On Wed, 10 May 2000 04:28:03 -0400, Donald E Davison wrote:
> Again, I thank everyone, including those of you who still do not
>believe mankind is causing the current rise in temperatures. I have
>abridged some of the letters.
>Much to the surprise of investigators, evidence is mounting that major
>changes in the earth's climate can take place in a very short time. Data
>from ice cores and ocean sediments suggest, for example, that 11,650 years
>ago the climate in Greenland switched from ice-age conditions to the current
>relatively warm conditions (a warming of 5 to 10 degrees Celsius on average)
>in only 40 years. [American Scientist]
These would seem to contradictory statements. The 11,650 BP climate
flip would be pretty hard to attribute to human activity, wouldn't it.
Especially *industrial* activity.
Few people are aware how warm things can become on Earth from time to
time. In the Eocene period (about 45 Million years ago), the extreme
north of Canada was covered with cypress trees --- about like the
Memphis, Tennessee area today. Paleo magnetic work demonstrates that
the area was no more than about 200 miles from its present location at
82-N latitude. Now *that's* warm.
I am not trying to belittle concerns that present human activity may be
contributing to present apparent warming trends, and the associated
rise in atmospheric CO2 is incontrovertible, however Earth has
undergone warmings (and coolings) substantially greater and more rapid
than anything yet attributable to human activity.
It is intriguing to add into this mix that the amount of carbon stored
in grasslands (before they got planted to maize and soya beans) was
greater than that held in the tropical rainforests. Degradation of soil
organic matter may in itself be a contributor to greenhouse gases (loss
of the carbon sink, plus mineralisation of stored carbon).
That's where we come in folks.
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