THE warming trend revealed by meteorological records is real, and not
a result of the ‘urban heat island effect’, where the waste heat of energy
consumed in urban areas creates ‘islands’ of heat. This is the conclusion
reached by a group of researchers from Britain, the USSR, Australia and
the US after they re-assessed data from both urban and rural sites around
the world covering the past hundred years.
Critics of claims that the world has warmed by 0.5Degree C over that
timespan have argued that most records come from cities. But the latest
analysis, which appears in last week’s issue of Nature (vol 347, p 169)
shows that this effect can account for no more than a tenth of the measured
increase. Even data from rural weather stations show a rise in global mean
temperatures of 0.5 Degree C during the 20th century.
