Without some water, no species can survive. The descendant of woodland-dwellers, Homo vates has retreated north before the advancing desert. Now he can retreat no more. He must find water or die.

THE ADVANCING DESERT

He was no plains-dweller adapted to the searing heat of the desert. He was in no way prepared for the dryness that had killed his tribe and was now killing him. His dark skin was protecting him from the worst of the sun’s blast, but without water he was going to perish.
They could not move northwards any more, his tribe and he, despite the fact that the arid lands were moving northwards year by year. They had tried to stay ahead of it, keeping abreast of the zone where there were still enough trees to supply their fruit and seeds, and still enough small animals for their protein; but now the people of the lush north barred their path. They were not moving away from their homelands just because the people from the marginal lands needed to survive. After a particularly fierce battle the southerners had to retreat and find their own way of life in the desert.
It has not worked. They are all dead but one, and he has not much longer to go.
The sun in his eyes dazzles him, the singing of the sands dulls his hearing, the dust in his nostrils clogs his sense of smell and taste. He is wandering lost and without the help of any of his senses. Hallucinations about his tribe force themselves upon him - waking nightmares that chide him for surviving while the rest perished. No matter, he is about to join them.
Then comes the other hallucination; the one about the water. Over there, about 500 paces away, if he has the strength, and just below the soil surface beneath the rocky ledge of a gully, lies enough water to save him. It is only a dream and not worth any attention.
Yet it is not like a dream, but more of a conviction that has been put into mind pictures. Over there lies enough water to save his life. He does not imagine it, he knows it.
He finds the strength to pull himself in that direction, slowly, on hands and knees against the abrasive sand and rock, until eventually he sees ahead of him the rocky outcrop and gully of his hallucination. With a final burst of energy he pulls himself into the hollow, and begins to dig the loose soil. After a while the fine powdery sand becomes coarser, cooler and more cohesive. It is coming out as lumps, stuck together by moisture.
He crams a handful into his mouth and sucks the water from it. Then he digs further and finds the sand becoming wetter and wetter.
After a long time he is finally refreshed. He must now look for food, which is another difficulty; but there will be plants and small burrowing animals around. Somehow he has solved the main problem of living in the desert.
He can see water.

Isolated from mainland evolution, island-dwellers have developed a high-protein diet and reduced in size. Now, as a new species Homo nanus, the islanders return to the mainland, where the tundra-dwellers have adapted as a leaf-eating forest people.

