Continuation of Current Patterns of Change in Arctic and North Atlantic Oceans Could Alter Ocean Circulation on Global Scale With Impact on Climate and Biosphere
08 November 2008
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| The dashed yellow line illustrates progression of first low salinity pulse after it exited the Arctic in 1989 and was advected downstream. Arrival dates, labeled in yellow, are indicated at each of the major shelf ecosystems, labeled in white. Colors correspond to mean sea surface temperatures for the decade of the 1990s (from orange [warmest] to purple [coldest]). Click to enlarge. Credit: Chuck Greene, Cornell |
In a November special issue of the journal Ecology, a group of scientists report that if current patterns of change in the Arctic and North Atlantic Oceans continue, alterations of ocean circulation could occur on a global scale, with potentially dramatic implications for the world’s climate and biosphere.
Charles Greene of Cornell University and colleagues reconstructed the patterns of climate change in the Arctic from the Paleocene epoch to the present. Over these 65 million years, the Earth has undergone several major warming and cooling episodes, which were largely mitigated by the expansion and contraction of sea ice in the Arctic.
When the Arctic cools and ice expands, the increase ice cover increases albedo. The resulting increased reflection of the sun leads to global cooling. Likewise, when ice sheets and sea ice contract and expose the darker-colored land or ocean underneath, heat is absorbed, accelerating climate warming. Currently, the Earth is in the midst of an interglacial period, characterized by retracted ice sheets and warmer temperatures.
A recurring theme in Earth’s paleoclimate record is the importance of the Arctic atmosphere, ocean, and cryosphere in regulating global climate on a variety of spatial and temporal scales. A second recurring theme in this record is the importance of freshwater export from the Arctic in regulating global- to basin-scale ocean circulation patterns and climate.
Since the 1970s, historically unprecedented changes have been observed in the Arctic as climate warming has increased precipitation, river discharge, and glacial as well as sea-ice melting. In addition, modal shifts in the atmosphere have altered Arctic Ocean circulation patterns and the export of freshwater into the North Atlantic.
The combination of these processes has resulted in variable patterns of freshwater export from the Arctic Ocean and the emergence of salinity anomalies that have periodically freshened waters in the North Atlantic.
—Greene et al. (2008)
Since the early 1990s, changes in Arctic Ocean circulation patterns and freshwater export have been associated with two types of ecological responses in the North Atlantic, the authors wrote.
The first has been an ongoing series of biogeographic range expansions by boreal plankton, including renewal of the trans-Arctic exchanges of Pacific species with the Atlantic. Since 1989, these plankton, native to the Pacific Ocean, have been colonizing the North Atlantic Ocean, a feat that hasn’t occurred in more than 800,000 years. These plankton were carried across the Arctic Ocean by Pacific waters that made their way to the North Atlantic.
The second response was a dramatic regime shift in the shelf ecosystems of the Northwest Atlantic that occurred during the early 1990s. This regime shift resulted from freshening and stratification of the shelf waters, which in turn could be linked to changes in the abundances and seasonal cycles of phytoplankton, zooplankton, and higher trophic-level consumer populations
When Arctic climate changes, waters in the Arctic can go from storing large quantities of freshwater to exporting that freshwater to the North Atlantic in large pulses, referred to as great salinity anomalies. These GSAs flow southward, disrupting the ocean’s circulation patterns and altering the temperature stratification observed in marine ecosystems.
—Charles Greene
In the continental shelf waters of the Northwest Atlantic, the arrival of a GSA during the early 1990s led to a major ecosystem reorganization, or regime shift. Some ocean ecosystems in the Northwest Atlantic saw major drops in salinity, increased stratification, an explosion of some marine invertebrate populations and a collapse of cod stocks.
The changes in shelf ecosystems between the 1980s and 1990s were remarkable. Now we have a much better idea about the role climate had in this regime shift.
—Charles Greene
The changes observed in recent decades are only the tip of the iceberg. Previous interglacial periods have ended when the global ocean’s deep circulation slowed in response to reductions in the formation of North Atlantic Deep Water (NADW) a large, deep mass of highly saline water in the North Atlantic.
