PLEASE NOTE:
*
CCNet 42/2002 - 27 March 2002
-----------------------------
"I weigh in on the side of the fence that the establishment
of an
impactor detection and deflection system need not take 100 or 200
years;
the basic self-organizing principle of complex systems could
bring it about
very quickly. All the basic systems are in place; at this point
it will
just take some prodding by people in the know to get it done. I
became
interested in all this after it became evident to me that the
Earth seems to
be resolving many of its problems presently; it would be a shame
if an
impactor would ruin all that."
--Don Stockbauer, 27 March 2002
"As we asteroid hunters go on debating about the factor that
influence funding, for our research here in India things have
been
rather interesting. For the last one year I have been trying with
little success to set up a small NEO follow-up observatory here.
But we
have better politicians here than in Australia, I guess. Here in
India, the
Senator for science and technology is a PhD is particle physics.
This
guy, who is highly qualified, is highly superstitious too.
Instead of
supporting asteroid research, he has introduced astrology courses
in
universities!"
--Vishnu Vardhan Reddy, New Delhi, India, 27 March 2002
(1) METEORITES TELL OF SHOCKING EXPERIENCE IN PLANETARY FORMATION
Ron Baalke <baalke@jpl.nasa.gov>
(2) DAVID WYNN-WILLIAMS - IN MEMORIAM
UK_Astrobiology_Network@ast.star.rl.ac.uk
(3) THE PROBLEM WITH 2002 CU11
Tumbling Stone, No. 12, March 2002
(4) 2002 CU11: A SCIENTIFIC BREAKTHROUGH
Tumbling Stone, No. 12, March 2002
(5) SENTRY: A MONITORING SYSTEM FROM NASA TO THE WEB
Tumbling Stone, No. 12, March 2002
(6) RAPIDITY WITH WHICH NEO DEFENSE COULD SELF-ORGANISE
Don Stockbauer <donstockbauer@hotmail.com>
(7) FUNDING NEO RESEARCH, INDIAN STYLE
Vishnu Vardhan Reddy <vishnureddy@hotmail.com>
(8) FOR THE RECORD: EVENTS IN AUSTRALIA
Michael Paine <mpaine@tpgi.com.au>
==============
(1) METEORITES TELL OF SHOCKING EXPERIENCE IN PLANETARY FORMATION
>From Ron Baalke <baalke@jpl.nasa.gov>
http://www.spaceflightnow.com/news/n0203/26planetform/
Meteorites tell of shocking experience in planetary formation
CARNEGIE INSTITUTION OF WASHINGTON NEWS RELEASE
March 26, 2002
The search for Earths around other stars is one of the most
pressing
questions in astrophysics today. To home in on what conditions
are necessary
for Earth-like bodies to form, however, scientists must first
solve the
mystery of how our own Earth arose. The formation of the dominant
constituent of meteorites -- tiny, millimeter-sized spheres of
melted silicate rock called
chondrules may hold the clue to this puzzle. A new model
published in this
month's journal, Meteoritics and Planetary Science, by Dr. Steven
J. Desch
of the Carnegie Institution of Washington's Department of
Terrestrial
Magnetism and a member of NASA's Astrobiology Institute, and Dr.
Harold C.
Connolly, Jr., of CUNY-Kingsborough College in Brooklyn, NY,
represents a
huge step in understanding chondrule formation and thus what went
on in our
early solar system. And it answers a series of problems that have
plagued
theoreticians for years. The model determines how chondrules
melted as they
passed through shock waves in the solar nebula gas. As chondrules
melted,
they changed from fluffy dust to round, compact spheres, altering
their
aerodynamic properties, and enabling the growth of larger bodies.
Because
shocks would melt chondrules early in the solar nebula's
evolution, the results
are consistent with the common idea that chondrule formation was
a prerequisite
to the formation of planets in general.
"This model may be the key that unlocks the secrets of the
meteorites," says
Desch. "It is the first model detailed enough to be tested
against the
meteoritic data, and so far it has passed every test. At the same
time, it
is providing a physical context for all that meteoritic data, and
is giving
us fresh insight about chondrule formation."
Researchers have long thought that the interstellar dust
coagulated to form
the planets, but they have not understood what the physical
conditions were
that led to centimeter-sized particles sticking together in the
first place.
Without understanding the origin of chondrules, the data-rich
meteoritic
record could not be used to assess the probability of Earth
forming, which
is essential information in the search for other life-bearing
planets.
"Astrobiology is about the progression from planetary
'building blocks'
through the formation of planets, their habitability, and the
origin and
evolution of life," adds Dr. Rosalind Grymes, Associate
Director of the NASA
Astrobiology Institute, a research consortium that provided
funding for the
study. "This work is at the early end of that progression,
and is
fundamental to understanding life on Earth, and life beyond
Earth."
Meteoriticists have determined a wide body of rules that models
of chondrule
melting must obey. For instance, scientists know that chondrules
reached
peak temperatures of 1800 to 2100 K for several minutes; that
they almost
melted completely; and that they cooled through crystallization
temperatures
of 1400 to 1800 K at rates slower than 100 K/hr, which kept them
hot for
hours. To prevent the loss of iron from the silicate melt,
pressures had to be
high -- greater than 0.001 atm -- which is orders of magnitude
higher than the expected
pressures in the nebula. A few percent of the chondrules stuck
together while still
hot and plastic. These "compound chondrules" tend to be
more completely
melted and to have cooled faster than the average chondrule.
Satisfying all
of these conditions simultaneously has been a challenge to
theorists. In a
1996 review article by Alan Boss of the Carnegie Institution of
Washington,
nine possible mechanisms were reviewed, including lightning,
shock waves,
and asteroid impacts. More recently, the "X-wind" model
has been introduced
by Dr. Frank Shu of UC Berkeley, in which chondrules are melted
near the
protoSun. Even melting by a nearby gamma-ray burst has been
considered. None
of these ideas, however, has been developed to the point to
calculate
cooling rates precisely enough to match what is known about
meteorites.
The model proposed by Desch and Connolly is the most detailed
physical model
yet of chondrule melting by any mechanism. It exactly correlates
the cooling
rates of chondrules -- a key meteoritic constraint -- with
physical
conditions in the solar nebula. The model includes several
previously
ignored effects, such as dissociation of the hydrogen gas by the
shock wave,
the presence of dust, and especially a precise treatment of the
transfer of
radiation through the gas, dust, and chondrules. According to the
model,
chondrules experience their peak heating immediately after
passing through
the shock front. Even though the gas is slowed almost
instantaneously, the
chondrules continue to move at supersonic speeds for minutes
until friction
slows them down. During this stage, chondrules emit intense
infrared
radiation. This radiation is absorbed by chondrules that haven't
reached the
shock front yet, and by chondrules that have already passed
through it. This
transfer of radiation is important to be calculated accurately,
since the
gas and chondrules cool only as fast as they can escape the
intense infrared
radiation coming from the shock front. With this effect included,
typical
cooling rates are 50 K/hr, which is exactly in line with what is
known about
the average chondrule. Moreover, Desch and Connolly predict a
correlation
with the density of chondrules: regions with more chondrules than
average
will produce chondrules that are more completely melted and
cooled faster.
This is because in dense regions radiation from the shock front
cannot
propagate as far before being absorbed and chondrules can escape
the
radiation from the shock front more rapidly. Compound chondrules
are
overwhelmingly produced in regions with high chondrule densities,
so the
extra heating and faster cooling of compound chondrules is easily
explained
by this shock model. Since the time a chondrule spends in a
semi-melted,
plastic state is also calculated by the model, even the frequency
of
compound chondrules can be determined -- it is on the order of a
percent,
satisfying another key constraint. Finally to satisfy another
condition,
shocks compress the gas to pressures orders of magnitude higher
than the
ambient pressure.
