Regional insights set latest study of climate history apart

Apr 22, 2013
Students use acoustic imaging to select a coring site in southern Alaska lake.

(Phys.org) —As climate studies saturate scientific journals and mainstream media, with opposing viewpoints quickly squaring off in reaction and debate, new findings can easily be lost in the noise.

But in the case of Northern Arizona University Regents' professor Darrell Kaufman and a study appearing in Nature Geoscience, obscurity is an unlikely fate.

What Kaufman—the lead co-author of "Continental-scale during the last two millennia"—and 78 experts from 24 countries have done is to assemble the most comprehensive study to date of temperature change of Earth's continents over the past 1,000 to 2,000 years.

By looking regionally, the researchers found considerable complexity hidden within a global average.

"We wanted a new and ambitious effort to reconstruct past climate," Kaufman said of the PAGES 2k network of researchers. "One of the strongest aspects of the consortium study is that it relies on regional expertise."

Members of the consortium represent eight continental-scale regions. They lent their insights about the best proxy records—such as tree-ring measurements—to use for a particular region, and how to interpret the data based on regional climatology.

While the study does not attempt to attribute temperature changes to natural or human-caused factors, Kaufman said the finding of a long-term trend that ended late in the 19th century is further evidence that increased have had an influence in later years.

"The pre-industrial trend was likely caused by natural factors that continued to operate through the 20th century, making 20th century warming more difficult to explain if not for the likely impact of increased greenhouse gasses," Kaufman said.

While that sounds like a familiar theme, the study's findings of regional variations are less well known. Because of extensive participation by scientists working in the , Kaufman said, data from those regions broadened what had been a view previously centered on Europe.

"We know the most about the long-term temperature history in Europe, but we find that not every region conforms with that pattern," Kaufman said. He noted that temperatures varied by region against the backdrop of the long-term cooling identified by the study.

The regional focus on the past 2,000 years is significant for two reasons, Kaufman said. First, climate change at that scale is more relevant to societies and ecosystems than global averages. And second, "regional scale differences help us to understand how the climate system works, and that information helps to improve the models used to project future climate."

Kaufman's own research team added to the strong regional input. His research in Alaska and elsewhere formed part of the dataset.

"The questions that my team hopes to address involve the larger climate system, and our research contributes one piece of the global puzzle," he said.

Kaufman's role as lead co-author came about partly from good timing—he was on sabbatical as a visiting scientist at the Bern, Switzerland, headquarters of Past Global Changes (PAGES) organization, as the data were being assembled, so he took the lead in writing the manuscript.

Later, as the paper underwent a substantial reworking to address the scrutiny of peer review, co-author Nick McKay, a post-doctoral researcher at NAU, "did the heavy lifting," Kaufman said. "He analyzed the data from each of the regions to uncover the most important similarities and differences, which we needed for the synthesis."

In another of the study's major contributions, the entire database on which it was based has been tabulated and will be made available publicly for further analysis. Kaufman and his co-authors have posted the data along with frequently asked questions about the study on the PAGES project website.

"My co-authors and I look forward to seeing the data used by others in future analyses because science moves forward with well-informed alternative interpretations," Kaufman said.

Explore further: Late 20th century was warmest in 1,400 years

Related Stories

Late 20th century was warmest in 1,400 years

Apr 21, 2013

Earth was cooling until the end of the 19th century and a hundred years later, the planet's surface was on average warmer than at any time in the previous 1,400 years, according to climate records presented ...

Arctic at warmest levels in 2,000 years or more

Sep 03, 2009

Arctic temperatures in the 1990s reached their warmest level of any decade in at least 2,000 years, new research indicates. The study, which incorporates geologic records and computer simulations, provides ...

Central European summer temperature variability to increase

Dec 18, 2012

More extreme heat waves have been observed in central Europe in recent years as summer temperature variability has increased on both daily and interannual timescales. Models project that as the climate warms throughout the ...

