Mad Planet | Page 2

gas. Soon men could not live within 500 feet of sea level. The lowlands went uncultivated, becoming jungles unparalleled since the first carboniferous period.
Then men died of sheer inanition at 1,000 feet. The plateaus and mountaintops were crowded with folk struggling for footholds and food beyond the invisible menace that crept up, and up--
These events occured over many years, several generations. Between the announcement of the International Geophysical Institute that carbon dioxide in the air had increased from .04% to .1% and the time when at sea level 6% of the atmosphere was the deadly gas, more than 200 years intervened.
Coming gradually as it did, the poisonous effect of the deadly stuff increased insidiously. First lassitude, then heaviness of brain, then weakness of body. The human population of the entire world slowly declined to a fraction of its former size. At last there was room in plenty on the mountaintops--but the danger level continued to rise.
There was but one solution. The human body would have to inure itself to the poison, or face extinction. It finally developed a toleration for the gas that had wiped out entire races and nations, but at a terrible cost. Lungs increased in size to secure the oxygen of life, but the poison, inhaled at every breath, left the few survivors sickly and perpetually weary. Their minds lacked energy to cope with new problems or communicate knowledge.
So after 30,000 years, Burl crept through a forest of toadstools and fungus growths. He was ignorant of fire, metals, or the uses of stone and wood. A single garment covered him. His language was a meager group of a few hundred labial sounds, conveying no abstractions and few concrete things.
There was no wood in the scanty territory his tribe furtively inhabited. With the increase in heat and humidity the trees had died out. Those of northern climes went first: oaks, cedars, and maples. Then pines, beeches, cypresses, and finally even jungle forests vanished. Only grasses and reeds, bamboos and their kin, flourished in the new, steaming atmosphere. The jungles gave place to dense thickets of grasses and ferns, now become treeferns again.
Then fungi took their place. Flourishing as never before 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 hanging sullenly overhead, the fungi sprang up. About the dank pools festering over the earth's surface, fungus growths clustered. 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 way 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.
The strange growths grouped themselves in forests, horrible travesties of the vegetation they had succeeded. They grew and grew with feverish intensity, while above them fluttered gigantic butterflies and huge moths, sipping daintily of their corruption.
Of the animal world above water, insects alone endured the change. They multiplied, and enlarged in the thickened air. The sole surviving vegetation--as distinct from fungi--was a degenerate form of the cabbages that had once fed peasants. On those rank, colossal masses of foliage, stolid grubs and caterpillars ate themselves to maturity, then swung below in strong cocoons to sleep the sleep of metamorphosis from which they emerged to spread their wings and fly.
The tiniest butterflies of former days grew until their gaily colored wings measured in terms of feet, while the larger emperor moths extended their purple sails to a breadth of yards upon yards. The overshadowing fabric of their wings would have dwarfed Burl.
Fortunately, they, the largest flying creatures, were harmless. Burl's fellow tribesmen sometimes found a cocoon ready to open, and waited patiently until the beautiful creature within broke through its matted shell and emerged into the sunlight.
Then, before it could gather energy from the air, or its wings swell to strength and firmness, the tribesmen attacked, tearing the filmy, delicate wings from its body and the limbs from its carcass. And when it lay helpless before them, they carried away the juicy, meat-filled limbs to be eaten, leaving the still living body to stare helplessly at this strange world through multifaceted eyes, and become prey to voracious ants who would soon clamber upon it and carry it in fragments to their underground city.
Not all insects were so helpless or harmless. Burl knew of wasps, almost the length of his own body, with instantly fatal stings. To all wasps, however, some other insect is predestined prey. The sphex feeds solely on grasshoppers; other wasps eat flies only. Burl's furtive tribe feared them but little.
Bees were similarly aloof. They were hard-pressed for survival, those bees. Few flowers bloomed, and they were reduced