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Re: Tends to moot that part of the debate though. Joel Send a noteboard - 28/08/2011 09:44:52 AM

OK then, though it does seem like using interstellar molecules for braking would be counterproductive. Racing to some significant fraction of c to quickly cross interstellar distances then using stray atoms struck along the way to slow while still traversing those distances is just throwing away energy no one has to spare (particularly if interstellar drag is so great it could significantly slow your craft; until you get where you're headed it's just one more thing to overcome).

It's a sail, you RETRACT IT when you don't need it. Classic solar sale design before we really knew atomic thick materials like Graphene could exist, basically called for you to line your spaceship up on a straight line between your star and the one you were headed to, then open the sail, slowly accelerating up, then out past the edge of the solar system when your push started to diminish relative to your drag (drag from space dust on one of these goes with the cube of your velocity) you haul it in and coast until you get to the edge of the target solar system and the put it back out, tweaking your course just a little along the way to fall into an orbit where you want to be, then you haul the sail in and recycle it. Something like Graphene, which is thin enough to actually make space dust useful for slowing down and not just starlight and solar wind, you'd probably scrap down for the hull of a rotating habitat a few miles in diameter to give your people-sicles some leg room. We usually assume ten light years as a good round number for trips, even with antimatter you're still talking decades to get anywhere, optimal fusion drive is like .1c IIRC, or a century, something like a sail can do anything from .00...01c to .99c, though probably .5c as a practical top, it's all about how much juice you can send at it. Keep in mind that as huge as the energy we're talking about here is, you're usually talk about around a year to distribute it over, 1 year at 1g or 'normal gravity' means even some gigaton ship the size of New York City would only need 1 minute of the sun's power output to get near light speed, some Texas-sized millimeter thick solar panels converting into lasers would be able to do that, with available tech, but we're talking Great Wall of China or Pyramids in terms of effort scale where we tend to currently do small house fences or sheds.

OK, yeah, retracting it makes sense, given that we're dealing with surface area rather than mass.

For us I'm still betting on vacuum cooled fusion as the long term answer; the big issue with fusion has always been getting a reaction big enough to be useful but small enough to control, and both the ease of the latter and the risk of failing seem much more favorable in high orbit. We might even be able to make batteries or hydrogen cells and drop them back down the well to Earth. But OK, if fusion makes gravity wells a negligible obstacle scooping hydrogen out of the nearest gas giant becomes viable; now all you have to do is develop an industrial capacity for controlled commercial fusion without fossil fuels. It's another case where that would be more plausible if we hadn't spent half a century (so far... ) trying and failing to do that even WITH fossil fuels. That's not to say it's impossible, I just still don't think it very plausible.

Well you've got to be careful talking about 'fusion' - and H-bomb is fusion, you can run a spaceship off H-Bombs, just farting them out behind you and riding the wave, you build a cone or hemisphere or dish on the back end of your ship to act as absorber and radiation shield then fire h-bombs out. If you're willing to go really big scale, like ships with megatons of cargo and mass, you can use H-bombs that are mostly fusionable material by mass instead of mostly conventional explosives and plutonium, and get a higher top speed, a few percent of light... you can also use that wonderful rear dish to smack with a laser beam too for more speed. Then you go ahead when your H-bombs are depleted and the laser is too far out and drag your dish in and recycle it into a much bigger thinner sail for braking. You don't need fossil fuels for nukes, nor to develop them, development is pretty much an automatic as soon as you realize mass=energy, and while we think of them as being industrial age, they aren't, they are simply the byproduct of having a generation or two of scientists who knew about relativity and basic quantum mechanics, which really had no involvement or dependence on fossil fuels. It's likely that without a manhattan project it might have taken an extra generation or two but probably not. You just don't get a basic knowledge of radiation and not realize that's how the sun works, every physicists knows how to build a nuke same as they know how to build a car or howitzer or rocket, they couldn't draw you a working schematic but they'd know it would work and the basics to start of and yield you a functional half-ass proto-type, it's inevitable that if you uncover radioactive material and recognize it's gaining it's energy from losing mass you will realize the sun works off the same concept and that you can build reactors or bombs form it.

