Wednesday, April 02, 2008

Letter to the editor: Facts on global warming

A long letter, maybe too long to print. I tried to write it for easy chopping

Sir,

I'd like to thank Dick Keane for rising to the challenge and
presenting tangible claims in contrast to the rhetoric of other
climate change sceptics.

He is correct that CO2 is a very small part of the Earth's atmosphere.
He is also correct that there is far more water vapour in the
atmosphere (although NASA's Earth fact sheet puts it at 25 times
greater than CO2 in contrast to Mr Keane's 100). Neither of these two
facts justify his claim that CO2 is therefore "almost completely
irrelevant as a greenhouse gas".

Different gases have different properties, including different greenhouse
properties. Despite its relative rarity, CO2 is still a major greenhouse gas.
Water vapour is indeed the greatest greenhouse contributor and probably
contributes 2 to 4 times more than CO2 but CO2 is far from "irrelevant".

The other important point is that the amount of water vapour in the
atmosphere is relatively unaffected by human activity. If we add extra
water to the atmosphere it soon condenses and falls as rain. CO2 in
contrast stays in the atmosphere until it is extracted by photosynthesis
or absorbed into the ocean.

Finally, Mr Keane says that it is "warmer oceans", not human activities
over the last 150 years that have caused the observed increase in CO2.
There are two problems with this.

It is indeed harder for CO2 to dissolve in warmer sea-water, however
over the industrial period, the oceans have been a net
absorber of CO2. This could only happen if the level of CO2 in the
atmosphere from other sources was enough to overcome the effect of the
warmth and force the oceans to absorb even more.

Secondly, all the oil, coal and gas we've burnt neatly accounts for the
increase in CO2 that we've seen. To suggest that something else caused
the increase begs the question, "what happened to all that we released?".

Nature spent hundreds of millions of years extracting a vast amount of
carbon from the atmosphere and burying it as fossil fuel. The idea
that we can release it all back into the atmosphere over a couple of
centuries with no side-effects is extraordinary. As such it requires
extraordinary evidence to back it up. This evidence has not been
presented.

The sources of my data are The Royal Society's report on ocean
acidification, NASA and www.realclimate.org,

I got the information on total human CO2 emissions from realclimate.org and I also used thier comparison of the relative strengths of greenhouse gases

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