The National Institutes of Health’s Natural Products Repository in Maryland — fifty thousand samples of plant, microbial and marine material from thirty tropical countries, stored in forty-one walk-in freezers — had been compactified, roughly catalogued and fired off to a cryogenic store in some deep-shadowed crater on the Moon. Some of the big bioprospecting drug companies, like Merck which had spent years trawling the flora and fauna of Costa Rica for resources for new products, had had similar repositories impounded and shipped off-Earth, though not without bloody battles over compensation.

And so on.

No time to classify, even to count the species, even those living; of Earth’s estimated thirty million species of plant and animal and insect, only a million had been identified and named by all the generations of biologists that had ever worked. Last chance to see.

There were problems, of course.

There was a lot of vertebrate bias, for instance, in the strategies for rescue. The big mammals and pretty birds were always top of the list, followed by other vertebrates, reptiles, amphibians, fish — even though many of the reptiles, for instance, were already literally drowning in the moisture-laden air that had followed the final melting of the ice caps, and the evaporation of so much ocean water.

And nobody could agree on the corner cases. Biodiversity or not, was it right to preserve the last samples of anthrax, or the Ebola virus, or the last tsetse flies?

And there were the bad guys. Like the cartel who had hunted down and wiped out the last elephants — before the geneticists managed to collect embryos for cryostorage — in order to get an all-time monopoly on ivory. Not to mention the reports, many substantiated, of crazies who were deliberately spreading the Moonseed, accelerating its propagation…

There were lots of reasons to do this, to evacuate the biosphere.

The new Moon needed to be colonized, of course, by the right creatures to coexist with mankind, to flesh out a new biosphere. And looking further ahead, a lot of people muttered vaguely about biodiversity. Nobody knew what benefits might be waiting to be discovered: new foods, better medicines, waiting to be derived from plants and animals yet to be catalogued.

And then there was the potential of species, far beyond their economic value to humans. It would have been hard to extrapolate the rise of mankind from the tree-dwelling mammals that hid from the dinosaurs seventy-five million years ago. Who could say what great societies might arise from the beetles and reptiles and birds, if they were only given the chance?

But for Henry there was a deeper sense of ethics involved.

Homo sapiens was one of the newest species on Earth. Maybe it was homo sap’s fault that this calamity had been visited on the planet; maybe it wasn’t. At any rate, wasn’t there an obligation on the species that commanded most of the planet’s primary production to save as many of the other, older species as it could?

But in the end, maybe it was going to make little difference. For there just wasn’t enough time.

Upcoming was the greatest extinction pulse of all, dwarfing even the end-Palaeozoic. This time there would be no recovery, no slow million-year clambering back to diversity, no reconquest of abandoned ecological niches. Now, evolution on Earth was at an end; now, whatever wasn’t sampled or collected was lost forever.

Even the rocks were going to die, this time. So here were Henry and his wife, running through the desert and grabbing the rocks and bones, for all the world like the Apollo astronauts during their three brief, precious days on the Moon… Apollo.

Suddenly, as seemed to happen too often these days, he was hit by a jolt of nostalgia. Apollo 11: Moonwalk parties, under clear starry skies, when Henry was eight or nine or ten. God, it seemed a million years ago, a world that was ten degrees cooler, or more, where there were still ice caps, and the new inland sea hadn’t covered over the state of Henry’s birth…

Jane tired first. The cancers and their treatment had left her weakened. She returned to the cool of the car and turned on the radio. Henry could hear the voices of news announcers.

The human world continued to turn. Less news than a decade ago, because less people. The volcanoes and the quakes and the floods and famine and war had killed off all but — the estimates went — around a billion people. Now, numbers were still declining, but more slowly. Almost gracefully.

Less news. Nuclear war in the Balkans. Mutant riots in Asia. There was something about the war crimes trial of Dave Holland, the former British Prime Minister, who, he vaguely recalled, Henry had once met. The trial had finished with Holland being convicted of genocide during that desperate last-ditch British invasion of southern Ireland, mounted from Ulster, Prime Minister Bhide apologizing to the world, a death sentence ordered…

But the murmur of words, emanating in digitized perfection from some satellite, meant little to Henry beside the dusty reality of these ancient rocks.

Henry laboured on as the sun climbed higher in the sky. The sun was surrounded by a Bishop’s Ring, fat and oppressive, volcano ash.

That night they ate their simple meal, and huddled together in zipped-up sleeping bags, and waited for the Moon to rise.

Here it came, fat and full and cloudy, banishing the stars. And as they watched, a fine, white streak flashed across the Moon’s fat equator, a meteor scratch that wrapped itself half the way around the twin planet.

Jane, her head cradled in Henry’s arm, stirred, half-asleep. “Do you think that was Jack?”

“Perhaps.” Or someone else’s child, he thought, falling to the Moon in one of the Arks, the huge, heavy, clumsy mass transports, cushioned by the Moon’s new atmosphere behind a fat aeroshell.

Henry’s outlandish scheme had worked.

It was no less difficult to get out of Earth’s gravity well than it had ever been. But the presence of a braking atmosphere on the Moon had reduced the fuel load the big Arks had to carry by an order of magnitude, and made mass evacuation, of humans and the biosphere, possible. Not only that, he had given them somewhere worthwhile to go.

And so the Shuttle-Zs launched almost daily, from Canaveral and Kourou and Baikonur, crude Saturn V-class boosters assembled from Space Shuttle technology, people crammed into sardine-can spaceships, fleeing to the Moon. He knew that Geena had emerged from her voluntary exile in the Russian heartland to work at Baikonur, trying to maintain some kind of standard of excellence among the fragmented, ill-trained and badly frightened work force there.

Or maybe it was a Chinese ship, or one of the Indian fleet, based on old Soviet-era Energia technology, built with such haste and crammed even more full than the Shuttle-Zs, with even less precaution and safety checks than in the western sites. The Indian failure rate was a whopping forty per cent, and the toll in lost lives, on those crowded space trucks, was immense. Frank Turtle, the strange little guy from the bowels of NASA who had done so much to return humans to the Moon, had lost his life when one of those big old Energia clones had dropped back to the launch pad on Sri Lanka and blown apart, taking half the island with it.

The rumours were that the failure statistics in China weren’t much better.

It wasn’t going to stop the launches, though, nor the desperate press of people to get themselves or their children on those ramshackle ships. And Henry knew that any government that tried to scale down its launch program would suffer massive civil unrest. The launches were a safety valve, he supposed, the promise of one route, at least, out of the trap Earth had become.