PLEASE NOTE:
*
CCNet 112/2000 - 1 November 2000
--------------------------------
"Contrary to some press reports in the late 1990's, the
variability
of Toutatis's orbit does not render the asteroid's path
unpredictable.
'Actually, we know Toutatis's orbit better than that of any other
near-Earth asteroid,' says Giorgini. 'The radar data we collected
during close approaches in the 1990's let us usefully predict its
trajectory
over a few hundred years, from about 1300-2500 AD. We're safe
from
collisions for at least several centuries.' Clearly, though,
continued monitoring is warranted."
-- NASA News, 31 October 2000
"Until recently, panspermia was not even regarded as a
scientific
hypothesis. Now that has changed."
-- Chandra Wickramasinghe, 30 October 2000
(1) TRICK OR TREAT: IT'S TOUTATIS!
NASA Science News <snglist@lyris.msfc.nasa.gov>
(2) THE NEW CASE FOR PANSPERMIA
Space.com, 30 October 20000
(3) METEORIC CLOUD OF COMET TEMPLE-TUTTLE
R. Nakamura et al.
(4) METEORS, METEORITES & COSMIC DUST
F.J.M. Rietmeijer
(5) THE WORLD'S LONGEST OBSERVATIONAL SEA-LEVEL RECORD
CO2 Science, 1 November 2000
(6) WILL THERE BE ENOUGH FOOD?
CO2 Science, 1 November 2000
(7) GOOD NEWS
Andy Smith <astrosafe@yahoo.com>
=============
(1) TRICK OR TREAT: IT'S TOUTATIS!
From NASA Science News <snglist@lyris.msfc.nasa.gov>
NASA Science News for October 31, 2000
NASA scientists are monitoring a large near-Earth asteroid that
tumbled past
our planet on Halloween 2000.
October 31, 2000 -- Most Halloween visitors are no more alarming
than, say,
an earnest-looking 3-foot vampire with an eye on the candy tray
-- easily
warded off with a bag of M&M's. But this year there's a more
sinister
Trick-or-Treater on our planet's doorstep: the near-Earth
asteroid 4179
Toutatis.
At 0430 Universal Time on Oct. 31st, the 5-km long space rock
passed less
than 29 lunar distances from Earth. There was no danger of a
collision, say
scientists, but astronomers are nevertheless keeping a watchful
eye on
Toutatis. It is one of the largest known "Potentially
Hazardous Asteroids"
(PHAs) and its orbit is inclined less than half-a-degree from
Earth's. No
other kilometer-sized PHA moves around the Sun in an orbit so
nearly
coplanar with our own.
A group of astronomers led by Steve Ostro (JPL) and Scott Hudson
(Washington
State University) is monitoring Toutatis this week using NASA's
Goldstone
planetary radar in the Mojave desert. They will bounce radio
signals off the
fast-moving asteroid to learn more about the path it follows
through space
and the peculiar way it spins.
Unlike planets and the vast majority of asteroids, which rotate
around a
single pole, Toutatis has two spin axes. It twirls around one
with a period
of 5.4 Earth-days and the other once every 7.3 days. The result
is an
asteroid that travels through space tumbling like a badly thrown
football.
[View an mpeg movie of Toutatis in motion, courtesy Scott
Hudson.]
"Our goal for 2000 is to double the radar time base
(currently 1992-1996),
thereby dramatically
fine-tuning our knowledge of the object's extraordinary spin
state as well
as its orbit," says Ostro.
"The 2000 close approach is more distant than our encounters
with Toutatis
in 1992 and 1996, when the asteroid passed 9 and 14 lunar
distances from
Earth, respectively," added Jon Giorgini of JPL's Solar
System Dynamics
group. "The radar echoes from this apparition are going to
be weaker, but
the ranging and velocity measurements will still be of great
interest."
That's because Toutatis follows an elliptical orbit around the
Sun that just
won't hold still. Orbital resonances and close encounters with
Venus, Earth,
Mars and Jupiter constantly alter the shape of the asteroid's
path as it
loops through the solar system every 3.98 years.
