The World Without Us

…until it stops at an electric fence. Two hundred kilometers of galvanized wire, pulsing 6,000 volts, now encircle Kenya’s greatest water catchment. Electrified mesh rises seven feet above ground and is buried three feet beneath it, its posts hot-wired to keep baboons, vervet monkeys, and ringed-tailed civets off them. Where it crosses a road, electrified arches allow vehicles to pass, but dangling live wires deter vehicle-sized elephants from doing the same.

It is a fence to protect animals and people from each other. On either side lies some of the best soil in Africa, planted in forest above and in corn, beans, leeks, cabbage, tobacco, and tea below. For years, incursions went in both directions. Elephants, rhinos, and monkeys invaded and uprooted fields by night. Burgeoning Kikuyu populations snuck farther up the mountain, felling 300-year-old cedars and podo conifers as they advanced. By 2000, nearly one-third of the Aberdares was cleared. Something had to be done to keep trees locked in place, to keep enough water transpiring through leaves and raining back into Aberdares rivers, to keep them flowing to thirsty cities like Nairobi, and to keep hydroelectric turbines spinning and Rift lakes from disappearing.

Hence, the world’s longest electric barricade. By then, however, the Aberdares had other water problems. In the 1990s, a deep new drain had opened at its skirts, cloaked innocently in roses and carnations, as Kenya passed Israel to become Europe’s biggest provider of cut flowers, which now exceed coffee as its main source of export income. This fragrant turn of fortune, however, incurs a debt that may keep compounding long after flower lovers are no longer around.

A flower, like a human, is two-thirds water. The amount of water a typical floral exporter therefore ships to Europe each year equals the annual needs of a town of 20,000 people. During droughts, flower factories with production quotas stick siphons into Lake Naivasha, a papyrus-lined, freshwater bird and hippo sanctuary just downstream from the Aberdares. Along with water, they suck up entire generations of fish eggs. What trickles back whiffs of the chemical trade-off that keeps the bloom on a rose flawless all the way to Paris.

Lake Naivasha, however, doesn’t look quite so alluring. Phosphates and nitrates leached from flower greenhouses have spread mats of oxygen-choking water hyacinth across its surface. As the lake level drops, water hyacinth—a South American perennial that invaded Africa as a potted plant—crawls ashore, beating back the papyrus. The rotting tissues of hippo carcasses reveal the secret to perfect bouquets: DDT and, 40 times more toxic, Dieldrin—pesticides banned in countries whose markets have made Kenya the world’s number-one rose exporter. Long after humans and even animals or roses go, Dieldrin, an ingeniously stable, manufactured molecule, may still be around.

No fence, not even one packing 6,000 volts, can ultimately contain the animals of the Aberdares. Their populations will either burst the barriers or wither as their gene pools shrink, until a single virus snuffs an entire species. If humans are snuffed first, however, the fence will stop dispensing jolts. Baboons and elephants will make an afternoon fete of the grains and vegetables in the surrounding Kiyuku shambas. Only coffee stands a chance to survive; wildlife don’t crave caffeine very much, and the arabica strains brought long ago from Ethiopia liked central Kenya’s volcanic soils so much they’ve gone native.

Wind will shred the polyethylene greenhouse covers, their polymers embrittled by equatorial ultraviolet rays whose potency is abetted by the flower industry’s favorite fumigant, methyl bromide, the most potent ozone destroyer of all. The roses and carnations, addicted to chemicals, will starve, although water hyacinth may outlast everything. The Aberdares forest will pour through the deactivated fence, repossessing shambas and overrunning an old colonial relic below, the Aberdares Country Club, its fairways currently kept trimmed by resident warthogs. Only one thing stands in the forest’s way from reconnecting the wildlife corridors up to Mount Kenya and down to the Samburo desert: a ghost of the British Empire, in the form of eucalyptus groves.

Among the myriad species loosed on the world by humans that have surged beyond control, eucalyptus joins ailanthus and kudzu as encroachers that will bedevil the land long after we’ve departed. To power steam locomotives, the British often replaced slow-maturing tropical hardwood forests with fast-growing eucalyptus from their Australian Crown colonies. The aromatic eucalyptus oils that we use to make cough medicine and to disinfect household surfaces kill germs because in larger doses they’re toxins, meant to chase off competitive plants. Few insects will live around eucalyptus, and with little to eat, few birds nest among them.