Precedent

Pastoralist Thomas Austin released two dozen European rabbits on his estate near Winchelsea to recreate the English country hunting he missed from home.

From those few animals the rabbits spread faster than any mammal ever recorded — within a decade two million a year could be killed without denting the population. They stripped vegetation and drove soil erosion, becoming a prime suspect in Australia's native-species losses, until a 1950s myxomatosis program cut numbers from an estimated 600 million to roughly 100 million.

After the Great Fire of 1910 — the "Big Burn," which scorched some three million acres and killed about 87 people — the young U.S. Forest Service resolved to eliminate wildfire altogether. By 1935 it was doctrine: the "10 a.m. policy" required every fire be controlled by 10 a.m. the morning after it was spotted.

But many forests are fire-adapted — lodgepole pine, jack pine and giant sequoia carry serotinous cones that depend on a fire's heat to open and release their seeds. A century of suppression let dead wood and underbrush pile up; combined with a hotter, drier climate, that stored fuel now drives larger, higher-severity "megafires" that scorch soils and kill even the mature trees that once would have survived. The Forest Service abandoned the 10 a.m. policy in 1978.

In June 1935, 102 cane toads were imported from Hawaii to Gordonvale to eat the cane beetles damaging the sugarcane crop.

The toads largely ignored the beetles and instead bred and spread — an estimated 200 million by 2011, across vast stretches of northern and eastern Australia. Their toxins kill native predators that try to eat them; northern quolls and monitor lizards crashed, with some yellow-spotted monitor populations down by up to 90 percent.

Stock Lake Victoria with the large, predatory Nile perch to build a high-value export fishery — the lake's hundreds of small native cichlids were judged commercially unproductive.

Introduced around 1954 and stocked again in the early 1960s, the perch erupted across the lake in the 1980s and devoured the endemic haplochromine cichlids — an estimated 200 species, roughly 40% of the 500-plus found nowhere else, driven to extinction or near it, among the largest vertebrate mass-extinctions of modern times. Losing the algae-grazing cichlids fed algal blooms and oxygen-starved dead zones, while the perch became a frozen-fillet export to Europe whose oily flesh had to be smoked — driving deforestation for firewood.

Launched in 1958 under the Great Leap Forward, the campaign mobilized the population to wipe out rats, flies, mosquitoes, and sparrows — the last for eating grain.

Citizens banged pots and drums to keep sparrows airborne until they dropped dead from exhaustion; authorities reported roughly two billion killed by 1959. With a key predator gone, crop-eating insect populations — including locusts — exploded and devastated crops, contributing to the Great Chinese Famine of 1959–1961 (whose principal causes were Great Leap Forward policies), with death-toll estimates ranging from about 15 to 55 million. China later imported sparrows from the USSR.

From the early 1960s, Soviet planners diverted the Amu Darya and Syr Darya rivers to irrigate desert farmland for cotton — "white gold" — across Central Asia.

Starved of inflow, the world's fourth-largest lake (about 68,000 km²) shrank to roughly 10 percent of its size by 2007; the eastern lobe vanished entirely in 2014. Salinity rose more than tenfold, collapsing a fishery that had supplied a sixth of the Soviet catch, while the exposed seabed became a salt-and-pesticide desert that still fuels toxic dust storms.

Soviet engineers spent decades planning to reverse rivers that "uselessly" drained into the Arctic — redirecting them south to irrigate Central Asia and even refill the Aral Sea, digging the canals with nuclear blasts.

Under the "Nuclear Explosions for the National Economy" program, the 1971 Taiga test set off three ~15-kiloton devices to excavate part of the proposed canal, leaving a radioactive crater lake; the full diversion would have needed more than 250 such explosions. Scientists warned it could alter Arctic Ocean salinity and ice — and the Politburo finally cancelled it in 1986.