"Steve Jackson" wrote in message
...
Let them think it through themselves - it is a debate after all,
isn't it? There are no certainties in this argument, and it may
take hundreds of years to resolve this issue.
No, it is not a debate. It is an established fact that carbon dioxide is a
greenhouse gas. Without it, the Earth would be frozen and life impossible.
Burning fossil fuels, i.e. oxidising organic carbon, adds CO2 to the
atmosphere. Since the start of the Industrial Revolution, by burning coal
and oil we have increased the carbon dioxide in the atmosphere from 280 ppm
to nearly 400 ppm, getting close to a 50% increase. Over the last 100 years
global temperatures have risen by about 0.8 degrees Celcius.
http://www.cru.uea.ac.uk/cru/info/warming/gtc.gif
This may not seem much, but its effect on water vapour content of the
atmosphere is significant. It is the increase in water vapour, the other
major greenhouse gas, which is causing Global Weirding as was shown in the
eponymous programme shown tonight on BBC 4. It will be repeated on saturday
evening at 8 pm.
In the graph it can be seen that the warming paused between 1940 and 1980.
It is believed that this was due to the industrial polution produced by the
western world absorbing and reflecting solar radiation. The pasue in warming
since 2000 is probably due to the Asian Brown Cloud, polution produced by
India and especially China now that all manufacturing industry (both heavy
and light) has been exported there.
Carbon dioxide is not the only thing that drives climate. As the pioneering
climatologist quipped "There are at least nine and twenty ways of
constructing a theory of climate change, and there is probably some truth in
quite a number of them." The greenhouse effect is one of the true theories
but at present it is masked by the others. This is what Anthony Watts
exploits in his web pages which are not science. They are psuedo science
propoganda. If you want your students discuss science I recommend you read
the RealClimate blog.
http://www.realclimate.org/
Cheers, Alastair.