PLEASE NOTE:
*
CCNet CLIMATE SCARES & CLIMATE CHANGE, 29 May 2002
--------------------------------------------------
"The icebergs breaking away from Antarctica in recent months
-- some
as big as small states -- are part of a process scientists say
marks a
return to ice conditions of years past. Several ice shelves
around
the continent have been growing in recent years, a process that
has
puzzled researchers concerned about possible global
warming."
--Randolph Schmid, AP, 23 May 2002
"Many records bear testimony to the reality of a
millennial-scale
oscillation in Holocene climate in Europe, the warm and cold
extremes of which are similar to what we know as the Medieval
Warm Period
and Little Ice Age. Where comparisons are possible, the available
data
suggest that the Modern Warm Period in which we currently live is
not much
different from that of most earlier warm periods and, in fact,
may actually
not yet be as warm as some of them."
CO2 Science Magazine, 29 May 2002
(1) ARCTIC ICE: IN MELTDOWN?
Radio Nederland, 21 May 2002
(2) ANTARCTIC ICEBERGS SEEN AS NORMAL
Newsday, 23 May 2002
(3) HOLOCENE CLIMATE RECORDS IN EUROPE
CO2 Science Magazine, 29 May 2002
(4) MEASURING CHANGES IN SEA LEVEL
CO2 Science Magazine, 29 May 2002
(5) REVERSING EXTINCTION: BREAKTHROUGH IN BID TO BRING TASMANIAN
TIGER BACK TO LIFE
Ananova, 28 May 2002
(6) A SLIGHT CHILL IN THE AIR: WHY SOLAR POWER IS IN DECLINE
The Christian Science Monitor, 23 May 2002
(7) A WARM POLAR WINTER WAS EASIER ON ARCTIC OZONE
Andrew Yee <ayee@nova.astro.utoronto.ca>
(8) TONY BLAIR'S HIDDEN AGENDA
A. Beal <a.beal@btinternet.com>
(9) AND FINALLY: BAD NEWS FOR COSMIC PESSIMISTS AS LIFE MAY GO ON
FOREVER
Nature, 27 May 2002
================
(1) ARCTIC ICE: IN MELTDOWN?
>From Radio Nederland, 21 May 2002
http://www.rnw.nl/science/html/ice020521.html
by Anne Blair Gould of our Science Unit, 21 May 2002
With many scientists predicting global climate warming, what can
Arctic
glaciers and icebergs tell us about possible changes in sea
level?
Scientists from all over the world gathered in The Netherlands
recently to
compare notes at the 'Arctic Science Summit Week'.
These days, we're all becoming familiar with phrases such as
'global
warming' as a result of a possible 'greenhouse effect'.
Temperatures may
increase by as much as one degree centigrade over the next 100
years, warn
scientists, and as result, polar ice will melt and sea levels
rise. But
what's the evidence?
Ice in Balance
One line of study is to work out whether glaciers are melting at
a quicker
rate than they are forming, which is what Professor Hans
Oerlemans of the
University of Utrecht in the Netherlands is attempting:
"When you go above the snowline, there is more snow
accumulating than ice
melting so a glacier is formed. But of course it doesn't pile up
forever. At
some stage, when the glacier reaches a certain thickness, ice
starts to flow
from the upper to the lower regions of the glacier where it
melts. For a
glacier in balance, this flow from the upper to the lower parts
exactly
matches the rate of melting in the lower regions - but if the
melting is
faster, the glacier becomes smaller."
So how does this translate into predictions about climate warming
and
melting ice?
"Most climate models predict that there will be an increase
in snowfall as
well as more melting - so which one will win? It's our task to
find out."
Sensitive Glaciers
Having studied glaciers in western Greenland, Vatnajökull in
Iceland, Norway
and Alaska, Professor Oerlemans has come to the conclusion that
"Glaciers in wet climates like Alaska and Iceland are much
more sensitive to
climatic variation than glaciers in dry areas like those in
Greenland and
the Canadian Arctic. Therefore we would expect these sensitive
glaciers to
react much more to global warming."
