Global Warming and Other Bollocks - Stanley Feldman

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to this effect, dwarfing any contribution from CO2.

      It is generally agreed that the water vapour and droplets in the clouds contribute, at the very least, 50 per cent of the total global warming effect, although many others suggest that the figure should be much nearer 93 per cent. The trouble is that the amount of water vapour in the atmosphere varies from time to time, and it is impossible to predict.

      A year without summer

      A lot of polluting particles in the atmosphere will enhance the effect of the clouds in insulating Earth from the effect of the sun. It is believed to be responsible for the absence of significant global warming in southern China and parts of India over the past 15 years (2008 saw their coldest winter for 50 years). Volcanic eruptions spew out polluting particles (as well as CO2 and other greenhouse gases), which influence the climate. The Tambora volcanic eruption of 1815 produced a year without a summer due to the water vapour and the particles released when it erupted. They formed a cloud over large parts of the planet. The Krakatoa volcanic explosion of 1883, which released huge amounts of debris, CO2 and sulphur dioxide into the atmosphere, affected the temperature of the world for two to three years. Although CO2 and sulphur dioxide are greenhouse gases, the world cooled.

      As a result of the reduction in the concentration of particle pollutants that used to hang in the air over London, before the Clean Air Acts of the 1950s, the sun’s rays are now better able to penetrate the atmosphere. This has led to an average increase in temperature in the city of about 2ºC. This is as great as the increase in temperature predicted in the next hundred years by some of the models of global warming! Together with urban warming, this has resulted in the temperature in central London being up to 4ºC warmer than the neighbouring countryside.

      Scientific controversy centres on the relative importance of the enormous, but almost impossible-to-measure, effect of water vapour and clouds, the effect of changes in the sun’s activity and the effect of the tiny but increasing 0.038 per cent of CO2 in the atmosphere, in the production of global warming. It is because these effects are impossible to separate and measure that it so difficult to make reliable mathematical models to predict the behaviour of Earth’s temperature in the future.

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       THE HISTORY OF THE ATMOSPHERE

      STANLEY FELDMAN

      DOGMA

      We know that mankind causes global warming.

      AS THE MOLTEN MASS that was to form our planet solidified, the gases from volcanic eruptions and constant asteroid bombardment came to determine the composition of its atmosphere. It is thought to have resulted in an atmosphere largely made up of water vapour, with around 15–20 per cent of carbon dioxide (planets such as Venus and Mars contain about 95 per cent CO2 in their atmosphere). Other gases that were present, as minor players, included sulphur dioxide, carbon monoxide and nitrogen. Even before the advent of plant life and photosynthesis, the concentration of CO2 was decreasing as more and more of it became converted to chalk and sand under the very high temperatures that were present as the fiery Earth started to cool. The greenhouse-gas effect of the huge amount of CO2 in the atmosphere up to 50 million years ago did not prevent the molten mass of Earth from cooling, although it may have slowed the process.

      Figure 3.1: Deep sea temperature – in spite of very high levels of CO2, Earth continued to cool. For the past 50 million years the level of CO2 has remained historically low.

      Although the first evidence of life can be traced back some 2–3 billion (thousand million) years, it was not until about 400–500 million years ago that the first recognisable animal life forms appeared. By this time it is calculated that the CO2 concentration in the atmosphere had decreased from 15–20 per cent to 4–5 per cent. By the time the first marine organisms emerged on to the swampy land, many millions of years later, the CO2 levels had fallen still further, to about 1.5 per cent in the atmosphere, many times higher than today.

      In spite of the enormously high levels of CO2 in the planet’s atmosphere when it was born, the Earth cooled down. This is not surprising, since it was originally very much hotter than the surrounding atmosphere. There is evidence that the cooling continued, even when the surface became much colder, causing large parts of the planet to be covered with ice. It is believed that this occurred about 600 million years ago; it was the time of ‘Snowball Earth’, just before multi-cellular life forms appeared. The period of Snowball Earth was followed by several million years of warming.

      The finding of fossil remains of gastropods in the trans-Antarctic mountains near the south pole is good evidence that the Antarctic was much warmer than today – indeed, warm enough to support animal life – about 15 million years ago. This means that the huge glaciation that formed the Antarctic must have occurred when the CO2 levels in the atmosphere were over 0.5 to 1.0 per cent. Although no one can be certain of the CO2 level at this time or the exact extent or duration of the glaciation, it is evident that, in the past, Earth has cooled to very low temperatures in spite of very much higher levels of CO2 than is present today.

      None of this is proof that CO2 has not been important as a global greenhouse gas in the past or that it does not play a part in determining the present temperature of our planet. However, it does indicate that high levels of CO2 in the atmosphere are not incompatible with global cooling. It must be borne in mind that many of the figures quoted are based on assumptions and calculations. This is why much of the argument about global warming has centred on what is happening now and how this relates to the period that we can measure with some accuracy, the past 1,000–2,000 years (see Figure 3.2).

      Figure 3.2: Temperatures on the surface of the Sargasso Sea over 3,000 years – evidence from isotope studies of marine organisms

      Evidence from ice-core samples

      They reveal that, for the past 500,000 years, the level of CO2 has been roughly stable at around the present levels of less than 0.04 per cent. Over this period of 100,000 years the Earth has cooled slightly, although from time to time the temperatures have fluctuated through swings of 3–4ºC.

      In order to get some idea of what the conditions were like further back in time we have to make assumptions based on the changes that we know took place. Primitive cellular animal life evolved between 500 and 300 million years ago. As life developed and photosynthesis occurred, large amounts of the CO2 were rapidly sequestrated from the atmosphere by plant and animal life and deposited as chalk, peat, shale, coal and oil. This produced a fall in CO2 concentration from a high of 4.0 per cent to the 0.038 per cent found today. The white cliffs of Dover were made of their calcified carcasses, and they contributed to many of our hills and to the coral of tropical islands. Throughout this time, the Earth was cooling and, although the CO2 levels were falling, they were many times higher than today.

      The CO2 produced today when we burn fossil fuels is merely returning into the atmosphere a minute part of the CO2 sequestrated by plant and animal life over hundreds of thousands of years. It

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