Evidence of climate change is all around us, we can’t overlook it - Yorkshire Post Letters

The complexity of climate science, and the inability of some climate change deniers to properly understand it, is well illustrated by a suite of recent letters in these pages. Charles Wardrop (July 23 and 27) is one of the perverse group of contributors I have previously mentioned, who contend that concerns over atmospheric CO2 are misplaced.

He refers on July 27 to "unproven climate change hypotheses" including "that greenhouse gases, notably CO2, are released from fossil fuelled energy generation". Does he really think it unproven that the oxidation of hydrocarbons produces carbon dioxide? He does his tenuous, misconceived arguments no favours with such obvious nonsense.

Mr Wardrop wishes to agree with Simon Watkins about Nimbyism, implying that Mr Watkins' letter (July 23) somehow supports his own climate denial, but it does no such thing.

Rather, although prompted by a planning proposal for a wind farm, Mr Watkins as an architect is simply calling for the right development in the right place, with appropriate sympathetic design for the context, and he recognises that so-called Nimby objections in planning disputes are often perfectly respectable.

In his own letter of July 23, Mr Wardrop counters a letter from Terry Brown (July 18) who said "Charles Wardrop is wrong to claim that Sun activity and atmospheric water vapour are responsible for global warming."

Mr Wardrop answers that "rises in atmospheric CO2 concentration (a negligible 0.04 per cent) exert negligible extra greenhouse effect because its infrared binding sites are saturated."

On this issue, both writers are partly right and partly wrong. However, the greater fault lies with Mr Wardrop, and his reference to "infrared binding sites"

is further nonsense. CO2 does not "bind" with infrared, it absorbs and re-emits the energy. Binding sites in a molecule are to do with bonding between atoms in chemical reactions. The interaction of a molecule with incident light is a matter of physics - energy absorption at specific frequencies stimulating intramolecular vibrations of the atoms and bonds.

By far the greatest influence on global climate is indeed the sun, as our only ultimate source of energy. But without the heat-trapping presence of CO2 in the atmosphere, and the orbital distance between our planet and the sun, we would not have liquid water and therefore no atmospheric water vapour and clouds in the sky, such that all known life could not exist.

Oxygen and nitrogen make up over 99 per cent of the atmosphere, but do not contribute to the greenhouse effect since they have only two atoms per molecule (Argon at under 1 per cent is monatomic). At least three bonded atoms are needed for a molecule to absorb light energy at infrared frequencies.

The proportion of CO2 in the atmosphere may be as little as 0.04 per cent (actually now 420 parts per million, compared to 280ppm just 200 years ago), but it is nonetheless the most abundant "greenhouse gas". Methane, with 5 atoms, is more powerful in greenhouse effect per molecule, but amounts to less than 2ppm.

Water vapour (H2O) also has a significant overall influence on climate regulation, but the fundamental issue with man-made climate influence, as I have previously explained, is that clouds, most of the CO2, and all the solar influence, have always been involved in creating the baseline position.

It is CO2 and methane proportions that have increased in the past two centuries - due substantially to human activities - at such an unprecedented and unnaturally rapid rate in close correlation with, and now generally accepted as the cause of, rapidly rising global mean temperatures.

Charles Wardop chooses to regard all this as “unproved hypothesis”, but the empirical evidence is all around us and increasingly incontrovertible. He should reconsider his attitude.