Seems to me the issue is manufacturing equipment to relatively fine tolerances, both for the reactor itself and machines to refine and enrich uranium. One of the points in that article about the prehistoric natural fission reactor is that the possibility of such a thing today had been ruled out because nothing like the required concentrations of U 235 exists naturally, but it was possible 2 billion years ago because there was 5 times as much. A species that didn't have to enrich its fuel wouldn't face that issue, but they'd still need reactors of sufficient quality they weren't going Chernobyl every other week; machine shops to ensure control rods move smoothly; mining, refining and metallurgy to get a turbine friction or the reactor itself don't reduce to slag. Automated emergency procedures that react before a human operator can even recognize a problem are at least HIGHLY ADVISABLE. All of that has to be possible on a scale great enough to produce practical nuclear reactors rather than one or two world wonders that consume the resources of entire nations for generations. If a species can industrialize without fossil fuels they can solve those problems the same way we did, but otherwise the local blacksmith pounding out the parts for a nuclear reactor seems to have an insurmountable challenge.

Probably; I'm reminded of James Burke again: Gears are a much bigger deal for industrialization (and printing presses) than fossil fuels, and predate widespread use of the latter. "Widespread use" is a key concept here, and why I keep fudging the distinction between "ability" and "mass production; " if you can't do it on a large scale, and repeatedly, it's just an impractical one hit wonder. I'm sure every ancient Egyptian would've been buried in a shiny giant limestone pyramid if he'd had the means, but half the reason pharoahs did it was because they wanted a monument to the fact THEY had the means practically no one else did. To take a more pertinent example, the same applies to Apollo 11; it's very impressive and hard to equal, but it wasn't the dawn of extraterrestrial man many hoped to see because by then it had long been well known that we simply had no means to travel to another star within a human life time, and the only extraterrestrial place we MIGHT be able to create a permanent residence in the Solar system is a heavily modified and/or encapsulated Mars. Of course, the flip side of Earthcentrism is that all of that could radically change for a species that just happens to inhabit a system where MULTIPLE planets can support them (though that might be unlikely unless they're either EXTREMELY adaptable, evolved in VERY common planetary conditions, or both).

Right, we have to recognize that initial conditions and cultures can vary the end results a lot, I subscribe to the camp that say life is probably absurdly common but that smart life is absurdly rare, that horses would not evolve into tool users even if left for a billion years, because there have been plenty of stars and planets that could and should have life for billions of years longer than us and even if we have to half ass colonization with millenia long trips to stars off current tech and never a drop better one should have an entire galaxy colonized within tens of millions of years, meaning anyone in the galaxy who beats us to the punch by a billion years should be everywhere by now. To me, the 'oh maybe they don't spread and overbreed' response is absurdity, since a desire to grow one's pop is practically axiomatic for anything that hauled itself to the top of the food chain for an entire planet. It also ignores scale, to go from one planet of a billion people to a billion planets of a billion people over a billion years, the extremely slow growth approach, would require that one double your pop only once every 30 million years, as opposed to 30 years. Even a racial obsession with not taking other possible people's worlds that might evolve wouldn't work, because you don't need to take their worlds, you could just grab a couple useless asteroids and turn them into big ring habs causing no harm and hidden from the natives till they were already at the point that they'd be thinking about how big and potentially inhabited the universe was. It's just a no odds kinda case.

The main problem strikes me as getting "over the hump" to multi-planet and multi-system level technology before an extinction level event comes along and knocks you back to the Stone Age (or right out of existence). Humans are kind of a mixed mag in that regard; on the one hand, our relatively long lifespans allow great knowledge acquisition and the ability to pass that knowledge along to future generations is a great plus; on the other hand, our inability to reproduce for the first decade of our lives and habit of waiting two or even three times longer slows the rate at which the species as a whole puts that knowledge to use. Life, smart or otherwise, is racing the clock from Day One to expand beyond their uniquely favored (or favorable) planetary environment before some periodic cataclysm comes along to turn a world ideally suited to them into something completely barren and toxic. If nothing else, take too long and the local star will go nova, not only making that system uninhabitable but probably most of those in the immediate vicinity.

In the end I have to agree that it may only seem fossil fuels are necessary due to biological bias; a microscopic species with brains based on quantum computing rather than electrochemical reactions might be able to do things with a single planets resources that would require a galaxy for us, and their centuries of fossil fuels might be no more than an Earthman who crashed and was crushed ages ago. Part of what makes things so dicey for us now is that we have ability to alter our ecosystem on a planetary level, so if we screw things up too badly we can't just pick up and move somewhere else.

