[meteorite-list] New Theory: Global Warming CausedbyTunguskaEvent/ climate change - ~ot

From: Charles Viau <cviau_at_meteoritecentral.com>
Date: Sun Mar 19 19:44:07 2006
Message-ID: <20060319050250.2107326560_at_ns4.beld.net>

Robert,

To you, Excellence in logic and interpretation.

Here we are, barely the last second in this planet's biography, and being
responsible for this particular cyclic temperature evolution that has
repeated itself over and over since the seas formed.... Talk about the
self-righteous ignorance exhibited by otherwise scholarly people.

Thanks for your well written and scientifically sane analysis.

CharlyV

-----Original Message-----
From: meteorite-list-bounces_at_meteoritecentral.com
[mailto:meteorite-list-bounces_at_meteoritecentral.com] On Behalf Of Sterling
K. Webb
Sent: Friday, March 17, 2006 7:54 PM
To: meteorite-list_at_meteoritecentral.com
Cc: ROBERT D. MATSON; mark ford
Subject: Re: [meteorite-list] New Theory: Global Warming
CausedbyTunguskaEvent/ climate change - ~ot

Hi,

    Well, it's time to jump in with both feet...

    Mark said:
> The earth is warmer now than it has
> been for many millions of years...

    Grrr. I don't blame Mark. This stupid
non-statistic has been repeated so many
times by a) people who should know better,
and b) people who do know better, that it's
acquired a life of its own. The NASA scientist
supposedly "persecuted" for his opinions on
global warming said it, then emended it to
"the last 700,000 years," then quit saying it,
possibly because it's completely untrue.

    The truth: 6000 years ago, halfway through
this temporary interglacial warm spell we're
having (the one that's almost over, that one),
the mean temperature of the Earth was four to
seven degrees (F.) warmer than today's climate,
depending on how you read the data and where
you're talking about.

    So, that 1,000,000 years is actually about
1700 years... But the judgment I draw from it
is this: The prophets of doom say an increase
of three to five degrees (F.) will cause great harm
to humanity. I look to the era when temperatures
were that high (4000 BC to 3000 BC) for evidences
of the disaster that befell humanity.

    Instead, I see, a vast expansion of agriculture,
the explosive growth of the first human cities on
the planet, human population growth from the
increased ability to survive, the invention of writing,
literature, knowledge, exploration, government,
sciences and technologies, skills and crafts...
In a word, I see that thing we call civilization, a
human gimmick to keep all of us alive and thriving,
and without which we wouldn't be here, most of us.

    Sounds really terrible, doesn't it?

    Yes, a rapid shift in climate will cause humanity
trouble. Trouble being pretty much the natural condition
of humanity, we have lots of practice: built a better levee,
change to better-suited crop plants, learn from Venice
and The Nederlands how to deal, etc.

    But... There's no "dealing" with a return of glacial
conditions. Never use the past tense when speaking
of "the ice age." This is the ice age, nor are we "out"
of it. (You sure?) Well, do you see ice anywhere on
the planet? (Well, yeah...) Case closed. If there's ice,
it's an ice age.

    You say, the CO2 levels are soaring and will soon
exceed 400 ppm? Well, during the Ordovician Period
(460 million years ago) CO2 concentrations were
4400 ppm, while temperatures then were about the
same as they are today. Are we absolutely sure CO2 is
the culprit? Shouldn't be.

    Before our present cool spell, there hasn't been any
episode as cool for at least 95,000,000 years, and no
really thumping good ice age for 270,000,000 years!
How'd we get here?

    After Chicxulub, there was a "cooling" but no ice age.
In fact, 55,000,000 year ago, the Earth warmed 9 to 18
degrees (F.) over a 10,000 year period for a warm spell that
lasted 80-120 thousand years. Plants in the southern US
spread 1,000 miles from the Gulf Coast to Wyoming, then
disappeared when the climate cooled off. Now, that's global
warming, but we humans sure didn't do it.

    Sea levels are the best indicators of an ice age. Suck
the water up on to the land in the form of ice, and the sea
level drops very noticeably. About 41,000,000 years ago,
ocean levels began to drop; at 29,000,000 years ago,
they tumbled, probably because the first ice sheets in
Antarctica formed. They may have melted away, because
sea levels partially recovered, then dropped again about
20,000,000 year ago, when the Antarctic ice returned.
But things kept cooling.

    By 14,000,000 years ago, Antarctic ice sheets were complete
and permanent. There was another sea level fall 10,000,000
years ago and by 9,000,000 years ago, the first glaciers on land
formed, in Alaska. By 6,600,000 years ago, South American
glaciers appeared. Then, suddenly at 3,250,000 years ago,
temperatures plunged to today's levels or cooler. The ice age
was on.

    By 2,000,000 years ago, the tropics show immense droughts,
another sign of a worsening ice age ( ice ages are dry episodes).
Between 3,250,000 years ago and 128,000 years ago, there were
34 episodes of severe glaciation, your classic ice age, each one more
severe. 700,000 years ago, the Arctic Ocean started to have pack
ice all year 'round. 72,000 years ago, the cold deepened dramatically,
and the last round of glaciation was one of the worse. It's a long way
from being over.

    Since this is climate, and the nature of climate is to always
change, and since ice ages appear to be driven (but not controlled)
by orbital changes in insolation, there are brief warm spells. The
latest nasty spell started about thirty-odd thousand years ago,
hitting rock-bottom temperatures about 28,000 years ago and
maximum ice coverage about 18,000 years ago.

