From an Oregon State University press release:
Ancient Hawaiian glaciers reveal clues to global climate impacts
CORVALLIS, Ore. – Boulders deposited by an ancient glacier that once covered the summit of Mauna Kea on the island of Hawaii have provided more evidence of the extraordinary power and reach of global change, particularly the slowdown of a North Atlantic Ocean current system that could happen again and continues to be a concern to climate scientists.
A new study has found geochemical clues near the summit of Mauna Kea that tell a story of ancient glacier formation, the influence of the most recent ice age, more frequent major storms in Hawaii, and the impact of a distant climatic event that changed much of the world.
The research was published in Earth and Planetary Science Letters by scientists from Oregon State University, the Woods Hole Oceanographic Institution, University of British Columbia and U.S. Geological Survey. The work was supported by the National Science Foundation.
“Mauna Kea had a large glacial ice cap of about 70 square kilometers until 14,500 years ago, which has now all disappeared,” said Peter Clark, a professor of geosciences at OSU. “We’ve been able to use new data to determine specifically when, where and most likely why the glacier existed and then disappeared.”
Mauna Kea, at 13,803 feet above sea level, is in a sense the tallest mountain in the world because it rises 30,000 feet from the sea floor. Dormant for thousands of years, it once featured a large glacier on its massive peak at the height of the last ice age about 21,000 years ago. As the ice age ended and the global climate warmed, the glacier began to disappear.
However, the new research found that the glacier on Mauna Kea began to re-advance to almost its ice age size about 15,400 years ago. That coincides almost exactly with a major slowdown of what scientists call the Atlantic meridional overturning circulation, or AMOC, in the North Atlantic Ocean.
The AMOC is part of a global ocean circulation system that carries heat from the tropics to the North Atlantic. This transported heat is the primary reason that much of Europe is warmer in the winter than would be expected, given the latitude of the continent.
Studies of past climate change indicate that the AMOC has slowed a number of times, in surprisingly short periods, causing substantial cooling of Europe. Because of that, the potential future decline of the current is of considerable interest.
But scientists have found that the AMOC does more than just keep northern Europe habitable. Its effects can extend far beyond that.
“The new data from Mauna Kea, along with other findings from geological archives preserved in oceans and lakes in many other areas, show that the decline of the AMOC basically caused climate changes all over the world,” Clark said. “These connections are pretty remarkable, a current pattern in the North Atlantic affecting glacier development thousands of miles away in the Hawaiian Islands.
“The global impact of the AMOC changes,” Clark added, “was just massive.”
The formation, size and movement of glaciers can provide valuable data, he said, because these characteristics reflect current and historic changes in temperature, precipitation or both.
The study concludes that the growth of the Mauna Kea glacier caused by the AMOC current changes was a result of both colder conditions and a huge increase of precipitation on Mauna Kea – triple that of the present – that scientists believe may have been caused by more frequent cyclonic storm events hitting the Hawaiian Islands from the north.
The findings were supported by measurements of an isotope of helium being produced in boulders left by the Mauna Kea glacier thousands of years ago. The amount of this helium isotope reveals when the boulders were finally uncovered by ice and exposed to the atmosphere.
The deposits containing the boulders are the only record of glaciation in the northern subtropical Pacific Ocean. Nearby Mauna Loa probably also was glaciated, but evidence of its glaciation has since been destroyed by volcanic eruptions.
The study by Clark and colleagues provides additional evidence that rapid changes in the AMOC can trigger widespread global change. Some past abrupt decreases in the AMOC have been linked to an increase of freshwater flowing off the continents into the North Atlantic.
The potential under global warming for increases in freshwater from melting ice and changes in precipitation patterns have heightened concerns about the AMOC and related climate effects in the future, researchers said.
It is my understanding that there are 11 “tubes” within the AMOC and that recently it was shown that only 2 of the “tubes” are “pumping” and sluggish at that. Do you have any current information? It may prove interesting if there was a total shut-down AMOC and the resulting cooling. It just might counter balance some of the climate change we are just beginning to see.
Why must they always have that final paragraph about “global warming”? It seems somehow obligatory.
Yet more solid proof, based on getting away from the computer and researching the facts, that the climate has been in flux for aeons. Thank you.
Interesting.
I assume, since it is not mentioned, that they dont know what controls the AMOC?
The potential under global warming for increases in freshwater from melting ice and changes in precipitation patterns have heightened concerns about the AMOC and related climate effects in the future, researchers said.
So the tactics are changing: “global warming” leads to “global freezing”.
The key to performing this “switch” is based upon getting people to accept that man is responsible for raising CO2 levels (hence the current onslaught of bogus CO2 papers).
Once this is achieved “they” can suddenly discover a new/refined feedback mechanism that changes the CO2 feedback to be either positive (when it is heating) or negative (when it is cooling)… either way they are trying to cook the books… either way it is your fault… either way you pay the price!
Surprising that Oregon State University is surprised. The North Atlantic is the major heat supplier of the Northern Hemisphere during the winter season, reaching the latitude of 80°North, much less the Northern Pacific (Aleutian) going up to about 55°North. There was a recent global cooling for three decades that commenced with WWII since 1940. For a couple of years the North Atlantic and the Western Pacific had been naval warfare battle ground, which may have contributed to the downward trend, details at: http://www.oceanclimate.de/;
http://climate-ocean.com/:
What did H.H. Lamb say in 1976?
___“The workings of the ocean have been too little considered in most text on climatology”. To little has change, although also H.U. Sverdrup advised three decades years earlier:
_____“….one cannot deal independently with the atmosphere or the oceans, but must deal with the complete system, atmosphere-oceans. This fact has been recognized in oceanography, where one gets nowhere by neglecting the relation to the atmosphere, but in meteorology it has not yet received sufficient attention.” (H.U. Sverdrup, 1942, “Oceanography for Meteorologists”, New York, 1942, Chapter X, p. 223
So this is what will happen to Hawaii when the global cooling starts.