But are any of these glaciers now actually shrinking? Still more
work is
needed.
"Even for the Greenland ice-sheet, where a lot of research
has already been
done, we cannot say yet whether it's shrinking or growing.
However another 5
to 10 years should give us a reliable answer."
Icecaps and Icebergs
Another line of research investigates how much the formation of
icebergs
will contribute to sea level rise. "One of the big unknowns
at present is
how much ice is lost from the Arctic icecaps through production
of icebergs
- a process glaciologists call calving," explains Professor
Julian
Dowdeswell, Director of the Scott Polar Research Institute at
Cambridge
University in the UK.
Sedimental Secrets
By studying how different ice formations from the past have left
their mark
in underwater sediments at the edge of continents, Professor
Dowdeswell
hopes to understand the rate at which icebergs are formed at the
edge of the
icecaps.
"We have recognised three different kinds of geological
structures formed
during past glacial periods. And what these tell us is that
ice-sheets can
be divided into fast and slow-moving elements."
Neglected Mass
Using this information in a present-day icy environment,
Professor
Dowdeswell can now calculate the volume of icebergs produced,
which then
melt in the sea.
"In our study site in Severnaya Zemlya in the Russian high
Arctic, we found
that production of icebergs accounts for about 40% of the mass
lost from the
icecap - a significant amount given that iceberg losses have
tended to be
neglected in most calculations of mass lost from arctic ice
caps."
==============
(2) ANTARCTIC ICEBERGS SEEN AS NORMAL
>From Newsday, 23 May 2002
http://www.newsday.com/news/nationworld/wire/sns-ap-antarctic-icebergs0523may23.story?coll=sns%2Dap%2Dnationworld%2Dheadlines
By RANDOLPH E. SCHMID
Associated Press Writer
WASHINGTON -- The icebergs breaking away from Antarctica in
recent months --
some as big as small states -- are part of a process scientists
say marks a
return to ice conditions of years past.
Several ice shelves around the continent have been growing in
recent years,
a process that has puzzled researchers concerned about possible
global
warming.
In the last three months -- autumn there -- several icebergs, one
the size
of Delaware and another nearly as big as Chesapeake Bay, have
broken free.
"The icebergs that have calved in last couple of months
probably don't have
much to do with global warming. It is part of a pattern of growth
and
retreat that is more or less normal," explained Ted Scambos
of the National
Snow and Ice Data Center at the University of Colorado.
University of Chicago researcher Douglas MacAyeal, who placed
automated
weather stations and tracking devices on one of the new icebergs,
said the
satellite and other technologies are allowing science for the
first time to
observe the birth of such large bergs.
The process, he said, is part of a natural cycle in which ice
shelves grow
and then calve icebergs over geological time scales.
A couple of the ice shelves along the coasts of the continent,
particularly
the Ross and Ronne shelves, have become more extended than they
were in the
past and are now returning to the limits that were normal from
about the
1950s to the 1970s, Scambos said.
Scientists are also much better able to track these icebergs
using
satellites, Scambos noted. "Anytime an event occurs we're on
it in a day or
two."
"It's a grand event, it's astounding event," when these
bergs break loose,
he said. "But it probably should not cause alarm ... the
shelves that are
calving don't seem to be retreating past their minimum historical
extent."
He added, however, that scientists don't have good long term
records of
Antarctic sea ice limits.
H. Jay Zwally of the NASA Goddard Space Flight Center in
Greenbelt, Md.,
reports in the June issue of the Journal of Geophysical
Research-Oceans that
the amount of floating sea ice surrounding Antarctica has
increased about 1
percent per year over the last 20 years.
The increasing amount of floating ice results from a combination
of
processes including changes in salinity and the amount of
overturning of the
water. Water with less salt freezes more easily and reducing the
rising and
falling ocean water means less heat comes up from below.