The source of the shock waves is not specified by Desch and
Connolly, but
they do identify gravitational instabilities as a likely
candidate, assuming
the solar nebula protoplanetary disk was massive enough. And
there are sound
theoretical reasons for believing it was. More importantly,
observations of
other protoplanetary disks in which planets are forming today
indicate that
sufficiently massive disks may be common. If shock waves
triggered by
gravitational instabilities are taking place in other
protoplanetary disks,
then the odds of chondrules melting and planets forming,
including Earths
around other stars are greatly increased.
==============
(2) DAVID WYNN-WILLIAMS - IN MEMORIAM
>From UK Astrobiology Network <UK_Astrobiology_Network@ast.star.rl.ac.uk>
With great sadness we have to inform you that David Wynn-Williams
was
tragically killed in a road accident whilst out jogging on
Sunday, March
24th.
No further details are as yet available about memorial services
and sending
condolences. Please let me (alan.penny@rl.ac.uk)
know if you want to be on
the distribution list when further details become available.
David was one of the founders of the UK Astrobiology Network, and
had a lead
role in the European Exo/Astrobiology Network Association, and in
the
International Journal of Astrobiology. His energy and positive
outlook will
be missed by all who knew him.
-------------------------------------------------------------------------
This notice is distributed in the UK as a service of the UK
Astrobiology
Network. http://astrobiology.rl.ac.uk/
================
(3) THE PROBLEM WITH 2002 CU11
>From Tumbling Stone, No. 12, March 2002
http://spaceguard.ias.rm.cnr.it/tumblingstone/issues/current/eng/2002cu11.htm
by Andrea Milani, Giovanni Valsecchi and Maria Eugenia Sansaturio
-
The asteroid 2002 CU11 was discovered on 7 February 2002; after
the data
were made public by the MPC, the CLOMON software robot monitored
it and
since 14 February identified it as a possible impactor; this
information was
posted on the "risk page" of the Near Earth Objects
Dynamic Site (NEODyS)
(http://newton.dm.unipi.it/neodys/).
Successive recomputations, using later
observations, confirmed the existence of an impact risk, in
particular for
the year 2049 (impacts in other years are also possible).
According to the
last computation (based on observations up to 23 march 2002) and
to our best
estimate of the impact probability, done with the experimental
CLOMON2
software, the 2049 impact has a probability of about 1 in 9,300.
2002 CU11 has an estimated absolute magnitude (dict.) 18.3 thus,
using the
average albedo and density of the Near Earth Asteroids (NEA, see
dict.) and
the properties of its orbital intersection with Earth, the best
estimate of
the energy which would be released in case of an impact is 53,000
Megatons
(MT, see dict.).
We have recently developed a metric to be used to assess the
relevance of
such a risk in comparison with the background risk by all Near
Earth Objects
(NEO, see dict.), both known and unknown, the Palermo Technical
Scale, PTS (
see T.S. issue number 11 to know more about the Palermo Technical
Scale ,
also see the scientific article by Chesley et al., 2002).
According to our standard model the risk of impact by 2002 CU11
in 2049
amounts to 45% of the risk, between now and 2049, for an impact
with energy
53,000 MT or larger; this corresponds to a value -0.35 in the
logarithmic
PTS. The PTS does not replace, but complements the simpler (and
thus easier
to use in communicating with a larger public) Torino Scale
(http://impact.arc.nasa.gov/torino/index.html),
which is, in this case, 1.
Copyright Tumbling Stone 2002
=================
(4) 2002 CU11: A SCIENTIFIC BREAKTHROUGH
>From Tumbling Stone, No. 12, March 2002
http://spaceguard.ias.rm.cnr.it/tumblingstone/issues/current/eng/break.htm
by Andrea Milani, Giovanni Valsecchi and Maria Eugenia Sansaturio
-
To put the detection of the 2002 CU11 impact possibility in
context, we need
some historical perspective.
Almost exactly 4 years ago an ambiguous announcement of a
possible asteroid
impact (by 1997 XF11 in 2028) raised the issue that the
scientific community
lacked the know how necessary to assess the impact risk, for low
probability
but nevertheless serious cases. This challenge was taken by some
as an
opportunity for controversy, by others as a job which needed to
be done.
Almost exactly three years ago the announcement by Milani,
Chesley and
Valsecchi of a possible impact (by 1999 AN10 in 2039) with a
probability of
1 in 1,000,000,000 (one in a billion) was met with an enormous
interest,
some disbelief and very aggressive polemics. We think that the
time has
shown the relevance of the conceptual breakthough on which that
announcement
was based.
To appreciate the changes which took place in only three years,
it is enough
to consider two points.
First, what was in 1999 an exceptional, surprising and even scary
announcement is now routine. The CLOMON robot, operating at the
University
of Pisa on a daily basis since November 1999, has recently been
joined by a
second, fully independent and even more automated software
system, the
Sentry of JPL (http://neo.jpl.nasa.gov/risk/).
Now both systems run daily
and maintain lists of several dozens of asteroids with Virtual
Impactors
(see dict.). Moreover, a third system (CLOMON2) has been
implemented at the
University of Pisa and is already being used experimetally with
good results
(e.g., the above mentioned figures for 2002 CU11 come from the
more advanced
CLOMON2 impact probability estimates). Also because of the 9
hours time zone
lag the systems at JPL and at Pisa actually run in an
asynchronous way and
provide more than daily surveillance. Needless to say, the
two teams
consult on each high risk case and mutually assist in the
progressive
upgrade of the subtle algorithms and of the complex software
required for
this task.
The second and even more impressive measure of the progress done
in 3 years
is in the numbers given above. The announcement raising such a
noise in 1999
was for an impact probability more than 100,000 times smaller
than the one
now announced on the NEODyS and the Sentry risk page (the
asteroid being of
comparable size). Unfortunately, it is quite possible that the
risk level
from 2002 CU11 will further increase in the next days and weeks.
The Virtual
Impactor for 2049 is very close to the nominal solution and the
observed arc
already spans 44 days, thus it would be normal for the impact
probability to
increase with a few additional observations, before it can be
ruled out by a
larger number of additional observations. In this case, the risk
could
become Torino Scale 2 and Palermo Technical Scale above 0, that
is, the risk
for this single VI would be more than the background risk from
the entire
NEO population (see NEO in dict). The attention of the internet
discussion
groups, not to speak of the media, to this case has been
zero. Observations
have kept coming in thanks to the action of the Spaceguard
Central Node
(SCN; http://spaceguard.ias.rm.cnr.it/SSystem/SSystem.html),
but even the
asteroid observers have not been paying too much attention.
Verifictaion and announcement
This impressive increase in the level of risk detected by our
monitoring
systems raises a new level of concern, and two main issues.
The first issue is that the International Astronomical Union
(IAU) Tehcnical
Verification Procedure (see http://web.mit.edu/rpb/wgneo/)
has to be
replaced by a totally different, indeed more important, IAU role.
We have
been the ones asking, since 1999, for a formal IAU procedure for
verification and controlled announcement, and the ones insisting
on the need
for everybody to abide by the IAU rules, once they were
established. The
purpose was to guarantee the scientists involved in these
computations
(mostly ourselves) against the disbelief in our results and also
against our
own possible mistakes. As long as a single team of a few
scientists, working
part time and with very limited resources, had to bear the entire
responsability for identifying the risk cases, such a procedure
was needed
and it was our right to ask for it. Thus we thank the IAU for
their support
and all the IAU offcials involved for the time they have consumed
in
defining and improving the technical verification procedure.
However, the situation is now totally different. The idea of
waiting for up
to 72 hours for verification of a VI identified by one of the
software
systems currently running is not even considered anymore. If our
American
colleagues are still sleeping during our early office hours, we
use the
messages from their robot to check our results; if we are already
in bed
during the American afternoon, the JPL group can use the output
from our
robot to check. A few hours is the maximum time needed for
verification, and
in some cases a few minutes are enough.
We are of course ready to provide every independent scientist
with the
detailed datasets necessary for a full verification of our
claims. But,
under the present circumstances, the most useful contribution by
independent
scientists would be in suggesting substantial improvements to the
theory of
close approaches (and resonant returns) on which our predictions
are based,
rather than in repeating the computation of a specific case,
since every
computation is already done at least twice (and often more than
twice) by
independent software systems. This new understanding is more
likely to
happen offline, within the time frame of innovative research,
rather than
under the pressure of a 72 hours deadline.