"Toutatis has a 3:1 orbital resonance with Jupiter and a 1:4
resonance with
Earth," explains Giorgini. "Thus, every third time
Toutatis orbits the Sun,
it returns to the same spot relative to Jupiter. Every 4th time
Earth goes
around the Sun, it and Toutatis end up in the same relative
position as
well. Up until about 1922, Toutatis also had numerous
close-approaches to
Venus and Mars." Such gravitational encounters, which nudge
the asteroid
from its intended path, are orbit-altering experiences for
Toutatis.
Contrary to some press reports in the late 1990's, the
variability of
Toutatis's orbit does not render the asteroid's path
unpredictable.
"Actually, we know Toutatis's orbit better than that of any
other near-Earth
asteroid," says Giorgini. "The radar data we collected
during close
approaches in the 1990's let us usefully predict its trajectory
over a few
hundred years, from about 1300-2500 AD. We're safe from
collisions for at
least several centuries." Clearly, though, continued
monitoring is
warranted.
"For our Goldstone radar observations in November we're
predicting an
initial range uncertainty of plus or minus 600 meters,"
continued Giorgini.
"If we acquire Toutatis much outside that expected
uncertainty level, it
could indicate the effect of unmodeled forces acting on the
asteroid over
the last 4 years-- for example, perturbations from other
asteroids.
(Toutatis's orbit extends from just inside Earth's to a point
deep within
the asteroid belt between Mars and Jupiter.)
"Depending on what we see, we may or may not end up with
some solar system
dynamics detective work."
Astronomers with backyard telescopes can see Toutatis for
themselves, but
not this week. On Oct. 31st the estimated visual magnitude of the
space rock
was +28. Even big professional telescopes have trouble with
objects that
dim. Toutatis seems so dark because the sunlit side of the
asteroid is
facing away from our planet as it glides by almost directly
between the
Earth and the Sun.
Fortunately for asteroid-watchers, Toutatis will brighten rapidly
in the
days ahead. By the end of November it will become a 14.5th
magnitude object
in the constellation Leo, well within reach of 8-inch or larger
telescopes
in the northern hemisphere. [View an ephemeris for your observing
site.]
If you miss Toutatis this time around, don't worry. Four years
from now it
will be back and brighter than ever. On Sept. 29, 2004, Toutatis
will pass
just 4 lunar distances from Earth -- that's closer than any other
known PHA
will come during the next 30 years. Toutatis will be so bright --
9th
magnitude near closest approach -- that skywatchers will be able
to easily
see it through binoculars. As viewed from Toutatis in 2004, the
Earth will
appear to be the size of the Full Moon.
"2004 should be a great year for radar observations of
Toutatis," continued
Giorgini. Radar maps will discern features just a few tens of
meters across,
substantially improving on radar images from 1992 and 1996. Data
from those
epochs revealed Toutatis as a strange-looking, peanut-shaped
object that
tumbles erratically through space. In fact, it may be two
asteroids that
stuck together when they gently collided in the distant past.
Giorgini and
his colleagues are hopeful that high-resolution radar data four
years hence
will reveal even more about this strange asteroid.
In the meantime, trick-or-treaters might ponder a new sort of
costume for
Halloween 2004 -- something scarier than a vampire that might
cause
unsuspecting grownups to drop the candy-tray altogether. Imagine
going from
door to door as 4179 Toutatis! ("I like the idea of dressing
up as
Toutatis," says JPL's Steve Ostro, "especially if the
kids imitate the
object's spin state when you answer the door.") True,
dressing up as lumpy
gray rock isn't glamorous, but ask any dinosaur, it sure is
scary!
=============
(2) THE NEW CASE FOR PANSPERMIA
From Space.com, 30 October 20000
http://www.space.com/searchforlife/aliens_all_001027.html
By Robert Roy Britt
Nestled safely inside the belly of a comet orbiting some unknown
star, a
microscopic alien sits dormant. Somewhere in this vast universe
-- perhaps a
place like Earth -- a greater destiny awaits the microbe. A place
to
flourish, become a nematode or a rose or a teenager.
