EVER since Al Gore published his book, An Inconvenient Truth, there has been a growing media storm. It reached its peak in November last year, when many hoped that the world's leaders might agree to a global emissions reduction.

Those whose hopes were dashed had forgotten Kyoto. At Kyoto, those self-same leaders had agreed to reduce emissions to below the 1990 levels. During the 12 years after the Kyoto Protocol was signed, emissions continued to grow. Copenhagen was preordained to be a flop.

In the lull, we have a chance to stand back, re-evaluate just where we are, and come up with a better strategy than that which was being thrust upon us at Copenhagen. The pleas to "Act now to save the world!" were misplaced.

What we find as we emerge into the cool, clear light of day is that the world has been warming for at least 150 years.

Whether man is responsible for this warming is still an open question. Humanity started burning fossil fuels to excess only after 1950. The warming pre-1950 cannot have been driven by fossil fuels. The best guess is that the warming is natural.

There is quite a lot of evidence to back this up. For instance, one of Gore's most graphic images was of the flooding that has been caused by sea-level rise. There are tide gauges around the world that measure the sea level. These show that the sea level has generally been rising at a rate of about 3mm a year for the past 150 years.

This is not true everywhere. In some places the land has also been rising. For instance, at Stockholm in Sweden, the sea level has been falling at about 2mm a year because the city is rising at about 5mm a year. Elsewhere, such as at Galveston in Texas, the land is dropping. The sea level at Galveston is rising at a rate of 6mm per year.

But these are the exceptions. Satellite measurements confirm about 3mm a year rise in the real sea level.

Critically, there is no evidence that the rise in sea level accelerated after 1950. That was when we really started to burn fossil fuels. Instead, the sea has simply continued its inexorable rise.

Why have we not seen it more obviously, as Gore would have us believe?

Well, if you live by the sea you will know that it rises and falls with every tide; that the tides are higher at some times of the month than at others; that the sea tends to be higher in summer than in winter; and that storms can raise the waves even higher.

Our defences against the sea are therefore many meters above the average sea level - the 3mm a year increase in sea level means that a wave overtops our defences twice a year, rather than once. Eventually it becomes a nuisance and we add another brick.

Do you really think that it is worthwhile shutting down our power stations and walking to work for that?

All the tales of disaster that we have been fed turn out to be similar.

Are storms getting more violent?

The World Meteorological Organisation, parent of the Intergovernmental Panel on Climate Change (IPCC), says: "The recent increase in societal impact from tropical cyclones has largely been caused by rising concentrations of populations and infrastructure in coastal regions." If there is more to be damaged, then more will be damaged.

Is the ice disappearing?

Almost imperceptibly. Forty years of satellite data show the sea ice cover of the globe to be essentially constant, apart from the seasonal changes (which are quite large).

There was a detectable drop in 2005-07, but levels are back to normal today.

A warmer world tends to be wetter, and this is apparent in Antarctica, where the balance of evidence from satellite measurements is that the ice is getting thicker.

Yes, the warmer seas are melting the edges, as Gore so enjoyed showing - but Antarctica is a big place, and the edges are small in comparison. So the ice is getting thicker because there is more snow.

Well, what about the glaciers?

Yes, they are shrinking, but that is what you would expect in a warming world. The first report we have of the snows on Kilimanjaro disappearing is 1880.

The IPCC made a mistake when it said the Himalayan glaciers would disappear by 2035 - it was misquoting a report, which said they might disappear by 2350. The melting of the Alpine glaciers is revealing footpaths that were used a millennium ago.

And the polar bears?

Yes, the population was under threat. It transpires that the Canadian provincial governments were issuing too many hunting licences. Since they cut the number by a factor of 10, the population has started to grow again.

Do we face devastating droughts and calamitous floods?

We may, but one thing is certain - the climate change modellers cannot tell us. Their models lack the detail essential to predict local conditions. As the IPCC admits, "advances have been made in developing probabilistic information at regional scales - but these methods remain exploratory".

Such predictions as they have made, in an exploratory way, have shown huge swings in rainfall. When we check these predictions against what has happened over the past 150 years, during which time the world has been warming naturally, there is no evidence for such huge swings.

Well, what about the predicted malaria epidemic?

The IPCC has consistently predicted an increase in malaria and other insect-born diseases. Over the past 150 years, there is absolutely no evidence for an increase due to the warming that has taken place.

In places where there has been an increase in disease, the cause has been a breakdown of public health controls.

The world never lacks doomsayers. Of late, they have been having a really grand time. However, the world has not yet come to an end, nor does it seem likely to do so.

We need to find better ways of adapting to the apparently natural climate change, that is true. But there is no haste to spend vast sums of money defending ourselves against threats which, by any rational analysis, are possibly illusory and probably not as severe as has been made out.

There are clearly identifiable problems we need to address before we spend another penny on climate change.

n Lloyd is with the Energy Institute at the Cape Peninsula University of Technology.

'Whether man is responsible ... is still an open question. Humanity started burning fossil fuels to excess only after 1950. The warming pre-1950 cannot have been driven by fossil fuels. The best guess is that the warming is natural'