There is a problem, different from verification of the risk
computations,
which has not been solved, and for which the IAU role is likely
to be
essential: what to do after a high risk case has been reliably
identified.
Cases of this nature require action within the astronomical
community to
ensure that the necessary observational resources are made
available at the
appropriate time. Moreover, although this has not happened yet,
we need to
be aware that at some future time there will be a risk case which
will not
be removed by observation, but will require an intervention well
beyond the
means and the responsibility of the astronomical community (see
T.S. issue
number 9 about deflection and other mitigation methods). We
suggest that the
appropriate IAU bodies start discussing about the possible
procedures to
take this kind of action, inside the astronomical community and,
if
necessary, with the relevant authorities.
The other issue is how to communicate the new and higher risk
levels to a
larger public. Our announcements are already public, in that they
are
available on web sites well known to the professional astronomers
and also
to the interested amateurs
(http://newton.dm.unipi.it/neodys/,
http://neo.jpl.nasa.gov,
http://spaceguard.ias.rm.cnr.it).
But to publicize these announcements, with
the purpose of arousing the public interest, is a quite different
story, and
the issue is whether we should either attempt or avoid this.
We are aware that many of the people involved in this discussion
are happy
to see that announcements for impact risks up to 100,000 times
larger than
the one of 1999 are now generating little, if any, media
coverage. To some
extent this is indeed a positive development, in that the
sensationalistic
and often distorted presentations of some previous announcements
did far
more harm than good. There has been an effect of immunization by
assuefaction, of the media and the public, against the poison of
scaremongering, as in the legend of the king Mythridates who used
to eat a
little poison every day to become resistant. At the same time the
public,
hence the political authorities, have become a little more aware
of the
reality and the proportions of the impact risk. However, such
awareness has
not yet resulted in any practical action to contribute to
decreasing the
risk, apart from public relation efforts which may or may not
convince the
public, but are unlikely to convince an asteroid heading our
way. As an
example, the work of the NEODyS group still does not have direct
support
from the scientific authorities, neither at the national
(Italian) level nor
at the European one. Thus the people who claim we should not
publicize our
work need to explain what we are supposed to do to obtain the
support
necessary to improve, even to continue, our work. Moreover,
immaginary risk
cases such as 2002 EM7 continue to attract the attention of the
media and
distract the public both from the general issue and from the real
risk cases
such as 2002 CU11.
What we will do in this case
We would like to conclude with what we propose to do to handle
the 2002 CU11
case, as well as similar cases which might arise in the near
future. This
because we believe it is better to be transparent in the
procedures and in
the dissemination of the information, and this has to be done on
the basis
of a policy decided in advance, not when we are already in an
emergency
situation.
First, all the data necessary for the verification of our risk
page
announcements will be made available automatically, and in real
time. In
this way every scientist with the necessary know how will be able
to check
our computations, maybe even using our free software
(http://copernico.dm.unipi/it/orbfit/),
although this makes the check not
really independent. What matters more, independent scientists
could check
and improve the theory behind our results.
Second, we will post the output of our computations on 2002 CU11
(and other
similar cases) as soon as they are complete and have been checked
by us. It
will often be the case that these computations will have been
already
duplicated and confirmed by Sentry, but also because of the time
zone lag
this may not always be the case.
Third, we will explain and advertize our results on the
professional PR tool
we have created for this use, the online journal Tumbling Stone
(http://spaceguard.ias.rm.cnr.it/tumblingstone).
Will this make imposssible verification and autoritative
statements by
organizations such as the IAU? Certainly not. Verification will
be possible
at all times, both by spontaneous initiative by independent
scientists and
by institutional refereeing organized by scientific bodies.
Authoritative
statements are welcome, and must be based only on the primary
sources, which
will be in all cases the already mentioned web sites of NEODyS,
Sentry, the
Spaceguard Foundation and Tumbling Stone.
Copyright Tumbling Stone 2002
====================
(5) SENTRY: A MONITORING SYSTEM FROM NASA TO THE WEB
>From Tumbling Stone, No. 12, March 2002
http://spaceguard.ias.rm.cnr.it/tumblingstone/issues/current/eng/2002cu11.htm
by Livia Giacomini
It took two years of hard work, but finally, on March the 12th,
NASA
announced that Sentry, its new automatic asteroid impact
monitoring system,
was beginning to be operated out of Jet Propulsion Laboratory.
Sentry was
built largely by Drs. Steve Chesley and Alan Chamberlin with
technical help
from Paul Chodas.
To be more precise, Sentry is a highly automated system, designed
to help
scientists better communicate about the discoveries of new,
potentially
threatening Near Earth asteroids (NEAs) and their follow-up
observations.
While completely independent from other scienitific teams, it is
in constant
communication with the NEODyS CLOMON impact monitoring system,
operated in
Pisa, and researchers from the two systems are cooperating to
check and
improve their results.
But how does this new tool work? First of all, it is important to
say that,
as it usually is today in the scientific world, Sentry is a
technological
tool which implements web based technology. In fact, all the data
calculated
is posted daily on the web, in the public Sentry risk page
(http://neo.jpl.nasa.gov/risk/)
which constitutes a very important tool for
research teams around the world as well as for amateurs.
The procedure to determine these parameters is quite clear: data
about NEAs
is drawn each day from the Minor Planet Center in Cambridge, and
it is used
to update the orbits, Earth approaches, and last but not least,
Earth impact
probabilities. Based on these calculations, several asteroids are
added
monthly to the web page which can be considered as an updated
list of
"dangerous" objects which must be followed up. These
objects are in fact
characterized by two aspects: first, they have orbits that can
bring them
close to Earth, and second, only a limited number of observations
are
available for each of them, so that their trajectories are not
well-enough
defined.
Normally, these NEAs are listed on the Sentry Impact Risk page
only to be
removed to a second no-risk page soon afterward. But pay
attention, this
procedure doesn't mean that there was an error while calculating
the risk.
In fact, as new observations become available, the knowledge of
the object's
orbit is improved (its region of uncertainty becomes smaller) and
its risk
promptly recalculated. The most likely outcome of the all
procedure is that
the object becomes harmless and is therefore removed from the
risk page.
But how does the public outreach of the Sentry system work? A
first
characteristic of the Sentry risk page is that the risk is
presented using
both the usual Torino Scale and the new, more technical, Palermo
Technical
Scale (click here to go to T.S. issue number 11, to know more
about the two
scales).
Thanks to the two scales, the risk of a single object is compared
to the
so-called background level (which is the average risk from the
entire NEO
population). A Palermo Technical Scale value less than zero and,
in most
cases, a Torino Scale value of zero, indicates that this risk is
below this
background level, and that the event can be considered only of
academic
interest, and not deserving public concern.
On the other hand, on the very rare cases when events have a
Palermo
Technical Scale value greater than zero, a Technical Review is
requested to
verify the calculations before the prediction is placed on the
Risk Page.
But Sentry is also a scientific instrument, meant to give to
scientists all
data and information about NEAs. For this reason, independently
from the
associated risk, for each object of the Risk Page there is a
separate page
providing more detailed technical information.
But let's come down to mathematics. The real question is: how are
the Earth
impact probabilities for near-Earth objects calculated? Every
day,
observations and orbit solutions are received from the Minor
Planet Center
and once an object has been classified as a NEA, and as soon as
enough
observations have been collected, an orbit determination process
is used to
find the orbit which best fits all the observations. But how is
this done?
The main idea is that an object's orbit follows some equations
that take
into account the gravitational attraction of the Sun, the
planets, the Moon,
and the three largest asteroids, Ceres, Pallas, and Vesta. Given
an
observed, initial position of an asteroid, its further positions
can be
computed solving these equations of motion. The difference
between these
computed values and the actually measured ones are called
observation
residuals. The overall orbit of the object (and therefore the six
orbital
parameters that characterize it) is determined iteratively
adjusting the
calculated and the observed positions until the sum of squares of
all the
observations residuals reaches a minimum value (this mathematical
procedure
is called minimum squares fitting, see this issue of T.S. to know
more).