Or the flip side, sentient glaciers who think on that time scale, Alistair Reynold's did a nice story on that, very hard SF guy too, his House of Suns is the only book I ever read that gave a galaxy wide civilization restricted to light speed a sane and probable construct.

As for packing up and moving somewhere else, I really don't know if AGW is as serious as many believe, though I don't think so. Regardless I just can't see it killing us off. We could always, lacking space travel, move a few thousand people to serve as breeder pop along with a lot of frozen sperms and eggs to the tops of tall mountains in pressurized, fission or solar powered habitats, and just wait for the CO2 to settle back down, it does get absorbed, if it goes all runaway and we think Venus might be our future, we could detonate a shit load of gigaton nukes and blow a big chunk of the atmosphere away, the oceans would spill out oxygen to replenish what was lost, the whole human race might be a few tens of thousands of people for a couple centuries or maybe a few millenia [I'm assuming the worst case scenario for everything then doubling it] then come back down and setup shop again running off say a target max pop of a billion all on solar and ethanol. Those, say, 20,000 people could come back down and reseed everything from their zoos and cryogenic lockers and be back up to a billion with normal population growth in about twenty generations, 4-500 years, tops. So even if we kill damn near everyone and we find ourselves having to abandon ship for say 500 years while the planet sucks the carbon back down, you're talking about a thousand year interregnum, we've already done those, not a big deal. I really can't imaigne a scenario... inside our control... that could plausibly wipe humans out, killing 99.9% of the pop is only a short term setback, since it would take ten doublings, about ten generations of normal growth or a couple centuries, to restore yourself.

The difference in those previous interregna was that we still had a survivable ecosystem; the notion of transplanting survivors to isolated mountain tops strikes me more as a hopeless attempt to evade the fact "we're all downstream from someone". If we wound up having to deal with hypercanes we'd probably have to live IN mountains, but the point is human or non-human actions are far more likely to turn the Earth into one of the far more common planets incapable of supporting human life than we are to develop the means to survive such conditions. There's also no guarantee the Earth would return CO2 levels to the current norm in a few centuries or even millennia, or that temperatures would return to what we consider normal even if it did. Climate feedback loops are hard to gauge, but the one thing we do know is that they are not only real but numerous. I'm not sure we have a precise read on what Earths "CO2" and/or "climate equilibrium" is, but it's subject to change even if man isn't messing it with it on a large scale and, for the most part, man can't mess with it on a large scale without some pretty resource intensive long term efforts. After all, even if global warming is as represented, it took nearly three centuries of concerted effort to get us where we are today, only a few degrees centigrade above where we were in 1750. Part of what's so unsettling about climatology is that the causal relationship between our behavior and our environment is extremely complex and hard to understand so anything we do to improve things might end up making them A LOT WORSE (e.g. reducing aerosol and SO2 emissions may reduce acid rain and (eventually) repair the ozone layer, but in the mean time they just contribute to global warming).

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This message last edited by Joel on 28/08/2011 at 09:48:14 AM

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If ever there was a reason to cut greenhouse gas emissions Camilla - 19/08/2011 10:14:00 AM 862 Views

I've seen Start Trek, I know the real threat is you killing whales. snoopcester - 19/08/2011 10:34:08 AM 520 Views

I know

Camilla - 19/08/2011 10:36:22 AM 469 Views

You make a fair point snoopcester - 19/08/2011 11:22:53 AM 444 Views

Re: You make a fair point Camilla - 19/08/2011 02:06:05 PM 420 Views

Re: You make a fair point snoopcester - 19/08/2011 02:10:43 PM 418 Views

It's the other other white meat.

Joel - 19/08/2011 07:13:19 PM 473 Views

There's so much wrong with that Isaac - 19/08/2011 01:08:57 PM 500 Views

"They don't recycle; kill them all. "

Joel - 19/08/2011 07:11:15 PM 496 Views

Very Space Hippy

Isaac - 19/08/2011 10:39:10 PM 513 Views

It's still debatable whether we've abandoned the evolutionary ladder. Joel - 19/08/2011 11:16:58 PM 589 Views

You'll welcome to debate that with a biologist, it's not my specialty or interest Isaac - 20/08/2011 04:46:43 AM 544 Views

I've seen a lot of mainstream biologists suggest human evolution may be mostly mental now. Joel - 21/08/2011 11:32:48 AM 561 Views

Neither of us are biologists though and it's not really relveant anyway Isaac - 21/08/2011 01:21:06 PM 504 Views

