what kind of evidence you require if you don’t accept observations from nature made by astronomers and astrophysicists.
Tim Clark (04:41:02) :
“During the summer, the study found that a whopping 77 percent of the changes in amounts of DMS were due to exposure to UV radiation.”
And how much does the Sun’s UV production vary?
The energetic [short wave length] UV flux is absorbed high in the stratosphere, and the near UV that reaches the surface varies very little, as far a the Sun is concerned. The actual amount is not determined by the Sun, but by local meteorological conditions [less UV when overcast, for example].
Nasif Nahle (08:36:43) :
I don’t know what kind of evidence you require if you don’t accept observations from nature made by astronomers and astrophysicists.
I’m not aware of any such evidence of climate change anywhere in the solar system except on Earth. The links you have provided were not evidence of climate change.
@ur momisugly Leif…
Coincidentally, two super-cyclones appeared in 1999: one in the Northwest on Mars and another in the Indian Ocean on Earth. The momentum delay between the two planetary events was eight months, which clearly suggests that another solar factor, besides the electromagnetic radiation, generates changes of planetary climates. My speculation is that the gravity field of planets is a sink-reservoir of energy which is picked up by matter particles and carried back to the atmosphere. Something similar to the production of muons as from ICR. Of course, Leif, it is just speculation.
I think Nasif Nahle has a point. I think we should give NASA billions of dollars (perhaps stop the wars in Iraq and Afghanistan to be able to finance this) and send satellites to every celestial body in our solar system (and beyond) to monitor the warming due to the sun.
Neven (09:41:31) :
send satellites to every celestial body in our solar system (and beyond) to monitor the warming due to the sun.
A comparison of ice cores from Earth, Mars, Europa, and elsewhere would throw light on many of these questions. Unfortunately we don’t have any [yet] so there is not evidence for any similar climate changes.
Leif Svalgaard (09:30:47) :
Nasif Nahle (08:36:43) :
I don’t know what kind of evidence you require if you don’t accept observations from nature made by astronomers and astrophysicists.
I’m not aware of any such evidence of climate change anywhere in the solar system except on Earth. The links you have provided were not evidence of climate change.
That is why I asked what kind of evidence you need. I cannot go to Mars or Titan, Uranus, Pluto, etc., to plant thermometers, radiometers, hygrometers, etc. all over the surface of those bodies. I have to rely on the data released by NASA from satellite-sensors measurements, so I am limited to revise few records gotten up to date; those which NASA wants to release whenever they wish to make them public. With the few data, the conclusion is that the change is occurring at least in seven bodies of the solar system; thus it is probable that the change is happening in the whole solar system, including the Sun.
Leif Svalgaard (09:50:10) :
Neven (09:41:31) :
send satellites to every celestial body in our solar system (and beyond) to monitor the warming due to the sun.
A comparison of ice cores from Earth, Mars, Europa, and elsewhere would throw light on many of these questions. Unfortunately we don’t have any [yet] so there is not evidence for any similar climate changes.
At least the ice cores of Mars started melting in 1998, perhaps before, and in Titan the methane ice is melting, similarly to the Arctic ice melting on Earth.
Which means that wearing a hat on a sunny day does not necessarily mean that you will have less UV than say on a cloudy day without a hat. Reflected UV from around you is just as bad on skin as “direct from above” UV. Wearing Sun protection ON THE SKIN of the entire face area, ears, neck, and eh em, bald spot, is essential at all times when out in the Sun for more than 10 minutes. Folks should take Vitamin D supplements if they stay out of the Sun or swath themselves in Sun screen. Skin cancer, even the less scary kind, should be taken seriously when they appear on these highly and shallow vascularized areas. Any rough whitish spot or mole-like dark spot should be looked at as soon as can be arranged by a dermatologist specialist in oncology.
We don’t need to wait for ice core data from Mars. Images of the Martian northern polar layer deposits correlate well with orbital forcing:
Nature 419, 375 – 377 (2002)
Orbital forcing of the martian polar layered deposits
Jacques Laskar, Benjamin Levrard & John F. Mustard
Since the first images of polar regions on Mars revealed alternating bright and dark layers, there has been speculation that their formation might be tied to the planet’s orbital climate forcing… Here we use a combination of high-resolution images of the polar layered terrains, high-resolution topography and revised calculations of the orbital and rotational parameters of Mars to show that a correlation exists between ice-layer radiance as a function of depth (obtained from photometric data of the images of the layered terrains) and the insolation variations in summer at the martian north pole, similar to what has been shown for palaeoclimate studies of the Earth…
Nasif Nahle (09:58:27) :
I cannot go to Mars or Titan, Uranus, Pluto, etc., to plant thermometers, radiometers, hygrometers, etc. all over the surface of those bodies.
