Managing grazing on grasslands in a more efficient way could significantly increase global milk and meat production or free up land for other uses.

About 40% of natural grasslands worldwide have the potential to support increased livestock grazing, according to a new study published in the journal Global Change Biology. This translates into a potential increase of 5% in milk production and 4% in meat production compared to the year 2000, or it allows for 2.8 million sq. km of grassland area to be released from production.

In order to feed the world’s growing population, global food production will need to increase, but at the same time, food production systems can affect the environment and climate.

“Grasslands are generally regarded to play an important role in increasing food production to meet future food demand,” said Tamara Fetzel, a researcher at the Institute of Social Ecology at Alpen Adria University in Vienna, Austria. “To achieve this target in a sustainable manner, our study suggests that we should focus on making more efficient use of currently available land resources instead of converting land from other uses.”

How much livestock grasslands can support depends on a number of variables, including climatic, biological and socioeconomic factors such as management, storage systems and biomass conservation. In the new study, the researchers explored the global-scale effects of seasonal patterns of biomass supply on the potential dynamics of grass-based livestock systems.

Fetzel and her colleagues identified areas where additional biomass could potentially be extracted from the landscape by comparing the current level of grazing intensity to the maximum levels supported in periods of minimum biomass supply, such as winter or dry periods. The researchers also discussed numerous socioeconomic and ecological constraints related to unlocking this potential, such as a lack of infrastructure, market access or knowledge, finance and labor constraints or the impacts of drought, and potential negative trade-offs such as loss of biodiversity or soil degradation.

“Grassland productivity and intensification potential are some of the most uncertain parameters in global land use assessments and are often used to estimate ambitious (greenhouse gas) mitigation targets. Making estimates of potential maximum grazing intensity more realistic by considering seasonal constraints reveals a certain potential to increase grazing intensity in some places yet shows that the actual grassland area available for other purposes remains limited,” said International Institute for Applied Systems Analysis researcher Petr Havlík, a study co-author who advised Fetzel with Karl-Heinz Erb from the Institute of Social Ecology Vienna.

The abstract in Global Change Biology can be found at http://onlinelibrary.wiley.com/doi/10.1111/gcb.13591/abstract.