Life, after all, is tenacious and thrives on change.
Over time, gravity performs a few plausible, but not routine
tricks, and the
comet is ejected from its stellar orbit like a rock from a
slingshot. For
more than a 100 million years it slips silently across the inky
vastness of
interstellar space.
Then gravity goes to work again. Another star tugs at the comet,
pulls it
in.
A few giant gaseous planets whiz by, their bulks tugging at the
comet,
altering its course slightly. Ahead now, growing larger, looms a
gorgeous
blue and brown marble. Water and land. Maybe some air.
Then with the force only the cosmos can summon, the comet slams
into the
third rock from a mid-sized, moderately powerful star. The alien
microbe
survives, emerges from its protective shell and spreads like the
dickens.
Thus began life on Earth, 3.8 billion years ago.
Or so goes one aspect of a theory called panspermia, which holds
that the
stuff of life is everywhere and that we humans owe our genesis
and evolution
to a continual rain of foreign microbes. It means, simply, that
we might all
be aliens.
It's an idea that has been around longer than Christianity, but
which still
struggles to gain strong support among most scientists.
But two recent discoveries are breathing new life into the
theory.
One study, reported in the October 27 issue of the journal
Science, shows
that a space rock could successfully transport life between
planets.
Another group of researchers, reporting in the October 19 issue
of Nature,
claims to have found and revived bacteria on Earth that were
dormant, in the
form of spores, hiding in New Mexican salt crystals for 250
million years.
Scientists called the implications of this second discovery
profound,
suggesting that if further study bears out the findings, it could
mean
bacterial spores are nearly immortal.
And if you are immortal, then what are a few billion years of
interstellar
travel?
"Until recently, panspermia was not even regarded as a
scientific
hypothesis," says Chandra Wickramasinghe, the concept's
leading proponent.
"Now that has changed."
Agreement, but still caution
In interviews with more than a half dozen respected scientists in
diverse
fields, it's clear that panspermia, or at least some aspects of
the theory,
is poised to jump to the forefront of study among scientists who
seek to
understand where and how life began. While the prevailing theory
holds that
life arose spontaneously out of a terrestrial, chemical soup,
panspermia's
defenders argue that such a miracle could happen almost anywhere.
This means we could have microbial ancestors, or even more
evolved cousins,
in unexplored corners of the cosmos.
"Both (new) studies lend a healthy boost to the plausibility
of panspermia,"
says Jay Melosh, a geophysicist at the University of Arizona's
Lunar and
Planetary Laboratory. "I just submitted a paper to (the
journal) Icarus that
says that an interstellar journey is overwhelmingly improbable.
However, a
number of factors -- including the recent Nature article -- are
making me
rethink this."
Like other scientists, Melosh still calls the interstellar
transfer of life
improbable, but expects research into the idea to ramp up.
Panspermia: Its own origins and evolution
The idea that the seeds of life are ubiquitous throughout the
cosmos goes
back to Anaxagoras, a Greek philosopher. In the 1800s, French
chemist Louis
Pasteur proposed that spontaneous generation of life could not
have occurred
on Earth. British physicist Lord Kelvin and others jumped on
Pasteur's
bandwagon and suggested that life might have come from space.
But modern-day panspermia advocates have been the Rodney
Dangerfields of
science.
In fact, just two leading researchers carry the bulk of the
panspermia
torch. The renowned Sir Fred Hoyle, known for his studies of star
structure
and the origin of the chemical elements in stars, has worked with
Chandra
Wickramasinghe over the past three decades to pioneer the modern
theory of
panspermia.
In the 1970s, Wickramasinghe and Hoyle found what they say are
traces of
life in the dust around distant stars. The duo then broadened the
panspermia
theory, arguing that a continual rain of life-altering stuff from
space --
including germs that arrive in cycles related to solar activity
-- has
affected the course of evolution. The seeds, they say, are still
coming.
