Will a warming climate turn Earth into a hot, hellish place like Venus? Not anytime soon. But a far-looking new study suggests that Earth's atmosphere possibly could grow so hot that our planet will experience what scientists call the “runaway greenhouse” effect.
The phenomenon occurs when a planet absorbs more solar energy than it can give off in return. That causes surface water to evaporate, fill the atmosphere with steam, and heat the planet until it's no longer habitable -- kind of like what's seen on Venus.
For the study, a team of astronomers used computer modeling to calculate the thermal radiation limit of the "runaway greenhouse" effect.
The new measurements suggest that the effect may be easier to initiate than had been previously thought. Yikes.
What does that mean for our future on the third planet from the sun?
"It used to be thought that a runaway greenhouse was not theoretically possible for Earth with its present amount of sunlight," study co-author Dr. Colin Goldblatt, a professor at the University of Victoria in Canada, told National Geographic. "We've shown that, to the contrary, it is theoretically possible. That doesn't mean it's going to happen -- but it's theoretically possible."
But don't be overly concerned. The research suggests that Earth would not move into the runaway greenhouse stage for a billion and a half years or so. Previous studies placed the possible "runaway greenhouse" effect on Earth at happening in around 2 billion years.
For now, the study may influence where habitable zones around a star are measured. Such zones indicate where a planet may have the right atmosphere to host life.
And with the new finding, “the habitable zone becomes much narrower, in the sense that you can no longer get as close to the star as we thought before going into a runaway greenhouse,” study co-author Tyler Robinson, a University of Washington astronomy postdoctoral researcher, said in a written statement.
The study published on July 28 in the journal Nature Geoscience.