This is occurring "possibly despite global warming and
possibly as a result
of global warming," he said.
At the same time, at the other end of the planet, Arctic ice has
been
decreasing.
And there is also melting on the Larsen Ice Shelf at the
Antarctic peninsula
that extends toward the tip of South America.
The collapse of that shelf, much farther north than the Ross and
Ronne
shelves, is thought to be related to temperature increases in
that region.
Larsen and the Antarctic peninsula "have experienced an
unusual and profound
warming trend," Scambos said. "Ice shelves that had
existed several thousand
years are retreating. The surprise is how fast the turnaround
occurred."
Satellite images show that the piece of the Larsen Ice Shelf
collapsed
during a five-week period that ended March 7. It splintered into
a plume of
drifting icebergs. The Larsen Ice Shelf has been under careful
observation
since 1995, when its northernmost sector collapsed in a similarly
dramatic
event. The shelf now is about 40 percent of its original size.
But glaciers elsewhere on the continent are both thickening and
thinning as
temperatures show conflicting climate trends.
On the Net:
National Ice Center: http://www.natice.noaa.gov
Copyright © 2002, The Associated Press
===============
(3) HOLOCENE CLIMATE RECORDS IN EUROPE
>From CO2 Science Magazine, 29 May 2002
http://www.co2science.org/subject/h/summaries/holoceneeuro.htm
The climate of the current interglacial, i.e., the Holocene,
exhibits a
millennial-scale oscillation that has resulted in
several-hundred-year
alternating warm and cold periods, the most recent of which is
the Modern
Warm Period that many people are telling us is due to the
CO2-emitting
activities of man. Before this claim is accepted, however,
it would seem
only prudent to determine if there is any evidence for similar
warm periods
in earth's recent history that were clearly not
man-induced. If there were
some such warm periods, for example, there would be no reason to
accept the
climate-alarmist claim that human activities have produced the
one in which
we currently live.
In an attempt to help resolve this issue, Karlen (1998) examined
proxy
climate data related to changes in the size of glaciers, the
altitude of the
alpine tree-limit, and the width of tree rings to derive a
history of summer
temperatures in Scandinavia over the last 10,000 years. The
results
revealed a number of long- and short-term temperature
fluctuations, the
warmer periods of which were "about 2°C warmer than at
present." In
addition, the data indicated the observed climate changes were
likely driven
by changes in solar radiation. It was also concluded that
"the frequency and
magnitude of changes in climate during the Holocene do not
support the
opinion that the climatic change of the last 100 years is
unique." Indeed,
the author of the report bluntly states "there is no
evidence of a human
influence so far."
In pursuing the same goal, Bianchi and McCave (1999) studied the
grain sizes
of North Atlantic deep-sea sediment cores that appeared to be
related to the
flow rate of the thermohaline circulation of the ocean in that
part of the
world. Covering the last 11,000 years, these data also
showed several
warm/cool oscillations that had a quasi-periodicity on the order
of 1500
years. These oscillations, according to the scientists, were
comparable to
the Little Ice Age and the Medieval Warm Period and appear to be
a
"recurrent feature" of Holocene climatic history.
In another approach to the question, Hormes et al. (2001)
determined the
ages of sub-fossil wood and peat samples from six glacier
forelands in the
Central Swiss Alps. Their data revealed several periods of
glacier recession
during the Holocene beyond present glacier positions.
Observational records
also indicated that since the 19th century the glaciers under
study have
twice retreated and subsequently readvanced, around 1920 and
1980. Hence,
the current terminus positions of the Central Swiss Alps glaciers
fall well
within their natural range of Holocene variability, indicating
nothing
unusual about the region's present climate.
