PLEASE NOTE:
*
CCNet, 089/2000 - 15 September 2000
-----------------------------------
"We now have a record from 23,500
feet in the atmosphere (about as
high as instruments are carried in a
weather balloon), one that
has been preserved naturally, that shows
the last 50 years were
warmer than any other equivalent period
in the last 1,000 years."
-- Lonnie
Thompson, Ohio State University
"We think this is alarming."
-- Ellen
Mosley-Thompson, Ohio State University
"Temperature measurements from two
Greenland Ice Sheet boreholes
were used to reconstruct the temperature
history of the Greenland
Ice Sheet over the past 50,000 years.
The data revealed that
temperatures on the Greenland Ice Sheet
during the Last Glacial
Maximum (approximately 25,000 years ago)
were 23 ± 2 °C colder
than at present. [...] The Medieval Warm
Period and the Little Ice
Age were also documented in the record,
with temperatures 1°C
warmer and 0.5-0.7°C cooler than at
present, respectively. After
the Little Ice Age, the authors report
that 'temperatures reached
a maximum around 1930 A.D.' and that
'temperatures have decreased
during the last decades.'"
-- Review of D.
Dahl-Jensen et al. (1998) Past temperatures
directly from the Greenland Ice Sheet. Science 282: 268-271
(1) 'NEAR-MISS' ASTEROID SNAPPED BY REMOTE CONTROL
ABC News, 12 September 2000
(2) ARIZONA'S MINI-BOOM IN METEORITE RECOVERIES
Ron Baalke <baalke@jpl.nasa.gov>
(3) NEW CLIMATE SCARE FUELS GLOBAL WARMING HYSTERIA
Andrew Yee <ayee@nova.astro.utoronto.ca>
(4) GREENLAND ICE CORES SHOW EVIDENCE OF MEDIEVAL WARM PERIOD
Center for the Study of Carbon Dioxide and
Global Change
(5) LIVING PROOF THAT HUMAN CULTURES CAN ADAPT TO CLIMATE CHANGE
Joel Gunn <jdgunn@mindspring.com>
========
(1) 'NEAR-MISS' ASTEROID SNAPPED BY REMOTE CONTROL
From ABC News, 12 September 2000
http://www.abc.net.au/science/news/stories/s174370.htm
Near-miss asteroid snapped by remote control
Tuesday, 12 September 2000
Australia's first remote-control telescope at Charles Sturt
University,
Bathurst, last week captured a sequence of photographs of a 'near
miss'
asteroid as it passed Earth.
Professor David McKinnon operated the telescope by remote control
via
the Internet to collect 21 pictures of the one-kilometre-wide
asteroid
over 30 minutes as it travelled through space at over 25
kilometres per
second. Dr McKinnon said the asteroid was only 12 times further
away
from Earth than the moon and had it hit Earth, it would have made
a
crater 250 kilometres in diameter and injected enough dust and
material
into the atmosphere to block out the Sun.
"It would have been similar to the event which brought an
end to the
dinosaurs", he said. "Life as we know it would have
finished." The 21
photographs, each of 30 seconds exposure, were 'stacked', to
produce
the accompanying image.
Dr McKinnon attributes the varying brightness of the asteroid, to
its uneven
shape and the fact that it is "tumbling" through space,
therefore exposing
different sides through time.
Images of the asteroid and other photos taken using the remotely
controlled
telescope can be seen here <http://www.csu.edu.au/telescope>.
==============
(2) ARIZONA'S MINI-BOOM IN METEORITE RECOVERIES
From Ron Baalke <baalke@jpl.nasa.gov>
News Services
University of Arizona
Tucson, Arizona
Contact Information:
David A. Kring, 520-621-2024, kring@lpl.arizona.edu
Sep 12, 2000
Seven New Meteorites Added to New Online Arizona Meteorite Map
By Lori Stiles
Arizona is experiencing a mini-boom in meteorite recoveries, and
you
now can view a web-based map that shows where the meteorites hit,
what
they look like and how they're classified.
The clickable map at http://www.lpl.arizona.edu/SIC/arizona_meteorites/
was created by David A. Kring, students Jake Bailey and Ross
Beyer, and
photographer Maria Schuchardt at the University of Arizona Space
Imagery Center.
Kring is director of the Meteorite Recovery Program and new
director of
the Space Imagery Center at the UA Lunar and Planetary Lab.
Scientists know of 39 meteorites found in Arizona during the past
110
years. About a third of these have been found in the past decade.
Seven
of those were identified in the past year by the UA Meteorite
Recovery
Program (MRP). MRP scientists also identified four others that
fell
outside of Arizona.
The seven new Arizona meteorites are listed in this month's
Meteoritical Bulletin. They are named Coyote Mountains, Dos
Cabezas,
Fish Canyon, Golden Rule, King Tut, Ragged Top and Wildcat Peak.
It's no coincidence that more Arizona meteorites are turning up,
Kring
says.