I'm not ignoring it, just wondering why over half the planet ignores it and lives in misery. Joel - 21/08/2011 01:55:53 PM 519 Views

If you have occassion to spend time in those places you'll know why Isaac - 21/08/2011 02:38:44 PM 450 Views

How does literal mud huts as the norm respresent living standards rising "a lot". Joel - 22/08/2011 12:29:35 AM 570 Views

You seem to have cherry-picked what you wanted to hear out of my comments Isaac - 22/08/2011 01:07:10 AM 341 Views

"It's a stability thing, not a Western greed thing" seemed to encapsulate your comments. Joel - 22/08/2011 03:10:17 PM 478 Views

Only if you really cherry pick them Isaac - 23/08/2011 02:48:08 AM 491 Views

This seems to have descended into an insoluble partisan debate. Joel - 23/08/2011 07:43:07 PM 553 Views

You're the one who dragged it to that Isaac - 23/08/2011 08:10:03 PM 467 Views

Did I? Joel - 25/08/2011 10:18:29 PM 460 Views

*rudely butts in* Vodalus - 23/08/2011 04:38:33 AM 534 Views

American companies don't go to China SOLELY to screw the working class, no;that's largely incidental Joel - 25/08/2011 08:03:05 PM 582 Views

we should abdon the myth of the evolutionary ladder random thoughts - 20/08/2011 11:49:35 PM 383 Views

Probably; as discussed in Brams thread it should never be seen as predictive, let alone prophetic. Joel - 21/08/2011 11:55:09 AM 492 Views

Well, for this context I think the use is okay Isaac - 21/08/2011 11:59:19 AM 462 Views

That's an interesting point about the NEED for fossil fuels as a stepping stone to advanced culture. Joel - 21/08/2011 12:33:59 PM 561 Views

Not a need, just an edge Isaac - 21/08/2011 02:06:23 PM 377 Views

There's industrialization and then there's industrialization. Joel - 22/08/2011 12:53:35 AM 739 Views

If you were more familiar with engineering you'd not say something like that Isaac - 22/08/2011 01:53:33 AM 735 Views

I dispute that industrialization is primarily about non-agricultural production. Joel - 22/08/2011 03:10:19 PM 641 Views

Well you can argue that with a dictionary I suppose Isaac - 23/08/2011 03:50:52 AM 499 Views

I'm not above that, but the dictionary definitions I've found are disappointingly self-referential. Joel - 24/08/2011 02:25:21 AM 427 Views

That tends to be the case, it is a kinda vague term outside of specific context Isaac - 24/08/2011 09:12:19 AM 587 Views

Tends to moot that part of the debate though. Joel - 26/08/2011 12:31:21 AM 600 Views

Re: Tends to moot that part of the debate though. Isaac - 26/08/2011 05:52:59 PM 758 Views

Re: Tends to moot that part of the debate though. Joel - 28/08/2011 09:44:52 AM 543 Views

yes I was just jumping into the middle of the discussion. random thoughts - 22/08/2011 03:03:49 PM 422 Views

and we wonder why so many people ignore "scientist" random thoughts - 19/08/2011 01:17:38 PM 518 Views

Think it's better to ignore "reporters on a slow news day," to be honest *NM* beetnemesis - 19/08/2011 02:38:23 PM 191 Views

Or even acquire a sense of humour. *NM* Camilla - 19/08/2011 08:36:07 PM 213 Views

That was the City of Pearl series by Karen Traviss Aeryn - 19/08/2011 02:04:51 PM 485 Views

Re: That was the City of Pearl series by Karen Traviss Camilla - 19/08/2011 02:06:27 PM 443 Views

Hypothetical aliens are perfectly wise aerocontrols - 19/08/2011 06:24:13 PM 432 Views

You may be confusing aliens with God.