Support for parts of panspermia
Other researchers agree that both space rocks and comet dust
might in fact
harbor organic matter. But how these ingredients for life might
travel from
one star to another is hotly disputed.
Even as doubters are beginning to give panspermia advocates a
little
respect, most say the likeliest transfers of life would occur
between
planets.
"That bacteria, or at least their spores, can survive for
such staggering
amounts of time makes their transport from planet to planet on
meteorites
possible," said Matthew Genge, a meteoritic researcher at
the London Natural
History Museum. "Bacterial spores in their very own kind of
suspended
animation could perhaps survive the millions of years it takes
for rocks to
travel from planet to planet."
But Genge, along with other scientists, cautioned that the
250-million-year-old bacteria found in New Mexican salt crystals
are not
conclusive. There is a chance the samples were contaminated with
more modern
bacteria, and follow-up studies need to be done.
Still, previous studies have found viable bacterial spores in 30
million-year-old amber. And last year's discovery of living
microbes deep in
the Antarctic extends the range of extreme conditions under which
life is
known to survive.
Few researchers question that life is hardy, and that it can hang
on for a
very, very long time. And some space rocks are known to make the
trip from
Mars to Earth in less than a year.
Death rays and cosmic cannon balls
The trick for a much lengthier interstellar journey would be
surviving
deadly cosmic rays.
Even the nearest stars known to have planets are many light-years
away. And
none has been shown to have habitable planets. Some nearby stars
are
becoming more interesting, however. The star Iota Horologii, just
56
light-years away, is the first to have a planet in an Earth-like
orbit and
to show other signs of solar system formation like our own.
But even 56 light-years is a bit longer than your average
commute.
"Herein lies the problem," Genge said. "In Earth
rocks, bacterial spores may
survive for millions of years cocooned beneath the Earth's
surface because
they are protected from radiation. On a meteorite in space, fast
moving
atomic and sub-atomic particles will plow through the meteorite
like cosmic
cannon balls. If they encounter an organism, DNA molecules will
be
shattered. If hit enough times, the organism will not
survive."
Several scientists suggest that to survive, a spore, seed,
bacteria or other
organism would need to be imbedded deep inside a good-sized space
rock,
perhaps 3 meters (10 feet) or larger, shielded from radiation.
Even then,
there is the problem of launching a star-orbiting rock or comet
into
interstellar space.
The only way to do this is through repeated, and tricky,
gravitational
interactions with planets, says Genge, explaining a process like
the one
NASA used to sling the Voyager spacecraft out of the solar
system.
"The thing is, it's taken a lot of very clever people,
powerful computers
and cutting-edge technology to do this," Genge says.
"Terrestrial meteorites
are just rocks and even with microbial passengers they are pretty
stupid and
thus have to rely on chance."
Earth as an exporter of life
Somewhat lost in the current panspermia revival is the intriguing
flip-side
of the "ubiquitous life" idea: If life could have come
here from somewhere,
why couldn't an Earth rock have been dislodged long ago, sending
life to
another planet or star system?
"It is possible that there are small fragments of the Earth
out there in
space today, some with microorganisms, that were blasted off the
Earth's
surface many millions of years ago," Genge says. "These
could reach the
Jovian moons and through extreme good fortune seed the water
oceans with
microorganisms."
Okay. How likely?
"The chances of this happening in reality are probably
similar to someone
finding their way home after being blindfolded and airlifted to
another
continent."
Genge and others say the more plausible scenario for the transfer
of life --
if it has ever occurred and given the scant solid evidence
currently
available -- is that it started on Mars and came to Earth. The
recent
discovery of water beneath the surface of Mars has researchers in
many
fields excited, suggesting that any life that was once there
might still
exist.
"I consider it almost inevitable that microorganisms have
been transferred
between Mars and Earth by hitching a ride deep inside rocks
blasted off the
surface by asteroid impacts," says physicist Paul Davies,
author of The
Fifth Miracle: The Search for the Origin and Meaning of Life.
While Davies says life could have moved in either direction, the
Mars-to-Earth scenario is his favorite, based on presumed state
of things a
few billion years back.