Utilizing yet another technique, McDermott et al. (2001) derived
a ð18O
record from a stalagmite discovered in a cave in southwestern
Ireland with a
time resolution that they say is "approximately an order of
magnitude better
than in the North Atlantic cores that record evidence for
quasi-periodic
(1475 ± 500 year) ice rafting during the Holocene."
Their data exhibited
climatic variations that are "broadly consistent with a
Medieval Warm Period
at ~1000 ± 200 years ago and a two-stage Little Ice
Age." Also evident in
their data are the ð18O signatures of the earlier Roman Warm
Period and the
Dark Ages Cold Period that comprised the previous full climatic
cycle of the
region.
Finally, Allen et al. (1999) analyzed sediment cores from a lake
in southern
Italy and from the Mediterranean Sea, deriving high-resolution
climate and
vegetation data sets for the last 100,000 years in this
region. Over the
warmest portion of the record, i.e., the Holocene, the organic
carbon
content of the vegetation reached its highest level, which was
more than
twice as great as that experienced over the earlier glacial
portion of the
record. Other data indicated that the greater vegetation
cover of the
Holocene led to less soil erosion.
In summary, many records bear testimony to the reality of a
millennial-scale
oscillation in Holocene climate in Europe, the warm and cold
extremes of
which are similar to what we know as the Medieval Warm Period and
Little Ice
Age. Where comparisons are possible, the available data suggest
that the
Modern Warm Period in which we currently live is not much
different from
that of most earlier warm periods and, in fact, may actually not
yet be as
warm as some of them. The data of Allen et al. (1999)
additionally suggest
that the biosphere was a full participant in the various climatic
fluctuations that occurred, both prior to and during the
Holocene, "contrary
to widely held views that vegetation is unable to change with
such
rapidity." And, of course, all indications are that warmer
has always been
better than colder in terms of plant productivity. In
conclusion,
therefore, there would appear to be no compelling reason to
believe that any
of the warming of the past century or so was necessarily produced
by the
CO2-emitting activities of man ... although even if some of it
were, that
would clearly not be bad!
References
Allen, J.R.M., Brandt, U., Brauer, A., Hubberten, H.-W., Huntley,
B.,
Keller, J., Kraml, M., Mackensen, A., Mingram, J., Negendank,
J.F.W.,
Nowaczyk, N.R., Oberhansli, H., Watts, W.A., Wulf, S. and
Zolitschka, B.
1999. Rapid environmental changes in southern Europe during
the last
glacial period. Nature 400: 740-743.
Bianchi, G.G. and McCave, I.N. 1999. Holocene
periodicity in North
Atlantic climate and deep-ocean flow south of Iceland.
Nature 397: 515-517.
Hormes, A., Muller, B.U. and Schluchter, C. 2001. The
Alps with little
ice: evidence for eight Holocene phases of reduced glacier extent
in the
Central Swill Alps. The Holocene 11: 255-265.
Karlen, W. 1998. Climate variations and the enhanced
greenhouse effect.
Ambio 27: 270-274.
McDermott, F., Mattey, D.P. and Hawkesworth, C. 2001.
Centennial-scale
Holocene climate variability revealed by a high-resolution
speleotherm ð18O
record from SW Ireland. Science 294: 1328-1331.
Copyright © 2002. Center for the Study of Carbon Dioxide
and Global Change
====================
(4) MEASURING CHANGES IN SEA LEVEL
>From CO2 Science Magazine, 29 May 2002
http://www.co2science.org/journal/2002/v5n22c2.htm
Reference
Douglas, B.C. and Peltier, W.R. 2002. The puzzle of
global sea-level rise.
Physics Today 55: 35-40.
What was done
The authors discuss a number of complexities associated with the
assessment
of global sea level change, review the current state of our
knowledge about
this important subject, and give their prognosis for the future.
What was learned
Mean global sea level (GSL), according to the authors, was
relatively stable
for the past few millennia, but it "abruptly began to rise
near the mid-19th
century." In this regard, however, they note that no
studies "have detected
any significant acceleration of GSL rise during the 20th
century."
