We lost seven billion people in the first year.
We had time to see it coming. Our extinction on Earth wouldn't be fast. It would smolder on for generations after the first decade knocked us down from twenty billion to one billion.
We had mass. We had energy. We had microwave cavitation drives. Enough to take us to the edge of the solar system. Enough to give us a chance in between the Sun and the stars.
When we left, we were down to five million.
It would be the end of humanity on Earth. But not the end of intelligent life there. If we couldn't keep the Earth, we could entrust it. Prometheus had to steal fire from the gods for us. But we gave minds to the beasts.
And into their blood and dreams, we wrote one burning message:
Fight back the Spongey.
It was the beginning of the end. Cordyceps, the tyrant of the insect kingdom, had found a foothold in mammals. Transgenic pigs, relied upon for organ donation, turned an agricultural problem into a wildfire that Humanity had no hope of stopping.
- met the wrong pig.
- the wrong ant-
And then one day -
The 29th century was pretty sweet for humanity. We'd overcome so many crises: Nuclear proliferation, too much carbon, too little phosphorous. We'd just started turning back the clock on global warming and ocean acidification.
A stable population of twenty billion people spinning on a blue marble, and life was finally getting better.
But twenty billion of a species is twenty billion hosts. Traveling, breeding, kissing, breathing, eating and drinking and doing everything life demanded of any animal.
Our parasites were evolving faster than we were. Toxoplasma Gondii was rampant, Plasmodium, Enterobius and Entaemobia was everywhere. Giardia and Influenza and Noroviruses flourished. But we had the tools to fight back against most of them, and for those we couldn't, quarantine and isolation kept the fires from spreading.
It took thirty years for Cordyceps to make the leap from pigs to humans. Twenty billion hosts, packed densely into their hives and cities. Fungal spores weren't like bacteria and viruses. They remained viable for years, in the air, in the water, in the ground.
They were everywhere, forever, and all the HEPA filters and antifungals in the world couldn't change the inevitable.