The theory of global warming is well-known, I obviously don’t need a cite. And ditto for the planet Venus.
But let’s consider the planet Venus. The atmospheric pressure is oppressive. And the surface temperature is hot enough to melt lead. Yet no one knows how it got that way (a science book I once read as a child asks, which one has the more unique past [earth or Venus]?).
Thus this leads to one inevitable question: Could we end up like Venus? I’m serious. Maybe not soon. But one day?
We’re not going to end up like Venus. We’re just too different, and there’s some indication, from recent studies, that we’ve been different for a long time (although the “runaway Greenhouse” model also still has currency)
Personally, I think it’s as likely, given our planet’s past history, that we end up a snowball again.
Starting in between half a billion and a billion years, from what I recall, the temp is going to really start going up. Eventually the sun will expand so far that it will swallow us up. I imagine that sometime between half a billion years and the end of our suns red giant phase the earth will be as hot as Venus, yes. It’s not going to happen from Global Warming though, if that’s what you are asking.
Wait … we’ve only got half a billion years til we get wiped out as a species if we don’t have interstellar capabilities? I thought we had four or five billion years! That does it, we need to increase NASA’s budget NOW!
To put it another way, all of the carbon that we are putting in the atmosphere originally came from the atmosphere but was put into the ground during the carboniferous period 350-300 million years ago. So worst case scenario we end up having CO2 concentrations at that level.
The world was very different then than it is now, and the species currently living on our planet are for the most part ill adapted to live in such a world, but it wasn’t anywhere near what its like on Venus.
Actually no. The Sun becomes warmer over time, so we could easily become warmer than that. Also the continents being configured differently could affect the climate as well.
As said, the Sun is slowly becoming warmer. Barring “human”* intervention it’s believed Earth has another half-billion years before a runaway greenhouse starts.
*Long before then I expect we’ll have changed into or been replaced by something that we wouldn’t consider human.
Some of the fossil fuel deposits are more recent, but yes, I think that about sums up the general idea of exactly what’s happening. Basically there is an active carbon cycle, and outside of that there is a very large amount of sequestered carbon that’s been out of the cycle for tens of millions and hundreds of millions of years. We’re returning it to the atmosphere at a rate that, relative to natural geological processes, is the rapidity of a bomb explosion.
Not necessarily “replaced,” if we go extinct. As sentient/sapient organisms, we occupy a unique niche in the ecosystem that never was before us in two billion years of life, and might never again be after us. We are highly unlikely.
We won’t end up like Venus, but the earth already overheated once about 250 million years ago. It got so hot that it caused the greatest extinction event in all of earth’s history. But don’t worry. The extremely hot temperatures didn’t last forever - only about 5 million years.
Google the Permian-Triassic extinction event for more details.
I was thinking more of the scenario where humanity dies out but our machines go on; some future AIs/robots take our place as Earth’s intelligent “life”.
Would you prefer ending up like Mars? If we lose our internal magnetic dynamo, it could happen.
But why would we lose it? The core spins. It has a lot of mass and a lot of angular momentum. It would take a lot of kinetic energy to stop the core from spinning. (Let someone else research the values of “a lot.”)
I saw a multi-season documentary that suggested such a thing happened long ago, and is likely to recur in the future. Apparently the technology needed to create square playing cards was lost somewhere in the cycle.
Nevertheless, it’s possible that Mars was more Earthlike in the past, but perhaps due to its smaller size, lost its protective magnetic shield earlier:
(bolding mine)
No, even if the trapped carbon in the crust were released we’ve had far greater carbon concentrations even more recently than 350m years ago that’s been cited above. So the last time we had really high carbon concentrations in the atmosphere I don’t think the sun has warmed enough in that span of time that a return to those conditions wouldn’t turn us to Venus under any theories I’ve seen put forward by serious researchers.
Venus almost certainly didn’t turn into what it is because of carbon based activities of organic entities on its surface. We all know that major volcanic eruptions here on Earth can have an immense impact on greenhouse gases in the atmosphere, one very big eruption could even surpass annual human production of such gases. I thought one of the most likely theories on what’s happened to Venus is it is much more volcanically active than Earth, with more frequent and more powerful eruptions. Earth would indeed probably turn into something like Venus if it had continuous large volcanic eruptions all the time. Because they keep adding more and more material into the atmosphere. But organically based sources of carbon in the atmosphere probably couldn’t get a planet to such a state because they’d have killed off lots and lots of the planet (and probably themselves) long before that after which the source of production would be gone (and probably have decreased as more and more of the planet died off) and presumably over millions of years the greenhouse gases would leave the atmosphere.
You need something that can’t be wiped out by a feedback cycle like that to turn a planet into a Venus, which means something unconcerned with the surface rising to insane temperatures or the air becoming toxic–and volcanoes are famously unconcerned with either of those things.
I don’t think that’s an accurate way to describe the current accepted science. It isn’t projected to be until about 1.1bn years from now that the Sun’s temperature increase is enough that all water escapes out of the atmosphere. At some point before that large bodies of water that we’re used to seeing like oceans would probably be gone.
Most dire for life on Earth starts 500m-600m years from now but it’s not going to be the water boiling off. Instead at that point the ironic thing is the Sun will solve any problems we have with CO2 in the atmosphere as the increased solar radiation hitting Earth will actually destroy minerals in the atmosphere. It is projected this will result in CO2 not being able to exist in a sufficient quantity in the atmosphere to support photosynthesis by trees. Some plants can survive on lower concentrations but it’d be pretty surprising if humanity “as it is today” could survive in a world where much of the world’s plant species were dead.
