Читать книгу Carbon Counter - Mark Lynas - Страница 8

There is no longer any serious scientific doubt that global warming is already under way. The earth is now 0.7°C warmer than it was 150 years ago, before the Industrial Revolution began to change the amount of greenhouse gases in the atmosphere. The graph on page 16 shows how air temperatures have risen since 1850. You can see that the rise has not been uniform, but has come in two distinct blips – between 1910 and 1940, and between 1970 and today. This begs the question of why temperatures stabilized, and even cooled slightly, after the Second World War, when emissions of carbon were rising rapidly. Scientists think that the culprit may have been another pollutant, sulphur dioxide, which acts to counteract warming by reflecting some of the sun’s heat. Thus ‘global dimming’ counteracted ‘global warming’, and the two forms of pollution to a certain extent cancelled each other out. Sulphur dioxide is now produced less, however, because it causes acid rain and has nasty effects on people’s health.

GLOBAL AIR TEMPERATURE 2005 ANOMALY +0.48°C (MEAN 1961–1990)

Tip: Sulphur dioxide was one of the main pollutants in the choking London ‘pea souper’ smogs of the 1950s, which were controlled by the Clean Air Act of 1956. It was produced as a by-product of burning fossil fuels (especially coal), because of small amounts of sulphur contaminating the fuel. Low-sulphur diesel is manufactured specially to reduce sulphur dioxide emissions.

FIVE HOTTEST YEARS IN DESCENDING ORDER