The final result of the orbit determination process is called the
nominal
solution. Of course, slightly different orbits may still fit the
observations and this set of orbits lies within what is called
the
uncertainty region, as all the points inside the region are
called virtual
asteroids. Whenever new optical or radar observations become
available,
automatic updates of this orbit are calculated, giving obviously
priority to
the objects that seem more dangerous. It is therefore clear that,
as new
observations of the object are made, the nominal orbit can change
and its
region of uncertainity can become smaller and smaller.
Orbits and regions of uncertainty are fundamental to make the
evaluation of
the real risk associated with the asteroid, or in other words,
the impact
probabilites. In fact, once the nominal orbit and its associated
uncertainty
region have been estimated, Sentry can simulate the object's
motion in time
for up to 100 years. This is done to determine its close
approaches to the
Earth, published in the Earth Close Approach Tables together with
the
relative impact probability. This projection in the future of the
uncertainty region is not a simple task from a mathematical point
of view
and it is not always possible. A first mean to achieve this goal
is to
compute these parameters by projecting the uncertainty region to
the close
approach time via so-called linearized techniques. Since these
techniques
lose accuracy when the uncertainties become large, close
approaches may be
calculated up to decades into the future for objects with
well-known orbits,
but only a few months or years for objects with poorly known
orbits.
On the other hand, Sentry also wants to estimate long-term
possibilities of
impact for objects with poorly known orbits. To estimate this
risk it uses
more sophisticated non-linear methods, which are integrated to
linear means
whenever the uncertainties in a close approach prediction are
large.
Sentry, together with other scientific services such as NEODyS,
is just one
example of the great efforts that every day is been made and must
be made to
improve our knowledge of asteroids and NEOs. In this optic, by
the year
2008, NASA has a congressionally mandated goal to find 90 percent
of all
Near Earth Objects larger than 1 kilometer. Of them, only about
500 have
been found. An estimated 500 or so, still remain undiscovered.
Copyright Tumbling Stone 2002
============================
* LETTERS TO THE MODERATOR *
============================
(6) RAPIDITY WITH WHICH NEO DEFENSE COULD SELF-ORGANISE
>From Don Stockbauer <donstockbauer@hotmail.com>
Dear Dr. Peiser:
I weigh in on the side of the fence that the establishment of an
impactor
detection and deflection system need not take 100 or 200
years; I've been
studying cybernetics
(http://pespmc1.vub.ac.be
) the past few years, and the basic
self-organizing principle of complex systems could bring it about
very
quickly. All the basic systems are in place; at this point
it will just
take some prodding by people in the know to get it done. I became
interested
in all this after it became evident to me that the Earth seems to
be
resolving many of its problems presently; it would be a shame if
an impactor
would ruin all that. Getting past their threat must surely
be a
prerequisite to a Type I civilization such as us moving on to
Type II and
III. Thanks for your time. I really enjoy the CCNet.
Sincerely,
Don Stockbauer
donstockbauer@hotmail.com
========
(7) FUNDING NEO RESEARCH, INDIAN STYLE
>From Vishnu Vardhan Reddy <vishnureddy@hotmail.com>
Dear Benny,
As we asteroid hunters go on debating about the factor that
influence
funding for our research here in India things have been rather
interesting.
With virtually no or little research in planetary sciences,
asteroids are a
thing of the past. The last successful asteroid hunter from India
was the
great British astronomer Norman Robert Pogson (he is better known
for his
Pogson step method used in variable star work) who
discovered five
asteroids from the Madras
Observatory in 1880s.
For the last one year I have been trying with little success to
set up a
small NEO follow-up observatory here. But we have better
politicians here
than in Australia I guess. Here in India, the Senator for
science and
technology is a PhD is particle physics. This guy, who is highly
qualified,
is highly superstitious too. Instead of supporting asteroid
research, he has
introduced astrology courses in universities! Can you imagine? So
it is not
the educational background that matters - what matters is
rational thinking,
which very few humans seem to have. This moronic senator has gone
overboard
and introduced astrology grants! Similar to our NEO grants -
where people
can apply for $35,000 grants to do astrology project. If such is
the state
of a country, which has a fifth of the world's population,
then I don't
blame the Luxembourg government. At least they don't give grants
for
astrology projects.
Lately, I have been getting some interesting ideas to exploit
this idiotic
senator. In the Hindu Vedanta (religious texts), there is a
chapter on the
end of the world due to an asteroid impact. Maybe I should use
that as an
excuse and get grants for NEO station here. I know if I work for
a week on
my dialogues and wear an orange dress like a Hindu holy man this
senator
will fall on my feat seeking my blessings..leave alone the
money for
grants. But again where do we draw the line.
When we try to explain things in a rational way the politicians
say we are
trying to scare them into funding NEO work. When we try to
education people
we are blamed for spreading rumours and false information about
threats due
to NEOs. I wonder what that Australian minister would have said
if a
Christian cult group had asked him for money or had someone
dropped a few
stones over his bedroom at night. It is sad that we spend more
time talking
about funding than doing actual research.
Clear Skies
Vishnu Vardhan
New Delhi, India
=============
(8) FOR THE RECORD: EVENTS IN AUSTRALIA
>From Michael Paine <mpaine@tpgi.com.au>
Dear Benny
Another excellent article from Rob Britt about the dilemma in
Australia
prompted me to document the events of the last few months. On 7th
January a
300m asteroid passed within 830,000 km of the Earth. It was
discovered only
a few weeks earlier.
(http://news.bbc.co.uk/hi/english/sci/tech/newsid_1746000/1746330.stm
)
The Age (Melbourne, Australia) ran an article about this
"near miss". They
contacted the office of Science Minister McGauran. A spokesperson
said he
(McGauran) "would investigate funding a program" (in
hindsight that
statement was probably just to get the reporter off her back).
(http://www.theage.com.au/news/national/2002/01/09/FFXWQ4DK6WC.html
)
Soon after this article was published Dr Benny Peiser contacted
me and said
he would like to organise an open letter to the Australian
government from
several NEO researchers. It would welcome the reconsideration of
funding by
the government and point out the risks of asteroid impacts and
the benefits
of Spaceguard. Dr Peiser asked that Jay Tate (Spaceguard UK) and
I help
draft the letter.
To our delight more than 90 reseachers subsequently agreed to be
signatories
to the letter, which Spaceguard UK posted to the Australian Prime
Minister
and several Ministers on 28 January
(http://www4.tpg.com.au/users/tps-seti/pr_oz_sg.htm
)
Also during January the "near miss" came to the
attention of producers of
two TV shows: 60 Minutes and Sunday Sunrise. Both interviewed
Paul Davies
and Duncan Steel and by coincidence, both productions were shown
on 17th
March. 60 Minutes also interviewed Peter McGauran. It appears
that he was either very poorly prepared for that interview or he
had decided
to be obstinate (or both!). He said the search effort was "a
fruitless,
unnecessary, self-indulgent exercise".
(http://news.ninemsn.com.au/sixtyminutes/stories/2002_03_17/story_531.asp
http://new.i7.com.au/sunday_sunrise/story.php?story=34
)
I think that most in the NEO community were stunned by this
misinformed
outburst from the Minister. He obviously did not like being put
on the spot
in front of a TV camera. He seemed to take it out the scientists
who had
simply pointed out that searching for asteroids is a good idea
and is highly cost effective. As far as I know the TV productions
were
initiated by articles in the newspapers, not by any lobbying - in
fact I
have found it extremely difficult to get the media to respond to
any
lobbying.
This week CCNet posted an item by Ed Grondine that addresses the
mistakes
made by the Minister and those of a reporter with The Canberra
Times.
