Global Mean Temperature ([Finale]: 6/25/09)

[PeZook]

Well, this has been sitting on my hard drive for about a year and a half, so I thought I'd better post it and wrap up this little run until I can go back and really revise the background of the story. This series has a little bit less story potential than I originally thought; there're only so many variations of "X eats/sleeps/has sex/survives natural disaster/hunts/flees from predator".

Well, every story needs a beginning, a middle and an end: a series which is going nowhere will quickly become boring, even if that's how most of life progresses.

Though in 10 million years, I seriously doubt humans (even with civilization reborn) would resemble us in any way we'd recognize today

[Surlethe]

Well, every story needs a beginning, a middle and an end: a series which is going nowhere will quickly become boring, even if that's how most of life progresses.

Yes, that's what I realized. It was still interesting when I could dump in background about "Shrub the King" and the "Bringers of Sunlight" or hint at love stories and murder mysteries, but after humans weren't humans anymore (and even leaving aside any problems with the timescale of evolution) there wasn't any human drama to make a story. It would turn into a history or evolutionary biology book - and while that's interesting in its own way, it doesn't make a good story.

Incidentally, I think this is part of why Stephen Baxter's books are mediocre at best. He has great Big Ideas, and his stories are grand in scope, but the stories are told to illustrate the Big Ideas, not vice-versa as it should be. It's neat and all to have a story tell about Xelee leaving the universe after losing a billion-year-long battle with photino birds, but if the human interest is jury-rigged in it won't be a good story.

Though in 10 million years, I seriously doubt humans (even with civilization reborn) would resemble us in any way we'd recognize today

I'm going for a human version of the Age of Dinosaurs. Not that that precludes intelligent life - but even that is going to be strange to us: look at how Jorgstund had to wear a breathing apparatus, since N or O2 were deadly to him. Who knows what his physical form looked like, other than that it was probably hominid? (I don't!)

[iborg]

It's a relatively happy ending for what was a pretty depressing (but a good read) story so far !

[GrayAnderson]

Having flipped through this, I did rather enjoy it...and it did remind me of Flood, albeit with (obviously) less water. I know the science wasn't great (I will hold that you'd have ended up with non-desert areas between the 60s somewhere, if just because there's a lot of water that's going to evaporate and land on some piece of land or another), but it was still a nifty read.

[Gil Hamilton]

I'm going for a human version of the Age of Dinosaurs. Not that that precludes intelligent life - but even that is going to be strange to us: look at how Jorgstund had to wear a breathing apparatus, since N or O2 were deadly to him. Who knows what his physical form looked like, other than that it was probably hominid? (I don't!)

Keep in mind that nitrogen gas is basically inert for all intents and purposes. It wouldn't be toxic. I'm not sure why O2 would be toxic too him if he was descended from terran lifeforms either, unless the partial pressure in the atmosphere was too much for him.

[Memnon]

I'm going for a human version of the Age of Dinosaurs. Not that that precludes intelligent life - but even that is going to be strange to us: look at how Jorgstund had to wear a breathing apparatus, since N or O2 were deadly to him. Who knows what his physical form looked like, other than that it was probably hominid? (I don't!)

Keep in mind that nitrogen gas is basically inert for all intents and purposes. It wouldn't be toxic. I'm not sure why O2 would be toxic too him if he was descended from terran lifeforms either, unless the partial pressure in the atmosphere was too much for him.

Yes, oxygen is toxic to us, to a degree - Oxygen Toxicity on wiki.
Pretty sure that's what you were referring to.

Also, it could be this:
Reactive Oxygen Species (wiki)

They are highly reactive due to the presence of unpaired valence shell electrons. ROS form as a natural byproduct of the normal metabolism of oxygen and have important roles in cell signaling. However, during times of environmental stress (such as for example, UV or heat exposure) ROS levels can increase dramatically, which can result in significant damage to cell structures. This cumulates into a situation known as oxidative stress.

[GrayAnderson]

I do have to wonder...did Mr. Jorgensen's trip back from Andromeda mean that humanity got some sort of colony ship off in the 21st Century? I'm just wondering (partly because of the major adaptations that probably allowed speciation within 50,000 years or so...do recall the number of splits within the human family in the last few hundred thousand years, after all) if there was a remnant that got away during that time.

And I would like to note that I think a good deal of what I like about Baxter is the scale he tackles, to a certain extent. I'm not as much a fan of his "post-human" works (that is, those dealing with long-run evolution in humanity), but I do like the somewhat drier Wells-esque style a good deal more than I like more narrative, human works.

[Baughn]

Me, I'm just not a fan of evolution, in general.

Why would it keep acting (in the normal sense) once we start using genetic engineering? Never mind full-body replacements, uploading and such..

Still, good story. I can overlook a few weak points, since those weren't part of the story you wanted to tell.

[Gil Hamilton]

Yes, oxygen is toxic to us, to a degree - Oxygen Toxicity on wiki.
Pretty sure that's what you were referring to.

Also, it could be this:
Reactive Oxygen Species (wiki)

They are highly reactive due to the presence of unpaired valence shell electrons. ROS form as a natural byproduct of the normal metabolism of oxygen and have important roles in cell signaling. However, during times of environmental stress (such as for example, UV or heat exposure) ROS levels can increase dramatically, which can result in significant damage to cell structures. This cumulates into a situation known as oxidative stress.