At these tipping points in the Earth’s history, NADW formation was disrupted by pulses of freshwater entering the North Atlantic. The slowing of the global ocean’s deep circulation results in less heat being transported to higher latitudes, accelerating ice formation and advancing the Earth into glacial conditions.
Recent modeling studies show that NADW formation will likely be resilient to freshwater pulses from the Arctic during the 21st century, according to the authors.
Continued exposure to such freshwater forcing, however, could disrupt global ocean circulation during the next century and lead to very abrupt changes in climate, similar to those that occurred at the onset of the last ice age.
If the Earth’s deep ocean circulation were to be shut down, many of the atmospheric, glacial and oceanic processes that have been stable in recent times would change, and the change would likely be abrupt. While the ecosystem consequences of gradual changes in the ocean are somewhat predictable, all bets are off after such abrupt changes occur.
—Charles Greene
Resources
Charles H. Greene, Andrew J. Pershing, Thomas M. Cronin, Nicole Ceci (2008) Arctic Climate Change and its Impacts on the Ecology of the North Atlantic. Ecology: Vol. 89, No. sp11, pp. S24-S38 doi: 10.1890/07-0550.1
These conclusions have been published time and again, so this is additional confirmation.
Posted by: Will S. | 08 November 2008 at 05:58 AM
Yet another refutation of the AGW nonsense.
If I can summarize:
Water from the Arctic is entering the North Atalntic as it always does when there is a periodic shift in the PDO and AMO phase (about every thirty years). Despite the foo-forah about Arctic melting what is actually happening is that lots of Arctic ice is being pushed by the reversed winds and currents, into the North Atlantic along the east coast of Greenland, in this phase of the Arctic MultiDecadal Oscillation. This makes for lower salinity and a lesser warming effect from the GulfStream. Europe will grow colder, not warmer.
Albedo changes are postulated to occur due to greater solar absorption if it were to occur.
This is the prime pollution effect from mankind's use of "Solar Energy", even though it is never mentioned, and Green Loons have never heard of it. But in the Arctic, it is seldom a choice between no cover and ice/snow cover. It makes no difference in the Albedo, if the ice/snow thickness is merely different at various locations during the PDO/AMO cycles.
The AGW hysteria is confimed to be just that, since there has been no global warming in ten years after but twenty years of hysteria while temperatures climbed by a fraction of a degree during the periodic warm phase portion of the cycle.
Good news. Fish food stocks are up. This has happened periodically, like in the 1920s and 1930s when the last such cycle occurred, but they posit a unique cross fertilization between the Pacific and Atlantic not seen since the last glaciation. I suspect these preliminary results will not stand as a unique event.
The Viking colonization of Greenland was dependent on fertile fisheries, as well as warmer Green land temperatures. When the LIA occured the other PDO phase predominated and fiseries declined as well as cooling Greenland.
I have some what jaundiced view of that posited unique finding, since so many fisheries worlwide have been mixed with intruders, over the last few hundred years. Although disruptive, eventually the expanded biota adjusts, in a beneficial overall way.
Posted by: stas peterson | 08 November 2008 at 09:12 AM
The article reports, "Since the 1970s, historically unprecedented changes have been observed in the Arctic as climate warming has increased precipitation, river discharge, and glacial as well as sea-ice melting."
Stas, you seemed to have completely misread this article. Which peer-reviewed journal articles are you pulling your information from?
Posted by: Will S | 08 November 2008 at 10:07 AM
Stan, guess who won the election?
Posted by: | 08 November 2008 at 10:09 AM
Stas wrote:
>The Viking colonization of Greenland was dependent on fertile fisheries
The main reason the Greenlanders failed is because they didn't take advantage of the fish right in their own waters. Where do you get your information from??