Recommended for you

Melting during cooling period

17 hours ago

(Phys.org) —A University of Maine research team says stratification of the North Atlantic Ocean contributed to summer warming and glacial melting in Scotland during the period recognized for abrupt cooling ...

Warm US West, cold East: A 4,000-year pattern

20 hours ago

Last winter's curvy jet stream pattern brought mild temperatures to western North America and harsh cold to the East. A University of Utah-led study shows that pattern became more pronounced 4,000 years ago, ...

User comments : 38

Adjust slider to filter visible comments by rank

Display comments: newest first

ubavontuba
1.8 / 5 (25) Apr 22, 2013
"The pre-industrial trend was likely caused by natural factors that continued to operate through the 20th century, making 20th century warming more difficult to explain if not for the likely impact of increased greenhouse gasses," Kaufman said.
So, apparently by default, cooling trends are "natural" and warming trends must be caused by human activity? LOL.

I love this logic:

Winter must be the natural state, and summer must be casued by human activity!

verkle
1.5 / 5 (22) Apr 22, 2013
uba---great catch.
I really don't like either winter or summer, though. Spring is my favorite time of year.

Maggnus
4 / 5 (16) Apr 22, 2013
So, apparently by default, cooling trends are "natural" and warming trends must be caused by human activity? LOL.

I love this logic:

Winter must be the natural state, and summer must be casued by human activity!


What are you on about now? I know comprehension is an issue for you, but seriously, you should take the time to actually read the articles you dismiss so readily.

And of course verkle agrees with you because, well, you are known to be a denier of the science of climate change and global warming. That means, he didn't even read as much as you did.

I just love you guys posting, you're so obviously biased against ANY science which even hints at climate change, you make it easy laugh at you and then to shrug you off.

ubavontuba
1.6 / 5 (24) Apr 22, 2013
So, apparently by default, cooling trends are "natural" and warming trends must be caused by human activity? LOL.

I love this logic:

Winter must be the natural state, and summer must be caused by human activity!


What are you on about now? I know comprehension is an issue for you, but seriously, you should take the time to actually read the articles you dismiss so readily.
Apparently, you haven't read the article.

And of course verkle agrees with you because, well, you are known to be a denier of the science of climate change and global warming. That means, he didn't even read as much as you did.
LOL. What have I supposedly denied?

I just love you guys posting, you're so obviously biased against ANY science which even hints at climate change, you make it easy laugh at you and then to shrug you off.
LOL. And I love you guys, proselytizing the doctrine of climate change, with virtually no understanding of the relevant sciences. LOL

djr
3.9 / 5 (15) Apr 22, 2013
The pre-industrial trend was likely caused by natural factors that continued to operate through the 20th century, making 20th century warming more difficult to explain if not for the likely impact of increased greenhouse gasses,"

So, apparently by default, cooling trends are "natural" and warming trends must be caused by human activity? LOL.

They don't say the 'cooling trend' - they say the 'pre-industrial trend' It would make sense to me that a 2,000 year trend - that occurred prior to the industrial revolution - would very likely be appropriately seen as a 'natural' ie not anthropogenic. A reversal of this trend - as we go into the industrial era - would appropriately suggest looking into a possible connection.

VENDItardE
1.3 / 5 (23) Apr 22, 2013
maggnus.....stop making an a$$ of yourself, just stop.
djr
4.1 / 5 (14) Apr 23, 2013
"maggnus.....stop making an a$$ of yourself, just stop."

Translation -" we don't like people who challenge us on the facts - we want unimpeded access to push our anti science agenda - please stop questioning us."
deepsand
3.3 / 5 (24) Apr 24, 2013
I love you guys, proselytizing [re.] climate change, with virtually no understanding of the relevant sciences.

Thank you for that very apt description of the denialists.
ubavontuba
1 / 5 (16) Apr 28, 2013
They don't say the 'cooling trend' - they say the 'pre-industrial trend'
Which was a cooling trend.