"Mars was a more favorable environment for life to get
started," Davies told
SPACE.com. "Being a smaller planet than Earth, it cooled
quicker, so the
comfort zone for deep-living organisms (the ones safe from
impacts) was
deeper sooner. It is easier for rocks to go from Mars to Earth
than vice
versa, because Mars has a lower gravity."
Davies is rock-solid in his belief that it takes rocks, serving
as
protective vessels, to move life from one planet to another. He
rejects the
idea that "individual microbes waft naked through outer
space" -- one of the
original tenets of the panspermia theory.
"I still believe it exceedingly unlikely that life could hop
from one star
system to another that way, largely because of the radiation
hazard," Davies
says. "It is possible for such transfer to happen inside
rocks, but the
chance of a rock blasted off Earth ever hitting another
Earth-like planet
beyond our solar system is infinitesimal."
So does this kill the idea that life on Earth arrived from
another star
system, that we might have distant ancestors -- or maybe even
cousins --
waving to us from an orbit around Iota Horologii?
"Clearly it's possible," Davies says, "but the
odds are exceedingly low."
Wickramasinghe, the primary panspermia proponent, responded with
a different
view:
"Not all microbes in interstellar space would survive of
course,"
Wickramasinghe said. "But the survival of even a minute
fraction of microbes
leaving one solar system and reaching the next site of planet
formation
would be enough for panspermia to be overwhelmingly more probable
than
starting life from scratch in a new location."
So despite all the new and important discoveries, we still don't
know how or
where life began. But the search for it has gotten a little more
interesting, now that we know we might all be aliens.
Copyright 2000, Space.com
============
(3) METEORIC CLOUD OF COMET TEMPLE-TUTTLE
R. Nakamura, Y. Fujii, M. Ishiguro, K. Morishige, S. Yokogawa, P.
Jenniskens, T. Mukai: The discovery of a faint glow of scattered
sunlight
from the dust trail of the Leonid parent comet 55p/Tempel-Tuttle.
ASTROPHYSICAL JOURNAL 540: (2) 1172-1176, Part 1 SEP 10 2000
A meteoric cloud is the faint glow of sunlight scattered by small
meteoroids
in the dust trail along the orbit of a comet as seen by an
earthbound
observer. While these clouds were previously only known from
anecdotes of
past meteor storms, we now report the detection of a meteoric
cloud by
modern techniques in the direction of the dust trail of comet
55P/Tempel-Tuttle, the parent of the Leonid meteor stream. Our
photometric
observations, performed on Mauna Kea, Hawaii, reveal the cloud as
a local
enhancement in sky brightness during the Leonid shower in 1998.
The radius
of the trail, deduced from the spatial extent of the cloud, is
approximately
0.01 AU and is consistent with the spatial extent mapped out by
historic
accounts of meteor storms. The brightness of the cloud is
approximately
similar to 2%-3% of the background zodiacal light and cannot be
explained by
simple model calculations based on the zenith hourly rate and
population
index of the meteor stream in 1998. If the typical size of cloud
particles
is 10 mu m and the albedo is 0.1, the brightness translates into
a number
density of 1.2 x 10(-10) m(-3). The meteoroid cloud would be the
product of
the whole dust trail and not only the part that was crossed in
1998.
Copyright © 2000 Institute for Scientific Information
Addresses:
Nakamura R, Kobe Univ, Informat Proc Ctr, Kobe, Hyogo 6578501,
Japan.
Kobe Univ, Informat Proc Ctr, Kobe, Hyogo 6578501, Japan.
Kobe Univ, Grad Sch Sci & Technol, Kobe, Hyogo 6578501,
Japan.
Univ Tokyo, Grad Sch Sci, Tokyo 1138654, Japan.
NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA.