Joel - 19/08/2011 07:08:01 PM 457 Views

Not confused aerocontrols - 19/08/2011 11:41:56 PM 475 Views

It's a an amusing disconnect to watch. Joel - 20/08/2011 12:25:00 AM 471 Views

Naturally. Camilla - 19/08/2011 08:36:28 PM 559 Views

So, basically, we're the poor white trash of the universe. Joel - 19/08/2011 07:06:23 PM 518 Views

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<quote id="223079">
<quote id="222925"><quote id="222850">OK then, though it does seem like using interstellar molecules for braking would be counterproductive.  Racing to some significant fraction of c to quickly cross interstellar distances then using stray atoms struck along the way to slow while still traversing those distances is just throwing away energy no one has to spare (particularly if interstellar drag is so great it could significantly slow your craft; until you get where you're headed it's just one more thing to overcome).</quote>
It's a sail, you RETRACT IT when you don't need it. Classic solar sale design before we really knew atomic thick materials like Graphene could exist, basically called for you to line your spaceship up on a straight line between your star and the one you were headed to, then open the sail, slowly accelerating up, then out past the edge of the solar system when your push started to diminish relative to your drag (drag from space dust on one of these goes with the cube of your velocity) you haul it in and coast until you get to the edge of the target solar system and the put it back out, tweaking your course just a little along the way to fall into an orbit where you want to be, then you haul the sail in and recycle it. Something like Graphene, which is thin enough to actually make space dust useful for slowing down and not just starlight and solar wind, you'd probably scrap down for the hull of a rotating habitat a few miles in diameter to give your people-sicles some leg room. We usually assume ten light years as a good round number for trips, even with antimatter you're still talking decades to get anywhere, optimal fusion drive is like .1c IIRC, or a century, something like a sail can do anything from .00...01c to .99c, though probably .5c as a practical top, it's all about how much juice you can send at it. Keep in mind that as huge as the energy we're talking about here is, you're usually talk about around a year to distribute it over, 1 year at 1g or 'normal gravity' means even some gigaton ship the size of New York City would only need 1 minute of the sun's power output to get near light speed, some Texas-sized millimeter thick solar panels converting into lasers would be able to do that, with available tech, but we're talking Great Wall of China or Pyramids in terms of effort scale where we tend to currently do small house fences or sheds.</quote>

OK, yeah, retracting it makes sense, given that we're dealing with surface area rather than mass.

<quote id="222925"><quote id="222850">For us I'm still betting on vacuum cooled fusion as the long term answer; the big issue with fusion has always been getting a reaction big enough to be useful but small enough to control, and both the ease of the latter and the risk of failing seem much more favorable in high orbit.  We might even be able to make batteries or hydrogen cells and drop them back down the well to Earth.  But OK, if fusion makes gravity wells a negligible obstacle scooping hydrogen out of the nearest gas giant becomes viable; now all you have to do is develop an industrial capacity for controlled commercial fusion without fossil fuels.  It's another case where that would be more plausible if we hadn't spent half a century (so far... ) trying and failing to do that even WITH fossil fuels.  That's not to say it's impossible, I just still don't think it very plausible.</quote>

Seems to me the issue is manufacturing equipment to relatively fine tolerances, both for the reactor itself and machines to refine and enrich uranium.  One of the points in that article about the prehistoric natural fission reactor is that the possibility of such a thing today had been ruled out because nothing like the required concentrations of U 235 exists naturally, but it was possible 2 billion years ago because there was 5 times as much.  A species that didn't have to enrich its fuel wouldn't face that issue, but they'd still need reactors of sufficient quality they weren't going Chernobyl every other week; machine shops to ensure control rods move smoothly; mining, refining and metallurgy to get a turbine friction or the reactor itself don't reduce to slag.  Automated emergency procedures that react before a human operator can even recognize a problem are at least HIGHLY ADVISABLE.  All of that has to be possible on a scale great enough to produce practical nuclear reactors rather than one or two world wonders that consume the resources of entire nations for generations.  If a species can industrialize without fossil fuels they can solve those problems the same way we did, but otherwise the local blacksmith pounding out the parts for a nuclear reactor seems to have an insurmountable challenge.

<quote id="222925"><quote id="222850">Probably; I'm reminded of James Burke again:  Gears are a much bigger deal for industrialization (and printing presses) than fossil fuels, and predate widespread use of the latter.  "Widespread use" is a key concept here, and why I keep fudging the distinction between "ability" and "mass production; " if you can't do it on a large scale, and repeatedly, it's just an impractical one hit wonder.  I'm sure every ancient Egyptian would've been buried in a shiny giant limestone pyramid if he'd had the means, but half the reason pharoahs did it was because they wanted a monument to the fact THEY had the means practically no one else did.  To take a more pertinent example, the same applies to Apollo 11; it's very impressive and hard to equal, but it wasn't the dawn of extraterrestrial man many hoped to see because by then it had long been well known that we simply had no means to travel to another star within a human life time, and the only extraterrestrial place we MIGHT be able to create a permanent residence in the Solar system is a heavily modified and/or encapsulated Mars.  Of course, the flip side of Earthcentrism is that all of that could radically change for a species that just happens to inhabit a system where MULTIPLE planets can support them (though that might be unlikely unless they're either EXTREMELY adaptable, evolved in VERY common planetary conditions, or both).</quote>

