Stephen Baxter - Moonseed

But the coup de grâce had been the giant magma plume that had burst, unexpectedly and explosively, through the crust beneath Yellowstone.

It was an explosion that had been ten thousand times as powerful as all mankind’s nuclear weapons, at their peak, ignited together. From a caldera the size of New Hampshire, blazing material had punched out of the atmosphere — some even entering low orbit — most of it falling back as giant fireballs which ignited what was left of the Earth’s vegetation.

And from the crater itself a huge fireball, followed by a dust plume, had swept up to the stratosphere, and added to the soot and dust from the burning forests to create a planet-covering pall of darkness.

Lights out, all over the Earth.

The atmospheric shock-heating was enough to cause oxygen and nitrogen to combine to nitrous oxide, which had combined with rain water to make acid; and enough acid rain had fallen on the planet to make the top three hundred feet of the oceans sufficiently acidic to dissolve calcareous shell material, so driving still more orders of life to final extinction. The food chains, already tenuous, had finally collapsed. Death soaked the planet, starting with the phytoplankton.

Ash falling, all over the Earth, like the thin layer that had been found in the rocks following the Cretaceous extinction, once puzzled over by scientists like Henry in bright, clean labs…

The magma plumes, giant wellings-up in the Earth’s molten substance that originated as deep as the core-mantle boundary, had been significant in Earth’s deep history. They had shattered continents, breaking up the Pangaea supercontinent, splitting Gondwanaland into two halves, splitting India, Madagascar and Antarctica from Africa. But all that had taken hundreds of millions of years. Now, the plumes” violence was manifested on timescales of mere decades, even years.

There was the mountain-building event in Antarctica, for instance, where the Indo-Australian plate had suddenly decided to set off south. More of the great magma plumes under Earth’s hotspots had come boiling through the crust, at the Canaries, under the tsunami-lashed wreckage of Hawaii, under Iceland. And the rift valleys all over the Earth had started to open up, in east Africa and Lake Baikal and the Red Sea, the continents just splitting apart. The river Rhine had disappeared into a crack in the ground, and then the graben through which it once flowed started to bubble with new ocean-floor plate.

What all the volcanism was mostly doing, in addition to killing people and boiling the seas, was pumping out a new atmosphere for the Earth: an unwelcome air of carbon dioxide and sulphur dioxide and hydrogen laced with arsenic and chlorine, that would, the estimates went, finish up ten times as thick as the old nitrogen-oxygen one. Immense greenhouse cycles had already started, and the oceans were evaporating and would soon start to boil…

And Henry’s beloved Earth was turning into what Venus used to be.

One large community of people had retreated to what was left of the oceans, sheltering from the heat there. But even the marine invertebrates were choking on ash. And the volcanism had polluted the water with exotic trace elements — like cadmium and mercury and iridium and osmium — and the oceans, the birthplaces of life on Earth, were, in their last days, becoming toxic.

But, in a way, it was geologist’s heaven. Processes that ought to take millions of years were occurring in mere years, even months. As if the Earth was trying to cram in her best special effects while she still had time. Geology, overwhelmed with unwelcome evidence, was at last becoming a mature science — just as, so he heard, fundamental physics had been galvanized by the study of the Moonseed processes, so that whole new areas of theory and technological achievement were being opened up.

None of it any use, though, in stitching poor Earth back together.

Dear Jane had called the sites of the great magma plumes Earth’s chakras. The energy centres, the wheel of light from which Earth’s energies were bleeding away. It was as good a description as any.

He stepped forward cautiously, keeping an eye on the compass set into his chest pack. The compass was inertial, a little spinning gyroscope system, like they used to use in aircraft and spaceships. It was the only type that was reliable nowadays; the electronic kind that communicated with the GPS satellites was too easily thrown out by the auroras and the big electrical storms that flapped around the planet, and you couldn’t use a magnetic compass, of course, since Earth’s magnetic field had gone to hell. The geophysicists said it was all to do with the melting of the ice caps and the oceans” evaporation, all that mass redistribution making Earth wobble like a kid’s top after a hefty kick. The reversals in the magnetic field’s polarity were coming about once a year now, thus screwing up the magnetosphere and letting through the cosmic rays, just adding to the fun down here, and coincidentally fouling up Henry Meacher’s map-reading…

But he couldn’t make head or tail of this damn astronaut’s compass.

Well, maybe it was a little brighter to his left, to the east, where the sun must be rising. Maybe there were miles of cloud above him, the evaporated oceans lofted into the sky; maybe his green Earth had turned to a pearly white ball like Venus had been, where an American needed a space suit to walk out of the big underground shelters; but as far as he knew the world was still spinning the right way.

Anyhow, he might get lost, but wasn’t going to come to any harm, on this plain of mud.

He stepped forward, carefully.

…It still seems remarkable to me to see Nadezhda bounding around in the low gravity without an ounce of self-consciousness.

Of course she has no memory of the Moon before the modification. It seems perfectly natural to her to lope around the mare with nothing more than cold weather clothing, sunglasses and an oxygen pack! I’ve shown her recordings of the old Apollo Moonwalks, but she doesn’t say much.

I suspect among the young people born here there is already a conspiracy theory circulating: that the Moon has always been this way — that maybe the old airless Moon never existed — that maybe our “terraforming” is a clumsy attempt to rectify some eco screw-up on a previously pristine Moon. God, if only that was true!

I do know that the images the young ones see of Earth are affecting them in ways we didn’t anticipate.

For sure, the kids are evolving away from us, Henry. Already. Oh, Nadezhda doesn’t look much different from me at her age, when I was nagging mum to take me to the McDonald’s on Princes Street; it’s going to take generations even to work through the obvious physiological changes — the low G adaptations, for instance; Nadezhda will have to spend her life on courses of treatment against bone calcium loss and body fluid imbalances.

But her children will be a little taller, and a little more resistant; and her grandchildren a little more so… and so on.

Humans will survive here. I’m sure of that now. What I’m not convinced about is how much they will care about old Earth.

The young ones already have their own agenda. It’s hard for them to have any loyalty for the home planet when they see that now you need spacesuits just to survive down there…

There has already been some trouble at the drop points in Procellarum. Resistance to new immigrants, even to accepting more loads of rocks and frozen bugs from Earth.

I just hope it all holds together long enough to get the best of it away, before the end.

Well, maybe it’s inevitable. We’ve done all we can to equip the kids and educate them. Now, the future is theirs…