From: men@bjerknes.colorado.edu (Matthew Newman)
Subject: Re: Lawyer's science vs. unbiased presentation of the facts
Organization: NOAA Climate Research Division
Date: Tue, 21 Jul 1992 17:07:34 GMT

In article <1992Jul20.164701.8222@techbook.com> szabo@techbook.com (Nick Szabo) writes:
>In article <1992Jul17.204754.12012@meteor.wisc.edu> tobis@meteor.wisc.edu (Michael Tobis) writes:
>

(I have tried to edit this down somewhat)

>
>Is this a joke?  There is no scientific definition of what constitutes
>the "natural" level of carbon dioxide.  Your defintion of "natural" as
>the near all-time low level is pure lawyers science, meant to leave a 
>misleading impression of the impact of CO2 rises.  Nor is VERY LARGE
>a standard scientific quantity. 
>
>
>>My use of the word 'natural' referred to the recent geological conditions of
>>the past two million years, when the geographic situation allows for
>>the glacial oscillations on a 10^4 yr. time scale popularly known as
>>"ice ages".
>
>The use of the word "recent" is far more accurate then "natural", and
>I suggest you use such meaningful words instead of lawyer's science that
>obscures what you are talking about.  It is no more or less misleading
>to call the Cambrian levels "natural", since life including vertebrates 
>thrived under those conditions with biodiversity greater than during the
>"ice ages", and would thrive again given an (unknown) time to adapt.  
>The CO2 fertilization effect implies that today's species are also
>adapted to CO2 levels much higher than current (they have not de-adapted
>in the last 30 million years).
>
>
>>>  There are many known climate 
>>>changes that were more rapid than the IPCC mean global warming (2.5C in
>>>c. 100 years), and many that were of greater magnitude, and from our
>>>scant look at recent climate history at least one (Younger Dryas) that was 
>>>both.  But you would rather hyperbolize about how VERY LARGE it is.
>>
>>These changes may exist, but they are extremely rare, and have never
>>occurred since civilization began, and would be extremely disruptive.
>
>ENSO is rare?  Ice age transitions are rare?  Pinatubo-sized volcanoes
>are rare?  Whoo boy.  You would also be hard pressed to demonstrate Younger 
>Dryas (greater than IPCC hypothesized global warming in both rate and 
>magnitude) is rare, since it is a newly discovered phenomenon of a kind 
>not yet looked for in other epochs (I hope they're looking now, though).
>Since the YD is quite recent, there could be dozens or thousands like
>it waiting to be found in the geological record.
>
>
>>From Crowley & North, _Paleoclimatology_, Oxford Press, 1991, p. 254:
>>
>>	"The CO2 perturbation therefore represents a major climate
>>	change, which will occur at a rate comparable to or exceeding
>>	any known to have occurred in earth history. 
>
>Looks like C&N have a bit of hyperbole of their own.  This is only
>true in the very narrow sense of CO2 increases over 300 years (and
>even that being unprecedented is conjecture; there are millions
>of 300-year chunks we haven't looked at for CO2 levels).  Most rational 
>observers would rate asteroid strikes, major volcanos, and Younger Dryas as 
>more severe, and some would include ENSO and Pinatubo since the rate of 
>change is larger.
>-- 
>szabo@techbook.COM  Public Access User --- Not affiliated with TECHbooks
>Public Access UNIX and Internet at (503) 644-8135 (1200/2400, N81) 

Ok, I know I'm going to regret entering this pointless discussion in
even the smallest way, but--

I understand the arguing about the existence and possible consequences
of an enhanced greenhouse effect (even though the amount of
misinformation and namecalling gets to be a bit much at times), but
this whole thread about the 'natural' level from which to measure CO2
increase really seems to be a complete smokescreen.

From the human standpoint, all that really matters is how much CO2
has risen in the last century or so, and how much (and how fast) it
will rise in the coming years.  Any 'natural' level is irrelevant
(except insofar as it might indicate processes that act to maintain
such a level), because our only concern is what will happen to our
current civilization.  Whether anthropogenic global warming is the 
fastest change the world has ever seen doesn't matter; only whether
it is a change that is too fast for *us* to adjust to without 
significant disruption.  (For example, if sea levels rise, will the
rise be so great that we can't save coastal cities; if weather
patterns change, will the change be so drastic that agriculture can't 
adapt quickly enough).  This would seem to make the comparison to ENSO
events and isolated volcanic eruptions more relevant, but these are
temporary occurences, and so can't give us useful information on our
ability to withstand more permanent changes.

This is also true from a global standpoint--can other life adjust to
such a change, or will we find that our civilization's survival is
threatened by the loss of too many species.

Sure, we can take the ultra long view and say that other climate
change has occurred before in Earth's history; there will always
be species that can take advantage of the new environment, and other
species that will lose out.  This does not seem particularly useful,
however, given the long time it takes for new species to evolve.  And
we hardly have to fear that humanity is going to be wiped out.  But
this doesn't strike me as much comfort.

Matt Newman
men@noaacrd.colorado.edu

Newsgroups: sci.environment