"It's simply a matter of explaining to people what to look
for," he
notes. "We have been making an effort to go out and talk to
groups who
are likely to find these things, like Arizona gold prospecting
clubs,
and explain what to look for.
"Plus, media coverage publicizing the finds is generating
more
searches," he adds.
Kring says the university meteorite recovery team finds one or
two
meteorites in about every 600 samples submitted for study.
To check if your suspect meteorite might be the real thing, look
at the
series of tips listed in Kring's on-line booklet,
"Meteorites and Their
Properties," at http://meteorites.lpl.arizona.edu
These tests will filter out 90 percent of the
"meteor-wrongs," Kring
notes. If the sample passes these tests, it's time to get an
expert
opinion. The public can contact meteorite experts through the UA
Mineral Museum at Flandrau Science Center, the UA Lunar and
Planetary
Lab, and Arizona State University's Center for Meteorite Studies.
The four non-Arizona meteorites recovered by the UA team during
the
past year are one from Roosevelt County, New Mexico, and three
from
Saudi Arabia.
================
(3) NEW CLIMATE SCARE FUELS GLOBAL WARMING HYSTERIA
From Andrew Yee <ayee@nova.astro.utoronto.ca>
Ohio State University
Contact:
Ellen Mosley-Thompson, (614) 292-6662; ethompso@magnus.acs.ohio-state.edu
Lonnie Thompson, (614) 292-6652; thompson.3@osu.edu
Written by Earle Holland, (614) 292-8384; holland.8@osu.edu
HIMALAYAN ICE REVEALS CLIMATE WARMING, CATASTROPHIC DROUGHT
COLUMBUS, Ohio -- Ice cores drilled through a glacier more than
four
miles up in the Himalayan Mountains have yielded a highly
detailed
record of the last 1,000 years of earth's climate in the high
Tibetan
Plateau. Based on an analysis of the ice, both the last decade
and the
last 50 years were the warmest in 1,000 years.
The core also showed a clear record of at least eight major
droughts
caused by a failure of the South Asian Monsoon, the worst of
these a
catastrophic seven-year-long dry spell that cost the lives of
more than
600,000 people.
The new findings, published in this week's issue of the journal
Science, outline data recovered from three cores drilled through
the
Dasuopu Glacier, a two-kilometer-wide ice field that straddles a
flat
area on the flank of Xixabangma, a 26,293-foot (8,014-meter) peak
on
the southern rim of the Tibetan Plateau. The international team,
including American, Chinese, Peruvian, Russian and Nepalese
members,
retrieved the cores during a 10-week, 1997 expedition to the
region.
The expedition was supported by the National Science Foundation.
"This is the highest climate record ever retrieved,"
explained Lonnie
Thompson, professor of geological sciences at Ohio State
University and
leader of the expedition, "and it clearly shows a serious
warming
during the late 20th Century, one that was caused, at least in
part, by
human activity. This is a very compelling story."
For the last 25 years, he and his colleagues have drilled cores
from
glaciers and ice caps in some of the most remote parts of the
planet in
an effort to recover records of ancient climate. Most current
predictions of global climate change suggest that early signs of
warming will be seen at high elevations where these ice caps
exist. So
far, Thompson's work has borne this out.
Researchers at Ohio State's Byrd Polar Research Center and the
Chinese
Lanzhou Institute of Glaciology and Geocryology divided the three
cores
and were able to identify annual layers for the last 557 years.
Samples
from these layers were analyzed for dust concentrations, chemical
composition and oxygen- and hydrogen-isotope ratios.
The isotope ratios let researchers extrapolate the air
temperatures
present when the ice was formed.. Dust concentrations give an
indication
of dryness or wetness in the region, and the analysis of
chlorides,
sulfates and nitrates provide clues about volcanic activity,
fossil
fuel burning and desertification.
"We now have a record from 23,500 feet in the atmosphere
(about as high
as instruments are carried in a weather balloon), one that has
been
preserved naturally, that shows the last 50 years were warmer
than any
other equivalent period in the last 1,000 years," Thompson
said.
The real surprise came with the monsoon records the core
revealed.
The South Asian Monsoon is a major climate event that cycles
annually
across India, Pakistan, the southern Himalayan region, the Far
East and
reaches as far west as Africa. In the summer, when the Eurasian
continent is warmed by solar radiation, prevailing winds flow
offshore,
leaving the region moisture-poor so that drying intensifies. When
the
cycle reverses, the winds flow onshore, heavily laden with
moisture
from the oceans, and bringing the heavy monsoon rains that drench
the
regions. Changes in the monsoon cycle can bring catastrophic
flooding
or droughts.
The core data showed that in 1790, the cycle changed, the rains
lessened and drought took hold in the region, a condition that
continued for seven years until 1796 when the monsoons returned.
"That event was major," Thompson said. "It killed
more than 600,000
people in one region of India alone. And that was at a time when
global
populations were much less than they are today." (Estimates
place the
world population in 1800 at 980 million.) "If a similar
event occurred
today, the social and economic disruptions would be
horrendous," he
said. Current world population is just over 6 billion people.
