FURTHER to recent correspondence concerning Global Warming, NASA data concerning surface temperatures is available from the GISS website - The Goddard Institute for Space Science, which interestingly was recently forced to recalculate some published data due to an error. Whether the resultant change was significant depends on your view of the argument. A recent report well worth reading is "Nature, not Human Activity Rules the Climate", published by the Heartland Institute, and available from a Google search. This raises some interesting and uncomfortable points for those convinced that only greenhouse gases from man made activity are changing the environment. Changes may well be occuring, but the mechanisms may equally be predominately natural. Further, we now have a report only this week that any warming effects will be reversed for the next ten years by natural processes, before supposedly resuming their upward trend. Logically we all want to minimise the harmful effects on the environment of our activities, but unless we really understand what is happening, and what the mechanisms are, how can we be sure that what we are proposing to do is, in fact, the best course of action?

Active, clear debate to try to develop a theory is required, rather that blind acceptance that it must be so. There is also a place for the apparently simple question, which needs to be answered clearly by any theory, so I offer the following: We know that Carbon Dioxide is a heavy gas, it collects at ground level, and is, in fact, about half as heavy again as air. This explains its use as a fire extinguishing agent as it sinks down and blocks out the oxygen (air) supply to a fire. If man creates large quantities of Carbon Dioxide at, or near, ground level, by what natural mechanism is this heavy gas lifted vast distances through much lighter air, into the upper atmosphere? Maybe a daft question, or maybe not?

C Westwood

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