Actually, I know all about oxygen, including that its highly reactive due to being a ground state triplet. However, at normal atmospheric pressure, oxygen isn't present in a high enough partial pressure to be dangerous to terranic life (this changes when you SCUBA dive, where pressures exist that increase the concentration of oxygen to a level that is dangerous). I don't see in 10 million years human descendants ceasing to be able to breath oxygen. It's reactivity mades it useful; as an oxidizing agent (heh) in metabolic processes. There isn't really a reason to change people being oxygen breathers and I don't see a natural way they could adapt to use something else as an oxidizer in metabolic processes.

[Slacker]

The asteroid impact could've kicked up some volcanic activity that added a lot of a noxious trace gas to the atmosphere-methane, maybe, or sulfur dioxide.

[Memnon]

Yes, oxygen is toxic to us, to a degree - Oxygen Toxicity on wiki.
Pretty sure that's what you were referring to.

Also, it could be this:
Reactive Oxygen Species (wiki)

They are highly reactive due to the presence of unpaired valence shell electrons. ROS form as a natural byproduct of the normal metabolism of oxygen and have important roles in cell signaling. However, during times of environmental stress (such as for example, UV or heat exposure) ROS levels can increase dramatically, which can result in significant damage to cell structures. This cumulates into a situation known as oxidative stress.

Actually, I know all about oxygen, including that its highly reactive due to being a ground state triplet. However, at normal atmospheric pressure, oxygen isn't present in a high enough partial pressure to be dangerous to terranic life (this changes when you SCUBA dive, where pressures exist that increase the concentration of oxygen to a level that is dangerous). I don't see in 10 million years human descendants ceasing to be able to breath oxygen. It's reactivity mades it useful; as an oxidizing agent (heh) in metabolic processes. There isn't really a reason to change people being oxygen breathers and I don't see a natural way they could adapt to use something else as an oxidizer in metabolic processes.

I'm not saying that people wouldn't be oxygen breathers - just that they may be adapted to very low atmospheric pressure/oxygen concentration. And yes, oxygen is indeed very useful in the ETC - that would seem to be the problem with a low oxygen conc.

[Mayabird]

I do have to wonder...did Mr. Jorgensen's trip back from Andromeda mean that humanity got some sort of colony ship off in the 21st Century? I'm just wondering (partly because of the major adaptations that probably allowed speciation within 50,000 years or so...do recall the number of splits within the human family in the last few hundred thousand years, after all) if there was a remnant that got away during that time.

The very first vignette mentioned space shuttles taking off from Florida in the late 21st century just before the big doom hurricane of doom wiped out the state. Surlethe said he'd come back to what happened to all that later, and so he did. Whatever space population got established was able to survive and spread.


Also ignoring the whole thing about O2 or N or whatever being toxic to him, it could be any other thing in the atmosphere, or something different mixture that he needs or different ratios of gases or just plain keeping himself from breathing in Earth germs in the off chance that they could still infect him. It'd really suck if his trip ended suddenly with a local grass mold liquifying his organs. Better not to take chances, and he might as well get the oxygen levels to something he's more used to while he's at it.

[PeZook]

Well, spacecraft are kept a lower total pressure (Apollo was at 30% sea level) and higher partial oxygen pressure to make engineering less complicated. If the people who took off from florida lived ten million years in a low-pressure environment, Earth would become pretty unbreathable

[Junghalli]

Skimmed through it. Good writing, the Shrub story was amusing. A bit too grimdark for my tastes though. All those poor generations of humans and posthumans, doomed to millions of years of primitivism. God it was depressing.

I know the science wasn't great (I will hold that you'd have ended up with non-desert areas between the 60s somewhere, if just because there's a lot of water that's going to evaporate and land on some piece of land or another), but it was still a nifty read.

Indeed, as I understand it a warmer world would be wetter than ours, not drier. If you look at the climate during the ice age, deserts were bigger than today and forests were much smaller. As I understand it, it's to do with the fact that a warm world charges up the water cycle. A slow water cycle and the ocean retains water more effectively and rain falls less frequently. A fast water cycle and rain falls more frequently, resulting in more water ending up on the continents. The best model for Surlethe's radically warmer world would probably be the Miocene world before the the glacial advances of the Pleistocene. Forests shrunk and grasslands expanded during the Miocene, as the climate cooled toward what it is today. During the warm Miocene periods there was a continuous belt of forest between Europe and East Asia, for instance.

Probably best to write it up to a premise conceit, like agriculture being completely lost.

[Mayabird]

I think he was basing it on the Permian-Triassic mass extinction, after which Earth (well, the one continent at the time) turned into a giant hot planetary desert for forty million years.

[Junghalli]

I think he was basing it on the Permian-Triassic mass extinction, after which Earth (well, the one continent at the time) turned into a giant hot planetary desert for forty million years.

That was shortly before the assembly of Pangaea. I don't know much about the details of the Permian-Triassic climate but I'd think the Permian was probably an arid period just because all the continents were conglomerated into one huge land mass, which would have giant deserts just by its very nature. Rain would have had a hard time reaching the interior.

I have a very hard time envisioning a hot desert world with our continental configuration. A hot world means the water cycle is supercharged as ocean evaporation rates increase. More water is being pumped into the atmosphere and it's going to rain out somewhere. I'm no climate expert but I think you'd need some seriously odd atmospheric circulation patterns to keep that somewhere from including the continents. Yes, you might get deserts where they don't exist now because of shifting weather patterns, but generally you should get more rain, not less. There are other factors as well, such as the fact that warm air retains moisture better so water should be more effectively transported into continental interiors on a hot world.