===========
(4) METEORS, METEORITES & COSMIC DUST
F.J.M. Rietmeijer: Interrelationships among meteoric metals,
meteors,
interplanetary dust, micrometeorites, and meteorites. METEORITICS
&
PLANETARY SCIENCE 35: (5) 1025-1041 SEP 2000
Meteor science, aeronomy, and meteoritics are different
disciplines with
natural interfaces. This paper is an effort to integrate the
chemistry and
mineralogy of collected interplanetary dust particles (IDPs),
micrometeorites, and meteorites with meteoric data and with
atmospheric
metal abundances. Evaporation, ablation, and melting of
decelerating
materials in the Earth's atmosphere are the sources of the
observed metal
abundances in the upper atmosphere. Many variables ultimately
produce the
materials and phenomena we can analyze, such as different
accretion and
parent-body histories of incoming extraterrestrial materials,
different
interactions of meteors with the Earth's middle atmosphere,
meteor data
reduction, and complex chemical interactions of the metals and
ions with the
ambient atmosphere. The IDP-like and unequilibrated ordinary
chondrite
matrix materials are reasonable sources for observed meteoric and
atmospheric metals. The hypothesis of hierarchical dust accretion
predicts
that low, correlated refractory element abundances in cometary
meteors may
be real. It implies that the CI or cosmic standard is not useful
to
appreciate the chemistry of incoming petrologically heterogeneous
cometary
matter. The quasi steady-state metal abundances in the lower
thermosphere
and upper mesosphere are derived predominantly from materials
with cometary
orbital characteristics and velocities such as comets proper and
near-Earth
asteroids. The exact influence of atmospheric chemistry on these
abundances
still needs further evaluation. Metal abundances in the lower
mesosphere and
upper stratosphere region are mostly from materials from the
asteroidal belt
and the Kuiper belt. Copyright © 2000 Institute for Scientific
Information
Addresses:
Rietmeijer FJM, Univ New Mexico, Dept Earth & Planetary Sci,
Inst Meteorit,
Albuquerque, NM 87131 USA.
============
(5) THE WORLD'S LONGEST OBSERVATIONAL SEA-LEVEL RECORD
From CO2 Science, 1 November 2000
http://www.co2science.org/journal/2000/v3n29c1.htm
Ekman, M. 1999. Climate changes detected through the world's
longest sea
level series. Global and Planetary Change 21: 215-224.
What was done
The author utilizes the sea level data set from Stockholm,
Sweden, on the
Baltic Sea, which stretches back over two and a quarter centuries
to 1774,
to investigate long-term sea level changes and their relationship
to various
climatic factors, noting that "long-term changes recorded at
Stockholm
represent, to a very large extent, the long-term behavior of the
entire
Baltic Sea as well as the adjacent part of the North Sea."
What was learned
Near the end of the Little Ice Age, the Stockholm record suggests
that sea
level was in a state of equilibrium, with a mean rate-of-change
of 0.0
mm/yr. In fact, the author concludes, on the basis of other
studies he
reviews, that "sea level changes due to northern hemisphere
climate
variations since 800 A.D. have probably always kept within -l.5
and +1.5
mm/yr, with an average fairly close to zero." Over the
past century,
however, the sea-level rate-of-rise as measured at Stockholm has
been
approximately 1.0 mm/yr.
Interannual variability in sea-level was also investigated; and a
number of
interesting relationships were discovered between sea level and
the
persistent winter winds of the region, which have been shown to
produce
deviations in annual mean sea level of as much as ±100 mm from
the smoothed
trend of the long-term record. Specifically, extreme low
water years were
found to have persistent winter winds from the northeast, while
extreme high
water years were found to have persistent winter winds from the
southwest.
What it means
In the words of the author, "there is an understandable wish
to identify a
possible accelerated sea level rise due to the greenhouse
effect."
However, as he notes, "we should point out here that this is
very
difficult," the main reason being that "during a
shorter time interval, say
one or a few decades, an apparent acceleration (or retardation)
might very
well be caused by anomalous winter wind conditions."
