In just 40 years from now, global food demand could double with potentially devastating consequences for planet Earth, a top eco professor has warned.

“Agriculture’s greenhouse gas emissions could double by 2050 if current trends in global food production continue,” said David Tilman, who is Regents Professor of Ecology in the University of Minnesota's College of Biological Sciences.

“Global agriculture already accounts for a third of all greenhouse gas emissions,” he added.

According to the prof, food production on that scale could massively inflate levels of carbon dioxide and nitrogen in the environment.

The end result could lead to the extinction of numerous species because of the demand for more land for farmers to grow the food needed, Tilman cautioned.

However, he noted that such a catastrophe can be dodged if the high-yielding technologies of rich nations are adapted to work in poor nations. The professor also urged countries across the globe to use nitrogen fertilizers more productively.

Poor countries are currently on a dangerous trajectory based on their current "extensive" agricultural practices, the report said.

Those nations are expected – by 2050 – to clear a land area bigger than the US, which has nearly two and a half billion acres. If wealthier countries step in and improve yields to achievable levels, that number could be reduced to around half a billion acres.

Based on 2005 figures, crop yields for the the world's richest nations stood at more than 300 per cent higher than that of poorer countries.

The research paper claimed that adopting nitrogen-efficient "intensive" farming practices would not only meet the globe's growing demand for food but also help reduce damage to the environment.

“Strategically intensifying crop production in developing and least-developed nations would reduce the overall environmental harm caused by food production, as well as provide a more equitable food supply across the globe,” wrote Tilman's colleague, Jason Hill, who is assistant professor in the College of Food, Agricultural and Natural Resource Sciences at the university.

During the study, the scientists looked at different ways of meeting demand for food and considered each methods' environmental effects.

Farmers can either push up productivity on existing land, clear more land, or combine the two methods. Scenarios were mulled over to work out how the amount of nitrogen use, land cleared, and resulting greenhouse gas emissions differed.

“Our analyses show that we can save most of the Earth’s remaining ecosystems by helping the poorer nations of the world feed themselves,” Tilman concluded. ®