Earth

“All right, lads, lassies. Shall we invite our wee devil out to dance?”

They laughed nervously.

Swiveling in its gimbaled supports, the resonator turned with accuracy finer than any human eye could follow. It aimed.

And they began.

PART VII

PLANET

A tug of war began, between sea and sky and land.

In the ocean, life was carnivorous and simple, a pyramid founded on the very simplest forms, the phytoplankton, which teemed in great colored tides wherever sunlight met raw materials. Of the elements they needed to grow and flourish, hydrogen and oxygen could be taken from the water, and carbon from the air. But calcium and silicon and phosphorus and nitrates… these had to be acquired elsewhere.

Some you got by eating your neighbor. But sooner or later, everything suspended in the sea must drop out of the cycle to join the ever-growing sediments below. Cold upwelling currents replenished part of the loss, dragging nutrients back up from the muddy bottoms. But most of the deficit was made up at the mouths of rivers, draining rain-drenched continents. Silt and minerals, the raw fertilizer of life, dripped into the sea like glucose from an intravenous tap.

On land, it took a long time for life to gain a foothold. And for a very long time there were just frail films of cyanobacteria and fungi, lacing the bare rock surfaces with filaments and tiny fibers. These first soils kept moisture in contact with stone longer, so

weathering hastened. The flow of calcium and other elements to the sea increased.

Plankton are efficient when well fed. And so, after the breakup of Gondwanaland, when many great rivers fed shallows teeming with green life, carbon was sucked from the air as never before. The atmosphere grew transparent.

At that time the sun was less warm. And so, deprived of its greenhouse shield, the air also cooled. Ice sheets spread, covering more and more of the Earth until, from north and south, glaciers nearly met at the equator.

This was no mere perturbation. No mere “ice age. ” Reflecting sunlight into space, the icy surface stayed frozen. Sea levels dropped. Evaporation decreased because of the chill. There was less rain.

But less rain meant less weathering of continental rocks… less mineral runoff. The plankton began to suffer and grew less efficient at taking carbon out of the air. Eventually, the removal rate fell below replenishment by volcanoes and respiration. The pendulum began to swing the other way.

In other words, the greenhouse grew back. Naturally. Within a few tens of millions of years the crisis was over. Rivers flowed and warm seas lapped the shorelines again. Life resumed its march — if anything, stimulated by the close call.

A tug of war… or a feedback loop . . . either way it succeeded. What matter that each cycle took epochs, saw countless little deaths and untold tragedies? Over the long term, it worked.

But nowhere was it written, in water or in stone, that it absolutely had to next time.

□ Dear Net-Mail User [□ EweR-635-78-2267-3 aSp]:

Your mailbox has just been rifled by EmilyPost, an autonomous courtesy-worm chain program released in October 2036 by an anonymous group of net subscribers in western Alaska. [□ ref: sequestered confession 592864 -2376298.98634, deposited with Bank Leumi 10/23/36:20:34:21. Expiration-disclosure 10 years.] Under the civil disobedience sections of the Charter of Rio, we accept in advance the fines and penalties that will come due when our confession is released in 2046. However we feel that’s a small price to pay for the message brought to you by EmilyPost.

In brief, dear friend, you are not a very polite person. Emily-Post’s syntax analysis subroutines show that a very high fraction of your net exchanges are heated, vituperative, even obscene.

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For one thing, your credibility ratings would rise. (EmilyPost has checked your favorite bulletin boards, and finds your ratings aren’t high at all. Nobody is listening to you, sir!) Moreover, consider that courtesy can foster calm reason, turning shrill antagonism into useful debate and even consensus.

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• LITHOSPHERE

When the tiny settlement had first been established on the salty verge of the Gulf of Mexico, tall ships wearing high-top wings of white sailcloth had to ride the tidal flow through a measureless, reedy delta in order to reach it. Negotiating the shifting cha

The port was meant to be a point of contact between three worlds — freshwater, saltwater, and the continental ocean of prairie rumored to stretch beyond the western hills. The village thrived in this role and became a town. The town, a metropolis. Time crawled by, as inexorable as the river.

Once a city has grown great and venerable, it takes on its own justification. Centuries passed. Eventually, the original raison d’etre for New Orleans hardly mattered anymore. A living thing, it fought to survive.

Logan Eng strolled a levee watching barges glide past sunken abandoned docks. Once, this had been the second-busiest port in North America, but today cargo ships passed on by, toward the big tube-reloading stations at Memphis, for example. This muggy evening, the main redolence was of mint-scented pine oils, added by the city to cover other, less pleasant aromas. Environment Department launches sniffed each barge suspiciously. But according to Logan’s ex-wife, it wasn’t bilge dumping that gave the river that greasy brown pungency, but the town’s own creaking sewers.

Of course, Daisy McCle

But time affects relationships, as well as cities. And Daisy, the purist, found it ever harder to accept Logan, who had in his heart something called compromise. Their first big fight came early on, when Alaska, Idaho, and other holdouts finally began taxing household toxics like ca

Logan came to envy other people, whose marriages might wither or flourish over mundane things like money or sex or children. For their part, he and Daisy had always earned more than they needed, even in these tight times. And their lovemaking used to be so good that even in middle age he still thought her the most desirable woman alive.