I explained the exact proposed mechanism in some detail previously. Great work in this field is being carried out by Dr Henrik Svensmark and coworkers in Denmark and elsewhere.

Briefly, the mechanism is that cosmic rays impact on the earth from deep space. These cosmic rays penetrate our atmosphere and lead to the formation of cloud cover. The cosmic rays nucleate sites in the atmosphere, from which clouds form from the natural water vapour.

If one puts a spoonful of coffee powder into a cup of microwaved water, the water forms bubbles of foam on the coffee grains. This is basically the same principle as the cosmic rays forming clouds in the atmosphere.

The earth’s magnetic field, which acts as a shielding, is altered by the sun’s activity, which, in turn, is indicated by means of the number of sunspots. As the earth’s magnetic shield varies, so the cloud cover varies. Few sunspots mean a weaker earth shield, which means more cosmic rays, which mean more clouds, which mean a cooling earth.

The correlation for this effect, going back thousands of years, is good, remarkably so. Scientifically, this looks believable, and it is consistent with the theory and observation.

In contrast, the argument that man-made carbon dioxide (CO2) is causing warming does not fit the facts at all. Firstly, there was no indus- trial CO2 produced in vast quanti- ties when the Roman Warming period occurred, or when the Medieval Warming period occurred. Both are well documented in various archives, such as the historical and archaeological.

But there is more – global warming is extremely complex, and it is really naïve to believe that a relatively simple theory will explain it satisfactorily. It is far too simple just to say: CO2 traps heat and, therefore, more CO2 means more heat, and so we have global warming.

As the makers of heat-seeking missiles know very well, the CO2 in the atmosphere has ‘windows’ in it. This means that certain ‘heat frequencies’ pass through the atmosphere easily but other frequencies are trapped. It is these windows that the missile uses to hunt its prey. As a consequence, there are ‘frequency bands’ related to the CO2 cover of the earth. In various ‘bands’, the infrared passes through easily, or not so easily.

Further, CO2 can trap incoming heat from space and outgoing heat being radiated from the earth. The frequency bands linked to the CO2 also become saturated – they cannot just keep sucking up more and more heat. Essentially, this CO2 argument is very complex.

Over the last century, the temperature changes in our planet’s atmosphere, let alone ground and sea, just do not match the atmospheric CO2 concentration at all. This is cause for warning bells that, perhaps, this whole CO2 argument is not correct.

In comparison, the cosmic ray and sunspot information match well. However, as I have said, this whole atmospheric temperature issue is very complex, and no capable scientist in the field is going to say otherwise.

Right now, we have been experi- encing a rather long period of sunspot inactivity on our sun, some 200 days plus. This has happened before.

Formal sun- spot data collection started in 1749 and has been monitored ever since. But long before that date, sunspots were known and informal measurements were taken. It is, therefore, known that the Little Ice Age, which took place from the midseventeenth century to the eighteenth century, was preceded and paralleled by a period of some 50 years with a virtual absence of sunspots, according to informal records.

In more recent times, we have had relatively long periods without sunspots. This year, we passed the mark of 200 days without sunspots, which is unusual. In fact, the sun has been blanker now than in any other year since 1954, when it was spotless for 241 days, and this year is now being called the sun’s quietest year of the space age.

The sun was also very quiet in 1913, so runs of 200-plus spotless days are rare, but not that rare. As I have already said, the global warming and cooling issue is complex, and so a run of 200-plus days without sunspots cannot be compared to a 50-year quiet period during the Little Ice Age, but it is cause for some scientific thinking.

Further, a cooling that could be initiated by a lack of sunspots will induce other climatic effects that will either favour warming or cooling. The jury is still out on exactly what happens, but the evidence for sunspot involvement in climate change is just too compelling for it to be brushed aside by those who want to cling to the simplistic idea that man-made CO2 is the only factor.