Atmospheric heating could turn Earth into another Venus

May 13th, 2008 - 11:53 am ICT by admin  

Washington, May 13 (ANI): A new study has found that prolonged heating of the atmosphere can shut down plate tectonics and cause a planets crust to become locked in place, a situation which could make Earth another Venus.

The team, which conducted the study, included researchers from Rice University in US, the University of British Columbia in Vancouver, Canada, and Louis Moresi of Monash University in Clayton, Australia.

According to lead author Adrian Lenardic, associate professor of Earth science at Rice University, the research team wanted to better understand the differences between the Earth and Venus and establish the potential range of conditions that could exist on Earth-like planets beyond the solar system.

The findings may explain why Venus evolved differently from Earth.

The two planets are close in size and geological makeup, but Venus carbon dioxide-rich atmosphere is almost 100 times more dense than the Earths and acts like a blanket. As a result, Venus surface temperature is hotter than that of even Mercury, which is twice as close to the sun.

The Earths crust, along with carbon trapped on the oceans floors, gets returned to the interior of the Earth when free-floating sections of crust called tectonic plates slide beneath one another and return to the Earths mantle.

We found the Earths plate tectonics could become unstable if the surface temperature rose by 100 degrees Fahrenheit or more for a few million years, said Lenardic.

The new findings show that prolonged heating of a planets crust via rising atmospheric temperatures can heat the deep inside of the planet and shut down tectonic plate movement.

The heat required goes far beyond anything we expect from human-induced climate change, but things like volcanic activity and changes in the suns luminosity could lead to this level of heating, said Lenardic.

We found a corresponding spike in volcanic activity could accompany the initial locking of the tectonic plates, he said. This may explain the large percentage of volcanic plains that we find on Venus, he added.

According to Lenardic, one of the most significant findings in the new study is that the atmospheric heating needed to shut down plate tectonics is considerably less than the critical temperature beyond which free water could exist on the Earths surface.

The water doesnt have to boil away for irrevocable heating to occur, said Lenardic. The cycle of heating can be kicked off long before that happens. All thats required is enough prolonged surface heating to cause a feedback loop in the planets mantle convection cycle, he added. (ANI)

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