It would make sense to me that a 2,000 year trend - that occurred prior to the industrial revolution - would very likely be appropriately seen as a 'natural' ie not anthropogenic. A reversal of this trend - as we go into the industrial era - would appropriately suggest looking into a possible connection.
Looking into ...sure. Asserting a correlation without direct evidence ...hardly.

ubavontuba
1 / 5 (15) Apr 28, 2013
"maggnus.....stop making an a$$ of yourself, just stop."

Translation -" we don't like people who challenge us on the facts - we want unimpeded access to push our anti science agenda - please stop questioning us."
So where are these supposed challenges on the facts Maggnus provided?

Proselytizing the doctrine of climate change, with hand-waving assertions, is not science.

ubavontuba
1 / 5 (13) Apr 28, 2013
I love you guys, proselytizing [re.] climate change, with virtually no understanding of the relevant sciences.
Thank you for that very apt description of the denialists.
Sure, but why an AGWite like you should be so proud of his anti-science/denialist stance is beyond me.

Here's the science:

http://www.woodfo...01/trend

So, when are you going to stop denying that according to the highly "bias corrected" (aka manipulated) data currently in vogue, the globe hasn't been warming for more than a dozen years?

deepsand
3.3 / 5 (21) Apr 28, 2013
UTube again trots out a cherry-picked data set that itself fails to support his own position.
ubavontuba
1 / 5 (18) Apr 28, 2013
http://www.woodfo...01/trend

So, when are you going to stop denying that according to the highly "bias corrected" (aka manipulated) data currently in vogue, the globe hasn't been warming for more than a dozen years?
UTube again trots out a cherry-picked data set that itself fails to support his own position.
And yet again, deepsand proves himself to be the science denier.

deepsand
3.2 / 5 (20) Apr 28, 2013
http://www.woodfo...01/trend

So, when are you going to stop denying that according to the highly "bias corrected" (aka manipulated) data currently in vogue, the globe hasn't been warming for more than a dozen years?
UTube again trots out a cherry-picked data set that itself fails to support his own position.
And yet again, deepsand proves himself to be the science denier.

UTube once again publicly demonstrates that he is scientifically illiterate.
ubavontuba
1 / 5 (17) Apr 28, 2013
http://www.woodfo...01/trend

So, when are you going to stop denying that according to the highly "bias corrected" (aka manipulated) data currently in vogue, the globe hasn't been warming for more than a dozen years?
UTube again trots out a cherry-picked data set that itself fails to support his own position.
And yet again, deepsand proves himself to be the science denier.
UTube once again publicly demonstrates that he is scientifically illiterate.
And yet again, deepsand proves himself to be the science denier.

deepsand
3.4 / 5 (18) Apr 28, 2013
UTube lives in a fantasy world where his uninformed and unsubstantiated opinions are the equal of better than facts.

Good night, Irene.
ubavontuba
1 / 5 (16) Apr 28, 2013
UTube lives in a fantasy world where his uninformed and unsubstantiated opinions are the equal of better than facts.
...says the science denier. LOL.

deepsand
3.2 / 5 (20) Apr 28, 2013
Continuing to trot out the same old cherry-picked data, UTube, data that does not even support your position, serves no purpose.

A lie, no matter how often you repeat it, remains a lie.

Your pointless repetition has is egregiously juvenile.

Grow up.

ubavontuba
1 / 5 (14) Apr 28, 2013
Continuing to trot out the same old cherry-picked data, UTube, data that does not even support your position, serves no purpose.
Assertions without supporting data are meaningless.

A lie, no matter how often you repeat it, remains a lie.
So why do you do that?

Your pointless repetition is egregiously juvenile.
...and, so why do you do that?

Grow up.
Yes, why don't you?

Budding Geologist
4.6 / 5 (9) Apr 28, 2013
Utube, you're the one flaming this comment section like a high school freshmen. I'm curious as to what career you have, since you claim to be so much more scientifically literate than the other posters on here.
ubavontuba
1 / 5 (12) Apr 28, 2013
Utube, you're the one flaming this comment section like a high school freshmen.
And we have yet another ad hominem attack from the AGWite community. Gee, what a surprise (not).

