date: Thu, 27 Sep 2007 11:19:28 +0100
from: Phil Jones <p.jonesatXYZxyz.ac.uk>
subject: Re: Science paper
to: "Ogden Annie Ms \(MAC\)" <A.OgdenatXYZxyz.ac.uk>, "Briffa Keith Prof \(ENV\)" <K.BriffaatXYZxyz.ac.uk>
We were both away yesterday. Keith is still. I'm back though and will
be here tomorrow. Away all next week, by the way.
I can see how the sentences in the abstract will be easily misused.
Article has nothing to do with the present though - lots of features 18,000
years ago were quite different!
At 14:59 26/09/2007, Ogden Annie Ms \(MAC\) wrote:
Dear Phil and Keith,
Please see message below re attached a paper from Science which Chemistry World is
asking if you would comment on. I gather you are both out of the office today so have
told the journalist that you are unlikely to pick this up in time - but, on the
offchance that you do, please feel free to send your comment to Simon direct.
Annie Ogden, Head of Communications,
University of East Anglia,
Norwich, NR4 7TJ.
Tel:+44 (0)1603 592764
From: Simon Hadlington [ mailto:firstname.lastname@example.org]
Sent: Wednesday, September 26, 2007 2:08 PM
To: Press Office
Subject: fao Annie
re Chemistry World.
here is the embargoed paper that is due to appear on the science website on friday and
below is the press blurb that came with it. Chemistry World will be running a piece on
the work and it would be very nice to have a few sentences from an independent third
party - ie hopefully someone from your climate change research centre - to say why the
work is significant. I'm happy to speak with someone or else equally happy to receive
four or five sentences in an email. Presumably the work could be grist to the mill of
the global warming sceptics - is there any reason why it shouldn't be?
Chemistry World wants to get something out to coincide with the embargo being lifted, so
really I'd need something by 10am at the latest tomorrow morning. If you could let me
know within the next couple of hours if you've found anyone that would be great.
freelance science journalist
York YO19 6DA
Carbon dioxide did not end the last Ice Age
Deep-sea temperatures rose 1,300 years before atmospheric CO2, ruling out the greenhouse
gas as driver of meltdown, says study in Science.
Lowell Stott, professor of earth sciences, University of Southern California
Click here for more information.
Carbon dioxide did not cause the end of the last ice age, a new study in Science
suggests, contrary to past inferences from ice core records.
There has been this continual reference to the correspondence between CO2 and climate
change as reflected in ice core records as justification for the role of CO2 in climate
change, said USC geologist Lowell Stott, lead author of the study, slated for advance
online publication Sept. 27 in Science Express.
You can no longer argue that CO2 alone caused the end of the ice ages.
Deep-sea temperatures warmed about 1,300 years before the tropical surface ocean and
well before the rise in atmospheric CO2, the study found. The finding suggests the rise
in greenhouse gas was likely a result of warming and may have accelerated the meltdown
but was not its main cause.
The study does not question the fact that CO2 plays a key role in climate.
Lowell Stott, professor of earth sciences at the University of Southern California,
examines a sediment core.
Click here for more information.
I dont want anyone to leave thinking that this is evidence that CO2 doesnt affect
climate, Stott cautioned. It does, but the important point is that CO2 is not the
beginning and end of climate change.
While an increase in atmospheric CO2 and the end of the ice ages occurred at roughly the
same time, scientists have debated whether CO2 caused the warming or was released later
by an already warming sea.
The best estimate from other studies of when CO2 began to rise is no earlier than 18,000
years ago. Yet this study shows that the deep sea, which reflects oceanic temperature
trends, started warming about 19,000 years ago.
What this means is that a lot of energy went into the ocean long before the rise in
atmospheric CO2, Stott said.
But where did this energy come from" Evidence pointed southward.
Waters salinity and temperature are properties that can be used to trace its origin and
the warming deep water appeared to come from the Antarctic Ocean, the scientists wrote.
This water then was transported northward over 1,000 years via well-known deep-sea
currents, a conclusion supported by carbon-dating evidence.
In addition, the researchers noted that deep-sea temperature increases coincided with
the retreat of Antarctic sea ice, both occurring 19,000 years ago, before the northern
hemispheres ice retreat began.
