We find ourselves in the Anthropocene, a new geological age where humans are the dominant driving force in the Biosphere. A reason for this is that live on a cultivated planet. Humans are farming more of Earth than ever before; 38% of the ice-free surface of the planet is today dedicated to agriculture (croplands cover 12%, pastures 26%).

Agriculture is becoming more and more intensive and having staggering environmental impacts. Expansion of farm-land is causing deforestation, mainly in the tropics, and leading to high emissions of greenhouse gases. Intensification of existing farm-land requires huge inputs in the form of water (70% of global freshwater withdrawals go to irrigation) and fertilizer that are disrupting global water, nitrogen and phosphorous cycles. There are also impacts on associated aquatic and marine ecosystems through the runoff of fertilizers and other toxic materials.

And while 1 in 7 people still lack access to food or are chronically malnourished, an increasing fraction of crops are being diverted to feed animals and generate biofuels. There are good estimates point that food production needs to be doubled to meet growing populations, projected dietary changes and bioenergy use increase.

This must not continue. But how do we transform agriculture to meet the twin challenges of food security and environmental sustainability. In a paper published recently in Nature, Jonathan Foley and colleagues from the US, Canada, Germany and Sweden map out the ways by which we can confront these challenges.

They outline four strategies that can together increase global food availability by 100–180%, meeting projected demands while lowering greenhouse gas emissions, biodiversity losses, water use and water pollution. Foley et al point out that all four strategies are required and that no single strategy is sufficient.

1. Stop the expansion of agriculture, especially in tropical regions where this occurs the most. The benefits of agricultural expansion, that drives tropical deforestation, to food gains are often very limited. The authors analysis shows that most gains in crop production of the past decades has been driven by intensification of agriculture.

2. Close the yield gaps in many parts of Africa, Latin America and Eastern Europe. Yield gaps refer to the difference between the amount of crops that could be grown potential in a given area compared to what is grown today. Better use of existing crop varieties with improved management should be able to close many yield gaps, while continued improvements in crop genetics could also help. Closing yield gaps without environmental degradation will require new approaches, including reforming conventional agriculture and adopting lessons from organic systems and precision agriculture.

3. Target particular ‘hotspots’ of low efficiency. Many farmed regions of the world use a disproportionate high amount of water and nutrient inputs relative to production. Such regions could be targeted by actions such as reducing excessive fertilizer use, improving manure management, and capturing excess nutrients through recycling, wetland restoration and other practices. Furthermore, agroecological innovations in crop and soil management show great promise for improving agriculture efficiency while greatly reducing harm to the environment.

4. Change market structures, alter dietary preferences and cut waste. A large chunk of food is never consumed but is instead thrown away, allowed to go bad or consumed by pests - approximately 30%-40% of food is lost this way. We can also increase food availability (in terms of calories, protein and critical nutrients) by shifting crop production away from livestock feed, bioenergy crops and other non-food applications. Even small changes in diet (for example, shifting grain-fed beef consumption to poultry, pork or pasture-fed beef) and bioenergy policy (for example, not using food crops as biofuel feedstocks) could enhance food availability and reduce the environmental impacts of agriculture.