I'm curious as to what career you have, since you claim to be so much more scientifically literate than the other posters on here.
And an argument from authority. Gee, what another surprise (not).

Is this the best you can do?

Why can't AGWites support their arguments with verifiable facts and references (rhetorical)? Because the facts and references belie their very assertions.

VendicarE
4.4 / 5 (7) Apr 28, 2013
Poor UbVonTard. He has been lying for years about how the world has been warming since the end of the last ice age.

In reality it has been generally cooling since then.

"So, apparently by default, cooling trends are "natural" and warming trends must be caused by human activity?" - UbVonTard

He has been told this, and shown this more than a dozen times, but he is somehow motivated to continue his non stop stream of lies.

What could be his motivation?
VendicarE
4.4 / 5 (7) Apr 28, 2013
"Apparently, you haven't read the article." - UbVonTard

Ya, he apparently did.

What is clear is that you haven't got a clue as to what the article states.

Poor Brain Damaged UbvonTard. In a universe filled with free information, he chooses to remain maximally ignorant.

Why else would you be attempting to deny the fact that the earth has been cooling since the peak attained just after the last ice age. Cooling until recently..

You know... The curve makes a nice hockey stick shape that you ignorantly deny.
VendicarE
4.4 / 5 (7) Apr 29, 2013
The preindustrial trend...

"Which was a cooling trend." - UbVonTard

What? You are changing your story again? You have been claiming over and over again that the earth has been warming since the end of the last ice age.

Now you claim the opposite.

Make up your mind. Fool.

VendicarE
4.4 / 5 (7) Apr 29, 2013
"Here's the science:" - Ubvontard

http://www.woodfo...00/trend

Your plot shows a globally rising temperature but is too short to have any statistical significance.

Here is a more meaningful one.

http://www.woodfo...93/trend

Poor UbVonTard. The statistical insignificance of his cherry picked start and stop times has been explained to him more than a dozen times.

But he persists on posting statistical nonsense.

It is all part of his mental disease.

VendicarE
4.5 / 5 (8) Apr 29, 2013
It is amusing to see how the people here who are literate in science continually rank UbVonTard's posts as low as possible.

Only Conservatives love liars.
deepsand
3 / 5 (18) Apr 29, 2013
Continuing to trot out the same old cherry-picked data, UTube, data that does not even support your position, serves no purpose.
Assertions without supporting data are meaningless.

Then why do you persist in doing that?
ubavontuba
1 / 5 (15) Apr 29, 2013
Oh look. The Vendispambot is up to its old tricks.

Poor Uba. He has been lying for years about how the world has been warming since the end of the last ice age.
When did I supposedly make this claim?

In reality it has been generally cooling since then.
Generally.

So, apparently by default, cooling trends are "natural" and warming trends must be caused by human activity? - Uba


He has been told this, and shown this more than a dozen times, but he is somehow motivated to continue his non stop stream of lies.

What could be his motivation?
What is your motivation for spreading libel and terrorist threats?

ubavontuba
1 / 5 (13) Apr 29, 2013
Apparently, you haven't read the article. - Uba
Ya, he apparently did.
Obviously not, but as spambots can't discern context, I'm not surprised you missed it.

What is clear is that you haven't got a clue as to what the article states.

Poor Brain Damaged Uba. In a universe filled with free information, he chooses to remain maximally ignorant.

Why else would you be attempting to deny the fact that the earth has been cooling since the peak attained just after the last ice age. Cooling until recently..
What a moron spambot. My very comment acknowledges this. LOL!

You know... The curve makes a nice hockey stick shape that you ignorantly deny.
Are you talking about the upside down hockey stick from the end of the ice age?

http://upload.wik...ions.png

ubavontuba
1.3 / 5 (14) Apr 29, 2013
The preindustrial trend...

