From the University of California – Los Angeles
Research also helps unravel the mystery of retreating glaciers in the Pacific Ocean’s western tropics
Using a cutting-edge research technique, UCLA researchers have reconstructed the temperature history of a region that plays a major role in determining climate around the world.
The findings, published online Feb. 27 in the journal Nature Geoscience, will help inform scientists about the processes influencing global warming in the western tropical Pacific Ocean.
The study analyzes how much temperatures have increased in the region near Indonesia, and how ocean temperatures affect nearby tropical glaciers in Papua New Guinea and Borneo. Researchers also evaluated the accuracy of existing climate model predictions for that region. The findings illustrate that the region is very sensitive to climate change and that it has warmed considerably over the last 20,000 years, since the last ice age.
The team chose the specific area examined in the study because it is Earth’s warmest open ocean region and a primary source of heat and water vapor to the atmosphere. As a result, temperature changes there can influence climate not just regionally, but globally.
“The tropical Pacific ocean-atmosphere system has been called a sleeping dragon because of how it can influence climate elsewhere,” said lead author Aradhna Tripati, a UCLA assistant professor in the departments of Earth, planetary and space sciences, and atmospheric and oceanic sciences.
Tripati and her team used a technique known as clumped isotope thermometry, which examines the calcium carbonate shells of marine plankton for subtle differences in the amounts of carbon-13 and oxygen-18 they contain. The researchers analyzed extensive modern and geological datasets, conducted theoretical calculations and examined climate model output. The group discovered that temperatures have changed by about 8 to 10 degrees Fahrenheit (4 to 5 degrees Celsius) over that span — more than scientists had previously thought, and more than most models have estimated.
“Most global climate models underestimate the average temperature variations that the region has experienced,” Tripati said, adding that the other models’ simulations may be incomplete or the models are not sensitive enough.
The UCLA team’s conclusions about temperature changes in the region also imply that there have been major fluctuations in the volume of water vapor in the atmosphere there.
As part of the study, Tripati and her colleagues also investigated what sets the past and present height of glaciers in the tropics, and why they have been retreating. To accurately estimate the height of tropical glaciers and average temperatures at altitude in this region, they found that atmospheric mixing, through a process known as entrainment, needs to be factored in.
“We found that the large amount of ocean warming goes a long way to explaining why glaciers have retreated so much,” said Tripati, a faculty member in the College of Letters and Science and a member of UCLA’s Institute of the Environment and Sustainability. “Throughout the region, they have retreated by close to a kilometer since the last ice age, and are predicted to disappear in the next one to three decades. Previously understanding this large-scale glacial retreat has been a puzzle. Our results help resolve this problem.”
Among the implications of the study are that ocean temperatures in this area may be more sensitive to changes in greenhouse gas levels than previously thought and that scientists should be factoring entrainment into their models for predicting future climate change.
The group has already begun a follow-up study, looking at sediment from Indonesia’s Lake Towuti to develop data that can be used to further improve models of climate and water cycling for the region. Researchers will also look at other places in the tropics, the Western U.S. and China.
Co-authors of the study are Sandeep Sahany, postdoctoral researcher in the department of atmospheric and oceanic sciences, Dustin Pittman, graduate student in the department of atmospheric and oceanic sciences, Robert Eagle, assistant researcher in the department of Earth, planetary and space sciences, Jonathan Mitchell, assistant professor in the departments of Earth, planetary and space sciences and of atmospheric and oceanic sciences, J. David Neelin, professor in the department of atmospheric and oceanic sciences and Luc Beaufort, a research scientist at the Center for Research and Teaching of Environmental Geosciences in Aix-en-Provence, France.
The research was supported primarily by the National Science Foundation.
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Paper: http://www.nature.com/ngeo/journal/v7/n3/full/ngeo2082.html
Modern and glacial tropical snowlines controlled by sea surface temperature and atmospheric mixing
Abstract
During the Last Glacial Maximum, tropical sea surface temperatures were 1 to 3 °C cooler than present1, 2, 3, 4, but the altitude of the snowlines of tropical glaciers5, 6 was lower than would be expected in light of these sea surface temperatures. Indeed, both glacial and twentieth-century snowlines seem to require lapse rates that are steeper than a moist adiabat7, 8. Here we use estimates of Last Glacial Maximum sea surface temperature in the Indo-Pacific warm pool based on the clumped isotope palaeotemperature proxy in planktonic foraminifera and coccoliths, along with radiative–convective calculations of vertical atmospheric thermal structure, to assess the controls on tropical glacier snowlines. Using extensive new data sets for the region, we demonstrate that mean environmental lapse rates are steeper than moist adiabatic during the recent and glacial. We reconstruct glacial sea surface temperatures 4 to 5 °C cooler than modern. We include modern and glacial sea surface temperatures in calculations of atmospheric convection that account for mixing between rising air and ambient air, and derive tropical glacier snowlines with altitudes consistent with twentieth-century and Last Glacial Maximum reconstructions. Sea surface temperature changes ≤3 °C are excluded unless glacial relative humidity values were outside the range associated with deep convection in the modern. We conclude that the entrainment of ambient air into rising air masses significantly alters the vertical temperature structure of the troposphere in modern and ancient regions of deep convection. Furthermore, if all glacial tropical temperatures were cooler than previously estimated, it would imply a higher equilibrium climate sensitivity than included in present models.
