AMHERST, MASS. — Next week my daughter will go back to elementary school, and I will be faced with a choice. At some point the curriculum will cover the environment, and she'll be taught that before Europeans settled the Americas the Indians lived so lightly on the land that for all practical purposes the hemisphere was a wilderness. The forests and plains, the teacher will explain, were crowded with bison, beaver, and deer; the rivers, with fish; flights of passenger pigeons darkened the skies. The continent's few inhabitants walked beneath an endless forest of tall trees that had never been disturbed.
But in recent decades most archaeologists, anthropologists, and geographers have come to believe that this Edenic image isn't true. When Columbus landed, the new research suggests, the Western Hemisphere wasn't filled with scattered bands of ecologically pure hunters and gatherers. Instead, it was a thriving, diverse place; a tumult of languages, trade, and culture; the home to tens of millions of people - more, some researchers believe, than Europe at that time.
Then, the majority of native Americans lived south of the Rio Grande. They were not wanderers with tepees; they built up and lived in some of the world's biggest, most opulent cities. Tenochtitlán, the greatest city in the aggressive military alliance best-known as the Aztec empire, may have had a quarter-million inhabitants - more than London or Paris. It glittered on scores of artificially constructed islands in the middle of a great lake in central Mexico. On first encountering this metropolis, the conquistadors gawped like yokels at the great temples and immense banners and colorful promenades. Hundreds of boats flitted like butterflies around the city's canals and the three grand causeways that linked it to the mainland. Long aqueducts conveyed water from the distant mountains to the city. Perhaps most astounding to the Spaniards, according to their memoirs, were the botanical gardens - at the time, none existed in Europe.
Far from being dependent on big-game hunting, most Indians lived on farms. (Otherwise, the cities wouldn't have survived.)
According to a painstaking 2000 inventory of the evidence by geographer William E. Doolittle of the University of Texas at Austin, agriculture occurred in as much as two-thirds of what is now the continental US, with large swaths of the Southwest terraced and irrigated. Among the Midwest and Southeast maize fields, thousands of earthen mounds - priestly ceremonial centers - stippled the land. When the Pilgrims landed, they discovered that Indians had peeled back the great forests of the eastern seaboard, lining the coast with farms that stretched inland for miles. (There was little farming in the Northwest, but salmon nets stretched across almost every ocean-bound stream in the region.)
Further south, Indians had converted the Mexican basin and Yucatán into artificial environments suitable for farming. Terraces and canals and stony highways lined the Western face of the Andes. Raised fields and causeways covered Bolivian Amazonia. Farms dotted Argentina and central Chile. At the time of conquest, Indians had converted perhaps a quarter of the Amazon forest into farms and agricultural forests - an area the size of France and Spain combined.
Where Indians didn't farm, they burned - mainly clearing underbrush to retool local ecosystems to encourage elk, deer, and bear. They burned enough trees to let bison, creatures of the prairie, survive from New York to Georgia. Indigenous fire had its greatest impact in the middle of the continent, which Native Americans transformed into a prodigious game farm. They burned the Great Plains and Midwest prairies so much and so often that they increased their extent; in all probability, a substantial portion of the grassland celebrated by cowboys was established and maintained by those who arrived there first.
"When Lewis and Clark headed west from [St. Louis]," wrote ethologist Dale Lott, "they were exploring not a wilderness but a vast pasture managed by and for Native Americans."
In sum, most researchers believe that at the time of Columbus the Western Hemisphere had been thoroughly painted with the human brush.
For the most part, this new perspective hasn't made its way into textbooks - or the lesson plans of this nation's hardworking elementary school teachers. Instead, they purvey, with the best of intentions, what geographer William Denevan calls "the pristine myth."
Like most parents, I don't want to get in a fight with my daughter's school. But I'd also like her to be taught something close to what most scientists believe.
One reason that this version of history continues to be taught is that it provides a way for schools to give lessons about conservation. In my experience, this has been transformed into the notion that we should return the land, as much as possible, to the wilderness it was before Columbus. Don't litter, do recycle, don't cut down the forests - we should learn from the Indians, the story goes, and leave the land alone.
At first glance, recognizing that the American landscape was heavily managed seems to undermine this view. For this reason, some environmentalists have rejected the new scholarship. But understanding that we inhabit a landscape irrevocably shaped by human beings doesn't imply that we should endorse careless wastefulness - let the bulldozers rip! Although Indian engineering led to some disasters, for the most part its impact on the environment was, as Mr. Denevan notes, "subtle, transformative, and persistent." The forests were burned and the land was farmed, but the soil was left largely intact, or even improved; despite their large numbers, there is little evidence that native Americans often exhausted or polluted water supplies, or overran their resource base.
As William I. Woods, director of the environmental studies program at the University of Kansas, has put it, their efforts were directed at constructing today the kind of environment they wanted to inhabit tomorrow - and they were usually quite good at it.
This is a lesson I wouldn't mind my daughter learning in school.
• Charles C. Mann is a correspondent for Science magazine and The Atlantic Monthly. His new book '1491,' debunks much of the conventional wisdom about the new world European explorers found.