A clear correlation between air pollution and drought has
recently been discovered at the Institute for Global Science
of the Hebrew University. In a study by meteorologist
Professor Daniel Rosenfeld on the basis of satellite data, it
was proven that minuscule particles of smoke and dust formed
by air pollution result in the formation of small droplets in
the clouds. This factor diminishes the chances of natural
rainfall. The study has brought progress in the understanding
of climatic phenomenon such as global warming, drought and
flooding and their correlation to air pollution.
The influence of air pollution on the decrease of
precipitation has been suspected for years, but until now it
could not be proven. Polluted air is carried by wind and
transferred to distant countries. The adverse affect of the
pollutants on rainfall is cumulative, gaining strength only
at great distances. Contradicting theories -- such as one
stating that air pollution increases rainfall in industrial
areas -- had also been suggested.
Professor Rosenfeld analyzed statistics culled by a NASA
satellite for the measuring of rainfall (known as a TRMM) and
found evidence of the correlation between air pollution and a
reduction of precipitation.
When droplets of water in the clouds are too small, they do
not combine to form raindrops and the cloud doesn't give off
rain. Polluted air is composed of smoke and tiny dust
particles, the result of industrial pollution and fires.
These particles penetrate the cloud and prevent the formation
of relatively large raindrops in the cloud. The polluted
particles also slow down the formation of ice and snow.
Professor Rosenfeld noted that polluted air reaching Israel
from distant places such as East Europe adversely affects the
formation of rain in the area. The extent of the influence of
air pollution in Israel on drought will be examined in
further studies.
