Global food demand could double by 2050, according to a new projection reported this week in the journal Proceedings of the National Academy of Sciences (PNAS).

The analysis also shows that the world faces major environmental challenges unless agricultural practices change.

Scientists David Tilman and Jason Hill of the University of Minnesota (UMN) and colleagues found that producing the amount of food needed could significantly increase levels of carbon dioxide and nitrogen in the environment, and may cause the extinction of numerous species.

These problems can be avoided, the researchers say, if the high-yielding technologies of wealthier nations are adapted to work in poorer nations, and if all countries use nitrogen fertilizers more efficiently.