From an Oregon State University Media Release (h/t to Leif Svalgaard)
Long debate ended over cause, demise of ice ages – may also help predict future
)
The above image shows how much the Earth’s orbit can vary in shape.
This process in a slow one, taking roughly 100,000 to cycle.
(Credit: Texas A&M University note: illustration is not to scale)
CORVALLIS, Ore. – A team of researchers says it has largely put to rest a long debate on the underlying mechanism that has caused periodic ice ages on Earth for the past 2.5 million years – they are ultimately linked to slight shifts in solar radiation caused by predictable changes in Earth’s rotation and axis.
In a publication to be released Friday in the journal Science, researchers from Oregon State University and other institutions conclude that the known wobbles in Earth’s rotation caused global ice levels to reach their peak about 26,000 years ago, stabilize for 7,000 years and then begin melting 19,000 years ago, eventually bringing to an end the last ice age.
The melting was first caused by more solar radiation, not changes in carbon dioxide levels or ocean temperatures, as some scientists have suggested in recent years.
“Solar radiation was the trigger that started the ice melting, that’s now pretty certain,” said Peter Clark, a professor of geosciences at OSU. “There were also changes in atmospheric carbon dioxide levels and ocean circulation, but those happened later and amplified a process that had already begun.”
The findings are important, the scientists said, because they will give researchers a more precise understanding of how ice sheets melt in response to radiative forcing mechanisms. And even though the changes that occurred 19,000 years ago were due to increased solar radiation, that amount of heating can be translated into what is expected from current increases in greenhouse gas levels, and help scientists more accurately project how Earth’s existing ice sheets will react in the future.
“We now know with much more certainty how ancient ice sheets responded to solar radiation, and that will be very useful in better understanding what the future holds,” Clark said. “It’s good to get this pinned down.”
The researchers used an analysis of 6,000 dates and locations of ice sheets to define, with a high level of accuracy, when they started to melt. In doing this, they confirmed a theory that was first developed more than 50 years ago that pointed to small but definable changes in Earth’s rotation as the trigger for ice ages.
“We can calculate changes in the Earth’s axis and rotation that go back 50 million years,” Clark said. “These are caused primarily by the gravitational influences of the larger planets, such as Jupiter and Saturn, which pull and tug on the Earth in slightly different ways over periods of thousands of years.”
That, in turn, can change the Earth’s axis – the way it tilts towards the sun – about two degrees over long periods of time, which changes the way sunlight strikes the planet. And those small shifts in solar radiation were all it took to cause multiple ice ages during about the past 2.5 million years on Earth, which reach their extremes every 100,000 years or so.
Sometime around now, scientists say, the Earth should be changing from a long interglacial period that has lasted the past 10,000 years and shifting back towards conditions that will ultimately lead to another ice age – unless some other forces stop or slow it. But these are processes that literally move with glacial slowness, and due to greenhouse gas emissions the Earth has already warmed as much in about the past 200 years as it ordinarily might in several thousand years, Clark said.
“One of the biggest concerns right now is how the Greenland and Antarctic ice sheets will respond to global warming and contribute to sea level rise,” Clark said. “This study will help us better understand that process, and improve the validity of our models.”
The research was done in collaboration with scientists from the Geological Survey of Canada, University of Wisconsin, Stockholm University, Harvard University, the U.S. Geological Survey and University of Ulster. It was supported by the National Science Foundation and other agencies.
UPDATE: Science now has the paper online, which is behind a paywall. The abstract is open though and can be read below:
| Science 7 August 2009:
Vol. 325. no. 5941, pp. 710 – 714 DOI: 10.1126/science.1172873 |
Research Articles
The Last Glacial Maximum
Peter U. Clark,1,* Arthur S. Dyke,2 Jeremy D. Shakun,1 Anders E. Carlson,3 Jorie Clark,1 Barbara Wohlfarth,4 Jerry X. Mitrovica,5 Steven W. Hostetler,6 A. Marshall McCabe7
1 Department of Geosciences, Oregon State University, Corvallis, OR 97331, USA.
2 Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada.
3 Department of Geology and Geophysics, University of Wisconsin, Madison, WI 53706, USA.
4 Department of Geology and Geochemistry, Stockholm University, SE-10691, Stockholm, Sweden.
5 Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA.
6 U.S. Geological Survey, Department of Geosciences, Oregon State University, Corvallis, OR 97331, USA.
7 School of Environmental Science, University of Ulster, Coleraine, County Londonderry, BT52 1SA, UK.
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Leland Palmer (03:03:49) :
..you should wonder what the ultimate source of those talking points was. There are apparently paid climate skeptics, and ExxonMobil has been widely reported to have spent at least 26 million dollars in the last decade supporting a network of such skeptics.