The authors' best estimate of the mean rate of GSL rise over the
past
century is, as they put it, "closer to 2 mm/y than 1
mm/y." With respect to
reasonably well understood sources of water that likely
contribute to this
rise, they say that 0.6 mm/y likely comes from thermal expansion
of the
oceans and that 0.3 mm/y likely comes from the melting of small
ice sheets
and glaciers, leaving about 1 mm/y to be explained (their
"puzzle"), if
their best estimate of GSL rise is correct.
How will the puzzle be solved? The authors describe new
satellite programs
designed to provide the answer; but they say that "several
years of data and
further efforts at interpretation will doubtless be
required."
What it means
At the current time, we know two things about mean global sea
level: (1)
after a several-millennia hiatus, global sea level began to rise
about 1850,
and (2) the rise since that time, to the best of our knowledge,
has been at
a constant rate. We also know that the air's CO2 content
began to rise at
about the same time, i.e., 1850. However, its rate of rise
has been
anything but constant. Over the first half of this period
(1850 to 1925),
for example, the atmosphere gained about 20 ppm of CO2, whereas
over the
second half (1925-2000) it gained about 65 ppm. Hence, it
would appear to
be a good bet that the historical rise in mean global sea level
has not been
driven by the concomitant rise in the air's CO2 content.
Copyright © 2002. Center for the Study of Carbon Dioxide
and Global Change
==============
(5) REVERSING EXTINCTION: BREAKTHROUGH IN BID TO BRING TASMANIAN
TIGER BACK TO LIFE
>From Ananova, 28 May 2002
http://www.ananova.com/news/story/sm_596915.html?menu=news.scienceanddiscovery
Scientists in Australia say they've achieved a major breakthrough
in their
bid to bring the extinct Tasmanian Tiger back to life.
Researchers have successfully copied individual genes from a
preserved tiger
pup using a process known as Polymerase Chain Reaction.
Project leaders say it's a critical step forward in their
research, as the
PCR technique allows fragments of DNA to be rapidly replicated.
The Australian Museum research team's next goal is to make large
quantity
copies of Tasmanian Tiger genes in an effort to construct
synthetic
chromosomes.
The Tasmanian Tiger - a striped marsupial wolf - died out in
1936. A tiger
pup was preserved in alcohol by the Australian Museum in 1866.
Samples of heart, liver, muscle and bone marrow taken from the
preserved pup
have been found to contain high quality DNA.
Museum director, Professor Mike Archer, said: "The PCR
technique was an
extremely critical step in producing sufficient amounts of
Tasmanian Tiger
DNA to proceed with the research."
He told Australian Museum Online researchers are working on a DNA
library to
ensure the Tasmanian Tiger genes are preserved forever.
Copyright 2002, Ananova
====================
(6) A SLIGHT CHILL IN THE AIR: WHY SOLAR POWER IS IN DECLINE
>From The Christian Science Monitor, 23 May 2002
http://www.csmonitor.com/2002/0523/p15s01-sten.html
By Laurent Belsie
LAKE ST. LOUIS, MO. - A shadow hangs over the booming solar
industry that no
one can quite explain. Big corporations have moved into the
business.
Homeowners, homebuilders, schools, even city halls are snapping
up the
technology. So why does fast-growing, progressive Oregon have
fewer
solar-heated homes today than in 1990?
Full article at http://www.csmonitor.com/2002/0523/p15s01-sten.html
===========
(7) A WARM POLAR WINTER WAS EASIER ON ARCTIC OZONE
>From Andrew Yee <ayee@nova.astro.utoronto.ca>
Rob Gutro
AGU Press Room Washington Convention
Center MAY 28, 2002
Rgutro@pop900.gsfc.nasa.gov
Phone: 202/371-5016
Cynthia M. O'Carroll
Goddard Space Flight Center, Greenbelt, Md.
cocarrol@pop100.gsfc.nasa.gov
Phone: 301/614-5563
Charles Rose
University of Maryland Baltimore County
crose@umbc.edu
Phone: 410/455-5793
RELEASE: 02-80
A WARM POLAR WINTER WAS EASIER ON ARCTIC OZONE
A NASA researcher has found unusually high levels of protective
upper
atmospheric ozone in the Arctic as a result of a rare sudden
warming during
the early winter of 1998.
