American climatologist David Travis made use of the tragic event of the Twin Towers destruction in New York on September 11th 2001, when airplanes stopped flying for three days. Travis expected a drop in temperature caused by the reduction of aerosol emissions into the atmosphere. The results were shocking. The temperature during those three days did not go down, but rose by an incredible 1°C. In the whole history of climate monitoring on the American continent there had never been such a dramatic change in temperature.

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