Climate catastrophes in the Solar System

Earth sits between two worlds that have been devastated by climate catastrophes. In the effort to combat global warming, our neighbours can provide valuable insights into the way climate catastrophes affect planets. From what scientists know now, it is possible that Venus and Mars started out a lot like Earth. At some point in time, each planet followed a path that changed its climate. The transition was from Earth-like to either a cloudy inferno (Venus) or a frigid desert (Mars). Data from Venus Express and Mars express is now helping scientists determine if, when and why each planet passed the point of no-return.

Modelling Earth’s climate to predict its future has assumed tremendous importance in the light of mankind’s influence on the atmosphere. The climate of our two neighbours is in stark contrast to that of our home planet, making data from ESA’s Venus Express and Mars Express invaluable to climate scientists. Venus is a cloudy inferno whilst Mars is a frigid desert. As current concerns about global warming have now achieved widespread acceptance, pressure has increased on scientists to propose solutions.

The key weapon in a climate scientist’s arsenal is the climate model, a computer programme that uses the equations of physics to investigate the way in which Earth’s atmosphere works. The programme helps predict how the atmosphere might change in the future.

“To members of the public it must seem like climate models are crystal balls, but they are actually just complex equations” says David Grinspoon, Denver Museum of Nature and Science, and one of Venus Express’s interdisciplinary scientists.

The more scientists look at those equations, the more they realise just how complicated Earth’s climate system is. Grinspoon puts the predicament like this: “In fifty or a hundred years, we will know whether today’s climate models were right but if they are wrong, by then it will be too late.”

To help increase confidence in the computer models, Grinspoon believes that scientists should look at our neighbouring planets. “It seems that both Mars and Venus started out much more like Earth and then changed. They both hold priceless climate information for Earth,” says Grinspoon.

The atmosphere of Venus is much thicker than Earth’s. Nevertheless, current climate models can reproduce its present temperature structure well. Now planetary scientists want to turn the clock back to understand why and how Venus changed from its former Earth-like conditions into the inferno of today.

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