"There are several factors that control polar ozone
including air
temperature in the stratosphere, the presence of polar
stratospheric clouds
(PSCs), and the timing and strength of large atmospheric waves
that bring
ozone to the poles from the tropics," said Susan Strahan, an
atmospheric
scientist at NASA's Goddard Space Flight Center, Greenbelt, Md.,
and author
of a paper being presented at the American Geophysical Union's
spring
meeting in Washington.
During the wintertime, as the temperatures drop, winds swirl
around the
poles and form a vortex. The atmospheric circulation brings ozone
from the
upper to the lower stratosphere, where temperatures are colder.
The stronger
the vortex, the less ozone is transported to the cold lower
stratosphere,
where breakdown of ozone by PSCs can occur.
During 1998, however, Strahan found that more low latitude air
surged
poleward in December of that year bringing higher levels of ozone
than usual
and warmer than normal temperatures into the Arctic vortex. From
January to
March, the high ozone air descended to lower altitudes in the
vortex, where
polar stratospheric clouds often form. These clouds form during
colder
temperatures and cause ozone molecules to break apart, but the
warm air that
surged with the ozone prevented the PSCs from forming.
"As a result, ozone in the lower stratospheric vortex was
higher than usual
this year because more ozone than usual was transported into
it," Strahan
said.
Strahan's research is supported by earlier findings by NASA's
Paul Newman in
2001 that said large-scale atmospheric waves carry ozone from the
equator to
the poles. Typically, ozone "piles up" in the
stratosphere over the tropics.
When the large-scale waves are stronger and occur more often than
usual,
they push more low latitude air northward, bringing high ozone
and warmer
temperatures with them to the poles.
According to Newman, "In cold years like 1997, weaker, and
less frequent
waves reduced the effectiveness of the Arctic heat engine and
cooled the
stratosphere, making conditions just right for ozone
destruction."
Strahan explained that in a cold year, with weaker waves, polar
ozone levels
get a "double whammy," because less ozone gets
transported to the poles from
the tropics because temperatures are lower, allowing more PSCs
form, which
leads to more ozone loss.
Strahan said that it is important to keep in mind that even
without ozone
loss by PSCs, the amount of ozone in the Arctic stratosphere
varies from
year to year depending on the strength of the large- scale waves
and the
quantity of ozone they bring. Further, she stressed that ozone
loss by
chlorine is controlled by temperature and only indirectly by the
variability
in the large-scale waves.
If the wave activity is strong enough to raise the vortex above
temperatures
where the PSCs can form throughout the winter, then the wave
activity can
prevent ozone loss. She said that December 1999 had little wave
activity, allowing
the Arctic vortex to become large and strong by the beginning of
winter. This
restricted the transport of ozone to the polar region, while at
the same time, the low vortex temperatures allowed a significant
amount of
PSCs to form and more ozone loss to occur during the winter of
1999 to 2000.
This research was funded under NASA's Earth Science Enterprise,
Atmospheric
Chemistry Modeling and Analysis Program (ACMAP).
Strahan will present this paper, "The Influence of Planetary
Wave Transport
on Arctic Ozone as Observed by POAM III" at the American
Geophysical Union
Spring 2002 meeting at the Washington Convention Center in
Washington, D.C.,
on Tuesday, May 28, 2002, at 9:30 a.m., Session A21E-05, Room
WCC20.