Which was a cooling trend." - Uba
What? You are changing your story again? You have been claiming over and over again that the earth has been warming since the end of the last ice age.

Now you claim the opposite.

Make up your mind. Fool.
Apparently you don't understand the contextual difference between warmer, and warming. LOL. Vendispambot is so easily confused. LOL.

ubavontuba
1 / 5 (13) Apr 29, 2013
Here's the science:" - Uba

http://www.woodfo...01/trend
Your plot shows a globally rising temperature but is too short to have any statistical significance.
Why then do you feel a need to falsely substitute the data (I corrected it to my original, above)? LOL

Here is a more meaningful one.

http://www.woodfo...01/trend
Oh, you mean this one where you've falsely extended a prior trend over the last dozen years?

Poor Uba. The statistical insignificance of his cherry picked start and stop times has been explained to him more than a dozen times.

But he persists on posting statistical nonsense.

It is all part of his mental disease.
Poor Vendispambot can't win an argument on the merits, so it has to lie, cheat, threaten, and bully.

You're an embarrassment to phys.org.

ubavontuba
1 / 5 (12) Apr 29, 2013
It is amusing to see how the people here who are literate in science continually rank Uba's posts as low as possible.
Conversely, they uprank a terrorist bully like yourself. That doesn't exactly lend much credence to the ranking system. LOL

AGWites think they can win by bullying. Even though most of the rankings are the work of one OCD individual using multiple sockpuppets, I think it's funny how I'm viewed as such a threat they feel the need to closely follow and downrank me.

Only Conservatives love liars.
The Vendispambot just wants to be loved. LOL.

ubavontuba
1 / 5 (13) Apr 29, 2013
Continuing to trot out the same old cherry-picked data, UTube, data that does not even support your position, serves no purpose.
Assertions without supporting data are meaningless.

Then why do you persist in doing that?
This is your shtick.

Are you ready to admit the world has been cooling for more than a dozen years (even using the manipulated data which is currently in vogue)?

http://www.woodfo...01/trend

Excalibur
3.1 / 5 (15) Apr 30, 2013
The automaton known as ubavontuba seems to be stuck in a loop.
deepsand
3 / 5 (16) Apr 30, 2013
Continuing to trot out the same old cherry-picked data, UTube, data that does not even support your position, serves no purpose.
Assertions without supporting data are meaningless.

Then why do you persist in doing that?
This is your shtick.

Are you ready to admit the world has been cooling for more than a dozen years (even using the manipulated data which is currently in vogue)?

http://www.woodfo...01/trend

"No, Global Warming Has NOT Stopped"

http://www.slate....vid.html
ubavontuba
1 / 5 (12) Apr 30, 2013
Continuing to trot out the same old cherry-picked data, UTube, data that does not even support your position, serves no purpose.
Assertions without supporting data are meaningless.
Then why do you persist in doing just that?
This is your shtick.

Are you ready to admit the world has been cooling for more than a dozen years (even using the manipulated data which is currently in vogue)?

http://www.woodfo...01/trend
"No, Global Warming Has NOT Stopped"

http://www.slate....vid.html
LOL A blog opinion piece written by an astronomer, who doesn't even deny the temperature trend has fallen flat, is the best climate "science" you could muster? LOL

Here, I have astronomers too:

http://english.ru...-expect/

LOL
deepsand
2.7 / 5 (14) Apr 30, 2013
Unable to comprehend the article, UTube resorts to attacking the author, who he knows absolutely nothing about, and the forum in which published.

How very "scientific" of him. :rolleyes:

Neinsense99
2.5 / 5 (11) May 26, 2013
The automaton known as ubavontuba seems to be stuck in a loop.

Automatons are insulted.

More news stories

Melting during cooling period

(Phys.org) —A University of Maine research team says stratification of the North Atlantic Ocean contributed to summer warming and glacial melting in Scotland during the period recognized for abrupt cooling ...