Arctic Could Face Warmer and Ice-Free Conditions (Pliocene projections - USGS)

U.S. Geological Survey ^ | Dec 29, 2009 | Unknown

[decimon]

There is increased evidence that the Arctic could face seasonally ice-free conditions and much warmer temperatures in the future.

Scientists documented evidence that the Arctic Ocean and Nordic Seas were too warm to support summer sea ice during the mid-Pliocene warm period (3.3 to 3 million years ago). This period is characterized by warm temperatures similar to those projected for the end of this century, and is used as an analog to understand future conditions.

The U.S. Geological Survey found that summer sea-surface temperatures in the Arctic were between 10 to 18°C (50 to 64°F) during the mid-Pliocene, while current temperatures are around or below 0°C (32°F).

Examining past climate conditions allows for a true understanding of how Earth’s climate system really functions. USGS research on the mid-Pliocene is the most comprehensive global reconstruction for any warm period. This will help refine climate models, which currently underestimate the rate of sea ice loss in the Arctic.

Loss of sea ice could have varied and extensive consequences, such as contributions to continued Arctic warming, accelerated coastal erosion due to increased wave activity, impacts to large predators (polar bears and seals) that depend on sea ice cover, intensified mid-latitude storm tracks and increased winter precipitation in western and southern Europe, and less rainfall in the American west.

“In looking back 3 million years, we see a very different pattern of heat distribution than today with much warmer waters in the high latitudes,” said USGS scientist Marci Robinson. “The lack of summer sea ice during the mid-Pliocene suggests that the record-setting melting of Arctic sea ice over the past few years could be an early warning of more significant changes to come.”

Global average surface temperatures during the mid-Pliocene were about 3°C (5.5°F) greater than today and within the range projected for the 21st century by the Intergovernmental Panel on Climate Change.

Read the full article at http://micropress.org/stratigraphy/.

Scientists studied conditions during the mid-Pliocene by analyzing fossils dated back to this time period. The USGS led this research through the Pliocene Research, Interpretation and Synoptic Mapping group. The primary collaborators in PRISM are Columbia University, Brown University, University of Leeds, University of Bristol, the British Geological Survey and the British Antarctic Survey. Learn more about PRISM research.

USGS provides science for a changing world. For more information, visit www.usgs.gov.

Subscribe to USGS News Releases via our electronic mailing list or RSS feed.

**** www.usgs.gov ****

Links and contacts within this release are valid at the time of publication.

[rightwingcrazy]

Count me in as a consultant. I’m not highly qualified, but I can give a highly qualified opinion on any subject.

[JustDoItAlways]

The sea surface temperatures in these regions in August is normally 6C to 12C. So, 10C to 18C would be 4C to 6C warmer than today.

Some of these newer isotopes like the Uk37 used in this study seem to be showing warmer temperatures than other isotopes do.

This chart should show a temperature history over 67 million years which are very similar to the locations chosen for this study.

3 million years ago +1.0C to +2.0C and 55 million years ago +12.0C. If we applied the same ratios as this study, temperatures would be closing in on 100C 55 million years ago. So they need to recalibrate these isotopes.

http://www.globalwarmingart.com/wiki/File:65_Myr_Climate_Change_Rev_png

[Old Professer]

This makes about the fourth piece I’ve seen based on these old proxies recently revealed where each new twist is a caution against repeating what took place years before there was any industrial activity or other source of man-made contribution.

Considering how hard the CRU worked to bury the warm period in the hockey Stick when there were men here in small number, all this noise seems to be just noise.

If this crap can happen without men around to stop it then, they must be imaging that we can forestall it now.

How ‘cool’ is that!?

[muawiyah]

The deal is that 3 million years ago is BEFORE the current Ice Age ~ which has been running for about 2 million years.

The ocean levels were higher and there was a greater current moving warm water into the Arctic.

One theory is that due to North America's tectonic plate moving further North this has blocked the flow of that warm water which then plunged the Earth into a very long ice age.

Until the plate rotates a different direction, North America will continue to move North and further reduce the flow of warmer water into the Arctic.

My simplistic, but most likely accurate estimation is that it's going to get colder for a very long time.

[o_zarkman44]

I have no disagreements with what you said.

