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Climate to Warm Beyond Levels Seen for 11,300 Years

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A new reconstruction of the Earth's climate history — dating back 11,300 years — found that the planet has rarely been warmer than it is today during that time, and that temperatures are likely to climb into unprecedented territory by 2100, due to increasing amounts of planet warming greenhouse gases in the air.

The study, published Thursday in the journal Science, confirms the now famous “hockey stick” graph that Michael Mann published more than a decade ago. That study showed a sharp upward temperature trend over the past century after more than a thousand years of relatively flat temperatures.

Credit: NASA

But the new report extends that research back much further, using evidence from the seafloor and from lake sediments to gauge past temperatures, not the tree rings previous researchers have used. “What’s striking,” said lead author Shaun Marcott of Oregon State University in an interview, “is that the records we use are completely independent, and produce the same result.”

The study is also truly global, based on records from 73 different locations around the world, not just regional. “As far as we know, this is the first time this has been done for the entire Holocene,” Marcott said. That’s the name of the period since the last of the great Ice Age glaciers melted back, which coincides with the rise of civilization.

The research aimed to understand whether the current warming is unprecedented in the Holocene period, or whether the same thing might have happened before, because of purely natural causes.

Based on the evidence, it has not. Since the ice sheets departed, the warming trend was found based on the chemical composition of ancient shellfish called foraminifera, variation in types of pollen extracted from lake sediments and other temperature-dependent measures. The data shows there was a long, gradual warmup for about 5,000 years, then a plateau of warm temperatures, and then an equally gradual cooling trend until about 200 years ago.

Marcott said that is in line with the gradual changes known as Milankovitch Cycles, caused by the Earth’s tilt and its orbit around the Sun. Based on where we are in those cycles, Marcott said, the planet should still be cooling. Not only is the Earth warming, it is warming much faster than a Milankovitch Cycle could possibly explain. “The temperature change is both too abrupt, and going in the wrong direction, to be natural” Marcott said.

This does not vary from the conclusions of other major reports, like the one issued by the Intergovernmental Panel on Climate Change (IPCC) in 2007, which stated, “There is very high confidence that the net effect of human activities since 1750 has been one of warming.”

While that was enough to convince most scientists of the need for swift and drastic action in cutting back greenhouse-gas emissions, the new report adds a deeper layer of evidence that could help convince policymakers.

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Comments

By breathin (Boulder, CO 80301)
on March 7th, 2013

Read The Great Waves of Change, free at greatwavesofchange.org, to know how to respond.

Reply to this comment

By Wade Hartwell (Calgary, Alberta)
on March 7th, 2013

thought you might like to read these stats….somewhat close to what you were talking about, just a few changes; Like WHY the earth is still on a warming trend!  I’m sure you won’t accept this…but just food for thought.  ha!

Reply to this comment

By Andrew (Austin, TX 78724)
on March 8th, 2013

Climate change is not the true problem.  Overpopulation is the problem.  If we all recycled and drove electric cars, but we increase our numbers to 10,000,000,000 , we have accomplished nothing.  And on the contrary, climate change may be the negative feedback that we finally need to do something about overpopulation.  Just think, the U.S. may become a desert, and we may all need to migrate to Northern Canada.  Canada will have to “secure their southern border” to keep those pesky U.S.er’s out.  It will be impossible to live within 50 miles of a coastline.  This will impact 5,000,000,000 people.  Coastliners will either be wiped out, or they must migrate.  They may not breed so prolifically after this.  It is amazing to me that scientists talk so much about climate change when overpopulation is the true emergency.  As NPG says: “All causes are lost causes without a reduction in population.”  This includes doing anything about climate change without reducing the population.  Let me re-state:  worrying about climate change while ignoring overpopulation “is a lost cause”.  A. Gray

Reply to this comment

By sue lane (houghton lake MI 48651)
on March 8th, 2013

Don’t you people know we’re on to you fear mongers. The real cause for the warming in the climate has to do with HAARP and geoengineering. ie The U.S.Air Force, who wants to control the weather by 2025.  I blame all the named winter storms on them too!  Not to mention all the other unregulated people spraying what ever the hell they please in our atmosphere. Wise up!  But I bet you stand to prophet from this agenda. Quit lying to the American people.

Reply to this comment

By Yvonne (Sedona, AZ 86336)
on March 8th, 2013

The problem of overpopulation will never be resolved, so we’re doomed…we may drag out the inevitable by introducing new technology, which adds even more manufacturing into the equation, in a last ditch effort to make more money for a limited few, while hoping for the best.. but the outcome will be the same. Mankind seems to have some type of pathetic need to control everything by war, caging wild animals, fighting every little bacteria, manipulating weather, and tearing up the landscape, all the while never thinking to look down from above at how they really are just a bunch of tiny little ants wrecking the garden. Earth is a miracle and so is mankind, therefore, we need to live in unison. Glad I don’t have children and it’s hard for me to believe those who do could be so selfish and irresponsible.