(http://abob.libs.uga.edu/bobk/ccc/cc032202.html
)
I also addressed some of these issues in a press release
(http://www4.tpg.com.au/users/tps-seti/spacegd3.html#pr020319
)
Anyway, Spaceguard UK is still waiting for a reply from the
Australian
government to the letter it sent in January. I think we can all
guess the
flavour of that reply (if it is ever forthcoming). Stay tuned for
the next
installment.
Michael Paine
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*
CCNet CLIMATE SCARES & CLIMATE CHANGE, 27 March 2002
----------------------------------------------------
The management and staff of CCNet would like to wish all our
readers
a happy Easter and Passover break.
--Benny Peiser
"A scientific study has found that the continued existence
of Tuvalu
is not threatened, as the Pacific Ocean is not rising. Tuvalu,
north of
Fiji, claims it's sinking under rising sea-levels which have
resulted from
global warming. Last month it told the Commonwealth leaders'
meeting in
Australia it was planning to sue western nations for their
failure to curb
so-called greenhouse gases. However, an Australian team known as
National
Tidal Facility, working from Flinders University in South
Australia, says
it has seen no significant rise in sea levels across the
Pacific."
--ABC News, 27 March 2002
"If there was truly a period near the beginning of the past
millennium when temperatures were as warm as they are presently,
for
example, but when the atmosphere's CO2 concentration was about 90
ppm lower
than it is today, and if that period was followed by a
several-centuries-long cold period with essentially no decline in
the air's
CO2 content, there would be little basis for invoking the
20th-century
increase in atmospheric CO2 concentration as a reason for the
planet's
return to the degree of warmth it had experienced a millennium
earlier."
-- Sherwood B. Idso, Keith E. Idso, 27 March 2002
(1) ANOTHER GLOBAL WARMING SCARE BITES THE DUST: PACIFIC OCEAN
SEA LEVEL NOT
RISING
ABC News, 27 March 2002
(2) ISLANDS DRAW ATTENTION TO GLOBAL WARMING
UPI, 26 March 2002
(3) SEA LEVEL TRENDS IN POLAND
CO2 Science Magazine, 27 March 2002
(4) MORE EVIDENCE FOR A 1500-YEAR CLIMATE CYCLE
CO2 Science Magazine, 27 March 2002
(5) THE MEDIEVAL WARM PERIOD AND LITTLE ICE AGE: THEIR UNTIEMLY
DEMISE AND
WELCOME RESURRECTION
CO2 Science Magazine, 27 March 2002
(6) WHAT WARMS UP CAN COOL DOWN
CNBC, 25 March 2002
(7) THE WEAKEST LINK, GOODBYE
Tech Central Station, 25 March 2002
====================
(1) ANOTHER GLOBAL WARMING SCARE BITES THE DUST: PACIFIC OCEAN
SEA LEVEL NOT
RISING
>From ABC News, 27 March 2002
http://abc.net.au/ra/newstories/RANewsStories_515013.htm
Scientific study says Pacific Ocean won't submerge Tuvalu
A scientific study has found that the continued existence of
Tuvalu is not
threatened, as the Pacific Ocean is not rising.
Tuvalu, north of Fiji, claims it's sinking under rising
sea-levels which
have resulted from global warming.
Last month it told the Commonwealth leaders' meeting in Australia
it was
planning to sue western nations for their failure to curb
so-called
greenhouse gases.
However, an Australian team known as National Tidal Facility,
working from
Flinders University in South Australia, says it has seen no
significant rise
in sea levels across the Pacific.
Funded by Australian aid, the Facility has been using a tidal
guage on
Tuvalu's capital, Funafuti, since 1993.
It calculates that in those nine years, the rise has been just
under one
milimetre a year, and historicial records going back to 1978,
show no
evidence of any acceleration in sea level trends.
Copyright 2002, ABC
MODERATOR'S NOTE: The paper ("Sea Level Rise in Tuvalu: It's
Present State")
with full research findings has just been published by the
National Tidal
Facility at Flinders University of South Australia) and can be
found at:
http://www.ntf.flinders.edu.au/
===============
(2) ISLANDS DRAW ATTENTION TO GLOBAL WARMING
>From UPI, 26 March 2002
http://www.upi.com/view.cfm?StoryID=26032002-112920-3331r
>From the Science & Technology Desk
HONOLULU, March 26 (UPI) -- Leaders of Pacific Island nations
want to hold
industrialized countries responsible for global warming -- saying
since they
emit the majority of greenhouse gases they should help prevent
rising sea
levels from swallowing up islands.
While scientists agree the Earth is warming and human activity
has
contributed to this climate change, they cannot come to a
consensus on what
the extent of the damage could be.
That does not matter to island nations, which have grown
impatient with the
debate while they watch their beaches slowly disappear.
They met in Honolulu to discuss the problem and Tuvalu Prime
Minister Koloa
Talake told the other nine Pacific Island leaders he has
witnessed the beach
outside his house lose about 50 yards over the past 50 years.
Talake also is expected to visit U.S. attorneys later this month
to discuss
possible legal action. Tuvalu is an island nation near New
Zealand and
Australia with a population of about 10,000 people.
"Pacific island nations are extremely vulnerable to changes
in the climate,"
Eileen Shea, climate project coordinator for the East-West Center
in
Honolulu, a nonprofit, private research institute that hosted the
meeting,
told United Press International. "They sit in the heartbeat
of the Earth's
climate system."
One of those nations is the Federated States of Micronesia, whose
president,
Leo Falcam, chair of the Pacific Islands Conference of Leaders,
took their
fight to Mexico this past week. Falcam has said he will use
whatever means
necessary to get major industrialized countries to pay attention
to this
threat.
While all islands could suffer from global warming, Pacific
Islands are more
vulnerable than those in the Atlantic or Indian oceans, Shea
explained,
because the Pacific is the largest body of water holding the most
islands.
The size of the Pacific also means its islands are more isolated
from larger
mainlands.
Islands depend on tourism to keep their economies afloat so
environmental
damage could have devastating short-term and long-term effects,
said Jeffrey
Langholz, professor of international and environmental policy at
the
Monterrey Institute of International Studies in Monterrey, Calif.
"I'm sure Hawaii will lose a lot of real estate," from
rising sea levels,
Langholz told United Press International. "The stakes are
high for those
(island) people."
The United States is responsible for about one-quarter of
greenhouse gas
emissions, he noted, adding it also produces a large percentage
of goods.
Langholz said, however, island nations do have a case in holding
industrialized countries, particularly the United States,
culpable for
rising sea levels and could be successful in getting the United
States to
finance strategies to minimize the impact of global warming on
islands.
"I think it's a good strategy for them," he said.
"Their backs are against
the wall."
There are no clear time table for islanders, but there are some
projections,
said Henry Pollack, professor of geophysics at the University of
Michigan at
Ann Arbor.
"The likely change of sea level in the 21st century (is) on
the low end
about 20 centimeters and on the high end of 80 centimeters,"
Pollack told
UPI. That would mean falls in the range of slightly less than 1
foot to 3
feet. "This is a century-long scenario," he added.
Global warming is not just an island issue, Pollack said.
"It concerns
people in Florida. A rise of 3 feet would mean a significant loss
of a part
of southern Florida." Parts of New Orleans already are under
sea level, he
said, and cities such as Miami, the California shoreline and the
country of
Bangladesh all could suffer.
"After 2050," Pollack said, "if the steps have not
put in place right, then
you're going to embark on the 80 centimeter path, so in a sense
our
grandparents and parents have already given us the first half
this century
... so in some ways we're going to have to live with what's in
place in
already."
Global warming could be curbed, however, so the Earth is dealing
with the
lower end of the spectrum, sea levels rising at 20 centimeters
instead of
80, he added.
Either way, island nation leaders feel they have no time to lose.
For them,
Shea said, this is by no means an environmental issue. "This
is a national
security issue," she said.
(Reported by Katrina Woznicki in Washington.)