ISLANDERS

The icecaps and glaciers are in full retreat now, melting away to the poles and withdrawing up the mountains. The climate is becoming warmer, changing the conditions not only in the arid tropics but over every climatic and vegetation zone of every continent. The retreat of the ice changes not only the climate but the geography as well. Meltwater, gushing from the rounded ice-tunnels and widening crevasses, floods into intertwined rivers that wash across the gravel plains and empty into the ocean, causing sea levels to rise over the whole world. In some places, however, once the unimaginable weight of ice is removed, the land surface rebounds like a slow spring, lifting it above its former level, and causing the sea level to fall back. Then there is the volcanic activity, mostly at the edges of continents and in strings of islands arcing across the oceans, producing new lands and destroying others.
All in all, it is a time of appearing and disappearing islands, of continents joined by land bridges which then submerge, and of lowlands engulfed by the seas and shallow seas that become plains bounded by the banked shingle and sand of former beaches.
The islanders have always found it easy to move from island to island, floating upon the trunks of trees wrenched from their forest stands, or on rafts built from the stems of smaller trees lashed together by vines and creepers. They have used vessels like this to support them while they dived for fish in the straits of the archipelagos. Now, however, this activity is dangerous. The changing weather patterns are producing unfamiliar winds and frequent storms, and changing the sea currents between the islands. More than one raft of island voyagers has disappeared in recent memory.
One has found itself on the beach of the mainland - a region the existence of which was only guessed at by the island people. After the rigours of the accidental voyage the new country may be either an unending source of plenty to the small hungry group of five islanders or deceptively barren. The islanders’ original digestive systems allowed them to eat almost anything, but millennia of island-dwelling on crags and slopes that supported few nutritious plants have changed all that. Now they can only subsist on the high-protein diet that they gained from birds and their eggs, and the fish and shellfish of the sea. No birds seem to nest on accessible crags here, and the shingle beach gives little purchase for shellfish.
There may also be enemies. Some huge figures are moving about down the beach. In build, they are somewhat like the islanders, but they are more than twice their size, and very slow-moving. There are about ten of them.
The islanders do not know these creatures for descendants of the tundra-dwellers. The tundra is dwindling away now, but for many thousands of years groups of its inhabitants have been spreading southwards, changing their diet and adapting their lifestyle as they went, through the coniferous forests and into the zone of deciduous woodlands. Because they have been forced to change all the time they have a better chance of survival than the groups of their relatives who remain static on the tundra. Now they are massive leaf-eating forest-dwellers – dim of wit but quite adaptable to changing conditions. However, they do retain the thick deposits of fat that are now superfluous to their purposes, and indeed could be disadvantageous to them in the hot times that may come. Nor do the islanders realize that the difference in size between them comes from the fact that the tundra-dwellers were created large by the ancient genetic engineers as a precaution against heat loss in the cold north, and the islanders have become small over the past few thousand years as an evolutionary adaptation to their limited resources.
The islanders have no fear of the great creatures. They see them, as they see all living things that are not their own kind, as food. Nimbly they sprint down the beach towards them. Alerted by the crunching and rattling of the shingle under the tiny feet, the big tundra-dwellers see the little figures coming, and dimly perceive that there is some kind of danger. They turn to lope back into the forest, but they are too slow.
Two of them are caught by the legs and brought down with a crash. One is knocked senseless by the impact, the other is killed by quick bites to the neck and face. The killing is not easy. The hide is thick and covered with a woolly pelt, and there are deep layers of fat beneath.
It is the blood that the islanders want, and they gorge themselves on that of the slain tundra-dweller, balancing their feast with the carbohydrates from the fatty deposits. The corpse carries more food than the group of islanders can eat at one time, and having satisfied themselves they leave the remains to the white seabirds that have gathered on the shingle to watch the feast. This seems to the islanders to be a waste of food.
Together they pull the corpse of the second tundra-dweller up the shingle and into the shade of the forest, before it begins to decay in the sun or is eaten by scavengers. If only there were some way of keeping such a big creature alive while feeding from it. Then there would not be so much waste.
The massive form stirs; it is not dead at all, merely stunned. The islanders seize it by the limbs and pin it to the ground. They are not letting this one get away, nor are they going to let it die and rot before they need the food again.

SCHOOLS OF AQUATICS

In the green depths the school of aquatics works its way along the ocean bed. Spread out over a large area, each individual invisible to the next, the school keeps in tight contact by wails, clicks and twitterings – distinct but comprehensible sounds that form a language.
The body of creatures moves northwards, along the lines of magnetic force which are becoming more powerful again as the centuries go by. The direction they take is north, as geography goes, but the magnetic influence that they follow is towards the south. Since the time when the magnetic field disappeared, producing the fatal effects on the technological civilizations of the time, a great change has taken place deep within the globe. The magnetic field has re-established itself, but now there is a south pole where the north pole once was, and a north pole where the south pole once was. This reversal has little relevance to any of the creatures that now inhabit the world.
The water temperatures and currents are also changing, and this is leading to different patterns of fish movement around the globe. It may be that shoals of fish are gathering in areas unexplored by the aquatics, areas now free of pack-ice. If that proves to be the case, then it will make sense to move into those areas. The tropics are becoming over-fished.
The ocean never was particularly productive of food, considering that it covers more than two-thirds of the surface of the Earth. Back in the days of technological man, the living resources of the water were seized, exploited and lost in a short period of time. Since then nature has restocked, but the aquatics have always been there. Like the technological man that created them, the population of the aquatics has grown and grown. As they come to understand more about their own bodies, about diseases and injury and about reproduction, the birth-rate has exceeded the death-rate. Also, the life span of the individual has increased enormously and has been doing so for tens of thousands of years.
Around the coral reefs of the tropics the fish are vanishing, and the other valuable sea creatures are dying off. Undesirable and inedible species are moving in to replace them. The once beautiful and colourful fringing reefs, barrier reefs and atolls are now rapidly becoming dead skeletons of their former glory. It is not just the fault of the aquatics. The sea level is rising everywhere as well, and the tops of the reefs cannot grow quickly enough to keep pace with this. As the water becomes deeper and darker, the algae that grow with the corals and help them to feed are dying off, and the corals themselves are perishing. Although the aquatics cannot see colour (the rod cells in their eyes were developed at the expense of the cone cells in order to increase their low-light vision) they can see enough to know that their preferred environment is slowly dying. The aquatic colonies are everywhere in the shallows that surround the small tropical islands, becoming more and more crowded and more and more desperate for new resources, new food, new spaces.
That is why schools of them are moving northwards into the cooler waters; and others are turning their attention to a hostile environment – that above the surface of the ocean.

