Polar core is hot stuff - There was once little difference between equatorial and arctic climates.

news@nature.com ^ | 31 May 2006 | Quirin Schiermeier

[neverdem]

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Published online: 31 May 2006; | doi:10.1038/news060529-5

Polar core is hot stuff

There was once little difference between equatorial and arctic climates.

Quirin Schiermeier

An underwater mountain range near the North Pole tells a story of arctic climates past. © Martin Jakobsson/IBCAO

A core of sediment pulled from the bottom of the Arctic Ocean has confirmed that, millions of years ago, the North Pole was as warm as a balmy summer day.

Drilling in the Arctic Ocean poses enormous technical difficulties, so relatively little has been discovered about the region's climate history. Now, the spoils of the Arctic Coring Expedition (ACEX), extend our knowledge from about half a million years to 80 million years ago.

"This will boost understanding of climate evolution, in the Arctic and globally," says Ursula Röhl, a marine geologist at the University of Bremen in Germany. "It's really fantastic that such an enormous advance is still possible these days."

Some initial findings from the cruise were released two years ago (see 'North Pole once enjoyed Mediterranean climate'). Now the researchers report several analyses of the sediment core in Nature¹.

The results are unexpected. Not only did the Arctic heat up to an extent that is inexplicable by current climate models, say the researchers, it also seems that the North Pole began to cool at about the same time as the Antarctic. This timing suggests that climate was being driven by a global factor, such as atmospheric levels of greenhouse gases, rather than something more local, such as geological upheaval.

"This is a major, major surprise," says Jan Backman, a marine geologist at Stockholm University in Sweden, who co-led the expedition.

Party of ice-breakers

Part of the Integrated Ocean Drilling Program, the US$10-million ACEX project was an adventurous undertaking.

In August 2004, two ice-breakers cleared the Vidar Viking's path to the Lomonosov ridge, a chain of underwater mountains that lie more than 975 metres below the ocean surface and rise up to 3 kilometres above the sea floor. These ice-breakers then sheltered the ship while it drilled for a record-breaking 430 metres of sediment at a point 250 kilometres from the North Pole. Previous cores were only 10 metres long at most.

The isotopic composition of organic carbon from shells and algae in the sediment reveals information about past temperatures. During a period of pronounced warming 55 million years ago, known as the Palaeocene/Eocene thermal maximum, average summertime temperatures in the Arctic Ocean rose to almost 24°C. This is ten degrees higher than what climate models for the period have come up with.

"The Eocene climate apparently knew surprisingly little differences between the poles and the equator," says Röhl.

Scientists believe that the atmosphere at the time was exceptionally rich in greenhouse gases. But Appy Sluijs, a palaeoclimatologist at Utrecht University in the Netherlands and first author of one of the papers², says that Arctic warming must have been amplified by an additional factor — possibly heat-trapping stratospheric clouds or hurricane-induced ocean mixing.

Impeccable timing

The sediment core also reveals the timing of the north's heating and subsequent cooling. Scientists have found evidence of the Antarctic starting to ice up from 43 million years ago. But evidence of glaciation and sea ice at the North Pole had only been found from about 6 million to 10 million years ago⁴.

Now geologists have found sand and pebbles in the central Arctic basin that they think can only have been carried there by icebergs 45 million years ago. So it seems that Arctic glaciation began around the same time as the southern freeze. "It revolutionizes our view on how ice and climate developed," says Backman.

"Understanding the geological past is absolutely essential for modellers," adds Röhl. "Only climate simulations that are able to correctly reproduce the past are likely to accurately predict the future."

Visit our newsblog to read and post comments about this story.

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References

1. Moran K., et al. Nature, 441. 601 - 605 (2006). | Article |

2. Brinkhuis H., et al. Nature, 441. 606 - 609 (2006). | Article |

3. Sluijs A., et al. Nature, 441. 610 - 613 (2006). | Article |

4. Lear C. H.,

   Elderfield P. H. &

   Wilson P. A. Science, 287. 269 - 272 (2000). | Article | PubMed | ISI | ChemPort |

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[neverdem]

Studies Portray Tropical Arctic in Distant Past This link is from the printer friendly page and the following pics are from the NY Times article with the same title.

Martin Jakobsson
The ship Vidar Viking had to remain stationary for days at a time amid drifting sea ice near the North Pole.

John Farrell/University of Rhode Island
Two scientists cutting a core into sections on the drill ship Vidar Viking during a 2004 mission by the Integrated Ocean Drilling Program.



John Farrell/University of Rhode Island
Coarse-grained sediments taken from the core samples of the floor of the Arctic Ocean in 2004 are examined under a light microscope.

[Spruce]

Bush's fault.

