Study pinpoints key 'leverage points' to feed more people with existing land

A new report from US scientists suggests that it may be possible to feed billions more people using only existing croplands. Published in Science, the report pinpoints key food systems 'leverage points' that hold the greatest the potential to boost global food security and protect the environment - focusing on 17 key crops that produce 86% of the world's crop calories and account for most irrigation and fertilizer consumption on a global scale.

Led by Paul West from the University of Minnesota's Institute on the Environment, the research report proposes a set of key actions in three broad areas that that have the greatest potential for reducing the adverse environmental impacts of agriculture and boosting our ability meet global food needs.

"This paper represents an important next step beyond previous studies that have broadly outlined strategies for sustainably feeding people,"​ said West. "By pointing out specifically what we can do and where, it gives funders and policy makers the information they need to target their activities for the greatest good."​

"By focusing on areas, crops and practices with the most to be gained, companies, governments, NGOs and others can ensure that their efforts are being targeted in a way that best accomplishes the common and critically important goal of feeding the world while protecting the environment." ​

Report details​

For each of the three key areas, West and his team identified specific 'leverage points', where nongovernmental organizations (NGOs), foundations, governments, businesses and citizens can target food-security efforts for the greatest impact.

They reported that the biggest opportunities cluster in six countries — China, India, U.S., Brazil, Indonesia and Pakistan — along with Europe.

"Sustainably feeding people today and in the future is one of humanity's grand challenges,"​ said West. "Agriculture is the main source of water use, greenhouse gas emissions, and habitat loss, yet we need to grow more food."​

According to West and his colleagues, the major areas of opportunity and key leverage points for improving the efficiency and sustainability of global food production are:

Previous research has detected the presence of a dramatic agricultural "yield gap" — difference between potential and actual crop yield — in many parts of the world.

The new study found that closing even 50% of the gap in regions with the widest gaps could provide enough calories to feed 850 million people.

Nearly half of the potential gains are in Africa, with most of the rest represented by Asia and Eastern Europe.

Agriculture is responsible for 20 to 35% of global greenhouse gas emissions, largely in the form of carbon dioxide from tropical deforestation, methane from livestock and rice growing, and nitrous oxide from crop fertilization.

The study found that the biggest opportunities for reducing greenhouse gas production are in Brazil and Indonesia for deforestation; China and India for rice production; and China, India and the United States for crop fertilization.

With respect to nutrient use, the study found that worldwide, 60% of nitrogen and nearly 50% of phosphorus applications exceed what crops need to grow. China, India and the U.S. — and three crops, rice, wheat and corn — are the biggest sources of excess nutrient use worldwide, so offer the greatest opportunity for improvement, said West and his team.

When it comes to water, rice and wheat are the crops that create the most demand for irrigation worldwide, they noted - with India, Pakistan, China and the US accounting for the bulk of irrigation water use in water-limited areas. Boosting crop water use efficiency could reduce water demand 8 to 15% without compromising food production, the authors suggested.

The third major category of opportunities characterised for boosting food production and environmental protection relate to making more crop calories available for human consumption by shifting crops from livestock to humans and reducing food waste, said West.

The crop calories we currently feed to animals are sufficient to meet the calorie needs of 4 billion people. The study noted that the US, China and Western Europe account for the bulk of this 'diet gap,' with corn the main crop being diverted to animal feed.

Although cultural preferences and politics limit the ability to change this picture, the authors noted that shifting crops from animal feed to human food could serve as a 'safety net' when weather or pests create shortages.

In addition, between 30% to 50% of food is wasted worldwide. Particularly significant is the impact of animal products: The loss of 1 kilogram of boneless beef has the same effect as wasting 24 kilograms of wheat due to inefficiencies in converting grain to meat, the team noted.

They suggested that food waste in the US, China and India have the biggest effect on available calories, noting that reducing waste in these three countries alone could yield food for more than 400 million people.

Source: Science​
Volume 345, Number 6194, Pages 325-328, doi: 10.1126/science.1246067​
"Leverage points for improving global food security and the environment"​
Authors: Paul C. West, James S. Gerber, et al​