Was Venus Habitable?
This article speculates that at some time in the past, Venus may have been somewhat temperate and could have had liquid water oceans. Currently, the thick atmosphere is almost entirely carbon dioxide, at a crushing pressure 93 times as at sea level on Earth. The average temperature is 460°C (860° F, hot enough to melt lead) planet-wide and even at night, because this heat is carried around the planet. There is no oxygen and no liquid water, and only the smallest trace of water vapor. Current Venus landers can only operate on the planet’s surface for a few hours due to the extreme atmospheric conditions. But it might not have always been that way, the article says:
The hellish planet Venus may have had a perfectly habitable environment for 2 to 3 billion years after the planet formed, suggesting life would have had ample time to emerge there, according to a new study. In 1978, NASA’s Pioneer Venus spacecraft found evidence that the planet may have once had shallow oceans on its surface. Since then, several missions have investigated the planet’s surface and atmosphere, revealing new details on how it transitioned from an “Earth-like” planet to the hot, hellish place it is today. It’s believed that Venus may have been a temperate planet hosting liquid water for 2 to 3 billion years before a massive resurfacing event about 700 million years ago triggered a runaway greenhouse effect, which caused the planet’s atmosphere to become incredibly dense and hot.
At NASA’s Goddard Institute researchers ran 5 different simulations based on various levels of ocean coverage. All of the simulations indicated that Venus may have been able to maintain stable temperatures ranging from 68° to 122° F for a period of 3 billion years. That would have enough for at least simple life to have formed.
The “resurfacing event”, they speculate, was massive volcanic outgassing of carbon dioxide. Something similar occurred on Earth at the end of the Permian period – 252 million years ago. That is known as the Permian Extinction where maybe 90% of life on the planet went extinct. The cause of the Permian Extinction is suspected to be volcanic activity related to the Siberian Traps, a caldera or series of calderas that erupted on a massive scale releasing huge amounts of carbon dioxide into the atmosphere and causing runaway greenhouse effect. There is some evidence that average global temperatures during the PE was as high as 140° F and ocean temperatures as high as 104° F.
In the September issue of National Geographic there was an article on the thawing of the arctic permafrost. The article says:
…researchers now suspect that for every one degree Celsius rise in Earth’s average temperature, permafrost may release the equivalent of four to six years’ worth of coal, oil, and natural gas emissions—double to triple what scientists thought a few years ago. Within a few decades, if we don’t curb fossil fuel use, permafrost could be as big a source of greenhouse gases as China, the world’s largest emitter, is today.
The question raised by all these articles is the Earth headed for similar runaway greenhouse effects that could bring a Venusian or Permian type catastrophe? I am still processing this information and have not come to any firm conclusions about what I believe or the level of alarm I should have. I have two questions that I would like to discuss today.
- To what extent do you think the problem of climate change exists? Is it overblown, about the right amount of alarm, or worse than even now thought?
- As people of faith, what should our response be?
I want to hear a range of opinions and the reasons you hold those opinions. Be civil – commence discussion…