While Eric Alexander is asking for evidence sources from man made climate change sceptics, letters 22/1, could one ask again for explanations from the protagonists?

As far as I am aware the scientists from the “man made” lobby do not dispute the Laws of Thermodynamics (which incidentally engineers had been using for some time before scientists formulated them), so why do they use the term “renewable energy sources”?

They must concede there is no such thing. As yet, energy cannot be created it can only be converted from one thing to another. Solar radiation, air flow and water flow are not renewable sources, repetitive and variable certainly, but not renewable.

Using these to create electricity with, let's be honest, pretty low efficiency, is removing energy from these sources. Environmentalists who believe all human energy requirements can be obtained from these sources presumably hold the belief that Nature “wastes” an immense amount of energy.

What they really mean is that human race can make better use of it than Nature or, more simply, that the human race has more need of it than what Nature uses it for. This does not seem to gel with the “saving the plant” incantations of the self-proclaimed environmentalists who seem to have very little understanding of even the little that is known about how the planet's environment's function, a reasonable deduction from their letters in these pages.

They seem to have a blind belief that the changes in Nature caused by the transfer of this energy from natural to human use will benefit the planet in general and the human race in particular.

All this because of an increase in a gas that makes up a mere 0.03% of the atmosphere that has been deduced to vary naturally (ie before human activities) by a far greater extent. (Also, presumably, the realisation that human civilisation is the least capable existence on the planet of adapting to natural phenomena.)

May one also reiterate the question to which an answer is still awaited. Why are the offending gases referred to as “greenhouse” gasses when they have nothing whatsoever to do with greenhouses?

Perhaps as a graduate scientist Eric can also explain how gases (CFC's), as inert as any on the planet, four to five times as dense as air, manage to get 20 miles up into the stratosphere, migrate to the polar regions and when there, at very low temperature, create a catastrophic chemical reaction. To the best of my knowledge something which some scientists seem to believe, but none has ever attempted to explain.

P D Somerville, Coningsby Road, High Wycombe.