The ice core record showed other serious monsoon failures and
ensuing
droughts in 1876-77, and around 1640, 1590, 1530, 1330, 1280 and
1230,
though none was as devastating as the 1790 event. Thompson's
paper
offered no indications of what might have triggered the monsoon
failures.
The data, however, do seem to point to the impact human
activities have
had on changing climate in the region. Core samples covering the
last
century reveal a four-fold increase in dust trapped in the ice
and a
doubling of chloride concentrations, suggesting an increase in
both
drying and desertification in the region.
"There is no question in my mind," he said, "that
the warming is in
part, if not totally, driven by human activity. I think the
evidence
for that is so clear -- not only from this site but also from
Kilimanjaro in Africa." Thompson led an expedition to the
ice fields
atop the highest mountain in Africa earlier this year. At least
75
percent of the ice there has disappeared since 1912, caused in
part, he
said, by global warming.
=================
(4) GREENLAND ICE CORES SHOW EVIDENCE OF MEDIEVAL WARM PERIOD
From: Center for the Study of Carbon Dioxide and Global Change
Dahl-Jensen, D., Mosegaard, K., Gundestrup, N., Clow, G.D.,
Johnsen,
S.J., Hansen, A.W. and Balling, N. 1998. Past temperatures
directly
from the Greenland Ice Sheet. Science 282: 268-271
Temperature measurements from two Greenland Ice Sheet boreholes
were
used to reconstruct the temperature history of the Greenland Ice
Sheet
over the past 50,000 years. The data revealed that temperatures
on the
Greenland Ice Sheet during the Last Glacial Maximum
(approximately
25,000 years ago) were 23 ± 2 °C colder than at present. After
the
termination of the glacial period, temperatures increased
steadily to a
maximum of 2.5°C warmer than at present during the Climatic
Optimum
(4,000 to 7,000 years ago). The Medieval Warm Period and the
Little Ice
Age were also documented in the record, with temperatures 1°C
warmer
and 0.5-0.7°C cooler than at present, respectively. After the
Little
Ice Age, the authors report that "temperatures reached a
maximum around
1930 A.D." and that "temperatures have decreased during
the last
decades."
The results of this study stand in direct contrast to the
predictions
of general circulation models (GCMs) that consistently suggest
there
should have been a significant warming in high northern latitudes
over
the past several decades. They also show large temperature
excursions
over the last 10,000 years, when the air's CO2 content was
relatively
stable. Both of these observations raise doubts about the ability
of
current GCMs to accurately forecast earth's climatic response to
the
ongoing rise in the atmosphere's CO2 concentration.
Copyright © 2000. Center for the Study of Carbon Dioxide and
Global
Change
=============================
* LETTERS TO THE MODERATOR *
=============================
(5) LIVING PROOF THAT HUMAN CULTURES CAN ADAPT TO CLIMATE CHANGE
From Joel Gunn <jdgunn@mindspring.com>
Dear Benny,
The juxtaposition of the two articles on global warming in your
14sep00
issue raises some interesting questions about methods in the
study of
global change. One emphasises the as-yet unfulfilled promise of
similations to predict climate, and the other points out the
imporance
of data recognition of rare events in climate history.
I did some geological background research on the occurrence of
large El
Ninos for my 1991 Climate Change article that seemed to show that
they
occur during transitive periods of rapid global warming,
apparently the
case in the current circumstance.
In another incident of global warming, the Medieval Maximum,
Native
Americans were able to farm and live settled lifestyles in the
American
Great Plains, unlike the roving bison hunters familiar to the
first
European observations during the Little Ice Age. During the yet
globally warmer Middle Holocene, the entire Great Plains seems to
have
been very sparsely populated and characterized by blowing
dust.
In both of these cases, important events that seriously impacted
the
course of human life occurred during transitional moments, as did
the
reassertion of ice age conditions around the North Atlantic at
12,700
years ago discussing by David Montgomery and Richard Sadler in
your
newsletter.
Global circulating models in various experiments take snap shots
of hot
world conditions and the indications are that the interiors of
continents would be desertified. Using data based regression
models, I
have projected similar hot world conditions. In both cases the
models
fail to detect the transitional events and circumstances. In the
case
of the simulations, it seems that computing power is still
insufficient
to model climate change on a continuous rather that static basis,
something one would hope that similations would come to. The
numerical
models are probably inherently unable to deliver such
transitional
states such as the large El Ninos during rapid warming or
increased
summer rainfall on the High Plains during intermediate episodes
of
warming. So far only hard data, in one case geological and the
other
human, seem to deliver the quality of the transitional
states. All of
this argues for continued efforts to temper modeling with data
from the
remote past when the world was warmer and colder than at
present.
Personally I think that the data from human cultures needs to be
given
more attention. Data from human cultures are the most sensitive,
if
complex to analyze. Humans are the primate order's answer to how
to
live in relatively unstable Pleistocene/Recent climates, as
nearly 3
millions years of continuous survival, even over survival,
indicates.
Joel Gunn
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