There is much controversy over these matters.

But our world has experienced variation over the centuries.

There are still memories of ice on the Thames and school closures in our country because of excess heat.

But farting cows are not the only cause! All animals, including humans and others, fart out methane and all rotting vegetation and the gas from bogs (often called marsh gas) gives off tons of methane and have done so over millions of years.

Where has it gone? Methane is highly flammable and when it meets a source of ignition such as fire or lightning it burns to carbon dioxide and water. It does not survive in the atmosphere.

So our dairy cows do little to cause global warming.

The greenhouse effect keeps us from freezing at night and acts as a blanket. Some gases trap the radiation from our earth and reflects it back to us. That is the greenhouse effect.

Carbon dioxide does a very small amount of this. The major greenhouse effect is water vapour and where it is absent, such as desert areas, the temperature at night drops to well below freezing. There is no greenhouse effect.

Many of our parliamentarians are either ignorant or deliberately avoiding the truth.

John Mills, New Plymouth