And that is why you have no evidence of climate changes except on Earth. The other things you quote are either clear seasonal changes or just weather based on a few isolated reports.
Tom P (10:12:00) :
We don’t need to wait for ice core data from Mars. Images of the Martian northern polar layer deposits correlate well with orbital forcing:
Nature 419, 375 – 377 (2002)
Orbital forcing of the martian polar layered deposits
Here the counterpart:
http://www.people.fas.harvard.edu/~phuybers/Doc/Mars_orbital.pdf
“…the stratigraphy appears more consistent with a stochastic signal than a set of superimposed periodic signals.”
Tom P (10:12:00) :
the insolation variations in summer at the martian north pole, similar to what has been shown for palaeoclimate studies of the Earth…
This is was was to be expected, and we’ll find similar things on other bodies when we get to them. But has, of course, no relevance to whether changing climate caused by intrinsic changes in the Sun occurs or has been observed [on Earth or elsewhere].
Leif,
I don’t know why you say there is no relevance. Laskar and colleagues are clearly saying that the insolation changes due to orbital variations, the Milankovitch cycles, are the dominant effect on the stratigraphy of the polar layer deposits.
Nasif,
Perron and Huybers certainly make the earlier work on the stratigraphy less certain in its attribution, but note the alternative explanations offered:
“Three possible explanations for why the PLD spectra fail to show a distinct orbital signal are: (1) the orbital influence is negligible, (2) our image-based reconstruction of the stratigraphy contains biases, or (3) the relationship between orbital variations and the stratigraphy is non linear and is not detectable with the linear spectral techniques we employ. Given the large amplitude of orbitally induced variations in insolation and the predicted sensitivity of polar ice to these variations, we expect orbital variations to influence the stratigraphy, and thus expect that explanation 1 is insufficient. Given the demonstrated effects of our estimated jitter and of noise, explanation 2 alone could be sufficient. We expect that explanation 3 is also sufficient to explain our inability to detect a distinct orbital signature.”
Hence the paper questions the detectability of the Milankovitch cycles in the PLD, but does not dispute their influence.
Tom P (14:06:49) :
I don’t know why you say there is no relevance. Laskar and colleagues are clearly saying that the insolation changes due to orbital variations, the Milankovitch cycles, are the dominant effect on the stratigraphy of the polar layer deposits.
There are two kinds of climate change that can be ‘related’ to the Sun: solar insolation and solar irradiance [+ whatever else is associated with solar activity]. Solar insolation has to do with the Earth [or Mars] and its orbit and orientation [and thus will vary even if the solar output were absolutely constant]. There is no doubt that solar insolation [on Earth and on Mars] as a result of orbital changes has a GREAT impact on climate. This is not the debate [for once, the time scale is so long that on a century scale there are no detectable changes in solar insolation due to orbital changes].
The debate is about whether solar irradiance [solar activity] has any influence. And here the jury is still out. In my opinion, there are certainly such changes, but they are small [a tenth of a degree] and thus of no practical interest [although of great scientific and theoretical interest]. The issue then is that if there were such solar changes they should then be the same for every body in the solar system. We have had a hard time to show that such changes are significant [if they were, we would not be discussing this] on the Earth, and there is not enough data to show that they have occurred elsewhere and in sync with either solar or terrestrial [caused by the Sun] variations. As usual, you’ll find all manner of claims for this, both pro and con. IMHO, there are none that are clear, direct, and compelling. Speculation is fine, if labeled as such, but to call it ‘evidence’ is just plain wrong.
Nasif Nahle (09:58:27) :
I cannot go to Mars or Titan, Uranus, Pluto, etc., to plant thermometers, radiometers, hygrometers, etc. all over the surface of those bodies.
This is exactly the reason I suggested to throw trillions of dollars at any scientist who claims he can set up a space program to do exactly this. Hasn’t Al Gore already set up some company to profit from this?
But this is all very logical and consistent for a true skeptic. The real question, Nasif Nahle, is: What do we do once it is established that the Sun is heating up the whole solar system? And would a possible solution be scientific, considering the fact that science is not able to explain the solar mechanism responsible for the HSSW (heliogenic solar system warming)?