Leland Palmer the funding of sceptics pales in comparison with the funding received by proponents of Man-Made Global Warming Fear mongering.
And there are many sceptic scientists who have received no funding whatsoever from ExxonMobile like Dr Christy or Dr Bob Carter.
Prof Bob Carter “In one of the more expensive ironies of history, the expenditure of more than $US50 billion on research into global warming since 1990 has failed to demonstrate any human-caused climate trend, let alone a dangerous one,”
http://www.news.com.au/couriermail/story/0,23739,21920043-27197,00.html
The U.S. alone has spent $30 billion on federal programs directly or indirectly related to global warming in just the last six years, according to one estimate.
http://www.foxnews.com/story/0,2933,249598,00.html
In addition to this is the funding from the UN, foundations, universities, foreign governments, etc. Huge sums of money continue to flow toward addressing climate alarmism.
Former Vice President Al Gore’s claimed on August 7, 2007 that $10 million dollars a year from the fossil fuel industry flows into sceptical organizations.
Gore launched a $100 million a year multimedia global warming fear campaign. Gore alone will now be spending $90 million more per year than he alleges the entire fossil fuel industry spends, according to an August 26, 2007 article in Advertising Age.
http://newsbusters.org/blogs/noel-sheppard/2007/08/26/global-warming-ads-al-gore-coming-soon
Dr. Roy W. Spencer, formerly a senior scientist for climate studies at NASA’s Marshall Space Flight Center and currently principal research scientist at the University of Alabama in Huntsville, “Of course, the vast majority of mainstream climate researchers receive between $100,000 to $200,000 from the federal government [to conduct research in] support of manmade global warming,”
http://www.tcsdaily.com/article.aspx?id=081307B
Follow the money. “Nothing wrong with making money at all, but when money becomes the motivation for a scientific conclusion, then we have a problem. For many, global warming is a big cash grab,”
http://epw.senate.gov/public/index.cfm?FuseAction=PressRoom.Blogs&ContentRecord_id=3a9bc8a4-802a-23ad-4065-7dc37ec39adf
The message – keep people alarmed – thats where the money is.
My I ask you why you believe in AGW? Have you examined the science and the predictions? What are your scientific credentials?
PS Just to help you with the maths 26 million = 0.026 Billion. 50 Billion spent on Man-made global warming research is 49.974 Billion more than you say is spent by Exxonmobile. Or in percentage terms 192,308% more than the Exxonmobile money.
And thats “May I ask you..”
I’ve read that the single comapny, ExxonMobil, has produced sufficient fossil fuels to account for roughly five percent of global warming.
The cost of global warming, if we ignite a methane catastrophe, could be infinite- it could destroy everything.
Here is a reference to a paper that estimates value of goods and services provided to humanity by the biosphere:
http://www.uvm.edu/giee/publications/Nature_Paper.pdf
So, speaking roughly and approximately, it seems to me that ExxonMobil should be fined something like 1.5 trillion dollars per year for the damage that they are inflicting on the world’s biosphere, since if a methane catastrophe is ignited, we are talking about an almost complete loss of those goods and services that the biosphere has given us in the past for free. Since a methane catastrophe, once ignited, woud be hard or impossible to stop, it seems legitimate to hold those companies that knowingly profited from igniting it legally liable for all of the damages caused by their actions.
Since their gross sales are about 350 billion per year, or so, it looks to me like their continued operation is a losing proposition.
If fighting global warming, cleaning up the mess that the fossil fuel companies have made, becomes too expensive for the public to finance, I think we should just go after the hugely rich stockholders of the fossil fuel companies such as the Rockefeller family, and hold them legally liable for the damage that they have knowingly done to the earth’s biosphere. Since their own scientists have been telling them for a couple of decades now that the link between global warming and fossil fuel use is incontrovertible, and they have been knowingly lying about it, I’d say the public has a very good case for complete nationalization of all oil companies and all profits those oil companies have ever made.
Oh, wait, I forgot punitive damages….
Ignore Leland and he might go away.
Quoting Harry Truman-
Oh, I don’t give ’em Hell, I just tell the truth, and they think it’s Hell.
Continuing with that theme-
The Council on Foreign Relations has been dominated by the Rockefeller family for decades. This is of course the same Rockefeller family is descended from John D. Rockefeller, founder of the Standard Oil oil monopoly that once controlled something like 90% of all the refinery capacity in the U.S. The Rockefeller family still retains enough control over ExxonMobil to oust the ex-CEO of ExxonMobil Lee Raymond, and send him back to Texas with his 450 million dollar golden parachute.
http://en.wikipedia.org/wiki/ExxonMobil
The Chairman Emeritus of the CFR, for example, is David Rockefeller.
