The Mad Planet

by Murray Leinster

When the twenty-first century drew to a close the whole human race began to revert to conditions closely approximating savagery. The low-lands were unbearable. Thick jungles of rank growth covered the ground. The air was depressing and enervating. Men could live there, but it was a sickly, fever-ridden existence. The whole population of the earth desired the high lands and as the low country became more unbearable, men forgot their two centuries of peace.

They fought destructively, each for a bit of land where he might live and breathe. Then men began to die, men who had persisted in remaining near sea-level. They could not live in the poisonous air. The danger zone crept up as the earth-fissures tirelessly poured out their steady streams of foul gas. Soon men could not live within five hundred feet of sea level. The low-lands went uncultivated, and became jungles of a thickness comparable only to those of the first carboniferous period.

Then men died of sheer inanition at a thousand feet. The plateaus and mountaintops were crowded with folk struggling for a foothold and food beyond the invisible menace that crept up, and up—

These things did not take place in one year, or in ten. Not in one generation, but in several. Between the time when the chemists of the International Geophysical Institute announced that the proportion of carbon dioxide in the air had increased from .04 per cent to .1 per cent and the time when at sea-level six per cent of the atmosphere was the deadly gas, more than two hundred years intervened.

Coming gradually, as it did, the poisonous effects of the deadly stuff increased with insidious slowness. First the lassitude, then the heaviness of brain, then the weakness of body. Mankind ceased to grow in numbers. After a long period, the race had fallen to a fraction of its former size. There was room in plenty on the mountaintops—but the danger-level continued to creep up.

There was but one solution. The human body would have to inure itself to the poison, or it was doomed to extinction. It finally developed a toleration for the gas that had wiped out race after race and nation after nation, but at a terrible cost. Lungs increased in size to secure the oxygen on which life depended, but the poison, inhaled at every breath, left the few survivors sickly and filled with a perpetual weariness. Their minds lacked the energy to cope with new problems or transmit the knowledge which in one degree or another, they possessed.

And after thirty thousand years, Burl, a direct descendant of the first president of the Universal Republic, crept through a forest of toadstools and fungus growths. He was ignorant of fire, or metals, of the uses of stone and wood. A single garment covered him. His language was a scanty group of a few hundred labial sounds, conveying no abstractions and few concrete things.

He was ignorant of the uses of wood. There was no wood in the scanty territory furtively inhabited by his tribe. With the increase in heat and humidity the trees had begun to die out. Those of northern climes went first, the oaks, the cedars, the maples. Then the pines—the beeches went early—the cypresses, and finally even the forests of the jungles vanished. Only grasses and reeds, bamboos and their kin, were able to flourish in the new, steaming atmosphere. The thick jungles gave place to dense thickets of grasses and ferns, now become treeferns again.

And then the fungi took their place. Flourishing as never before, flourishing on a planet of torrid heat and perpetual miasma, on whose surface the sun never shone directly because of an ever-thickening bank of clouds that hung sullenly overhead, the fungi sprang up. About the dank pools that festered over the surface of the earth, fungus growths began to cluster. Of every imaginable shade and color, of all monstrous forms and malignant purposes, of huge size and flabby volume, they spread over the land.

The grasses and ferns gave place to them. Squat footstools, flaking molds, evil-smelling yeasts, vast mounds of fungi inextricably mingled as to species, but growing, forever growing and exhaling an odor of dark places.