IT may well amaze many of your readers to realise that there is still a very small number of our fellow countrymen who remain in denial over the reality of man-made climate change.

They try to tell themselves and others that it is all due to the natural cycles of the sun and/or sunspot activity.

They choose to ignore the fact that sunspot activity is currently at a very low level, the lowest point in the current 11-year cycle and according to NASA, total mean solar heating has shown no increase since 1975; in fact a slight decrease.

This coincides with the period of greatest increase in global heating in recent times. Last year we have had our hottest summer and winter temperatures on record. The 10 hottest years ever recorded in the UK have all occurred since 2002. Meanwhile our CO2 emissions continue to rise. Measurement of polar ice cores has shown that at no time in the last 800,000 years did CO2 emissions exceed 280ppm until the Industrial Revolution. Since then it has steadily increased until now, when it has reached 407ppm.

In the whole of human history CO2 has never been higher. The correlation is clear, when greenhouse gases, particularly CO2, go up, so does temperature.

Some say, aren't clouds a form of greenhouse gas? Scientific opinion suggest that these can influence temperature in two ways. Heavy low cloud can reflect the sun's rays back into space and has therefore a cooling effect, whilst thinner higher cloud can increase the greenhouse effect. However, clouds are transient - their effect is not cumulative. CO2 on the other hand accumulates in the atmosphere and breaks down only very slowly. Today's CO2 emissions will affect temperature for well over 100 years. Some will persist for over a thousand years.

Of course, there are other greenhouse gases, methane and nitrous oxide in particular. These are also increasing, at least in part, due to the Earth's warming.

Over a 100 year period methane has a global warming potential of approximately 28 times more than CO2, though in 2017 methane represented only 10 per cent of global greenhouse gas emissions compared to CO2 82 per cent.

Also, it only resides in the atmosphere for nine to 12 years. Hence it does not persist and accumulate for as long as CO2.

Volcanoes are another interesting case; though their eruptions may put some heat into the atmosphere, the particles that accompany their eruptions stay in the upper atmosphere for some time, spreading around much of the Earth and shading the planet from incoming solar radiation. This has a marked cooling effect (1815 eruption of Mount Tambora resulted in 'the year without a summer' 1816, soaring food prices and famine).

When the need for renewable energy is stressed, adverse comment is sometimes heard regarding the costs involved. Strangely enough the same people who loudly complain of these costs are silent when the full costs of fossil fuels are considered.

The International Monetary Fund, a highly respected international financial organisation, recently calculated that the degree of subsidy globally to the fossil fuel industry amounts to $5.2tn (approx £4tn) per year.

The European Commission reported in 2016 that the figure for the UK was £10.5bn compared to £8.3bn for renewables.

Very recently it has been reported in the journal Advances in Atmospheric Science that the heat in the world's oceans reached a record level in 2019, showing 'irrefutable and accelerating' heating of the planet. This indicates clearly the extent of the climate emergency as the oceans absorb more than 90 per cent of the heat trapped by the greenhouse gases emitted by fossil fuel burning.

The Earth is getting hotter, yet heat from the sun is decreasing. So perhaps Mr Haskell can tell us, from his book of climate fairy tales, where he thinks this heat is coming from?