Water carries sound long distances, so the aquatics have been able to develop a complex system of communication. This keeps the school in contact when on the move, but allows sufficient space to feed.

50,000 YEARS HENCE AQUATICS Piscanthropus submarinus As millennia pass, the aquatics become even more perfectly adapted to their seagoing existence. They become less bulky and more streamlined, with more efficient paddles and swimming organs. They begin to resemble the extinct seals and, like them, subsist on a diet of fish. However, they do not need to breath at the surface of the water. Their gills can extract all the oxygen they need from the sea. With the retreat of the pack-ice, aquatics move into unknown waters. This is essential if they are to survive a steady increase in population.

MELTING ICE

She will be able to remember her way home, she keeps telling herself. No matter how far the drifting mat of vegetation takes her or her family, she will remember her way back.
She, and the rest of her tribe, have been blessed in this. They have a knowledge that enables them to navigate to any place they want to go. The area where they live has been occupied by their ancestors since before the coming of the ice. Because of this they can actually remember the coming of the ice, and the places to which the different generations moved. It has all changed now that the ice is going back, leaving the landscape different from how it was before. Nevertheless they have always been able to travel to whatever place their ancestors knew would be good for food or shelter.
Now the ability had let them down. They wanted to go to a great river that their ancestors remembered from the dim past. Plenty of the fish were to be had in that river, and good shelters in the gorges through which it ran. However, when they arrived, the gorges had been gouged out by ice into a broad U-shaped valley with little shelter anywhere.
What is more, the river was in spate. The ice, away up at the head of the valley, must have been melting much more quickly than usual, and the water was hurtling down the valley floor in brown and white torrents, tearing at the river’s bed and banks. The floor of the lower valley seemed to have been clear of ice for many years, because a coniferous forest had begun to grow in the soggy peaty soil. It was in this forest that the small group were resting when a sudden surge of the river wrenched away that part of the bank, trees and all. The intertwined roots and the solid trunks of the trees had bound the soil together and kept the whole chunk afloat as a kind of a raft, and the unfortunate group was carried away downstream.
Then night had fallen. The roaring of the river became quieter as it widened and slowed. There was no moon and the banks became invisible in the darkness.
She had panicked. With no visual landmarks her memory was not functioning. Another sense deep within her, a sense that should help her to find direction, was still working but it was very weak. She knew from experience that when she relied on this other sense and thought that a certain place was in one direction, it always turned out to be in the completely opposite direction. Something big must have changed completely since the days before the ice. She had had to resign herself to the possibility that she would never see her tribe again.
Now it is dawn, a cold grey dawn that brings nothing to warm the huddled and shivering figures on the floating island. The land has gone now and there is nothing to be seen but grey choppy sea. The drifting island consists of little more than a few trees and some trapped soil. There is no cover or shelter anywhere, let alone food.
The food will be irrelevant. They will all die of cold and exposure before they starve to death; unless they can remember something that their ancestors used to do under these circumstances.
There was something, she remembers vaguely.
It was something to do with rubbing sticks.

CONTENTS