Ancient “Hyperthermals” a Guide to Anticipated Climate Changes
Scripps researchers document the history of sudden global warming events, impacts on marine life
By Mario Aguilera, Scripps Institute News (h/t to Dr. Leif Svalgaard)
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| Sediment samples in the lab of Richard Norris obtained by the Ocean Drilling Program reveal the mark of “hyperthermals,” warming events lasting thousands of years that changed the composition of the sediment and its color. The packaged sediment sample on the left contains sediment formed in the wake of a 55-million-year-old warming event and the sample on the right is sediment from a later era after global temperatures stabilized. |
Bursts of intense global warming that have lasted tens of thousands of years have taken place more frequently throughout history than previously believe, according to evidence gathered by a team led by Scripps Institution of Oceanography, UC San Diego researchers.
Richard Norris, a professor of geology at Scripps who co-authored the report, said that releases of carbon dioxide sequestered in the deep oceans were the most likely trigger of these ancient “hyperthermal” events. Most of the events raised average global temperatures between 2° and 3° Celsius (3.6 and 5.4° F), an amount comparable to current conservative estimates of how much temperatures are expected to rise in coming decades as a consequence of anthropogenic global warming. Most hyperthermals lasted about 40,000 years before temperatures returned to normal.
The study appears in the March 17 issue of the journal Nature.
“These hyperthermals seem not to have been rare events,” Norris said, “hence there are lots of ancient examples of global warming on a scale broadly like the expected future warming. We can use these events to examine the impact of global change on marine ecosystems, climate and ocean circulation.”
The hyperthermals took place roughly every 400,000 years during a warm period of Earth history that prevailed some 50 million years ago. The strongest of them coincided with an event known as the Paleocene-Eocene Thermal Maximum, the transition between two geologic epochs in which global temperatures rose between 4° and 7° C (7.2° and 12.6° F) and needed 200,000 years to return to historical norms. The events stopped taking place around 40 million years ago, when the planet entered a cooling phase. No warming events of the magnitude of these hyperthermals have been detected in the geological record since then.
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| Richard Norris in his lab with ancient sediments obtained by the Ocean Drilling Program reveal the mark of “hyperthermals,” warming events lasting thousands of years that changed the composition of the sediment and its color. The dark color in the large sediment core sample at left depicts the onset and aftermath of a 55-million-year-old warming event when changes in ocean temperatures altered the composition of marine life. |
Phil Sexton, a former student of Norris’ now at the Open University in the United Kingdom, led the analysis of sediment cores collected off the South American coast. In the cores, evidence of the warm periods presented itself in bands of gray sediment layered within otherwise pale greenish mud. The gray sediment contained increased amounts of clay left after the calcareous shells of microscopic organisms were dissolved on the sea floor. These clay-rich intervals are consistent with ocean acidification episodes that would have been triggered by large-scale releases of carbon dioxide. Large influxes of carbon dioxide change the chemistry of seawater by producing greater amounts of carbonic acid in the oceans.
The authors concluded that a release of carbon dioxide from the deep oceans was a more likely cause of the hyperthermals than other triggering events that have been hypothesized. The regularity of the hyperthermals and relatively warm ocean temperatures of the period makes them less likely to have been caused by events such as large melt-offs of methane hydrates, terrestrial burning of peat or even proposed cometary impacts. The hyperthermals could have been set in motion by a build-up of carbon dioxide in the deep oceans caused by slowing or stopping of circulation in ocean basins that prevented carbon dioxide release.
Norris noted that the hyperthermals provide historical perspective on what Earth will experience as it continues to warm from widespread use of fossil fuels, which has increased carbon dioxide concentrations in the atmosphere nearly 50 percent since the beginning of the Industrial Revolution.
Hyperthermals can help scientists produce a range of estimates for how long it will take for temperatures to fully revert to historical norms depending on how much warming human activities cause.
“In 100 to 300 years, we could produce a signal on Earth that takes tens of thousands of years to equilibrate, judging from the geologic record,” he said.
The scientists hope to better understand how fast the conditions that set off hyperthermals developed. Norris said that 50 million year old sediments in the North Sea are finely layered enough for scientists to distinguish decade-to-decade or even year-to-year changes.