[SunkenCiv]

Thanks decimon.

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[SunkenCiv]

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	Gods Graves Glyphs	Thanks decimon. It's a little late this week to post a bunch of GGG topics, and I'm about to go to bed, AND tomorrow is spoken for, hmm, guess it'll be easy to do the Digest on Saturday. :') To all -- please ping me to other topics which are appropriate for the GGG list. GGG managers are SunkenCiv, StayAt HomeMother, and Ernest_at_the_Beach
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[gleeaikin]

I think the complaint is about summer sea ice. Your picture are for December. Do you have anything for August? or July?

[gleeaikin]

I seem to recall that about 3 million years ago was when the two hemispheres became connected by the isthmus of Panama, which caused major changes in ocean circulation and temperature distribution.

[muawiyah]

I was there. Horrible, horrible thing ~ just a peaceful middle-class school of sharks and next thing you know we were separated into two species ~ and it took forever to swim around Tierra del Fuego to meet up with old friends (and kissing cousins of course).

[Mike Darancette]

This period is characterized by warm temperatures similar to those projected for the end of this century, and is used as an analog to understand future conditions.

So warmer temperatures in the Arctic are or have been the norm? So what is the cause of the earlier warm periods?

Blame Panama for the earlier warm period.

[icwhatudo]

Sure (July 2009 is not available so I used 2008):

[colorado tanker]

I agree with you guys. Of course it was warmer in the Pliocene. The characteristic of the beginning of the Holocene is our cycle of glacial and interglacial periods. Taking the climate as a whole we've been in a kind of ice age the whole time.

Most scientists think this happened when the isthmus of Panama closed blocking global ocean currents.

So, the pattern is unlikely to break until plate tectonics breaks up the North/South America land mass.

Aren't geologists supposed to know this stuff?

[muawiyah]

I think the closing of the Isthmus was about 7.5 million years ago and that coincides with the development of the present ice sheet on that continent.

The North American deal is more recent ~ 3 million years or so ~ and it moved into position to support year round ice and also to restrict the flow of warmer water into the Arctic ocean basin.

[colorado tanker]

I read several papers online and the consensus seems to be the Isthmus closed 3.5 to 2.5 million years ago. I found an outlier calling it at 5 million years ago, but they have to resort to some exotic speculation as to how the closing could first cause the Pliocene warm and then cause the Holocene glacial cycles. It makes most sense to me that the closing coincided with the ending of the Pliocene warm. A couple of papers make the excellent point that this likely was not a sudden occurrence, but likely for a time was intermittent, open during interglacial periods of high sea levels and closed during glacial lows.

[muawiyah]

Just reading my Science News ~ came in today's mail ~ they have an article about the Straits of Gibraltar. They formed 5.0 to 5.5 million years ago when the Atlantic cut through the uplift that'd earlier blocked the Mediterranean from the main body of the Ocean.

This lowered aggregate Ocean levels ~ and could have "cooled things down". The Ice Age started up 2.5 million years later ~

[colorado tanker]

Almost everything I've read says scientists think the alteration of ocean currents, creating among other things the Gulf Stream, and divergence of salinity levels in the Atlantic and Pacific triggered the onset of the glacial cycles, but I can't tell you just how that worked.

It's interesting the opening of the Straits of Gibraltar came just before the Pliocene Warm. Any connection?

[muawiyah]

There are a whole bunch of things that've happened over the last 10 milliion years. The closing of Panama is probably the biggest, but the rest of South America formed and the various lakes and large inlets were filled in or lifted up.

North America rotated to begin enclosing the Arctic, and when that's done we're back to Snowball Earth where there really isn't any circulation of water currents between the equator and the poles.

The Leftwingtards will undoubtedly object to the use of nuclear energy to "restore circulation" claiming that this will disturb the ecological balance (of that time).

[colorado tanker]

Well, by then they'll be back to screaming about global cooling. Will they demand we all buy SUV’s to try to stave off the cold???

[Miss Marple]

“The Cloud Mystery” on YouTube explains climate change with cosmic rays. I find it very believable. Actual experiments and real numbers, not “massaged” statistics.

Also check the book “The Chilling Stars” by Henryk Svenmark. Svenmark is the scientist featured in the documentary “The Cloud Mystery.”