I WAS interested to read Rex Hora`s letter on carbon dioxide and the greenhouse effect.

It seems that the warming role of carbon dioxide may have been overstated and that in fact water vapour is far more important.

Any statistician will accept that correlations are not necessarily causes.

Many aeons ago when the last ice ages ended levels of CO2 rose. However, they rose 800 years after the warming and not before the thaw.

This is known as the warming CO2 time lag problem.

Even more curious is the assertion by some scientists that carbon dioxide is actually a cooling agent as in dry ice and does not keep the planet warm at all.

Solar physicists are now predicting a mini ice age to start by 2030 or even sooner.

Today's Letters

Therefore we may need more power generating capacity to keep warm.

Coal is certainly not an ideal fuel and we should endorse cleaner energy.

However freezing to death is not much fun either and wind turbines will not function at all under ice.

Like Mr Hora I also consider myself a green environmentalist.

SUSAN THOMAS

Magdalen Road,

Oxford