Co-authors of the paper include researchers from the National Oceanography Centre Southampton at the University of Southampton in England and the Center for Marine Environmental Sciences, University of Bremen, Germany.
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Do their results tie in with ice core data, or does CO2 in the ice cores lag behind the warm ocean sediment accumulation? They don’t really know that the CO2 came first, do they? (it must be CO2 because we can’t think of anything else…)
A Hyperthermal, without human intervention; did somebody bump their head?
Well whaddyknow?
I have seen too many sound pieces of field research subjected to twisted interpretations of the data produced to support some fashionable fancy based entirely on supposition.
These connections are usually tenuous to say the least or as here untenable. As are a couple of the other reports cited below.
It is the way of the world I suppose.
Kindest Regards
Leif Svalgaard says:
March 16, 2011 at 6:06 pm
tallbloke says:
March 16, 2011 at 5:01 pm
Logic fail. When it warms the oceans release Co2 and get more alkaline.
Logic should be applied correctly. The release does not need to have anything to do with warming oceans. See e.g. http://en.wikipedia.org/wiki/Lake_Nyos
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Leif, I don’t mean to butt in, but the study tied itself to warming. And, states it is less likely, that their results were found because of external issues………….. such as a volcano.
“The authors concluded that a release of carbon dioxide from the deep oceans was a more likely cause of the hyperthermals than other triggering events that have been hypothesized.”
Nyos releases CO2 cause of a nearby volcano.
This “news release” is so far from being a scientific paper that it deserves being trashed on arrival. Frankly, there is no way to determine if public relations screwed it up or the original work was absurd. No references, no footnotes, no anything to validate their statements – which look a lot like hypotheses.
I never expected Scripps to sink this low.
They just need one more workaround………
Why did temperatures and CO2 levels crash after one of their hyperthermals?
What they call “historical norms” are ice ages….
…why didn’t the magic elevated CO2 prevent the planet from going into another ice age
If CO2 is driving temperature like they claim it is. If CO2 raises temperatures to where the feedbacks tipping points cause run away global warming…
…why is it that every time CO2 and temperature levels have been high
….the planet goes right back into another ice age
Some one ask Harry Reid or some other person or group who fought Yucca Mountain Underground Nuke storage for years and years how they feel about being responsible for all that above ground spent nuke rod storage in the U.S. seeing how things go when things go wrong like in Japan just now.
***The events stopped taking place around 40 million years ago, when the planet entered a cooling phase. No warming events of the magnitude of these hyperthermals have been detected in the geological record since then.***
Not interglacials?
Mike D. says:
March 16, 2011 at 6:27 pm
If so, assuming the “episodes” are valid findings, were all the possible causes considered? For instance, what about solar variation? Can we be sure that the sun is (and has always been) unwavering in its output?
The thermal episodes were real enough, one can debate their cause. Personally, I think the CO2 hypothesis is plausible, although a lot more CO2 than what we have now must be involved. I don’t think the Sun is the driver, because a main sequence star is very stable.
The abstract says that the common rapid CO2 release events in this time period were then re-sequestered by the ocean just as rapidly (versus the CO2 carbon cycle models which assume that it must be sequestered geologically in sedimentary rock).
In this time period, the North Atlantic was just opening up and massive surface and shallow ocean volcanoes would have produced huge CO2 releases every few thousand years.
The PETM CO2 release event is assumed to take 200,000 years to be resequestered but this study says that the ocean reabsorbs it much faster (obvious to those who have reviewed the carbon-cycle models using the actual numbers).
It is probably just another climate science study that really is talking about one thing but gets spun and re-spun into a massive global warming storyline.
This is actually common in this field. A researcher spends a lot of time and money gathering data but to eventually get it published, a global warming spin has to put on it. The researcher still wants to get something out of all that effort and does want to get to published in Nature so he/she just goes along with the spin – knowing the data showing something else completely still gets published in the meantime.
