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Tropical areas expanding due to pollutants, says new study

Researchers have found that black carbon aerosols and tropospheric ozone, a constituent of smog, are pushing the tropics toward the northern and southern poles.

tropical waterfallEnlarge
A new study says that the world's tropical belt is expanding due to pollutants. (Thomas Coex/AFP/Getty Images)

The world's tropical belt may be expanding due to man-made pollutants, a new study says.

Researchers at the University of California, Riverside, have found that black carbon aerosols and tropospheric ozone - a pollutant when found in high concentrations - are pushing the tropics toward the northern and southern poles.

More specifically, the push southward of the tropical belt has largely been blamed on the depletion of stratospheric ozone, reported Phys Org.

Yet, researchers found that the push northward was largely due to human-made pollutants.

UPI reported that the tropics have widened by 0.7 degrees latitude per decade since 1979.

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Researchers warn that the expansion creates dire problems for subtropical areas and cause greater storms.

“If the tropics are moving poleward, then the subtropics will become even drier,” said lead author Robert J. Allen, according to PlanetSave.

“If a poleward displacement of the mid-latitude storm tracks also occurs, this will shift mid-latitude precipitation poleward, impacting regional agriculture, economy, and society.”

The team looked at climate models from 1979 to 1999, which, researchers said, underestimated the movement of the tropics by one third.

When black carbon and tropospheric ozone were added to the equation, the models began to match what was happening in reality.

The findings were published in the journal Nature.

http://www.globalpost.com/dispatch/news/science/120517/tropics-expanding-due-pollutants-says-new-study