Looks like a pretty small and localized sample size:
Figure 1: Sites studied.
Shown are core locations (806B, MD97-2138, V24-109) and mountains that were glaciated at the LGM
daddylonglegs on March 15, 2014 at 2:11 am
…”To describd this as greater sensitivity to climate change is a sign of dysfunctional logic or the deliberate intention to confuse and mislead. It is introducing redundant and fictitious …”
…”It makes no sense except as a deliberate atempt to deceive.”
—————
Having spent a decade grubbing for grants and writing academic papers , I do agree the process is somewhat is intended to deceive. As a researcher you’re interested in something that practically no one else is interested in, and you need to beg someone (usually the [government]) to pay for the study, so you make it sound much more important than it actually is.
My colleagues and I would laugh about the fact that the introductory paragraph in all our papers, and all papers in our field, would start off with [big] grandiose claims of being relevant to curing cancer. We knew the connection of out research to actually curing cancer was so remote it was downright ridiculous.
Ironically I’m now in BigPharma actually working on compounds that actually do cure cancer, so maybe it wasn’t a joke after all ? 🙂
Steve B says:
“Very very funny and the Sydney Inner City Greens can join the Melbourne Inner City Greens in Tassie for a green luv in.”
Actually, from the election results, there don’t seem to be many greens left in Tassie 🙂
Oh sooooo sweet !!!
More likely this will become part of the “missing heat found in the ocean” explaining the “pause” that’s been going on the last couple of decades. Since the models fail to include the ocean as some vast sink storing heat, actually sucking it out, much like recharging a battery. Thus, the next round of the climate shrieker industury will likely be how they’ve “adjusted” their models to include the heat battery and, gee, you better pay more ’cause when the battery gets full….
The last Ice Age finished 12,000 years ago are they now saying that it did not happen?
I always switch off now when i reach this point in these papers.,
“Among the implications of the study are that ocean temperatures in this area may be more sensitive to changes in greenhouse gas levels “
I guess the study was done before this last winter’s “ice age” onset!
(Any marine biologist know how the currently cool ENSO waters affect plankton there?)
I suppose the answer to my following question is that if “sustainability” is in your charter, any deviation from present conditions is bad by definition — but I have to ask it anyway: Why is it necessarily bad that glaciers are disappearing from tropical islands?
The researchers analyzed extensive modern and geological datasets, conducted theoretical calculations and examined climate model output.
mmmm did they check there theoretical outputs to observed data for validity by chance???
Berényi Péter says:
March 15, 2014 at 2:36 am
“Come on. During the Last Glacial Maximum, which ended 19 thousand years ago ………..”
I like your comment the best. A fact that probably never entered their minds..
“A sleeping dragon” Yikes! I’m sooo scared. Quck, somebody tell Obama and Kerry. ;^)
Just thought of something: This article smells like a computer generated one. You don’t suppose it is fake?
Mac the Knife says:
March 14, 2014 at 10:17 pm
______________________________
+1
If fake articles can be generated using random input jargon, articles loosely based on real data could also be generated via automatic computer generation. That technology, applied to actual research certainly saves time and would relieve poor writers of the task of generating their manuscript. hmmmmm. Regardless, something isn’t right here with the way the abstract reads, that’s for sure. The article is way to “jargony” and has that “look at all the big words and complicated sentences I use” computer language feel to it as I read it.
In order to estimate the ECS the authors had to assume how much warming was due to natural recovery from an ice age and how much was due to GHG’s. It seems they assumed all or most of the warming was due to GHG’s which would indicate a high ECS. I would have chosen a low ECS case so the study would be inline with modern data.
The findings illustrate that the region is very sensitive to climate change and that it has warmed considerably over the last 20,000 years, since the last ice age.
Warmed considerably when the glaciers melted, it has been cooling ever since. What crap!!
http://i45.tinypic.com/2yo1hsy.jpg
“The findings illustrate that the region is very sensitive to climate change and that it has warmed considerably over the last 20,000 years, since the last ice age.
The team chose the specific area examined in the study because it is Earth’s warmest open ocean region and a primary source of heat and water vapor to the atmosphere. As a result, temperature changes there can influence climate not just regionally, but globally.”
