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explain
I mean, shit, no one in this conversation has done me that courtesy - all I've gotten so far is a Jurassic Park quote, a chain of false equivalencies, and a hundred downvotes... and I'm not even the one making a claim (other than "we don't know enough to make a claim").
But fuck it, here ya go:
We've set off positive feedback loops that are warming the climate at a rate that keeps catching us off guard because we don't know what the fuck we're dealing with. Because we don't know what we're dealing with, we don't know what will end those positive feedback loops, so the extreme end of worse-case-scenario is Earth gets better and better at soaking up the sun's energy - heat increases enough and things like oceans evaporating start to happen; more heat, the crust start to melt.
There comes a point in all of that where even the most resilient of life finally dies off. You can't just count on adaptation/evolution when the planet is made of boiling iron.
...people keep talking about things like nuclear war scrubbing the surface and extremophiles eventually emerging as the next batch of life to take the reigns... Earth's combined nuclear arsenal is barely a spark compared to the forces at play here - which is a literal star, and a planet's increasingly efficient ability to soak up that star's rays.
This is unlike any previous mass extinction event we're aware of - the only data we have is what's unfolding in real time, so there is no basis to any assumption, good or bad.
That worse case scenario is as much speculation on my part as the prevailing "life, uh, finds a way" sentiment, but I'm having a hell of a time convincing anyone here that NONE of us knows shit. People seem to think life will prevail no matter what, but that's just blind optimism.
tldr,
My take: things might be bad.
The rest of Lemmy's take: things will be fine.
Well, you are correct that Earth's nuclear weapons are literally a poofing fart compared to the energy we could potentially get from the sun, and we do have precedent for the sun creating extremely hostile conditions due to greenhouse gasses in one of our nearest neighbors, Venus.
But we need to examine what we're talking about here specifically. I am not a geophysicist so I don't have the numbers, but in order for your "concern" to have teeth you would need to show that there's anything we can do here and no or even in the next thousand years that could change the nature of Earth's atmosphere enough to replicate the kinds of conditions that created Venus's current conditions.
And not only that, you need to compare what we could possibly do, even intentionally, that would come remotely close to some of the other greenhouse heating events that we've experienced in the past, and we've had some real doozies. We've had Earth heat up to scorching conditions from the planet turning inside-out several times, we've had Earth become a giant ice-ball. We've had impacts in the distant past that make the Chicxulub impactor look like a bottle-rocket misfire. And still, Earth regained equilibrium enough to support life. Over the last 4.5 billion years or so it doesn't appear we've experienced anything that turned Earth's surface and subsurface hostile to all forms of life, so it's pretty safe to say that unless we start deliberately steering planetoids into our crust, which isn't out of the question knowing our warlike ways, we're probably not going to unintentionally create Venus-like conditions on Earth.
And of course we have to address the fact that we're not even sure if Venus is sterile, there are increasing signs of bacterial life in the atmosphere so it's quite possible that once life gets a foothold it may be incredibly hard to dislodge.
This isn't an argument against the serious threat that we pose to the ecosystem, or to say that we're not in extreme danger of ruining the current biosphere of the planet, we are in fact in the middle of a human-made mass-extinction. It's not good. Our worst-case scenario sees a planet completely devoid of ice, no clouds, an atmosphere that consists of a hot haze that heat can't escape from for thousands of years and an ecosystem collapse killing off most land animals. But it won't be the end of life. Just another setback.
This is important to make clear because truth is important, speculation is not helpful when it points out unlikely extremes, it gives ammunition to deniers when you proclaim factually improbable extremes. Things are absolutely going to get bad, but there's no reason at all to hype it to an extreme or you shoot yourself and your cause in the face.
Here's the discussion I was after!! Seriously, thank you! 🍻
Mixing and matching a bit, but this seems like a good thing to start on:
This is important to make clear because truth is important, speculation is not helpful
Speculation is all any of us are doing - that's what I keep trying to hammer home.
Life has endured a lot, but that does NOT mean it can endure anything. Folks here have a blind faith that it can, and blind faith gets under my skin.
But we need to examine what we’re talking about here specifically.
Self-admitted speculation on my part; speculation conflated as fact from just about everyone else.
in order for your “concern” to have teeth you would need to show that there’s anything we can do here and no or even in the next thousand years that could change the nature of Earth’s atmosphere enough to replicate the kinds of conditions that created Venus’s current conditions.