The main problem strikes me as getting "over the hump" to multi-planet and multi-system level technology before an extinction level event comes along and knocks you back to the Stone Age (or right out of existence).  Humans are kind of a mixed mag in that regard; on the one hand, our relatively long lifespans allow great knowledge acquisition and the ability to pass that knowledge along to future generations is a great plus; on the other hand, our inability to reproduce for the first decade of our lives and habit of waiting two or even three times longer slows the rate at which the species as a whole puts that knowledge to use.  Life, smart or otherwise, is racing the clock from Day One to expand beyond their uniquely favored (or favorable) planetary environment before some periodic cataclysm comes along to turn a world ideally suited to them into something completely barren and toxic.  If nothing else, take too long and the local star will go nova, not only making that system uninhabitable but probably most of those in the immediate vicinity.

<quote id="222925"><quote id="222850">In the end I have to agree that it may only seem fossil fuels are necessary due to biological bias; a microscopic species with brains based on quantum computing rather than electrochemical reactions might be able to do things with a single planets resources that would require a galaxy for us, and their centuries of fossil fuels might be no more than an Earthman who crashed and was crushed ages ago.  Part of what makes things so dicey for us now is that we have ability to alter our ecosystem on a planetary level, so if we screw things up too badly we can't just pick up and move somewhere else.</quote>

As for packing up and moving somewhere else, I really don't know if AGW is as serious as many believe, though I don't think so. Regardless I just can't see it killing us off. We could always, lacking space travel, move a few thousand people to serve as breeder pop along with a lot of frozen sperms and eggs to the tops of tall mountains in pressurized, fission or solar powered habitats, and just wait for the CO2 to settle back down, it does get absorbed, if it goes all runaway and we think Venus might be our future, we could detonate a shit load of gigaton nukes and blow a big chunk of the atmosphere away, the oceans would spill out oxygen to replenish what was lost, the whole human race might be a few tens of thousands of people for a couple centuries or maybe a few millenia [I'm assuming the worst case scenario for everything then doubling it] then come back down and setup shop again running off say a target max pop of a billion all on solar and ethanol. Those, say, 20,000 people could come back down and reseed everything from their zoos and cryogenic lockers and be back up to a billion with normal population growth in about twenty generations, 4-500 years, tops. So even if we kill damn near everyone and we find ourselves having to abandon ship for say 500 years while the planet sucks the carbon back down, you're talking about a thousand year interregnum, we've already done those, not a big deal. I really can't imaigne a scenario... inside our control... that could plausibly wipe humans out, killing 99.9% of the pop is only a short term setback, since it would take ten doublings, about ten generations of normal growth or a couple centuries, to restore yourself.</quote>

The difference in those previous interregna was that we still had a survivable ecosystem; the notion of transplanting survivors to isolated mountain tops strikes me more as a hopeless attempt to evade the fact "we're all downstream from someone".  If we wound up having to deal with <a href="http://en.wikipedia.org/wiki/Hypercane">hypercanes</a> we'd probably have to live IN mountains, but the point is human or non-human actions are far more likely to turn the Earth into one of the far more common planets incapable of supporting human life than we are to develop the means to survive such conditions.  There's also no guarantee the Earth would return CO2 levels to the current norm in a few centuries or even millennia, or that temperatures would return to what we consider normal even if it did.  Climate feedback loops are hard to gauge, but the one thing we do know is that they are not only real but numerous.  I'm not sure we have a precise read on what Earths "CO2" and/or "climate equilibrium" is, but it's subject to change even if man isn't messing it with it on a large scale and, for the most part, man can't mess with it on a large scale without some pretty resource intensive long term efforts.  After all, even if global warming is as represented, it took nearly three centuries of concerted effort to get us where we are today, only a few degrees centigrade above where we were in 1750.  Part of what's so unsettling about climatology is that the causal relationship between our behavior and our environment is extremely complex and hard to understand so anything we do to improve things might end up making them A LOT WORSE (e.g. reducing aerosol and SO2 emissions may reduce acid rain and (eventually) repair the ozone layer, but in the mean time they just contribute to global warming).
</quote>

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