"However, with the benefit of hindsight we can now explain why there has been a trend towards more rapid temperature rises in recent years; it is because mankind has cut back its emissions of lead and sulphates,"
Lead pollution in the air stimulates the formation of ice particles in clouds. A team of scientists from the USA, Germany and Switzerland has found that particles containing lead are excellent seeds for the formation of ice crystals in clouds. This not only has a bearing on the formation of rain and other forms of precipitation but may also have an influence on the global climate. This is because the heat given off from the earth's surface is more efficiently radiated into space by ice clouds (cirrus) with lead-containing particles
In comparison to clouds with a low lead content, clouds with a high lead content thus actually help cool the earth. Over the last twenty years, there has been a continuing decrease in the rate of anthropogenic lead emissions. This may mean that the greenhouse effect is now even more pronounced because lead-containing clouds once previously helped limit it.(read more...)