Why? My only real claim is that we don't know shit. I've hypothesized a range, based on our lack of understanding, spanning from "everything will self-correct and life will be hunky-dory" to "our atmosphere is doing the magnifying-glass thing, and the sun is plenty capable of cranking out enough energy over the course of a million years to melt Earth thoroughly enough that it doesn't support life"
Others are making the claim that life WILL be fine. You've done the most to defend that claim (again, thank you!!) but for some reason folks seem to expect the burden of proof to fall on me for pointing out that a huge array of things could happen vs their claim that one specific thing will happen.
The 'teeth' of my concern stems from the exponential nature of the temperature increase we're seeing; the myriad of climate articles about "we thought the last year was gonna be bad, but not this bad!!"; and the presence of positive feedback loops (which I haven't actually defined, and it just donned on me that that term might be causing some miscommunication here, so just in case: "positive" doesn't mean "good" or anything. A positive feedback loop is one that produces an effect that makes the next 'loop' even more severe than the previous, which makes a stronger effect that bumps up the next loop and so on. They're self-aggravating until some other force cuts the process off. Most of the ones I'm familiar with are physiologic, and they tend to be super dangerous. An environmental example would be that permafrost traps methane; heat melts permafrost; methane releases and does its greenhouse thing; greenhouse thing leads to more heat; permafrost melts faster; methane releases faster; climate warms faster; permafrost melts; methane releases; climate warms; melt; release; warm; etc. It does this until there's no permafrost left to melt, no methane left to release, or something happens that actively interrupts the cycle like some kind of terraforming or weird space shit that somehow gets something tidally locked between the Earth and the sun that cuts off our supply of heat... in which case we've now got an even bigger fish to fry).
We’ve had Earth heat up to scorching conditions from the planet turning inside-out several times
Now that is relevant to what we're talking about! My question is the extent of turning inside out - was there life before hand that survived the process, or did it form after the fact? If the former, were there pockets of relatively unaffected 'safe spots' for life to wait out the worst, or did it somehow survive the planet being completely/uniformly molten? I know there's life that can survive extreme temperatures, but are things like molten iron within those survivable temps?
You mentioned a few other 'doozies' but I don't see the relevance of those ones other than to showcase life's resilience... which is great, but again that doesn't make it absolute. I'd point to the rest of the observable universe as contrary evidence. We have a sample size of exactly ONE planet out of trillions that we're sure there's life on. The conditions for life to exist relative to what the universe is capable of dishing out... that sweet spot is tiny! I just can't wrap my head around why I getting so much heat for suggesting a literal star is capable of nudging a planet out of that range.
And of course we have to address the fact that we’re not even sure if Venus is sterile, there are increasing signs of bacterial life in the atmosphere so it’s quite possible that once life gets a foothold it may be incredibly hard to dislodge.
Definitely an intriguing point, but even giving that the benefit of the doubt and assuming there's microbes in Venus's atmosphere, is that a guarantee that microbes will persist on Earth's? If shit gets hot enough to sterilize life through and beneath the crust, I wouldn't have high hopes for atmospheric critters surviving the beating.
speculation is not helpful when it points out unlikely extremes, it gives ammunition to deniers when you proclaim factually improbable extremes. Things are absolutely going to get bad, but there’s no reason at all to hype it to an extreme or you shoot yourself and your cause in the face.
With you there... although, I can't see humanity actually getting ourselves out of this one. I'll vote and act according to preservation, but... even as bad as we can credibly predict things will get, we aren't really doing shit to stop it. Looking again to positive feedback loops, our limited power might have been in not unleashing them... But now? We're fucked.
My only real claim is that we don’t know shit.
This is partially true. But I want to stress partially.
We do have very robust models of climate, of exchange cycles, of how chemicals and atmospheres and heat and cold and life all interplay, if we didn't have these models we wouldn't be aware of the impending danger and we would be saying "wow this hot spell sure is lasting" so let's give science some credit here.
And that's MY only position and reason for pushback. There STILL can be things done to avert the worst-case models, it's going to be bad but it could also be a lot worse if no action is taken, and more likely than not, our species is going to slide through this one like Indiana Jones grabbing his hat behind the lowering stone block, but it's not going to be without a lot of suffering and sorrow and loss of life.
But if this science denial/doubting continues, we might not gain enough traction and momentum in our education and outreach efforts to ensure actions are taken to reduce the amount of harm coming. The harm coming is going to be worse than anything we have imagined in Humanity's long history, but we CAN get through it, we may even fix it if enough people can start working together. Maybe a few more degrees and people's discomfort will finally drive our species to avert course at the last second like we tend to do a lot.
