The American prairie was so vast, so alien, it shattered comprehension.

Newcomers to the seemingly endless grasslands that once spanned approximately a quarter of North America often hit a psychic wall, descending into fits of mania. Prairie madness, as the phenomenon came to be known, was recorded by the journalist E.V. Smalley in 1893 after a decade of observing life on the frontier: “An alarming amount of insanity occurs in the new Prairie States among farmers and their wives.”

America’s treeless, isolated expanse put early European settlers to the test. Drought, loneliness, and debt drove many to failure, forcing the homesteaders to retreat East.

But those who stayed unwittingly launched one of history’s largest terraforming projects, rewiring the land, the climate, and the future of the continent.

In Sea of Grass: The Conquest, Ruin, and Redemption of Nature on the American Prairie, longtime Minnesota journalists Dave Hage and Josephine Marcotty trace this staggering transformation.“ The Europeans who colonized North America in the 19th century transformed the continent’s hydrology as thoroughly as the glaciers,” they write. “But, remarkably, they did it in less than 100 years instead of tens of thousands.”

In putting hundreds of millions of acres of prairie to the plow, settlers not only forcibly displaced Indigenous nations, but completely altered the region’s ancient carbon and nitrogen cycles. They also turned the region into an agricultural powerhouse. The deep black soil once prevalent in the Midwest — the result of thousands of years of animal and plant decomposition depositing untold carbon stores into the ground — became the foundation of the modern food system. But the undoing of the American prairie also dismantled one of the Earth’s most effective climate defenses.