In this regard, the author notes that from the end of the 1700s
to the
beginning of the 1900s, there was a rapidly decreasing number of
dominating
winter winds from the northeast, which winds typically tend to
reduce the
sea level at Stockholm; and, hence, the gradual disappearance of
these winds
should have led to a gradual increase in the rate-of-rise of sea
level
there, which just happens to be what occurred over this period of
time,
i.e., the mean rate-of-rise of sea level rose from 0.0 mm/yr to
something
significantly higher. After that, the winter winds
gradually shifted to
where the dominant mode was from the southwest, which winds tend
to promote
high sea levels at Stockholm, so that the rate-of-rise in
sea-level would
have to continued to increase. The net result of these wind
regime changes
would thus have been a continual increase in the rate-of-rise of
sea-level
over the entire two-century period, resulting in a mean sea level
trend of
1.0 mm/yr over the 20th century.
In light of these observations, there appears to be no need to
invoke an
inordinate amount of global warming to account for the historical
increase
in the rate of sea-level rise at Stockholm over the past two
centuries,
although some of the late 19th and early 20th century rise could
well have
come from the amelioration of cold Little Ice Age
conditions. In addition,
the author states that "values of present secular sea level
rise approaching
2 mm/yr, suggested by some authors, are unlikely;" and this
remark leads us
to question the 1930-present value of 2.2 mm/yr derived from the
tide gauge
measurements reported in our Journal Review Six Thousand Years of
Sea Level
Change in Eastern Maine.
Copyright © 2000. Center for the Study of Carbon Dioxide
and Global Change
==============
(6) WILL THERE BE ENOUGH FOOD?
From CO2 Science, 1 November 2000
http://www.co2science.org/journal/2000/v3n29b1.htm
Will There Be Enough Food?
Idso, C.D. and Idso, K.E. 2000. Forecasting world food supplies:
The impact
of the rising atmospheric CO2 concentration. Technology 7S:
33-56.
Background
As the world's population continues to climb, there is increasing
concern
about the sustainability or carrying capacity of the planet; and
in making
decisions about long-term research and development policies,
movers and
shakers from many sectors of the global economy need to know if
there will
be sufficient food fifty years from now to sustain the projected
population
of the globe. After all, it is only prudent that we attempt
to gain such
insight into the human condition (see our Editorial: Prudence
Misapplied),
for we all have a stake in the future progression of man and
womankind.
What was done
The authors developed and analyzed a supply-and-demand scenario
for food in
the year 2050. Specifically, they identified the plants
that currently
supply 95% of the world's food needs and projected historical
trends in the
productivities of these crops 50 years into the future.
They also evaluated
the growth-enhancing effects of atmospheric CO2 enrichment on
these plants
and made similar yield projections based on the increase in
atmospheric CO2
concentration likely to have occurred by that future date.
What was learned
The authors determined that world population will likely be 51%
greater in
the year 2050 than it was in 1998, but that world food production
will be
only 37% greater if its enhanced productivity comes solely as a
consequence
of anticipated improvements in agricultural technology and
expertise.
However, they further determined that the consequent shortfall in
farm
production can be overcome - but just barely - by the additional
benefits
anticipated to accrue from the aerial fertilization effect of the
expected
rise in the air's CO2 content, assuming no Kyoto-style cutbacks
in
anthropogenic CO2 emissions.
What it means
In order to avoid the unpalatable consequences of widespread
hunger in the
decades ahead - as though there were not enough of it already -
it would
appear to be necessary to allow the air's CO2 concentration to
rise at an
unrestricted rate. Consequently, efforts designed to
discourage CO2
emissions are seen in this light to be inimical to our future
well-being, as
well as that of generations yet unborn.
Copyright © 2000. Center for the Study of Carbon Dioxide
and Global Change
(www.co2science.org
============================
* LETTERS TO THE MODERATOR *
============================
(7) GOOD NEWS
From Andy Smith <astrosafe@yahoo.com>
Hello Benny,
It is always good to see the CCN light-house beacon burning, as
we steer
toward our goal of asteroid/comet emergency (ACE) preparedness
and as we
realize how important it is for us to work togeather, with
openness, candor
and respect.
