Claims lacking in scientific credibility

Sir, – Who do we believe on climate change, asks Duncan Kennedy (Letters, November 10).

We believe the scientists, Duncan, that’s who and global warming denials like ‘CO2 is not the culprit’ (November 8) do not help Duncan or any of the paper’s other readers, especially when the letters are lacking in scientific credibility.

For example, the statement CO2 isn’t responsible for causing runaway global warming is plausible simply because runaway global warming is not yet happening.

What scientists fear most is that if the rise in temperature caused by CO2 is not halted, we will reach the stage where water will evaporate at an increasing rate thus accelerating the build-up of vapour in the atmosphere.

Earth will then become locked into an irreversible cycle of increasing atmospheric water vapour followed by even higher temperatures.

This is what scientists mean by runaway global warming which in time will cause the Earth to end up like Venus.

Attributing claims to David Bellamy in support of scientifically weak claims cannot be excused.

The sun does indeed have an effect on global warming because it emits the radiation which is absorbed by atmospheric greenhouse gases.

That radiation is infrared and is also absorbed by the planet’s surface only to be re-emitted and absorbed by the greenhouse gases. The gas molecules thus become energised in the form of trapped heat which lasts as long as the energised molecules persist in the atmosphere.

Cosmic rays are a type of energetic particle such as atomic nuclei or protons which are fragments of atoms.

They come from the sun and other galactic sources and cause their own kind of havoc not connected with global warming. Scientists have debated a possible role of cosmic rays in global warming but they are not considered to have statistically significant influence on changes in cloud cover. Studies indicate cosmic rays have no causal relationship to changes in global temperature.

The writer’s claims on netzero and computer failings likewise lack scientific credibility. Without citing sources to what the writer references as if it were empirical data, these claims can only be regarded with a healthy degree of scepticism.

Iain Jack, Woodlands Road, Blairgowrie.