Finally, Stott and colleagues found a correlation between melting Antarctic sea ice and
increased springtime solar radiation over Antarctica, suggesting this might be the
As the sun pumped in heat, the warming accelerated because of sea-ice albedo feedbacks,
in which retreating ice exposes ocean water that reflects less light and absorbs more
heat, much like a dark T-shirt on a hot day.
In addition, the authors model showed how changed ocean conditions may have been
responsible for the release of CO2 from the ocean into the atmosphere, also accelerating
The link between the sun and ice age cycles is not new. The theory of Milankovitch
cycles states that periodic changes in Earths orbit cause increased summertime sun
radiation in the northern hemisphere, which controls ice size.
However, this study suggests that the pace-keeper of ice sheet growth and retreat lies
in the southern hemispheres spring rather than the northern hemispheres summer.
The conclusions also underscore the importance of regional climate dynamics, Stott said.
Here is an example of how a regional climate response translated into a global climate
change, he explained.
Stott and colleagues arrived at their results by studying a unique sediment core from
the western Pacific composed of fossilized surface-dwelling (planktonic) and
bottom-dwelling (benthic) organisms.
These organisms foraminifera incorporate different isotopes of oxygen from ocean water
into their calcite shells, depending on the temperature. By measuring the change in
these isotopes in shells of different ages, it is possible to reconstruct how the deep
and surface ocean temperatures changed through time.
If CO2 caused the warming, one would expect surface temperatures to increase before
deep-sea temperatures, since the heat slowly would spread from top to bottom. Instead,
carbon-dating showed that the water used by the bottom-dwelling organisms began warming
about 1,300 years before the water used by surface-dwelling ones, suggesting that the
warming spread bottom-up instead.
The climate dynamic is much more complex than simply saying that CO2 rises and the
temperature warms, Stott said. The complexities have to be understood in order to
appreciate how the climate system has changed in the past and how it will change in the
Stotts collaborators were Axel Timmermann of the University of Hawaii and Robert Thunell
of the University of South Carolina. Stott was supported by the National Science
Foundation and Timmerman by the International Pacific Research Center.
Stott is an expert in paleoclimatology and was a reviewer for the Intergovernmental
Panel on Climate Change. He also recently co-authored a paper in Geophysical Research
Letters tracing a 900-year history of monsoon variability in India.
The study, which analyzed isotopes in cave stalagmites, found correlations between
recorded famines and monsoon failures, and found that some past monsoon failures appear
to have lasted much longer than those that occurred during recorded history. The ongoing
research is aimed at shedding light on the monsoons poorly understood but vital role in
Sciences press release
Warming >From High to Low:
Analysis of a new sea-sediment core in the Pacific suggests that the warming that
followed the last glacial period began in the high latitudes of the Southern Hemisphere
before sweeping into the tropics. The findings could help sort out the sequence of
climate changes underlying the dramatic switch that turned an ice age into today's
interglacial climate, say Lowell Stott and colleagues. Carbon-14 dating of organic
material in the core suggests that deep tropical waters in the western Pacific warmed up
by about 2 degrees Celsius between 19,000 and 17,000 years ago, 1,500 years earlier than
comparable warming in the tropical surface waters and 1,000 years before atmospheric
carbon dioxide began to rise. The source of the tropical deep heat may have been an even
earlier heat wave in surface waters closer to the South Pole, warmed by an increase in
solar radiation at the hemisphere's higher latitudes.
ARTICLE #23: "Southern Hemisphere and Deep Sea Warming Led Deglacial Atmospheric CO2
Rise and Tropical Warming," by L. Stott at University of Southern California in Los
Angeles, CA; A. Timmermann at University of Hawaii in Honolulu, HI; R. Thunell at
University of South Carolina in Columbia, SC.
CONTACT: Lowell Stott at +1-213-740-5120 (phone), or stottatXYZxyz.edu (email)
Ananyo Bhattacharya PhD
Acting Deputy Editor, Chemistry World
Tel: +44 (0)1223 432 184
Mob: +44 (0)7766 257 642
Fax: +44 (0)1223 426 017
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