Copyright © 2002 United Press International
===============
(3) SEA LEVEL TRENDS IN POLAND
>From CO2 Science Magazine, 27 March 2002
http://www.co2science.org/journal/2002/v5n13c2.htm
Reference
Wroblewski, A. 2001. A probabilistic approach to sea level rise
up to the
year 2100 at Kolobrzeg, Poland. Climate Research 18: 25-30.
What was done
The author was primarily concerned with forecasting how much the
southern
Baltic Sea might rise by the end of the current century. We,
however, are
more interested in what the data of the past century reveal.
What was learned
Based on data from 1901-1990, there was a linear increase in mean
annual sea
level at Kolobrzeg of 12 ± 2 cm per century. Over this
same period,
however, there was no trend in annual sea level maxima. Two
high values
stood out above the rest in the 1980s, but two similar spikes
occurred in
the 1940s; and there were half a dozen comparable high values in
the first
two decades of the record.
What it means
The author's analysis of the mean annual sea level data for the
southern
Baltic seaport of Kolobrezeg yields results that are compatible
with the
results of most other such studies that have been conducted. The
author
notes, for example, that "neither in the world ocean nor in
European seas
(Woodworth 1990, Gornitz & Solov 1991, Douglas 1992) has
there been any
acceleration in sea level rise in the 20th century."
Superimposed upon the slow upward trend in mean sea level, it is
surprising
that annual maximum sea levels due to storm surges have not risen
over the
past century. One can only conclude these events have become less
intense in
recent years (and possibly less frequent).
References
Douglas, B.C. 1992. Global sea level acceleration. Journal of
Geophysical
Research 97: 12,699-12,706.
Gornitz, V. and Solov, A. 1991. Observations of long-term tide
gauge records
for indicators of accelerated sea level rise. In: Schlesinger,
M.E. (ed.)
Greenhouse Gas-Induced Climatic Change: A Critical Appraisal of
Simulations
and Observations. Elsevier, Amsterdam, pp. 347-367.
Woodworth, P.L. 1990. A search for acceleration in records of
European mean
sea level. International Journal of Climatology 10:
129-143.
Copyright © 2002. Center for the Study of Carbon Dioxide
and Global Change
===========
(4) MORE EVIDENCE FOR A 1500-YEAR CLIMATE CYCLE
>From CO2 Science Magazine, 27 March 2002
http://www.co2science.org/journal/2002/v5n13c3.htm
Reference
de Garidel-Thoron, T. and Beaufort, L. 2001. Millennial-scale
dynamics of
the East Asian winter monsoon during the last 200,000 years.
Paleoceanography 16: 1-12.
What was done
The authors reconstructed a 200,000-year history of primary
productivity
(PP) in the Sulu Sea north of Borneo (8°47'N, 121°17'E), based
on abundances
of the coccolithophore Florisphaera profunda measured in a
36-meter giant
piston core retrieved from a depth of 3600 meters. Three
time-slices were
explored in particular detail in order to determine
high-frequency cycles in
the PP record: one from 160 to 130 ka, one from 60 to 30 ka, and
one from 22
to 4.1 ka.
What was learned
The finest-scale repeatable feature observed in all three
time-slices was a
climate-driven PP oscillation that had a mean period of
approximately 1500
years.
What it means
With respect to the ~1500-year PP cycle, the authors say its
occurrence in
the three different time-slices is suggestive of "a common
origin and an
almost stationary signal across different climatic
conditions." They also
point out the PP cycle's similarity to the 1470-year temperature
cycle
observed by Dansgaard et al. (1984) in the Camp Century d18O ice
core
record, the ~1500-year d18O and chemical markers cycles observed
by Mayewski
et al. (1997) in the Summit ice core, the 1470-year climate cycle
found by
Bond et al. (1997) in North Atlantic deep-sea cores, and the
1500-year
climate cycle found by Campbell et al. (1998) in an Alaskan lake,
which
observations lead the authors to suggest there is also "a
common origin" for
the documented cyclicity in the climate of both high and low
latitudes.
(See also Bond et al., 2001.)
Once again, we thus have powerful evidence for a persistent,
global,
millennial-scale cycle of climate that occurs throughout glacial
and
interglacial periods alike, the most recent manifestations of
which are the
Medieval Warm Period and Little Ice Age. Projecting this
cyclical behavior
forward - which is about as sound a thing as one could ever do,
based on
hundreds of thousands of years of unfailing repetitive behavior -
we see we
are on the threshold of a several-hundred-year period of what we
could well
call the optimum climatic conditions of the Modern Warm
Period. Hence,
there is no compelling reason to believe that any of the warming
of the past
century is related to the historical and still-ongoing rise in
the air's CO2
content. It is merely a continuation of what has happened
over and over,
again and again, throughout the history of the planet as far back
in time as
can be traced.
References
Bond, G., Kromer, B., Beer, J., Muscheler, R., Evans, M.N.,
Showers, W.,
Hoffmann, S., Lotti-bond, R., Hajdas, I. and Bonani, G.
2001. Persistent
solar influence on North Atlantic climate during the Holocene.
Science 294:
2130-2136.
Bond, G., Showers, W., Chezebiet, M., Lotti, R., Almasi, P.,
deMenocal, P.,
Priore, P., Cullen, H., Hajdas, I. and Bonani, G.
1997. A pervasive
millennial scale cycle in North-Atlantic Holocene and glacial
climates.
Nature 278: 1257-1266.
Campbell, I.D., Campbell, C., Apps, M.J., Rutter, N.W. and Bush,
A.B.G.
1998. Late Holocene ca.1500 yr climatic periodicities and
their
implications. Geology 26: 471-473.
Dansgaard, W., Johnsen, S.J., Clausen, H.B., Dahl-Jensen, N.,
Gundestrup, N.
and Hammer, C.U. 1984. North Atlantic climatic
oscillations revealed by
deep Greenland ice cores. In: Hansen, J.E. and Takahashi,
T. (Eds.),
Climate Processes and Climate Sensitivity, American Geophysical
Union,
Washington, DC, pp. 288-298.
Mayewski, P.A., Meeker, L.D., Twickler, M.S., Whitlow, S., Yang,
Q., Lyons,
W.B. and Prentice, M. 1997. Major features and
forcing of high-latitude
Northern Hemisphere atmospheric circulation using a 110,000-year
long
glaciogeochemical series. Journal of Geophysical Research
102:
26,345-26,366.
Copyright © 2002. Center for the Study of Carbon Dioxide
and Global Change
================
(5) THE MEDIEVAL WARM PERIOD AND LITTLE ICE AGE: THEIR UNTIEMLY
DEMISE AND
WELCOME RESURRECTION
>From CO2 Science Magazine, 27 March 2002
http://www.co2science.org/edit/v5_edit/v5n13edit.htm
The Medieval Warm Period and subsequent Little Ice Age - which
followed hard
on the heels of the Roman Warm Period and Dark Ages Cold Period
(McDermott
et al., 2001) - were long considered to be classic examples of
the warm and
cold phases of a millennial-scale climate oscillation that has
reverberated
seemingly endlessly throughout glacial and interglacial periods
alike (Oppo
et al., 1998; McManus et al., 1999), as well as across the early
Pleistocene
(Raymo et al., 1998).
In addition to their intrinsic historical value, the last of
these warm and
cold periods have particular relevance to the highly-charged
global warming
debate. If there was truly a period near the beginning of the
past
millennium when temperatures were as warm as they are presently,
for
example, but when the atmosphere's CO2 concentration was about 90
ppm lower
than it is today, and if that period was followed by a
several-centuries-long cold period with essentially no decline in
the air's
CO2 content, there would be little basis for invoking the
20th-century
increase in atmospheric CO2 concentration as a reason for the
planet's
return to the degree of warmth it had experienced a millennium
earlier, as
Idso (1988) argued nearly 15 years ago and Broecker (1999, 2001)
has
reminded us more recently.