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tallbloke says:
March 16, 2011 at 5:01 pm
“These clay-rich intervals are consistent with ocean acidification episodes that would have been triggered by large-scale releases of carbon dioxide. Large influxes of carbon dioxide change the chemistry of seawater by producing greater amounts of carbonic acid in the oceans.”
Logic fail.
When it warms the oceans release Co2 and get more alkaline. That raises airbourne Co2 which is then absorbed back into the ocean when it cools, making it less alkaline again.
These people are talking nonsense.
You are missing the fact that the concentration of CO2, and the ocean temperatures are not uniform with depth. The source of the CO2 is the deep part of the oceans which are very cold and dissolve a lot of CO2. If there is periodic overturning of the oceans the CO2 rich cold water comes to the surface, gets warmer and loses CO2 to the atmosphere. This mechanism is apparently favored because such deep ocean water overturnings can be periodic, and a regular periodicity of the warmings has been observed.
This is not the only paper in which changes in ocean circulation are associated with Greenhouse warming events.
http://www.nature.com/nature/journal/v439/n7072/abs/nature04386.html
Abrupt reversal in ocean overturning during the Palaeocene/Eocene warm period
The supplementary Information [not paywalled] has a lot of details about the data
http://www.nature.com/nature/journal/v471/n7338/extref/nature09826-s1.pdf
It is one thing to discover an interesting phenomenon in nature and another thing entirely to try explain it. Having noted the existence of hyperthermals which is interesting the authors immediately try to connect this with current global warming speculations. But to say that “In 100 to 300 years, we could produce a signal on Earth that takes tens of thousands of years to equilibrate, judging from the geologic record” explains nothing either about the cause of the hyperthermals or about any meaningful signal on earth.
Latitude says:
March 16, 2011 at 7:08 pm
If CO2 is driving temperature like they claim it is. If CO2 raises temperatures to where the feedbacks tipping points cause run away global warming…
…why is it that every time CO2 and temperature levels have been high
….the planet goes right back into another ice age
=================================================
Well, Lat, knowing you, I know this is only a rhetorical question coming from you. You already know the answer, but others may not be so enlightened. And there probably isn’t enough space here to properly give all of the information, so, I’ll try to be brief.
Others, recently, have attempted to explain this scarcely known phenomenon. But, they lacked complete understanding. Certain NOAA personnel have attempted to characterize this as Warm Arctic Cold Continents, we know this isn’t an accurate description of the dynamics occurring. Sadly, some have beat Dr. Syme to publishing in a peer-reviewed journal. (I understand its a grueling process for those that don’t conform to current thought, so its understandable how many wouldn’t know about the precise dynamic.) But, it is all fairly straightforward and more precisely worded, and more accurately worded as simply warmcold.
You see, it isn’t necessary for the poles to be warm, it is anywhere on the planet. If some parts of the planet is warm, specifically, (and thought to be exclusively) warmed by CO2, we know this generates cold. We know the poles don’t matter because of the spherical nature of the globe. Indeed, how else could we explain the very occurrences described in this paper? Or even the occurrences of this winter? It is, none other than the dreaded warmcold. I hope I’ve cleared some things up for some people. 🙂
More tendentious shroudwaving speculation masquerading as “science”.
The only useful thing I get from it is the new name for our anxious chums trousering tax funds for their “research”.
Hyperthermalists.
Hmmmmm.
I like that.
So Leif, if you did read it, what do you think of their hypotheses, methods and results? Let’s see some real discussion of the findings, not just a bunch of pooh-poohing, conjecture and jokes. The summary of the report at the link does not say why they think CO2 is the likely cause, rather than a result of the noted changes.
Hyperthermals. Intense, sudden warmth. Reminds me of…Yep! Sounds like hot flashes to me. Gaia, Geea, or whatever her name is, needs to sit down with a bottle of chocolate wine. It’s called ChocoVine, imported from Holland. Dutched chocolate and fine red wine. What’s not to like? Chocolate and red wine all together in a bottle. It will chase those hyperthermals right out of the atmosphere and cool the raging Gaia beast. Not that I have any experience with that sort of thing. I’m just fine. And don’t you be saying anything different.
I’ve stated several times on this site that I do not believe the mid-ocean ridge and undersea volcanoes are properly considered in climate models.