Scott Borgerson, a visiting fellow at the CFR, (meaning he’s a member of the CFR think tank and is on the payroll) has been touting the value of Arctic resources lately, in a series of articles in the CFR’s journal Foreign Affairs, and testimony before Congress.
His message?
The Arctic is melting, it doesn’t really matter why. It’s just melting, is all, with “stunning speed”, so that the Arctic might be ice free in the summer by 2013.
This opens up business opportunities in the Arctic including access to many trillions of dollars worth of oil and natural gas, constituting something like 22% of all the remaining undiscovered hydrocarbons on the planet.
And we better hurry, before the Russians get it.
In testimony before the House foreign relations committee, Borgerson wistfully noted that the Russians have some really nice ice breakers, and what the U.S. really needs is a really nice fleet of nuclear powered ice breakers ourselves, at a couple of billion dollars per ship, built with public money, of course. We need these icebreakers presumably to break the ice for following oil tankers, especially during the fall, winter and spring. These oil tankers would presumably be harvesting oil from oil wells drilled in the ice free Arctic summers, under what is currently polar icecap.
Notice the different messages here, for different groups.
For the poor people duped by their network of climate skeptics, the message is that global warming is not occurring, at all.
For investors, and people that read the CFR;s output, the message is “Go North, Young Man!”. There’s money to be made in the Arctic, when the ice melts.
For a list of Borgerson’s articles, and links to his testimony before Congress, go here:
http://www.cfr.org/bios/13363/
Here’s a sample:
http://www.foreignaffairs.com/articles/64905/scott-g-borgerson/the-great-game-moves-north
The Great Game Moves North
“The results are staggering”, indeed.
ExxonMobil appears to want the Arctic to melt, so that they can drill for oil under our current polar icecap, IMO.
And they are knowingly willing to risk igniting a methane catastrophe, to get that oil and natural gas.
I’m sorry, I forgot about voting for either Rex Tillerson or David Rockefeller for Emperor of the World.
Leland is such a complete hypocrite, isn’t he? Quoting Truman makes him even more insufferable; Leland actually believes he’s got a handle on the truth! What normal person can tolerate a preachy environut?
The non-wacko scientific community doesn’t publish about a methane catastrophe because it’s so improbable. If people started sending manuscripts around to be peer reviewed, arm-waving about the danger of the [pretty much non-existent] methane ices supposedly littering the sea floor, the laughter from normal scientists would make them slink away.
Leland says “if we ignite a methane catastrophe, could be infinite- it could destroy everything.” But at the same time, our favorite hypocrite admits to having carbon spewing children, and he admits to driving a carbon spewing automobile [and most likely more than one], and he admits to using carbon spewing heat for his carbon spewing home. I would ask Leland how he can be so hypocritical, but his cognitive dissonance provides him with logic-free cover. The answer, of course, is for Leland to immediately stop his use of fossil fuels. But like Al Gore, Leland only preaches at everyone else to stop their use of fossil fuels, while Leland enjoys the benefits of his extravagant petroleum burning.
To solve the invented methane crisis, Leland says, “it seems to me that ExxonMobil should be fined something like 1.5 trillion dollars per year for the damage that they are inflicting on the world’s biosphere.” Of course any such fine would be simply passed on to the consumer in the form of much higher prices, hitting the poorest really hard; Leland likes that, being an elitist. And Al Gore would agree with him.
Nobody likes a hypocrite. Leland’s only honest course of action requires that he must give up the use of any and all fossil fuel-based energy. Whining that Exxon should be fined, while still using their products, is a clear cop out. When Leland gives up the benefits of petroleum, he will be on the road to credibility. Until then, Leland is a monumental hypocrite, serene in his cognitive dissonance.
Hi Smokey-
Hi Smokey-
Also, not so. I’m much more of a populist, than an elitist. For elitists, look among the financial elite, and I’m one of the po’ folk.
Yeah, we saw some of that financial efficiency of huge oil companies, during the Bush Administration, during which they colluded to drive the price of oil up by excessive futures speculation, and made huge profits from four dollar per gallon gasoline.
If we nationalized the oil companies, the price of gasoline would go down. If we convert most of our transportation fleet to become plug in hybrids and use electricity, the demand for gasoline will become more flexible, and the price of gasoline will go down.
That’s really what ExxonMobil’s disinformation campaign is all about. Through paid spokespeople like Rush Limbaugh, they seek to convince people that giving up their really most basic human right – the right to a stable climate – is in their self interest.
Considering the huge value of the free goods and services we currently receive from the biosphere, an unstable climate cannot possibly be in the self-interest of the great majority of the people.
“That’s really what ExxonMobil’s disinformation campaign is all about. Through paid spokespeople like Rush Limbaugh, […]”
It wouldn’t surprise me that $26 million wouldn’t cover Rush’s golf expenses for a year. Where did the rest of the money go?