Faced with this dilemma, the political forces that view the
theory of
CO2-induced global warming as a mighty lever for moving the
nations of the
earth in the direction of global governance - via the
establishment of an
entity with power to regulate nearly all forms of human
enterprise in the
guise of protecting the planet from the climatic consequences of
CO2-producing activities - realized they had a serious problem on
their
hands. To keep their political juggernaut alive, therefore, they
had to
"deep-six" the concept of both the Medieval Warm Period
and the Little Ice
Age, in order to imbue their program with a semblance of
rationality; and
they saw the perfect opportunity to do so in a pair of papers
published by
Mann et al. (1998, 1999).
These papers presented an entirely new perspective on earth's
climatic
history over the past thousand years, which was different from
what had
previously been accepted by even the Intergovernmental Panel on
Climate
Change (Houghton et al., 1990). Whereas IPCC documents up
to at least 1995
had faithfully depicted the existence of both the Medieval Warm
Period and
Little Ice Age, the new history - derived from a few select proxy
temperature records - showed, in the words of Esper et al.
(2002), "an
almost linear temperature decrease from the year 1000 to the late
19th
century, followed by a dramatic and unprecedented temperature
increase to
the present time," which is now routinely described as
"the warmest period
of the past millennium."
Thus died the Medieval Warm Period; and with its passing, the
Little Ice Age
also succumbed. With not much else to block their progress,
the political
forces behind the Kyoto Protocol consequently began to press
forward in a
major way; and they would probably have quickly achieved their
goals, but
for the stubborn resolve of a U.S. president who refused to
cooperate. Now,
however, thanks to the meticulous and careful work of Esper et
al., both of
these unique climatic periods have been resurrected, and they
stand as
stronger and healthier witnesses than ever to the intellectual
bankruptcy of
the climate-alarmist claim that the warming of the past century
is
CO2-induced.
So what did Esper et al. do? In the simplest of terms, they
employed an
analysis technique that allows accurate long-term climatic trends
to be
derived from individual tree-ring series that are of much shorter
duration
than the potential climatic oscillation being studied; and they
applied this
technique to over 1200 tree-ring series derived from 14 different
locations
scattered over the extratropical region of the Northern
Hemisphere.
Two separate chronologies were thus developed: one from trees
that exhibited
age trends that are weakly linear and one from trees with age
trends that
are more nonlinear. The results, in their words, were
"two nearly
independent tree-ring chronologies covering the years
800-1990," which were
"very similar over the past ~1200 years." These
tree-ring histories were
then calibrated against Northern Hemispheric (0 to 90°N) mean
annual
instrumental temperatures from the period 1856-1980 to make them
compatible
with the temperature reconstructions of Mann et al.
What do the results show? The biggest difference between
the Esper et al.
and Mann et al. temperature histories is the degree to which the
coolness of
the Little Ice Age is expressed. The Little Ice Age is much
more evident in
the record of Esper et al., and its significantly lower
temperatures are
what make the Medieval Warm Period stand out more dramatically in
their
temperature reconstruction. Also, they note that "the
warmest period covers
the interval 950-1045, with the peak occurring around
990." This finding,
they say, "suggests that past comparisons of the Medieval
Warm Period with
the 20th-century warming back to the year 1000 have not included
all of the
Medieval Warm Period and, perhaps, not even its warmest
interval."
In commenting on these findings in a companion
"perspective" paper, Briffa
and Osborn (2002) make several interesting and important
points. First,
they acknowledge that "the last millennium was much cooler
than previously
interpreted" and that "an early period of warmth in the
late 10th and early
11th centuries is more pronounced than in previous large-scale
reconstructions." In fact, the Esper et al. record
makes it abundantly
clear that the peak warmth of the Medieval Warm Period was fully
equivalent
to the warmth of the present.
This fact reaffirms the point raised by Idso (1988), i.e., that
there is no
need to invoke CO2-induced global warming as a cause of the
planet's
recovery from the global chill of the Little Ice Age.
"Since something
other than atmospheric CO2 variability was ... clearly
responsible for
bringing the planet into the Little Ice Age," as he phrased
it, "something
other than atmospheric CO2 variability may just as well have
brought the
planet out of it." And that something else, as
suggested by Esper et al.,
is probably "the 1000- to 2000-year climate rhythm (1470 ±
500 years) in the
North Atlantic, which may be related to solar-forced changes in
thermohaline
circulation," as has recently been described in compelling
detail by Bond et
al. (2001) and which we heartily endorse.
Briffa and Osborn also note that Esper et al.'s record clearly
shows that
the warming of the 20th century was actually "a continuation
of a trend that
began at the start of the 19th century." In addition,
the Esper et al.
record indicates that the Northern Hemisphere warmed in a
consistent
near-linear fashion over this entire 200-year period, contrary to
the
climate-alarmist claim of unprecedented warming over only the
last century.
Hence, the new data do great damage to the claim that
CO2-enhanced
greenhouse warming is responsible for the temperature increase
that brought
us out of the Little Ice Age, since the increase in the
atmosphere's CO2
concentration over this period was highly non-linear, rising by
only 10 to
15 ppm over the 19th century, but by fully 70 to 75 ppm over the
20th
century, with no analogous increase in the latter period's rate
of warming.
Finally, Briffa and Osborn say that "we need to know why it
was once so warm
and then so cool, before we can say whether 21st-century warming
is likely
to be nearer to the top or the bottom of the latest IPCC
[predicted
temperature] range." Actually, we probably already
know the answer to this
question: the extremes of warmth and coolness to which they refer
were
likely caused by "solar-forced changes in thermohaline
circulation," as
suggested by Esper et al. and described by Bond et al. In
any event, it is
becoming ever more clear with each passing day that these
significant
climatic changes were not caused by changes in the air's CO2
content.
Dr. Sherwood B. Idso, President
Dr. Keith E. Idso, Vice President
References
Bond, G., Kromer, B., Beer, J., Muscheler, R., Evans, M.N.,
Showers, W.,
Hoffmann, S., Lotti-Bond, R., Irka Hajdas, I. and Bonani,
G. 2001.
Persistent solar influence on North Atlantic climate during the
Holocene.
Science 294: 2130-2136.
Briffa, K.R. and Osborn, T.J. 2002. Blowing hot and cold. Science
295:
2227-2228.
Broecker, W.S. 1999. Climate change prediction. Science 283: 179.
Broecker, W.S. 2001. Glaciers that speak in tongues and other
tales of
global warming. Natural History 110 (8): 60-69.
Esper, J., Cook, E.R. and Schweingruber, F.H. 2002. Low-frequency
signals in
long tree-ring chronologies for reconstructing past temperature
variability.
Science 295: 2250-2253.
Houghton, J.T., Jenkins, G.J. and Ephraums, J.J. (Eds.). 1990.
Climate
Change: The IPCC Scientific Assessment. Cambridge University
Press,
Cambridge, UK.
Idso, S.B. 1988. Greenhouse warming or Little Ice Age demise: a
critical
problem for climatology. Theoretical and Applied
Climatology 39: 54-56.
Mann, M.E., Bradley, R.S. and Hughes, M.K. 1998. Global-scale
temperature
patterns and climate forcing over the past six centuries. Nature
392:
779-787.
Mann, M.E., Bradley, R.S. and Hughes, M.K. 1999. Northern
Hemisphere
temperatures duing the past millennium: Inferences,
uncertainties, and
limitations. Geophysical Research Letters 26: 759-762.
McDermott, F., Mattey, D.P. and Hawkesworth, C. 2001.
Centennial-scale
Holocene climate variability revealed by a high-resolution
speleotherm ó18O
record from SW Ireland. Science 294: 1328-1331.
McManus, J.F., Oppo, D.W. and Cullen, J.L. 1999. A
0.5-million-year record
of millennial-scale climate variability in the North Atlantic.
Science 283:
971-974.
Oppo, D.W., McManus, J.F. and Cullen, J.L. 1998. Abrupt climate
events
500,000 to 340,000 years ago: evidence from subpolar North
Atlantic
sediments. Science 279: 1335-1338.
Raymo, M.E., Ganley, K., Carter, S., Oppo, D.W. and McManus, J.
1998.