God, it was nice trying my hand at some WUWT humor for just this once. That sarcasm just felt great. I can’t wait till I’m 50 years older than now and get the real sarcastic juices flowing! 😉
Tom P (14:06:49) :
Perron and Huybers certainly make the earlier work on the stratigraphy less certain in its attribution, but note the alternative explanations offered:
“Three possible explanations for why the PLD spectra fail to show a distinct orbital signal are: (1) the orbital influence is negligible, (2) our image-based reconstruction of the stratigraphy contains biases, or (3) the relationship between orbital variations and the stratigraphy is non linear and is not detectable with the linear spectral techniques we employ. Given the large amplitude of orbitally induced variations in insolation and the predicted sensitivity of polar ice to these variations, we expect orbital variations to influence the stratigraphy, and thus expect that explanation 1 is insufficient. Given the demonstrated effects of our estimated jitter and of noise, explanation 2 alone could be sufficient. We expect that explanation 3 is also sufficient to explain our inability to detect a distinct orbital signature.”
Hence the paper questions the detectability of the Milankovitch cycles in the PLD, but does not dispute their influence.
I stand corrected.
Explanation 3 is near to what is happening today with climate and solar irradiance. We have not completely understood how the solar irradiance affects the climate of Earth, although we are able to observe the correlation.
Leif Svalgaard (14:56:11):
But has, of course, no relevance to whether changing climate caused by intrinsic changes in the Sun occurs or has been observed [on Earth or elsewhere].
I have thought on many alternatives. A three-dimensional model of Higg’s fields and our current knowledge on how a system can slip from high energy density to low energy density fields could explain some important aspects about the effect of solar radiation on the Earth’s climate which you have not seen until present.
However, the terms have been taken so many times for supporting pseudoscientific ideas that any work which mentions it is discredited immediately. When talking about pseudoscience I am referring to those “thermal loops” creators of energy from the nothingness in the AGW idea.
My hypothesis is quite different to those AGW “thermal loops” because the energy provided by the Sun would only be passing through a quantum tunneling, which for other particles is experimentally demonstrable and has been demonstrated by experimentation. The solar photons would be transposing quantum barriers through a process similar to Schrödinger wave-equation. For example, the photon leaving the photosphere of the Sun towards the Earth would carry an initial load of energy; as the quantum transposes the Solaris Coronae, it would be carrying the same amount of energy, but its amplitude would have changed when entering to space. The particle as it is leaving the photosphere would have a total energy density higher than its potential energy. Nevertheless, its total energy density would be lower than its potential energy as it has transposed the quantum barrier.
Well… That’s speculation, but it is a superb explanation. Isn’t it? 🙂
I suspect this study of the PETM has been carefully placed to allow the end of “anthropogenic global warming” to begin. From here on, slowly and carefully controlled studies will allow the skeptical view to be heard. And with the half-right claim, the global warmists can say “See, CO2 causes half the warming!”
My theory is this paper sets the nail in the AGW coffin. Now to hammer it home.
Nasif Nahle (19:58:45) :
Well… That’s speculation, but it is a superb explanation. Isn’t it? 🙂
no, total nonsense.
Leif Svalgaard (21:46:35) :
Nasif Nahle (19:58:45) :
Well… That’s speculation, but it is a superb explanation. Isn’t it? 🙂
no, total nonsense.
It happens in other systems of the real world. What is needed is to apply it to solar irradiance, not mathematically, but by instruments. If it is feasible, then the mechanism would be elegantly and scientifically explained. The Sun is the largest particle collider in the solar system, after all. At least quantum tunneling occurs in the real world and it does not violate thermodynamics laws, while those “climatic loops” start wrong since the starting dismissing the three laws of thermodynamics.
The readers of this blog understand neither basic logic nor modeling. Let’s think this through logically. A study comes out that says that massive global warming in the past was caused by a smaller increase in CO2 than what we see today, and you draw the conclusion that… that means global warming isn’t caused by CO2? The only logical conclusion is the exact opposite of that–that models UNDERestimate CO2’s impact on climate!
Your line of reasoning is “models say that CO2 causes global warming, the models are wrong, therefore CO2 doesn’t cause global warming.” Well there’s a missing link in that logic chain, because the model can be wrong in BOTH directions. Sure, models could overestimate CO2’s impact on climate, but in this case the models have been UNDERestimating the impact, because they didn’t give enough weight to positive feedback mechanisms. Namely, as CO2 causes the planet to warm, permafrost melts, releasing methane (an even more powerful GHG) into the atmosphere, causing more warming, causing more methane to be released. It’s what we call a “runaway greenhouse effect.” If the models are wrong in this case, it lends MORE evidence to global warming’s reality, and MORE cause for concern. It amazes me how deniers’ religious zealotry is so strong that they can find proof of their case in something that says the exact opposite.