> Ah of course, I see it now. Obviously that culture that pumped
> all that CO2 into the atmosphere 150,000 years ago completely
> wiped themselves off the face of the earth. We must learn from
> their mistakes. Remember the Alantians!
>
It is true that the CO2 level has been about as high as it is now in the
past. Obviously that wasn't caused by civilization. But, if one does a
back of the envelope calculation of the amount of CO2 produced, one finds
numbers that are close to the rise observed in the last 50 years. Plus,
since that chart is on a large time scale, (5000 years per tic mark) it
represents averages over long periods of time.
If you look at
http://cdiac.esd.ornl.gov/trends/co2/graphics/lawdome.gif
you will see the last 1000 years. It shows a fairly flat baseline around
280 ppm from 1000 to about 1875. It then ramps up to around 340 ppm in
1980. If you look at the first plot, you will see that 340 ppm is higher
than CO2 has been in 160,000 years. And, the projections are that it will
go to about 560 by the middle of this century if the present use trends
continue.
I have never claimed that this will end life on the earth. It will change
things however. Since we built our civilizations around the present
climate, a number of people will lose as a result of these changes.
Let me give you a simple example of this. If the Artic ice continues to
shrink at the present rate, there will be open water at the North Pole by
the middle of the century. This may change the ocean currents, and drive
the Gulf Stream away from Europe. Anchorage Alaska is at the same latitude
as Scotland. Can you imagine if the weather in Scotland beings to resemble
that at Anchorage?
Dan M.
> Sorry, it's been a long day.
>
Its OK Kevin. But you know me, I argue with #s. :-)