“[…] they seek to convince people that giving up their really most basic human right – the right to a stable climate – is in their self interest. […]”
Ahhhh… Now we come to the crux of your misunderstanding. Since when has the climate ever been stable? The earth’s climate has always been changing one way or another without the help of mankind, thank you very much.
Talking about “the right to a stable climate” is nonsense. Be sure to yell that out to the next glacier that plows through Indianapolis, as one surely will. Earth’s climate has never been stable. I’ve got a couple of million years of history on my side of the argument. What do you have; unproven climate models? I’ll stick with geological evidence on the climate change topic.
Hi H.R.
Rush Limbaugh’s last contract was for 400 million dollars, for 8 years. That’s fifty million dollars per year.
Limbaugh claims himself to be a “friend to corporate America”.
Oh really?
Who knew?
I’ve been Googling Clear Channel, which is Limbaugh’s employer, and looking for connections to oil. So far, no luck, though. Clear channel is currently controlled by a group of private equity firms. I’ll keep digging, and let you know what I find out, though.
The climate in the past has changed very slowly, compared to today’s “geologically instantaneous” changes. And the changes are accelerating.
That’s what Al Gore’s “hockey stick” graph is all about.
One time that the climate may have changed almost as fast as today, was during the Permian-Triassic mass extinction, which killed something like 95 percent of all marine species, and something like 80 percent of terrestrial species. It was the most severe mass extinction in history, and was the only known mass extinction of insects. It was probably due to a methane catastrophe, certainly the isotope signature of a massive Carbon 13 negative shift, almost certainly caused by the release of trillions of tons of isotopically light methane, is there in the sediment. The oceans apparently turned anoxic, there was large production of hydrogen sulfide by the oceans, and it took the earth’s climate roughly 100,000 years to recover.
One way to think about it is that climate change has been so slow in the past that any systematic change was unlikely to be observed in any single human lifetime.
Any systematic change within a single human lifetime likely means that the system is out of control. And what we are seeing right now is perceptible (massive) change in the polar caps, for example, within a few years. Also, the vast majority of the changes we are seeing are in a single direction – warming.
I know that the observational evidence for AGW, which is massive, is ignored or ridiculed on this blog. But it is certainly there. Hundreds or thousands of observations and scientific studies, from many different fields of science, point to warming, as detailed in the latest IPCC report, and other even more alarming findings since then.
Concerning rates of climate change, the Permain- Triassic mass extinction doesn’t seem like a very good role model, does it?
Howdy Leland:
“Hi H.R.
Rush Limbaugh’s last contract was for 400 million dollars, for 8 years. That’s fifty million dollars per year.”
How much of that $400 million was paid by Exxon Mobil? You’re a little short of pertinent facts. We were discussing Exxon Mobil paying $26 million to Rush et al. Break down that $400 million will ya or are you telling me that Exxon Mobil pays Rush $50 million per year? Heck skip that. All I ever asked for was a breakdown of the $26 million: who, what, when, where, how much?
“That’s what Al Gore’s “hockey stick” graph is all about.”
Um… Mann’s methodology produces a hockey stick with random noise as input (see Climate Audit for a thorough discussion of of Mann’s methodology). Mann’s hockey stick is about a couple of years of wasted time and money, not climate change.
“One time that the climate may have changed almost as fast as today, was during the Permian-Triassic mass extinction, which killed something like 95 percent of all marine species, and something like 80 percent of terrestrial species. It was the most severe mass extinction in history, and was the only known mass extinction of insects. It was probably due to a methane catastrophe, certainly the isotope signature of a massive Carbon 13 negative shift, almost certainly caused by the release of trillions of tons of isotopically light methane, is there in the sediment. The oceans apparently turned anoxic, there was large production of hydrogen sulfide by the oceans, and it took the earth’s climate roughly 100,000 years to recover.”
I agree wholeheartedly that there has and will be mass extinctions such as the Permian-Triassic mass extinction. But where was humankind’s fingerprint in that pie, or in the other mass extinctions for that matter? I’m still having a hard time understanding where the catastrophe is going to come from wrt CO2 if CO2 is increasing but temperatures (or more importantly, ocean heat content as measured by the Argo bouys) is essentially flat.
So where are the feedbacks that cause runaway global warming? It’s never happened before when CO2 levels were much, much higher than current times. Where were the feedbacks then? Why will they work “this time” but they didn’t work in the past?
Milankovitch cycles coupled with the positions of the continental land masses get my vote for controlling influence wrt global climate change. Glacials and interglacials are just weather until the continents move about into a position for real global climate change. That is, if an asteroid doesn’t get us first.