But science denial has been an agent of chaos that has put us here to begin with. I don't like using science to predict the near future and then abandoning it when we need to make educated speculation on what can and cannot happen. If you truly believe that this trend is going to lead to iron boiling on Earth's surface, that's fine and you can believe that and it's not a hill worth a fight much less a death, I'm just telling you that's not what's going to happen. Life will survive us.
The "exponential" heating curve you're seeing on the graphs is a measurement of rates of change, NOT a measurement of maximum possible heat indexes or a prediction of long-term climate models, because Earth's climate is complicated, it tends to change itself over long periods of time.
The most extreme instance we can see in the fossil/geological record was the Permian Extinction, where Earth lost 96% of all life, this was due to the Earth basically disemboweling itself across what's now Russia and Siberia. This was a lake of fire that covered a sizable portion of Earth and gases and ash that plunged the Earth into a runaway greenhouse with deadly acid oceans and then eventually back to frozen snowball as the greenhouse gases began to stabilize (most greenhouse gases don't have geologically long lifespans unless some process is replenishing them like Venus's volcanic activity, even Carbon will eventually react or bond with things and over vast stretches of time be pulled back into the Earth from a variety of biological and abiotic processes.)
It's also speculated that life was already thriving while Earth was undergoing the Late Heavy Bombardment, a period of around a billion years where Earth was just getting pummeled by everything from space debris to small planetoids, this was the period of time that saw the formation of the landscape of the Moon, and Earth didn't look too different, with seas of molten lava and craters everywhere.
While sure it's possible for a runaway greenhouse to create sterilizing conditions, there is just no scenario where we can see that as an outcome from human activity based on what we know.
And speculation does have its limits, we're just all trying to be smart here and show we understand those limits. Just because there are gaps in our knowledge, we don't need to summon Russel's Teapot.
In agreement with almost everything you posted... although that has me continuing to scratch my head at the disconnect leading up to now.
Just a handful of points to address-
If you truly believe that this trend is going to lead to iron boiling on Earth’s surface
I don't, nor did I ever claim to. I do believe the fireball we live next to, which is large enough to fit a million-and-some-change Earths inside of it, has more than enough energy to make that happen, especially over the course of a million years, if the right circumstances align; and that those circumstances are within the scope of possibility our universe is capable of serving.
The case I'm trying to make isn't to support the worse case scenario; but to emphasize that there are a ton of possible scenarios, some really really good, others really really bad; and that we cannot point to any one of them and credibly claim "That IS going to happen!"
Life will survive us.
Absolutely. But that life has its limits, just as we have ours. And when those limits are met, there may be an even more resilient flavor of life that takes the stage; but that chain isn't infinite, especially within the scope of a single planet. Further narrowed to the million-year scope of this conversation... yeah my wager is with everyone else here that there will probably still be life left on Earth. I just can't say with absolution that there will be.
Russel’s Teapot
I'm not sure if that's directed at my inability to prove the worse case scenario (gotta reiterate - that was never my goal!) or the inability to prove life will prevail. Either way, you're correct to call it out as a fallacy. At this point I think we're mostly just splitting hairs over where to draw the line between 'might' and 'will'. I tend to treat absolutes at face value, so things like "life WILL survive" vs "life WILL PROBABLY survive" are two very very different things. The former has no room for error, regardless how minute. Or to the previous point "Life will survive us" vs "Life will survive -period-"; can say the first with certainty, but not the second.
I gotta get my ass to bed, but I can't overstate how refreshing your posts are. The amount of strawman in this thread was really getting under my skin. Not used to seeing that here, even if the source of the discussion is just a 4 panel meme.
I am happy to have raised the bar a little for online science discussion, it's very tempting and easy to rip someone's throat out if you don't understand what they're trying to communicate, and sadly I think that weird dopamine hit of attacking a stranger has become a worldwide addiction reaching pandemic proportions. But we're really shooting all ourselves in the foot by making a world where we can't talk to strangers. People stay strangers that way and strangers are less inclined to help each other, and in the coming decades... we will really, really need each other.
That all said, I am passionate about science with decades of study, and lately, specifically, geology and climate... I highly recommend some youtube channels like https://www.youtube.com/@HistoryoftheEarth or https://www.youtube.com/@myroncook for some starting points that are accessible and fascinating looks at the long, intense, unimaginable history of our planet, or another way of looking at it, the story of how rocks became something that can question where they came from.
Subbed the channels. It's not my area of study, but I've definitely got at least a hobbyist-level of interest in things like physics and astronomy, which Earth sciences ofc fall into. Next semester of nursing school starts NEXT WEEK (fuuuuuuuuuuuuuuuuck) so I probably shouldn't dive down any new content rabbit holes at this point, but it's in my feed now so definitely marked for future down time!