Carbon dioxide acts like a greenhouse gas and can heat a planet’s atmosphere – nothing new so far. But it can be so potent in its greenhouse quality that it can burn out a planet’s entire hydrosphere, leaving it devoid of any liquid water.

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In million and millions of years, the Sun will start to shine brighter and brighter, sending more light and heat Earth’s way. As a result, the planet’s temperature will increase to a point where liquid water simply becomes unstable. Earth will become uninhabitable, as many other planets have already become. A new study found that CO2 could have a similar effect in time.

Max Popp and colleagues from the NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, United States, modeled the effect of changing CO2 on an idealized planet: one completely covered in water. They showed that as CO2 levels reach 1,520 parts per million, average surface temperatures are forced to exceed 330 K (~57°C). Cloud feedback effects destabilize the planet’s climate, creating moist conditions in the upper atmosphere, where water is quickly lost in outer space. Today average CO2 levels are over 400 ppm, for the first time in a million years.

However, while rising CO2 levels can pose huge problems for us (and every other creature on Earth), this won’t happen in the foreseeable future, but in millions of years. However, this could be important for finding habitable planets. Life as we know it relies on water and so far, we haven’t found any planet with liquid water outside our solar system.

Reference: Max Popp et al. Transition to a Moist Greenhouse with CO2 and solar forcing, Nature Communications (2016). DOI: 10.1038/ncomms10627