    It was a good one, as cold spells go. On the French Riviera,
85% of the mammal fossils are those of reindeer (caribou). The
reindeer bones are buried in the permafrost. (Yeah, like Alaska
today, so if you're going to Nice or St. Tropez, pack the FUR
bikini...) About 30 miles north of my house in S. Illinois, there
was a white wall about half a mile high, stretching across the
landscape for hundreds of miles...

    About 14,000 years ago, things began to warm up, and after
some fits and starts, the continental glaciers went away, only
10,300 years ago, initiating our present "summer vacation"
from the ice age. It's an interesting number because these
warm spells only last for about 11,000 years. Some are as
short as 8,000 years and every once in a while, they last for
up to 20,000 years (the last time that happened was 130,000
years ago). But (always a hitch, isn't there?) no one is
really certain why. There are great arguments about the
orbital timing, about which cycle influences which climatic
factor, and so forth.

    So, the discouraging thing is that "summer vacation" may
be almost over. Well, you say discontentedly, it's not like
they were going to throw a switch and -- presto! -- it's an
Ice Age. Gee, I hate to really disappoint you, but it may very
well be that it's exactly like that. For decades, evidence has
been accumulating of a very rapid turnover in conditions, as
short or shorter than the uncertainties in the dating methods
used to observe it. The last I heard, somebody had been
able to pinpoint a major climatic shift in an ice core that
happened in less than three years!

    The "switch" is oceanic currents which transport warmth
from the equator toward the poles, particularly in the northern
hemisphere. Stop those currents, break the circulation pattern,
and it's just like throwing a switch. Some of you may recall a
2004 movie, "The Day After Tomorrow," which was widely
pounded by critics as The Dog of All Time. It seems to have
particularly annoyed a generation brought up on the Global
Warming Faith. Well, quite apart from intrinsic artistic merit
(mediocre), there was absolutely nothing in that movie that
couldn't happen, albeit a little slower and with less drama.
Frozen solid in a week, frozen solid in a year; not really
more convenient...

    Rob said:
> I would consider an ice age worse than the present...
> but I don't think anyone is too concerned about it
> happening in the next century...
    Rob, if you're making a list of the concerned, you can
put me at the top of it. You see, there are both hot and
cold running varieties of Chicken Little.

    Paradoxically, global warming may contribute to
sudden cooling. Increased Arctic melt could trigger a
shutoff of the warm mid-level currents by disrupting
their northern upwelling, which could cause a 7 to 12
degree drop in temperature in a matter of months. The
one indisputable thing one can say about our warm
interglacial episode is that it won't last. They never
do. Yes, someday, our millions of years of ice age will
end, things will get back to "normal," and we can
vacation in the rain forests of Antarctica once again,
but that day is not now, and it is not tomorrow.


Sterling K. Webb
------------------------------------------------------------------------
----- Original Message -----
From: "mark ford" <markf_at_ssl.gb.com>
To: <meteorite-list_at_meteoritecentral.com>; <ROBERT.D.MATSON@saic.com>
Sent: Friday, March 17, 2006 2:46 AM
Subject: RE: [meteorite-list] New Theory: Global Warming
CausedbyTunguskaEvent / climate change - ~ot



Hi Rob,

Well, 'Worse' meaning, the entire world's landmass that is currently at
5 meters or below, above sea level, most probably won't be .... I'd say
that would be a start.... :)

Of course you might argue it won't effect 'us', but then why do we
bother having kids?

They key at the moment is 'they' just have no idea what will happen and
when, the theories seem to range from 'global cooling' to 'complete
catastrophe' unless they can model it in enough detail, there are just
too many factors to get answers.

The earth is warmer now than it has been for many million of years, and
the rate of warming is accelerating. - will it be a problem?, who knows.

Can we do anything about it? Probably not, but unless we have some idea
about what is going on we will never know if there is something we
should be doing. Countires need to start thinking about planning for sea
level rise and especially air stream changes, since it often takes many
decades to change country wide infrastructure, - for example people
still seem intent on building on flood plains.

Whilst I don't attribute it to global warming, Here in Southern Britain
we are currently facing the worst drought for 80 years, rainfall is way
way below average, and we have a hosepipe ban in place (and yes it is
still winter!), I can imagine what could happen if global warming really
did happen...


Best,
Mark



-----Original Message-----
From: ROBERT.D.MATSON_at_saic.com [mailto:ROBERT.D.MATSON@saic.com]
Sent: Thursday, March 16, 2006 11:55 PM
To: mark ford; meteorite-list_at_meteoritecentral.com
Subject: RE: [meteorite-list] New Theory: Global Warming Caused
byTunguskaEvent / climate change

Mark suggested:

> On the same note, I invite as many people as possible to install this
> screen saver application: http://bbc.cpdn.org/ it has been produced
> by the BBC and is using distributed computing (i.e our own domestic
> computers) to accurately model the earths climate hopefully they will
> get a better insight into what really is going to happen when the
> climate gets worse.

I was in agreement with you up until those last five words...
"Worse" than what? Or more specifically, worse by what metric and
what timescale? For example, I would consider an ice age worse than
the present (as far as the earth's current life forms are concerned),
but I don't think anyone is too concerned about it happening in the
next century. --Rob


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Received on Sun 19 Mar 2006 12:02:46 AM PST