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Subject:

Re: Human induced extinctions: Gray article

From:

Lisa Dangutis <[log in to unmask]>

Reply-To:

Discussion forum for environmental ethics.

Date:

Tue, 1 May 2001 19:11:27 EDT

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (118 lines)

Once extint, things are extinct. I think the point is to avoid that.
Nothing more, nothing less.

Have a nice night,
Lisa Dangutis


In a message dated 05/01/01 4:06:00 PM Eastern Daylight Time,
[log in to unmask] writes:

> In the Gray article is a reference to the acknowledged scientific fact that
>  there was a cataclysmic decline in species during the Devonian period,
>  approximately 400 million years ago. Gray argues in a round about way that
>  this is an example of what Nature herself can do without the help of man.
>  Now the argument that he uses to support his thesis is based on a theory
>  that the cause of this extinction about 400 million years ago was a meteor
>  that struck earth in Central Americas.
>
>  The last argument is actually is based on a current theory. There are other
>  possible explanations. One of which is that during this time when a massive
>  extinction occurred was that there were numerous large volcanic eruptions
on
>  the Indian subcontinent which spewed massive amounts of aerosols and carbon
>  dioxide into the troposphere and the next upper layer of atmosphere. It has
>  not been established yet what was the exact cause of the large species die
>  off. However it is speculated that in North America the forests were all
>  burned off. This lead to additional amounts of CO2 being deposited into the
>  atmosphere and along with vastly lower rates of insolation that
temperatures
>  fell considerably. The result was that in the Northern hemisphere all
>  animals larger than about the size of a rat died off. In the southern
>  hemisphere the effects were not as severe simply because it takes about 2
>  years for the earth's air masses to exchange between hemispheres. Now the
>  point that I wanted to make is this:
>
>  Gray argues that if nature is doing this, then it makes no sense to take
>  precautions at all to protect species nor their habitats. The only
>  environmental values that should be protected are immediate values, rather
>  than values expressed in terms of geological time scales. In fact he cites
>  an auther who claims that there were once more phyla on earth prior to
>  nature causing this extinction. The error here is obvious for any scientist
>  in climates. The accepted hypothesis is that during this major extinction
>  the direct cause of extinction was due to cool temperatures, low oxygen
>  levels and a serious shortage of food or prey. Now at this time in
>  geological history there was vastly more forest covering the earth. This
was
>  *before* any of the ice ages occurred. The Antarctic was still forested.
The
>  probability of recovery from the a large meteor landing in Central America
>  therefore was much greater than it is now assuming a similar meteor or
>  volcanic event was to ensue today. If a meteor or volcanic event of similar
>  magnitude occurred today, the probability of the earth's tropospheric
>  conditions (oxgyen levels, CO2, etc.) recovering to levels that would
>  support large animals would be very much reduced. One of the reasons for
>  this lack of recovery is related to the diminished extent of the world's
>  forested areas caused in main part by man. The quickest way for the oxygen
>  content of the troposphere recovering is through photosynthesis. The amount
>  of photosynthesis is directly proportional to the area of forest, and the
>  rate of photosynthesis of the oceans. Since dying and dead trees emit vast
>  amounts of CO2, there would be a very great increase in CO2 (magnitudes
>  larger than that from erupting volcanos or the direct effects of a large
>  meteor) and a corresponding decline in oxygen after a meteor or a severe
>  volcanic event. The chances of a rapid recovery occurring today given the
>  fact that over 50% of the worlds forests have been removed means that the
>  ability of the earth's biosphere to survive would be reduced simply because
>  it would take that much longer for the oxygen levels to recover to an
>  optimum or minimum level required by some life forms. In fact the current
>  speculation by climate scientists <some of whom are contrarians> is that
the
>  oxygen levels in the atmosphere are currently below the optimum, therefore
>  to stimulate the evolution of more oxygen some anthropic generation of CO2
>  would be beneficial because it is felt that the current levels are
>  dangerously low for many species....therefore an increase in CO2 would
>  stimulate photosynthesis and therefore there would be more O2 in the
>  atmosphere.
>
>  The only long term carbon storage (sink) other than in protected forests
>  exists in oceans, but the rate of absorption compared to that sequestered
in
>  forest biomass is much slower. The argument that if nature does something,
>  then it is okay for humans is therefore unscientific and therefore unsound.
>  This argument would suggest that it is okay to permit industry that has an
>  accumulative net negative effect on coral reefs. Gray disputes that coral
>  reefs have any benefit overall to life since he sees them as unimportant;
>  although he does not say this outright, he says it does not matter in the
>  long run if the Great Barrier Reef dies out. To say this also means that if
>  the coral reefs were wiped out by climate change induced by anthropogenic
>  green house gases via 'bleaching', then it is also okay. However the
>  ecological fact remains that coral reefs provide an important carbon sink
or
>  source to the world's atmosphere and oceans of CO2. These reefs act like a
>  buffer and recovery system for life itself when a catastrophic natural
>  disaster takes place. So by arguing for a 'no virtue' approach to resource
>  management, ie., lets emulate natural events like volcano's and meteors,
>  then this approach may actually contribute to the improverishment of life
on
>  earth.
>
>  Most if not all climate scientists are arguing for reforestation and
>  afforestation since this will increase the rate of carbon sinks in the
>  biosphere and diminish the impact of additional greenhouse gases on
inducing
>  climate change. Even the contrarians are maintaining that this is a good
>  idea since trees capture solar energy and this energy can be used to fuel
>  electric plants, and to produce biofuels. Now does it make any sense to
>  argue for not restoring the biological productivity of previously forested
>  land simply because in the past it is hypothesized that a meteor caused the
>  atmosphere in the Northern Hemisphere to become so cold, oxygen deprived,
>  and inhospitable for a few short years?
>
>  Reforestation of the Amazon of 75 million hectares which were degraded and
>  denuded over the last 5 decades would contribute to the resilience of the
>  earth's biosphere and help to mitigate such natural disasters as volcanic
>  eruptions and meteors on the climate of the earth. Am I wrong on this?
>
>  chao
>

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