Posted by: Will S | 08 November 2008 at 10:10 AM
And the Troll returns with the same old lies;
@Stas "The AGW hysteria is confimed to be just that, since there has been no global warming in ten years"
Then, how about:
every year since 1992 has been warmer than 1992
the ten hottest years on record occurred in the last 15
every year since 1976 has been warmer than 1976
the 20 hottest years on record occurred in the last 25
every year since 1964 has been warmer than 1956
every year since 1917 has been warmer than 1917
Global warming did NOT stop 10 years ago- http://scienceblogs.com/illconsidered/2006/04/warming-stopped-in-1998.php
And we've had global warming in effect for ~100 years, not just 20! - http://scienceblogs.com/illconsidered/2006/03/what-about-mid-century-cooling.php
And Will is right about the Vikings- http://scienceblogs.com/illconsidered/2006/03/greenland-used-to-be-green.php
Posted by: ai_vin | 08 November 2008 at 10:54 AM
You really have to smack these trolls down as fast as they pop up. After watching 8 years as the oil companies and the Whitehouse gave the deniers a louder voice than they deserved- http://video.google.com/videoplay?docid=522784499045867811 -I have no patience for these loons anymore.
Posted by: ai_vin | 08 November 2008 at 11:19 AM
Fish stocks are up?????? Where does this anti AGW stuff come from?
Don't just look at the catches. Look at the inventories. Look at the state of the inventories. Smaller, more juvenile fish. Stocks are down worldwide. They are catching fish that was once considered commercially fringe and now marketing it. It called scraping the bottom of the barrel.
People read. These outrageous statements of ideologically spawned garbage totally insult those people who actually read more than some right wing derived muck.
Stan, AGW is recognized by every recognized scientific organization. Your continual obsessive need to deny it utimately stems from the fact that your logic is simply wrong and not scientific. It's a view looking for reasons and frankly it doesn't care what those reasons are. You've been wrong over IPCC reports over NO2. You've been wrong over N-Am CO2 uptake. Frankly trying to tire others out by spewing force this stuff is futile. Go read something more than the dreck that's reinforing your obviously warped views.
Posted by: aym | 08 November 2008 at 12:19 PM
This report with its 25 citations (I stopped counting after C ) is a credit to the authors and shows how well referenced a report needs to be to stand the ranting denialist nonsense. And still they keep coming.
Absolute Hedras!
Makes you wonder what he gets off on, cracks me up.
Posted by: arnold | 08 November 2008 at 03:00 PM
This reminds me of something I watched almost 20 years ago- http://video.google.com/videoplay?docid=6514270139930450081 -it's old, dated and even quaint but the idea of global warming causing Arctic Ocean circulation patterns to change is right there.
Of course we know a lot more now but it is fun to compare their predictions to what really happened during the last 20 years.
Posted by: ai_vin | 08 November 2008 at 03:17 PM
Unlike y'all who receive your AGW daily fix from press releases of the AGW proponents, seeking contributions, I read the scientific papers on both sides. And then decide. Its easy to see that the Science has revealed the AGW hypothesis is increasingly discredited. Scientists increasingly disbeleive it, even as politicians and polemicists embrace it more fervently.
Try this for no warming over for
the past ten years.
http://icecap.us/images/uploads/MSUCRUCO2.jpg
The only historical time series that shows any warming is the one run by that corrupt hack James Hansen, who holds neither climate, meteorology, nor IT degrees, and is totally unqualified for the position he holds in NASA. He has constantly "adjusted the data" for the historical US time-series ground-level weather data, with no comprehensible and published reason for doing so. The database in his control deviates ever more from the other four existing time series weather databases in the world, which continue to largely agree. Some of his "corrections and adjustments" are patently ludicrous, showing that some large metropolitian areas have no urban island heat effect at all. And are cooler than some presumed rural sites, where data has been lost.
IMHO he should go on trial for destroying the integrity of a precious data source. Instead Algore's appointed political tool, continues to recieve millions in personal compensation, above and beyond his bloated salary, for spouting the AGW party line, saying and doing what he does.
He is a living example of Lysenkoism in action, come to the USA.
It is clear that that much of the global warming baloney rests on the trace rise in CO2, from a doctored artificially low base level, (see Jaworowski), and the dramatically over-exaggerated effect that it supposedly causes.
Within 5 years AGW will exist like "Acid rain", "Ocean Death", "Y2k", "Nuclear fallout", "DDT", and the "Heartbreak of Psoriasis" as phony put-up jobs of over-eager propaganda polemicists seeking an easy buck. Meanwhile there is much damage that will be done.
