The expansion of farmland is the main cause of biodiversity loss on land. And climate climate could exacerbate those losses, according to a new study.

Over the next 40 years, under a high-emissions scenario, warming temperatures are expected to make more than 1 million square miles of wilderness — representing 7 percent of the world’s total remaining wilderness outside of Antarctica — newly suitable for growing crops. Most of this land is in northern areas, including Canada, Scandinavia, and Russia.

As cropland goes barren elsewhere, the study warns, northern wilderness could be turned over to farming. Without protection, the “vital integrity of these valuable areas could be irreversibly lost.”

The paper, published in the journal Current Biology, found that climate change will shrink the variety of crops that can be grown on 72 percent of land currently farmed worldwide. As the global population rises and large areas of farmland become unsuitable for growing, land must be used more efficiently, said lead author Alexandra Gardner, a postdoctoral researcher at the University of Exeter.

“We can feed a larger population on the farmland we already have,” Gardner said. To do so, she said, humans must curb meat consumption, cut food waste, and grow crops suited to their local climate.