If climate change continues unabated, nearly every ecosystem on the planet would alter dramatically, to the point of becoming an entirely new biome, according to a new paper written by 42 scientists from around the world.

They warn that the changes of the next 200 years could equal—and may likely exceed—those seen over the 10,000 years that ended the last Ice Age. If humanity does not stop emitting greenhouse-gas emissions, the character of the land could metamorphose: Oak forest could become grassland. Evergreen woods could turn deciduous. And, of course, beaches would sink into the sea.

“Anywhere on the globe, the more you change climate, the more likely you are to see major ecological change,” says Stephen Jackson, an author of the report and the director of a climate-adaptation center at the U.S. Geological Survey.

“Having this kind of change occur at such a massive scale in such a short period of time is going to create unprecedented challenges for natural-resource management,” he told me.

The paper, published Thursday in Science, tries to find clues about the world of the future by examining the ecology of the past. Between the peak of the last Ice Age, about 20,000 years ago, and 1800 A.D., the world warmed by between 4 and 7 degrees Celsius. This warming transfigured the landscape: It erased the mile-high plateau of ice that sat on Manhattan Island, for instance. By melting this and other continent-sized ice sheets, that ancient warming—which was caused by minute shifts in the Earth’s orbital path—raised global sea levels by almost 400 feet. If that sounds fun, it could happen again, within the lifetime of babies born today: Earth could experience 4 to 5 degrees Celsius of warming by 2100 if humanity does not slow the emission of heat-trapping gases.