For more information and images:
http://www.gsfc.nasa.gov/topstory/20020528polarwinter.html
============================
* LETTERS TO THE MODERATOR *
============================
(8) TONY BLAIR'S HIDDEN AGENDA
>From A. Beal [mailto: a.beal@btinternet.com
]
Dear Benny,
It seems to me that there are two problems with Tony Blair's
speech about
the need to 'stand up for proper science' (CCNet 23/05/02):
(i) many of the concerns over genetically modified crops are
actually based
on 'proper science', not emotion and
(ii) while Mr Blair was telling the Royal Society about how much
he supports
science, in Gateshead he has been giving his backing to a college
which
teaches creationism in its science classes.
Is Mr Blair really committed to science, or does he have another
agenda?
Yours sincerely,
Alasdair Beal
===============
(9) AND FINALLY: BAD NEWS FOR COSMIC PESSIMISTS AS LIFE MAY GO ON
FOREVER
>From Nature, 27 May 2002
http://www.nature.com/nsu/020520/020520-11.html
An accelerating universe does not have to fry life.
PHILIP BALL
Life can carry on indefinitely. Physicists in the United States
have come to
the comforting conclusion that just because the universe is
accelerating as
it expands, this does not necessarily sound the death knell for
life in the
far future1, as some have claimed2.
In the right kind of accelerating universe "life can go on
indefinitely",
say Katherine Freese of the University of Michigan and William
Kinney of
Columbia University in New York. We don't know whether ours is
the right
kind, so the doomsday scenario is still possible, but at least
there's hope.
An accelerating universe limits how much energy is available to
life because
distant regions get too far away to be reached by organisms
confined to
travelling below the speed of light.
Faced with finite energy resources, organisms can use up energy
more slowly
by slowing down their metabolism. In principle there's no limit
to how
sluggish life can get, so it could eke out an existence
indefinitely.
But there's a snag. To have any sort of metabolism - to do
anything, in
other words - an organism has to get rid of heat.
This can only happen if the organism is hotter than its
surroundings,
because heat can flow only from hot to cold. An organism that is
cooler than
its environment will eventually fry.
There's a limit to how cool an accelerating universe can get. As
life slows
to conserve its limited energy supplies, it too will cool.
Eventually,
though, it will hit this temperature limit and stop being able to
shed heat.
Freese and Kinney now suggest that this lower temperature limit
need not be
fixed, but might itself decrease over time. It all depends on why
the
universe is accelerating.
Constant worry
One reason why a universe might expand is that empty space
actually exerts a
pressure that counteracts the force of gravity. This pressure is
quantified
by the so-called cosmological constant, inserted into Einstein's
equations
of relativity, which describe the structure of space and time.
A universe with a cosmological constant acquires a background
radiation. It
is this warm vacuum that some believe will eventually fry
ultra-sluggish
life.
Freese and Kinney reckon that two alternative explanations for
the
acceleration of the expanding universe - quintessence and
cardassian
expansion - give life a rosier prognosis.Maybe one day we'll
figure out how
to synthesize a new universe in a lab, set off a Big Bang, and
move into it
The quintessence model invokes a kind of vacuum energy like that
produced by
a cosmological constant. But crucially, this energy, and thus the
background
temperature, decreases with time. The same is true of cardassian
expansion.
This means that a life form could conceivably slow its metabolism
down to
avoid running out of energy, while keeping pace with the cooling
universe so
that it can always radiate heat into a cooler environment.
Even if the universe does turn out to be dominated by a
cosmological
constant, Freese and Kinney are reluctant to give up hope. One
day, they
speculate, we might figure out how to synthesize a new universe
in a
laboratory, set off a Big Bang, and move into it, abandoning our
present
universe as a lost cause.
References
Freese, K. & Kinney, W.H. The ultimate fate of life in an
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universe. Preprint.(2002).
Krauss, L. M. & Starkman, G. D. Life, the universe, and
nothing: life and
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© Nature News Service / Macmillan Magazines Ltd 2002
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