Some facts: Worldwide there is a tiny rise in trace atmospheric CO2 by about 2.8 petagrams per year. North American contributions from all Sources both man-made and natural, is about 1.3-1.5 petagrams per year. When it comes to Sinks for that CO2, each continent and ocean takes some, just as they produce some.
Significantly, North America absorbs 1.6-1.7 petagrams per year of Carbon. Read the scientific papers.
So despite all the obfuscating goo and dribble, North America, not only consumes all the CO2 it produces, but also fixes about 11% of the rest of the world's atmospheric CO2 output too.
With the prevailing winds blowing generally West to East, the air arriving in the West Coast has been measured to have more CO2 in it, than the air exiting on the East Coast, on average.
So we produce 27% of the worlds goods, use 24% of the world's energy and constitute only 5% of the world's population. And also remove all of our CO2, and then some more.
Where do you find that reported? You don't. Why?
Why is N. America so fortunate? Is it luck? No. It is so because North Americans have invested in land set-asides and preserves long before there was a carbon sink to worry about, since the 1860s. We have more parks and wilderness acreage set-aside, than all the area of the original 13 States of the US. You didn't know that did you? Canada is similar.
Try reading the real Science papers for a change.
http://icecap.us/images/uploads/MSUCRUCO2.jpg
and also:
http://www.sciencemag.org/cgi/content/full/282/5388/442?ijkey=mon8W/Sb1uNZ6
As for universal approval of AGW theory, even the IPCC has had its fill of ever greater claims of atmospheric CO2 persistence with absolutely no scientific experimental evidence to back it up. The IPCC in AR4, have explicitly given the doomsters until the next IPCC Report due around 2011, or they will revert to proven Henry's Law science that says that CO2 washes out of the atmosphere in 5.7 years and not years, decades, centuries, or millenia. Or whatever the AGW proponents seem to need, to buttress their erroneous theories, at the moment.
The theoretical foundations of the entire GHG hypothesis is also now under attack. Dr. Ferenc Miskolczi's work at NASA, before he left there, is as fundamental a revision of atmospheric radiation phenomena, as Einstein's revisions of Newton Laws were, in their way. His theoretical work is being highly received in the theoretical community and is confirmed by his much more correct calculation of measured GHGs effects. His theory that modifies GHG effects including postualting a "saturated GHG effect, even explains some heretofor impossible evidence that was inexplicable. The missing Tropical tropospheric hot spot, the low coefficient of GHG, the "iris effect",and the "no runaway" condition among others.
He doesn't even have to resort to look for the chunk of Outer Space between your shoe-tops and the soles of your feet that I'm sure you observe everyday. The one that conventional theory says MUST be there, to prevent the Oceans from supplying all the (H2O) GHGs needed for the atmosphere to runaway in a global warming GHG calamity.
Posted by: | 10 November 2008 at 01:28 PM
I don't normally respond to anonymous posters, but this one simply set up too many soft pitches;
First, the anon provided a link that seemed to come from the Hadley Centre, so I went and retrieved this image;
http://www.metoffice.gov.uk/research/hadleycentre/images/anomaly75_07.gif , and
http://hadobs.metoffice.com/hadcrut3/diagnostics/HadCRUT3_bar.png
Nothing like the anon's...
"Try reading the real Science papers for a change."
It is unclear if the anon understands what an actual peer reviewed science paper is. Or where to find them.
"...they will revert to proven Henry's Law science that says that CO2 washes out of the atmosphere in 5.7 years and not years, ..."
Oh, this is Stan. Hi anon Stan!
Posted by: Will S | 10 November 2008 at 05:09 PM
Yeah and I really love his line; *Within 5 years AGW will exist like "Acid rain", "Ocean Death", "Y2k", "Nuclear fallout", "DDT", and the "Heartbreak of Psoriasis" as phony put-up jobs*
Yes of course, lets conveniently forget that acid rain, DDT, etc. were very real problems, causing very real effects back in the day, and the only reason they seem like a dream now is that someone stood up, got some protective laws passed and allowed the environment to recover. I know because I was there, I lived through it. How old IS this guy?
Posted by: ai_vin | 10 November 2008 at 06:51 PM