Reply to this comment

By Leo Horishny (Sun Valley, NV 89433)
on March 8th, 2013

I agree with you Andrew from Austin and it’s interesting to note how your observations are ignored in the overall discussions about economies and global climate change.

The only good thing about climate change passing a tipping point is that it will cure the overpopulation input problem that won’t be addressed.

Reply to this comment

By Anonymouse
on March 8th, 2013

Overpopulation is a myth that has been espoused since the1600’s. A recent study has shown that temp increases before CO2 levels do. Also, we are still in an ice age from the Pleistocene epoch and will be out of it once the ice at the poles is gone, as has happened in cycles before…

Reply to this comment

By Jon (4573)
on March 8th, 2013

Shouldn’t the title read “...NOT seen for 11,300 years” ?

Reply to this comment

By Eddie Sharpe
on March 9th, 2013

Oh look. It’s worse than we thought.  That’s the thing about such indirect evidence. It’s easier to infer all sorts from the uncertainty, than from the hard evidence of no statistically significant warming for 23 years now from the satellite data.

Reply to this comment

By William G (Lincoln, England)
on March 9th, 2013

‘Warmer’ ?  Where is the graph of the heat content of the biosphere over the last 10000 years. ?

Reply to this comment

By Withheld Name (Houston, TX)
on March 9th, 2013

Real simple solution.  We all need to do the following things:

1. Stop eating all meat except fish.
2. Sell your car for scrap metal and replace it with either a bicycle or an electric vehicle.
3. Install as many solar panels as you can fit on your roof and, if needed, in your yard.
4. Call your power company and tell them to disconnect you from the grid.
5. Find 7 billion friends to do the exact same things.

That’s it.  Easy as pie.  We should have this knocked off in a year, don’t you think?

Reply to this comment

By Brian Sandle (Christchurch/New Zealand/8083)
on March 9th, 2013

I don’t think population control does much when I look at China with the strongest population control but the greatest increase in emissions.

Reply to this comment

By Brian Sandle (Christchurch/New Zealand/8083)
on March 9th, 2013

73 locations hopefully without local intensification. And if any were in the stratosphere I think there would be cooling as the greenhouse blanket stops the heat rising?

Antarctic sea ice should be increasing. Heat comes to the Antarctic in undersea currents, melts subsurface ice which produces water less salty than sea water, so it rises and freezes more easily than sea water on reaching the surface.

Large icebergs should be calving as the subsurface ice melts.

With more sea ice near the Antarctic the sun’s heat will be reflected away more so surface cooling should be happening at the Antarctic. By the time the Antarctic surface starts warming things will be very far gone.

Increased temperature increases sea evaporation. I don’t know how far the vapour travels but if it can get to Antarctic then I would expect more snow there.

Where are we up to with remote vehicle surveying of the subsurface Antarctic ice?

Reply to this comment

By Christina A. (Atlanta GA 31141)
on March 9th, 2013

The planet Earth has been here for millions of years, it will survive without Human beings.  Humans need this planet, but the planet does not need us.

Reply to this comment

By Leslie Graham (Denver )
on March 11th, 2013

“A recent study has shown that temp increases before CO2 levels do”

Not true.
Recent studies show just the opposite.
But so what if the older studies showed the initial temperature rise caused by the onset of a new Milankovitch cycle led to outgassing of CO2 from oceans.. Whether it followed the initial rise or - as is now known - occurred simultaneously makes no diference whatsover.
It’s long been known (except to the denial industry’s most gullible dupes) that CO2 works as both a FORCING AND A FEEDBACK!
Duh!
Your desperation is so evident. What you are doing is known in the scientific community as “clutching at graphs”.
The old “Co2 lags temperature” myth was shredded years ago.
There is NO ‘debate’ in the scientific community about AGW and there hasn’t been for decades.
Out of the 13,950 peer-reviewed studies published in the last twenty years only 24 (yep 24!!) reject the consensus.
Get used to it.
THE CLIMATE HAS ALWAYS CHANGED!
In the past, every time CO2 levels have risen the climate has changed.
The laws of physics don’t give a damn where the CO2 comes from.
CO2 rises = the climate changes.
Every single time.

Reply to this comment

By John Watson (New Bern, nc )
on April 12th, 2013

Didn’t the authors of this study have to admit that when they attempted to apply the methodology of their “reconstruction” to the 20th century (the only period for which there are actual temperature records) that the results weren’t “statistically robust”? (This is a rhetorical question, I know that they did))
Since their methodology doesn’t compare to instrument records, doesn’t the reconstruction become useless?

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