It looks like there’s going to be a while before humanity can undertake any serious effort to terraform Mars. According to a new study published today in the journal Nature Astronomy, the red planet doesn’t have enough carbon dioxide reserves to be released back into its atmosphere and warm up Mars long enough to support liquid water on its surface.
As NASA points out, the Mars terraforming ideas that our scientists have come up with so far are based on the release of greenhouse gases into the Martian atmosphere in order to thicken it up and “trap heat and warm the climate.”
The only greenhouse gases that exist on Mars in notable amounts, albeit currently frozen, are carbon dioxide (CO2) and water vapor (H2O), notes New Scientist.
“If there is enough carbon dioxide, we could warm up Mars in 100 years once we start,” Chris McKay, from NASA’s Ames Research Center in California, said in a statement.
But it seems these plans will have to wait until new technologies are developed, Bruce Jakosky from the University of Colorado, Boulder, and Christopher Edwards of the Northern Arizona University in Flagstaff have uncovered.
After combing through data from three separate NASA missions, Jakosky and his co-author found out that Mars doesn’t actually have sufficient carbon dioxide left on its surface and under its crust to produce a greenhouse effect.
“Our results suggest that there is not enough CO2 remaining on Mars to provide significant greenhouse warming were the gas to be put into the atmosphere; in addition, most of the CO2 gas is not accessible and could not be readily mobilized,” explained Jakosky. “As a result, terraforming Mars is not possible using present-day technology.”
With the help of data from NASA’s Mars Reconnaissance Orbiter, Mars Odyssey spacecraft, and MAVEN (Mars Atmosphere and Volatile Evolution) spacecraft, the two researchers went through all the possible sources of carbon dioxide on Mars and found them insufficient to raise the planet’s temperature high enough for it to support liquid water.
“These data have provided substantial new information on the history of easily vaporized (volatile) materials like CO2 and H2O on the planet, the abundance of volatiles locked up on and below the surface, and the loss of gas from the atmosphere to space,” Edwards pointed out.
While enough water vapor could hypothetically be harvested from the rich supplies of ice water on Mars, the red planet still lacks the needed carbon dioxide to warm its atmosphere enough for the water vapor to persist.
Only 6.9 Percent
Mars currently has 0.6 percent of Earth’s atmospheric pressure — about six millibars, as opposed to one bar measured at sea level on our home planet. However, Mars would need a CO2 pressure similar to Earth’s total atmospheric pressure in order to warm up sufficiently and allow liquid water to cling to its surface.
Yet all its carbon dioxide reservoirs combined, laboriously exploited over extensive periods of time, would only bring Mars’ CO2 pressure to about 7 percent that of Earth’s — woefully insufficient for an Earth-like atmosphere in which plants could grow freely and build up oxygen levels over a period of a few centuries and allow astronauts to walk the red planet with just breathing masks on and without wearing space suits.
The most readily available source of carbon dioxide lies within the Martian polar ice caps, but vaporizing this resource would only increase the atmospheric pressure to 1.2 percent, Jakosky and Edwards have found.
Heating the dust particles in the Martian soil to release carbon dioxide would add another small percentage, bringing the total up to 4 percent of the required pressure to warm up Mars.
In addition, mining the mineral deposits beneath the red planet’s surface would yield less than 5 percent of the needed pressure, depending on how deep we’d have to dig for them.
“Just using the deposits near the surface would require extensive strip mining, and going after all the CO2 attached to dust particles would require strip mining the entire planet to a depth of around 100 yards,” states NASA.
Other options, such as building up Mars’ atmosphere from outgassing produced by geologic activity or bombarding the red planet with comets and asteroids to import volatiles, have been deemed impractical. According to the study, the first scenario would require a period of 10 million years just to get to a pressure of 12 milibars, whereas the second option would need thousands of celestial bodies to pummel the planet and transfer the necessary carbon dioxide.
While the scientists don’t say that terraforming Mars is an impossible dream, they do however point out that it would take considerably longer to achieve than previously believed.
“If there’s not enough carbon dioxide, terraforming would take thousands of years or more but it’s still possible,” said McKay.