Global Warming – Myth or Reality?

‘Climate change’ (or the ‘greenhouse effect’) is very much THE subject of the moment for scientists, the media, politicians and the general public. Among its many more or less transitory ‘fashionable’ aspects have been: the threat of a new Ice Age; the nuclear winter; acid rain; the Sahel drought; the forests (and especially the Amazon) as the ‘lung’ of the planet; the hole in the ozone layer, which seems to be closing up again; ElNino, ruler of the world ... Some of these subjects are still very much ‘alive’, and share the spotlight with the greenhouse effect itself. The greenhouse effect, however, is the undisputed star of the show, while we await the possible appearance, sooner or later, of some new fad or passing craze, as we tire of the old, or change our (manifold) interests...The idea of temperature rising as CO2 levels increase is an old one, and seems logical enough in most minds. We can understand it and experience it (e.g., at a business meeting or social eventin a closed and poorly ventilated space). The engineer Charles Vernin has calculated that 100 people gathered together will produce about 26 litres of CO2 in one hour, at the rate of 16 respirations per minute (i.e., a total of 2,600 litres); if the space they occupy measures 200 m2 and is 4 m high, giving a volume of 800 m3, the concentration of CO2 at the end of the hour will be of the order of 0.003 25, or 3,250 ppm, in other words about 10 times greater than the ‘normal’ concentration of CO2 in the atmosphere. Even if the temperature has risen slightly during the gathering (and not only because of the CO2), it will not have been necessary to clear the room, since the critical level would be more than 20,000 ppm.