GOOD NEWS
We've come a long-way, in the last decade, and nothing makes that
progress
more evident than a look at the NEO discovery numbers. This is
our third
year of triple-digit discoveries. We should reach a global
discovery rate of
one NEO per day, this year.
This is quite a contrast to the one-per-month rate, in 1995, and
the average
discovery rate of less than 2 per year, which we have had for the
last two
centuries. The MPC data shows that we have good data on about
1156 NEO
(collected over the last 200 years) and 73% of those discoveries
were made
in the last 5 years.
In the last year, LINEAR has been responsible for about 71% of
the activity.
LONEOS, SPACE WATCH, CATALINA, NEAT and the
Tholen/Whitley Team contributed 11, 7, 5, 3 and 3%,
respectively. We are very grateful to all of these excellent
teams, to the
dozens of smaller contributors, to the MPC and all who are
helping with this
extremely important task.
We are still a long way from the RAMA goal of 12 per day (by
2130), but we
are making great progress. With just the existing teams, we
should be able
to reach the 4 digit level. Think what we could do with the
addition of that
Mars early warning system. It is also great to see private
investors (Space
Frontier and others) and other governments beginning to support
this task.
ACE SCALE
Each step number, on our 10 step exponential Asteroid/Comet
Emergency (ACE)
comparison scale, is approximately equal (order-of-magnitude) to
the log of the destructive
energy (in megatons)of the object on that step. The step number
plus one is
also about equal to the risk interval (in years). As an example,
a Step 3
object (about 200 meters wide), hits every 10,000 years or so and
has about
1,000 megatons of destructive energy.
We pointed-out, in our earlier message, that the Step 1 object is
about the
size of the Tunguska and Barringer objects (50 meters) and each
increasing
step represents an object which is twice the width of the object
on the
preceeding step. The Step 10 object is about the size of
Hale-Bopp (25
kilometer range).
We have been using this scale for about 10 years, to give public
groups a
feel for the relative hazards and risks we face. We point out, of
course,
that the destructive energy varies with the object density and
velocity.
We welcome inputs which will help to improve this tool. It is
like most
natural disaster scales (Richter, etc.)in that it is a simple
exponential comparison of the
destructive energies. We have received several positive comments
and we welcome others.
CIVIL EMERGENCY PREPAREDNESS
As we identify and find ways to quantify and counter the various
impact
effects, we will send inputs to CCNet. In this note, we want to
call
attention to the major electro-magnetic radiation disturbances
which may be
associated with even ACE Step 1 events. We are continuing to get
information
from the ongoing Tunguska studies and these disturbances, it
seems, could
complicate emergency communications and operations. In the case
of the
Tunguska impact, it appears there may have been significant
global
disturbances, in the then primative communications networks
(telegraph). We
would appreciate additional information on this problem.
POSSIBLE OXYGEN PROBLEM
It also seems that with large object impacts (which could trigger
fires over
a major fraction of the globe and partialy block sunlight, for
extended
periods - shutting-down the natural oxygen factory), we could
experience
significant changes in the atmospheric oxygen levels and we need
to factor
this into our emergency planning. With smaller impacts, the ratio
of burn
area width to impacting object width seems to be about three
orders of
magnitude.
It looks like a 10% oxygen atmosphere will still sustain animal
life. We are
looking at this, with the help of some of the agricultural,
inhalation and
physiology experts in our area, and we will provide future
updates on our
progress.
TSUNAMI EMERGENCY PREPAREDNESS PLANS (TEPP)
Some of the island emergency preparedness groups have good TEPP
and we are
studying these plans and communicating with them and with the
Tsunami
warning and other emergency preparedness groups, to do what we
can to raise
the coastal city readiness levels. We will also update CCNet on
this
activity.
We would very much like to communicate with any other groups
concerned with
ACE preparedness planning.
We've made a lot of progress, in the last decade, but we
obviously have a
long way to go, in all of the important activity areas (early
warning,
defense and civil preparedness).
We again want to thank all of the CCNet members for what they are
doing.
Cheers
Andy Smith
----------------------------------------
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