Have a little glacier with your lava.
So, have I got this right….Warming might cause greater melting of ice/permafrost/whatever. The resulting injection of freshwater into Northern waters results in a slowdown of the AMOC. That in turn could result in cooling in lower latitudes (glaciers on Mauna Kea etc).
Is that a self-regulating climate feedback system?
Question from an “ignorant bystander” how does a cooling mechanism cause more fresh water run off? Surely it was locked up in the growing ice fields postulated in this article?
The picture of the idiot standing in the glacial field has me deeply concerned. One of the main features of glacial rock is smooth edges and fine dust. These look very angular, perhaps too angular. Proof for the existence of glaciers relies on landscape features such as valleys, rounded rocks, displaced boulders and large quantities of moraine. Don’t see it here. Perhaps it’s elsewhere on the island.
“Some past abrupt decreases in the AMOC have been linked to an increase of freshwater flowing off the continents into the North Atlantic.”
Anyone have some references for this?
So this is the AMOC?
http://www.whoi.edu/page.do?pid=12455&tid=441&cid=19061&ct=61&article=9986
O.T. But,
DMI has now up-dated and shows sea ice extent is now above 2007, 2008, 2009 and a shade under the 2005 value!
http://ocean.dmi.dk/arctic/icecover.uk.php
Glacier loss in Hawaii tied to change in North Atlantic AMOC current
Not a surprise at all.
These links reveal that there is substance to it.
http://www.vukcevic.talktalk.net/LFC1.htm
http://www.vukcevic.talktalk.net/NFC1.htm
http://www.vukcevic.talktalk.net/PDO.htm
I did expect that eventually more evidence will be presented to support my conclusions.
rbateman says: August 6, 2010 at 1:25 am
So this is what will happen to Hawaii when the global cooling starts.
Have a little glacier with your lava.
Icelanders alone can’t have all the pleasures all the time.
Neil. The freshwater influx WAS the cooling mechanism. When the huge North American meltwater lake broke through and drained into the North Atlantic, it’s lower density formed a barrier to the warm waters of the gulf stream and diluted the salinity of the deeper returning flow, shutting off the ability of the cooling stream to drop down into the return “pipe.”
Friar said: “The resulting injection of freshwater into Northern waters results in a slowdown of the AMOC.”
From the sea ice discussion threads, I thought it was the lack of refreezing that slows down the AMOC. It wouldn’t surprise me that too much Arctic ice would ultimately slow down the AMOC since there would be no open water to freeze or thin ice to grow thicker. Without newly frozen ice, there is no source of dense salty water to sink and kick off the circulation.
“There was a recent global cooling for three decades that commenced with WWII since 1940. For a couple of years the North Atlantic and the Western Pacific had been naval warfare battle ground, which may have contributed to the downward trend…”
Well…the cooling that started in the 1940s also was when the PDO went negative which, BTW, it has done again recently. I’d be more willing to believe the climate shift was due to a widespread temp swing in the largest ocean rather than a few ships steaming around…ya’know?
Must be something wrong with either the science or the press release. That readvance they are talking about must be the Yonger Dryas Stadial which maybe (but far from certainly) was caused by a slowdown in AMOC. However that started about 12,800 years ago, not 15,400. At about 15,000 there was instead major warming and meltback of glaciers.
Given the lack of anthropogenic CO2 being pumped into the atmosphere 16 odd thousand years ago, what triggered the last AMOC event and what proof exists that the next event will be any different?
“Some past abrupt decreases in the AMOC have been linked to an increase of freshwater flowing off the continents into the North Atlantic.”
Could they possibly be referring to the Younger Dryas? There were completely different circumstances then – mile-high ice sheets melting, creating a gigantic lake which then burst through an ice dam, flooding into the north Atlantic.
They seem to just keep recycling the same old ridiculous CAGW/CC scares.
stephen richards says:
August 6, 2010 at 2:50 am
My thoughts too.
Maybe it was just a névé, a patch of permanent snow/ice with no flow. Glaciers in Iceland with nearby lava have reduced the lava to black sand by repeated freeze/thaw cycles.
stephen richards says:
August 6, 2010 at 2:50 am
Smooth edges come from wear as the rocks are transported. These are near the mountain top and weren’t transported very far. Given the whole island is a volcano, glacial erratics (I assume that what you meant by displaced boulders) would be hard to identify. Large quantities of moraine – check. The photos don’t show a terminal moraine, that happens at the glacial face where debris is pushed or dropped off as the front melts. Cape Cod and the nearby islands are one of the best examples of terminal moraines. When you say valleys, I assume you mean U shaped valleys and hanging valleys, both require a long period of glaciation to dig out the U shape, I’d guess these photos are too high and, the glaciers never large enough, and didn’t have time.
The best examples of those I’ve seen were on my first long bicycle tour. The lower stretch of the Skagit River in Washington State on Rt 20 is a broad U shape, and I saw a waterfall or two on the far wall from a V shaped valley that fed into the excavated space. The upper reaches are also great, and at bicycle speed there’s lots of time to consider what you’re seeing. And stop for yet another photo.
crosspatch says, August 6, 2010 at 12:16 am: Why must they always have that final paragraph about “global warming”? It seems somehow obligatory.
That is what’s known within the science community as “The Money Shot.”
“However, the new research found that the glacier on Mauna Kea began to re-advance to almost its ice age size about 15,400 years ago”
This is quite misleading, since 15400 years ago was still well within the last glaciation (and the Laurentide ice sheet was still immense).