— I find those two statements curious when they are taken together. The region is sensitive to climate change, yet it seems to drive climate change? No wonder they picked that region!
So, they think the hockey stick is wrong? Other than that, it was reminiscent of the self-congratulatory Anne Elk skit on Monty Python.
I’d bet the authors would claim that their main point is that they may have discovered a more reliable paleo-climate proxy. Okay, that’s great (if it holds in other parts of the world, if other climate proxies are fairly accurate, etc etc), but they spend most of their press release talking about climate change in general, postulating about model and climate sensitivity, climate impacts, and the like. Why the f do our climate scientists do this to themselves???
For all the rhetoric about “climate denial” and all of the other psudonames for CAGW skeptics, this article only serves as evidence that it is the climate scientists, themselves, who are their own worst enemy.
“The tropical Pacific ocean-atmosphere system has been called a sleeping dragon because of how it can influence climate elsewhere,” said lead author Aradhna Tripati, a UCLA assistant professor in the departments of Earth, planetary and space sciences, and atmospheric and oceanic sciences.”
I think we all know why the “sleeping dragon” analogy was used. Dragons are dangerous, and usually fire-breathing creatures, and as such, are better left sleeping. The implication being that man’s noisy CO2 just might wake the dragon and then, why, it would be “game over for our climate”.
The glaciers shrink, the glaciers grow
A measure of the falling snow
And worries that they come and go
Will only bring us pointless woe
For man can neither speed nor slow
Their ups and downs of endless flow
So what has been will still be so
No matter what we think we know
Eugene WR Gallun
Key point. During almost all of the period of time investigated, when temperature rose 4-5 degrees and glaciers retreated, CO2 was at pre-industrial (“safe”) levels; or did I miss something.
Renaldo says:
March 14, 2014 at 11:01 pm
“Please let me know when . . .”
Just one word to say to you: guyot
I don’t get why so many think the LGM was edenic. It wasn’t. The LGM was the coldest time on Earth since the Karoo Ice Age of 250,000,000 years ago. Far from being the “ideal” global temperature, the LGM was the all-time nadir.
And please note that today the globe is a mere 4degC warmer than rock bottom. We don’t live in a warm age but a very cold one, relative to the normative temperature for Planet Earth.
Warmer is better. Warmer means longer growing seasons, more rain, more bio-productivity, more biodiversity, more Life In General.
The “authorities” are paranoid as geese that it might get a degree or two warmer. But warmth is a boon, not a curse. Their paranoia is tragically misplaced.
Warmer Is Better. Fight the Ice
“Using extensive new data sets for the region, we demonstrate that mean environmental lapse rates are steeper than moist adiabatic during the recent and glacial.”
That statement in their paper demonstrates to me that they are assuming that the relative humidity was 100% during the last glacial maximum and that it is 100% today. The adiabatic lapse rate is how fast the temperature drops with altitude as a packet of air rises and does work on the surrounding air but has no increase in the internal energy due to heat. The moist adiabatic lapse rate is based on 100% relative humidity in the air and is ~ 5C/1000m. The dry adiabatic lapse rate is for unsaturated air (less than 100% relative humidity) and is ~ 10C/1000m. Their assumption of the moist adiabatic lapse rate is invalid because, in effect, they are assuming a constant relative humidity at 100%.
It is quite apparent, from examination of the differences in adiabatic lapse rates, that the temperature at different elevations is not only dependent upon the temperature at sea level, but on the relative humidity of the atmosphere at those locations. When you see that the sea level temperatures have changed less than 4C since the last glacial maximum, it is obvious that in order for the temperatures at higher elevations to have increased more than 4C, there must have been an increase in the relative humidity. Given that sea levels rose 120m during the interval, and covered previously exposed land, it is easily conceivable that the relative humidity of the air at the elevations where these tropical glaciers formed also increased, reducing the adiabatic lapse rate which led to an increased temperature at those elevations relative to the temperature at sea level.
lf there claim that this area in the western Pacific was 4C to 5C cooler is true.
Then this could give some clues to what the weather was like in this area during the ice age.
What it suggests to me is that there was a increase in rainfall / cloud cover and less sunshine in this area during the ice age. Also it was very likely that a powerful jet stream was forming over this area that was drawing a lot of warm and moist air from the area and pushing it up into the Arctic. The fact that there was wide spread ice sheets over North America but little over NE Russia during the ice age, would help to support this idea. As this jet stream pattern would likely to of been pushing warmer air up towards NE Russia, but then would risk bringing cold Arctic air down across North America.
Looks like a pretty small and localized sample size:
So was a single tree – YAD06 IIRC – on the Yamal peninsula, but that didn’t stop them basing the whole CAGW mass hysteria on it.