Those events certainly have a component that is more or less constant and therefore more or less predicable over geographic times. (able to be smoothed reasonably)
However, those events also would have periodic episodes of especially turbulent occurences.
I have no doubt that periodically the undersea super volcano eruption occurs (like Yellowstone), or that the mid-ocean ridge splits far more than usual (consider a continental plate more or less round that slips all the way around rather than laterally).
This would account for the additional CO2 as the limestone, plants and shells nearby are vaporized, and would also account for chemistry changes causing extinctions on land and in the sea. Depending on what exactly is released and in what quantity, it’s easy to conceive of toxic conditions being generated in the seas and out gassing to the atmosphere.
The belief that the Ring of Fire or the mid-ocean ridge is a constant makes as much sense to me as the belief that the sun’s output is constant in frequency, wavelength and amplitude. Meaning, “not”.
I do not accept that plate tectonics always occurs at a glacial pace, I believe sometimes there are huge slippages and sometimes there are huge tears, all dependent on the physics of the mantle, outer core, and inner core. Physics we obviously don’t well understand.
No surprise here to me. The Earth burps.
Er, substitute the obvious ‘geologic’ for the comical ‘geographic’ in my previous post.
Proof reading for the win.
“Norris noted that the hyperthermals provide historical perspective on what Earth will experience as it continues to warm from widespread use of fossil fuels, which has increased carbon dioxide concentrations in the atmosphere nearly 50 percent since the beginning of the Industrial Revolution.”
There is that little scale issue again cropping up in Dick Norris’s mud study that must essentially turn mankind’s puny contribution into the Chuck Norris of molecules as usual.
Ka-ching $.
Latitude says:
March 16, 2011 at 7:08 pm
If CO2 is driving temperature like they claim it is. If CO2 raises temperatures to where the feedbacks tipping points cause run away global warming…
…why is it that every time CO2 and temperature levels have been high
….the planet goes right back into another ice age
Sexton’s explanation was gibberish.
The right explanation is that in the case of ice age cycles there seem to be three mechanisms involved. The primary driver is the earth’s orbital and axial precession, changing the distance between the earth and sun and the angle of the tilt axis. As the tilt angle increases, and the distance to the sun in the northern hemisphere summer increases, the earth’s reflectivity decreases, the oceans get warmer and emit CO2. Both of these phenomena make the earth even warmer. When the tilt angle decreases and the distance between earth and sun in the northern hemisphere decreases, the process reverses itself. The albedo and CO2 are not the driving force, in the case of the ice age cycles, but are feedback reactions to the cyclical earth’s orbital and axial changes, called the Milankovitch cycles.
The modern industrial emission of CO2 is a driving force, and over time the resulting global warming can result in the emission of additional CO2 from the oceans.
Others have put the temp PETM temperature spike at 2-3°C.
http://i54.tinypic.com/2yxm9o9.jpg
carbon-based life form says:
March 16, 2011 at 8:02 pm
what do you think of their hypotheses, methods and results?
I don’t have strong opinions on this. Their results are described in the supplementary information http://www.nature.com/nature/journal/v471/n7338/extref/nature09826-s1.pdf and should give interested parties enough to go on. I do find it interesting that they use ‘astronomical tuning’ to fix the timing.
Those darn continents keep sliding around, opening and closing pathways for currents, closing and opening oceans, pushing up mountains, altering freshwater rivers, and rifting apart land masses. The follow-on effects are oh so complicated.
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apachewhoknows says:
March 16, 2011 at 7:12 pm
Some one ask Harry Reid . . .
Harry is busy trying to shut down one of Nevada’s thriving attractions:
http://www.lasvegassun.com/news/2011/feb/23/reids-call-brothel-ban-real-showstopper/
Reid seems interested in taking the nation’s mind in a direction other than housing, employment, spending, health care, and . . .
Hyper-thermals lasted from 40,000 to 200,000 years before temperatures returned to “normal”. Just how long has something got to last before it becomes the new “normal”? 2? 5? 10 times the entire history of civilization? As Latitude said, “normal” equals ice-age by that reckoning. Who needs it?