Millennial-scale climate instability during the early Pleistocene
epoch.
Nature 392: 699-702.
Copyright © 2002. Center for the Study of Carbon Dioxide and
Global Change
=========
(6) WHAT WARMS UP CAN COOL DOWN
>From CNBC, 25 March 2002
http://moneycentral.msn.com/articles/invest/extra/9227.asp
Don't buy that snorkel and fins just yet. Despite reams of
evidence pointing
to a warmer planet, millions of years of history offer a less
alarming
perspective.
By Emory Thomas, Jr.
Scenarios don't often get more apocalyptic than this: The United
Nations'
Intergovernmental Panel on Climate Change concluded that the
Earth's average
temperature is likely to rise by 2.5 to 10.4 degrees by the end
of the 21st
century. Taking the middle range, a five-degree increase by 2100
would make
the Earth hot enough to cause more tropical diseases, droughts,
floods, heat
waves, severe weather -- ultimately displacing or killing mass
numbers of
people.
OK, fine. But is it worth worrying about in any immediate sense?
Worth
adjusting those investments for? Of course not.
Setting aside the vigorous debate about whether (or how much)
manmade
contributions to the greenhouse trend are to blame for the
climatic
predicament, global warming is fairly well documented and
confirmed.
A provincial government report in British Columbia, for instance,
recently
documented a wide range of changes there: an infestation of pine
beetles
where once it was too cold for them to live; the warming of the
salmon-filled Fraser River; the slight rise in average sea levels
compared
with 1909. A New York Times magazine piece recently traced the
findings of a
naturalist in northern Alaska who found that the Artic summer was
arriving
earlier every recent decade. And the recent collapse of an
age-old Antarctic
ice shelf the size of Rhode Island brings some immediate validity
to the
warming phenomenon.
That said, global warming and all its attendant catastrophes
aren't a done
deal. In fact, the historical record shows that some periods
undergo quick
(in evolutionary terms) shifts in climate, both back and forth.
In other
words, just because the globe has been heating up over the past
century
doesn't mean it won't be cooling down over the next century
(despite the
best efforts of our industrial society to heat it).
Consider the recent revelations offered by a report in The New
Yorker
magazine, in which correspondent Elizabeth Kolbert tracked the
findings of
scientists in Greenland. By drilling deep into the ice there and
analyzing
weather cycles, scientists have concluded that climates tend to
change
quickly and drastically -- contradicting our myopic view that
today's
predictable weather patterns are the norm.
"By now," Kolbert reported, "the adherents of
neo-catastrophism include
virtually every climatologist of any standing."
Consider, for example, a period about 12,000 years ago. Greenland
abruptly
warmed by more than 8 degrees in just one decade. And this,
despite the
distinct absence of human intervention.
But it goes the other direction, too. For hundreds of millions of
years, a
pattern has emerged, with 10,000 years of warmth alternating with
90,000
years of cold. Given that our hot streak is just about 10,000
years old, we
could be poised for a reversal of climatic fortune. In fact, even
the very
warming of the planet could -- ironically -- trigger a cold snap.
If melted
glacier water re-routes the Gulf Stream, air currents could well
take a turn
for the frozen.
What to make of all this catastrophic talk? If you're wise,
nothing. The
fact is, no one knows what temperature this crazy world will be a
few dozen
years from now, much less next year.
So if it's warming up outside, simply enjoy the sunshine.
©2002 Microsoft Corporation. All rights reserved.
==========
(7) THE WEAKEST LINK, GOODBYE
>From Tech Central Station, 25 March 2002
http://www.techcentralstation.com/1051/envirowrapper.jsp?PID=1051-450&CID=1051-032502A
By Howard Fienberg 03/25/2002
It is often said that a warming world will lead to greater
epidemics of
infectious diseases like West Nile and dengue. But the 10th
International
Congress on Infectious Diseases (March 11-14) did not talk much
about
climate change. In fact, when discussing common diseases like
malaria, most
attendees expressed concerns about the pricing of anti-malarial
drugs and
the growth of drug-resistance.
So why do infectious disease researchers appear so disinterested
in global
warming? Because their research does not indicate any simple link
between
global climate changes and the spread of infectious disease. For
instance, a
new article in the journal Nature (Feb. 21) examining malaria
could find no
association whatsoever. Oxford zoologist Simon I. Hay and his
coauthors
looked at temperature, rainfall, vapor pressures and the number
of months
suitable for the transmission of malaria at four sites in the
highlands of
East Africa. They found no change in these factors "during
the past century
or during the period of reported malaria resurgence."
What else could have caused the uptick in malaria? At Kericho,
the
researchers point to the growth of anti-malarial drug resistance
(those
drugs having been the public health response to the large
epidemics
sixty-some years ago). Similarly, drug resistance, rather than
climate
changes resulting from local deforestation, seems a more likely
culprit in
the Usambara mountains of Tanzania. In Southern Uganda,
"epidemiological
changes have been attributed to the shorter-term climate
phenomenon of El
Nino, which is suggested to cause changes in vector
abundance." In the
fourth site, Muhanga, changes in land use may be at least as
important as
increases in temperature in causing an increase in malaria.
Across other highland African areas, "increases in malaria
have been
attributed to population migration and the breakdown in both
health service
provision and vector control operations." The researchers
conclude that,
given the climate variability in East Africa, "associations
between local
malaria resurgences and regional changes in climate are overly
simplistic."
Changes in the weather can have dramatic impacts on diseases and
the pests
that spread them. However, as the Nature study hints, and a
report from the
National Research Council pointed out last year ("Under the
Weather"), the
relationship traditionally drawn between climate and disease can
be
misleading.
Other influences, such as ecological, biological and societal
changes, can
have an even greater impact. Malaria and dengue outbreaks might
be caused by
anything from deforestation to population increases. And thanks
to increased
globalization, diseases can be transported worldwide in a matter
of hours.
This does not mean that the climate has no impact. The life
cycles of many
disease pathogens and vectors are directly or indirectly
influenced by
changes in temperature, precipitation and humidity, affecting
"the timing
and intensity" of outbreaks. Unfortunately, most of the
links made between
climate and disease result from computer models.
Computers can calculate anything, but effectively including all
relevant
factors in a climate model is no easy feat. Inevitably, computer
climate
models only capture part of the story of infectious diseases. The
NRC
cautioned that such models are good for some kinds of analyses,
but "are not
necessarily intended to serve as predictive tools," since
they cannot "fully
account for the complex web of causation that underlies disease
dynamics."
University of Edinburgh biologist Mark Woolhouse has highlighted
the
challenges in this kind of modeling. Commenting on the Nature
study on the
website BioMedNet (Mar.8), he mentioned three problems: disease
surveillance
data "are often of poor quality"; outbreaks
"undoubtedly" spring from more
than one cause; and the trouble in determining the right climate
variables
to study. So how can researchers be expected "to detect any
signal amongst
the noise"?
The NRC report stressed that there are a lot more possible
influences than
climate, including "sanitation and public health services,
population
density and demographics, land use changes, and travel
patterns." So strong
public health measures "such as vector control efforts,
water treatment
systems, and vaccination programs" remain the most effective
weapons in the
battle against infectious disease.
Centers for Disease Control entomologist Paul Reiter thinks that
North
Americans and Europeans have forgotten that malaria and dengue
are not just
tropical diseases (New Scientist, Sep. 23, 2000). In the 1880's,
malaria
existed in most of North America. In the 1920's, "epidemics
killed hundreds
of thousands in the Soviet Union, right up to the Arctic
Circle." In 1922,
Texas was estimated to have 500,000 cases of dengue. While public
health
schemes and socioeconomic improvement moved us away from the
mosquitoes,
much of the rest of the Earth's peoples have not been so
fortunate.
It would be a shame if our misperceptions prevented us from
properly dealing
with infectious diseases, which kill millions of people worldwide
every
year. Global warming may or may not be a disaster waiting to
happen, but
lumping it together with more tangible public health problems
probably won't
help solve either one.
Copyright 2002, Tech Central Station
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