[Liberty Valance]

Last thing I remember is the freezing cold
Water reaching up just to swallow me whole
Ice in the rigging and howling wind
Shock to my body as we tumbled in
Then my brothers and the others are lost at sea
I alone am returned to tell thee
Hidden in ice for a century
To walk the world again
Lord have mercy on the frozen man

Next words that were spoken to me
Nurse asked me what my name might be
She was all in white at the foot of my bed
I said angel of mercy I'm alive or am I dead
My name is William James McPhee
I was born in 1843
Raised in Liverpool by the sea
But that ain't who I am
Lord have mercy on the frozen man

It took a lot of money to start my heart
To peg my leg and to buy my eye
The newspapers call me the state of the art
And the children, when they see me, cry
I thought it would be nice just to visit my grave
See what kind of tombstone I might have
I saw my wife and my daughter and it seemed so strange
Both of them dead and gone from extreme old age
See here, when I die make sure I'm gone
Don't leave 'em nothing to work on
You can raise your arm, you can wiggle your hand(unlike mysef)
And you can wave goodbye to the frozen man

I know what it means to freeze to death
To lose a little life with every breath
To say goodbye to life on earth
To come around again
Lord have mercy on the frozen man
Lord have mercy on the frozen man

[BipolarBob]

Bush's fault.

Yes the baked beans caused it.

[HiTech RedNeck]

Imagine the burgeoning tropical vacation industry in Antarctica.

[gleeaikin]

Were the poles in roughly the same place they are now, 45 and 80 million years ago?

[Jedidah]

This is not news. Perhaps this particular expedition is, but scientists and archaeologists have known for many years that tropical life once existed in the Arctic.

Take, for example, the woolly mammoths that have been excavated in Siberian tundra, sometimes with green plants still preserved in their stomachs or under their bodies.

http://www.geocities.com/aleph135/mammoths17.html

http://www.geocities.com/stegob/mammoth.html

[neverdem]

Report Shows AIDS Epidemic Slowdown in 2005

Countries Under-Reporting Bird Flu

FReepmail me if you want on or off my health and science ping list.

[coconutt2000]

Maybe they'll find evidence of Bush's time machine that he used to cause global warming and global cooling before men were around.

[Gondring]

It's not merely saying there were warm conditions in the polar regions...read the article.

[DeuceTraveler]

There is an unproven scientific belief out there that every now and then the planet 'flips' and the north and south poles realign to another geographic portion of the Earth, which also causes natural phenemonon such as floods, volcanic eruptions, and regions that were warm and sunny to quickly turn into an 'ice age'. This would seem to support that theory.

[DeuceTraveler]

See above post.

[USFRIENDINVICTORIA]

I don't know about flipping -- but it does appear to tilt and wobble. I learned the term "Milankovitch Cycle" from DBrow on this thread:

http://www.freerepublic.com/focus/f-news/1641377/posts

Posts # 24 and #29.

[ko_kyi]

Way to break out the JT!

[Robert A Cook PE]

Yes, the physical poles (axis od rotation) has not changed.

The precession of the axis about the north pole is very small (much less than 1/4 of one degree) acting over a 24,000-some-odd period, but that seems to match with some of the more recent ice ages.

This period (45 million years ago) is about 20 million after the dinosaur-die-off at 65 million BC. So I don't see it being related to that.

24 deg C is about mid-70's; so what they're saying is that the climate on th north slope was temperate. That would require that the mid-latitudes were very hot (more than 100+ average) so there MUST be some indication of massive changes in the mid-latitudes for this period.

Near equator areas would be 110-120 average temperatures for many years. This is impossible for modern plant life, so you'd have evidence there as well: much more evidence than pebbles on a single core drill on an underground mountain in the Arctic.

If no evidence elsewhere on the planet?

Forget the theory of "north pole hot."

[Air Force Brat]

The reversal of the Earth's magnetic poles is not an "unproven scientific belief." It's a widely accepted explanation for observed conditions in the magnetic polarity of magnetite (a magnetic mineral) in the rocks extruded originally as basalt lava from oceanic ridges.

This page from the U.S. Geological Survey (http://pubs.usgs.gov/gip/dynamic/developing.html) provides a summary.

[Air Force Brat]

The reversal of the Earth's magnetic poles is not an "unproven scientific belief." It's a widely accepted explanation for observed conditions in the magnetic polarity of magnetite (a magnetic mineral) in the rocks extruded originally as basalt lava from oceanic ridges.

This page from the U.S. Geological Survey (http://pubs.usgs.gov/gip/dynamic/developing.html) provides a summary.

[Air Force Brat]

Whoops. My apologies!

[Ole Okie]

Maybe they'll find evidence of Bush's time machine>>

That's Rove's Time Machine and Hurricane Formation and Guidance machine combined.

[DBrow]

The poles of rotation don't flip- where would the energy come from? The North pole wobbles a bit (for the Egyptians 3000 yrs ago Thuban was the pole star, not Polaris) but remains pointed roughly at Draco or Ursa Minor.

But the magnetic poles certainly do flip, this has been shown through magnetometry of the rocks along the Atlantic Ridge and in other places. Nobody is sure why.