“We’re living in a time of unprecedented change,” says Jon Foley, executive director of the California Academy of Sciences.

“Just in the last 50 years, our population itself has more than doubled in size, the economy grew about seven-fold during the same time, and the combination of those two…has led to about a tripling of global food consumption and water consumption and a quadrupling of fossil fuel combustion.”

Such rapid growth poses major challenges for meeting food demands in a way that sustains natural resources for future generations, says Foley in this week’s podcast.

Running Out of Land

“Agriculture is by far the biggest thing we do in the world, in terms of land area,” Foley says. Farmland takes up between 30 and 40 percent of all land on Earth. “By comparison, about one percent of the Earth’s land surface is in cities and suburbs today, yet half of us live there.”

Land isn’t the only natural resource being consumed in massive quantities for agriculture. Foley says about 70 percent of water withdrawals are used to irrigate crops and 90 percent of that is not returned to its original source. In the United States alone, the U.S. Geological Survey estimates 39 percent of all freshwater is used for crop irrigation, the majority of which evaporates or transpires in the fields.

Many crop irrigation systems, particularly spray irrigation, are inefficient, says Foley. “This is an evaporation machine, not an irrigation machine…it’s only by accident that some of that water enters the soil.”

Agriculture is also one of the largest human contributors to climate change, responsible for approximately 30 percent of greenhouse gas emissions, he says. “If you want to tackle economic sectors that contribute to climate change, you would have to start, every single time, with agriculture first.”

Not Only a Supply Problem

The environmental footprint of agriculture makes achieving food security a daunting challenge, but equally important are politics and poverty.

Foley says that the estimated 850 million to 1 billion people who face food insecurity today do so not because there isn’t enough food, but because of social and political barriers to accessing or affording food, such as disenfranchisement or disempowerment. “Essentially, it’s a problem of poverty and institutions, not one of agronomy.”

Institutional poverty, conflict, and even gender inequities are all social contributors to food insecurity.

Changing Consumption Patterns

“We’re certainly bumping into the limits of what our planet can comfortably do to sustain the human enterprise,” Foley says, and we have to find innovative ways to feed a growing population in a sustainable way. “Feeding the world is not optional, but neither is sustaining our planet.”

One technique Foley suggests is to increase the efficiency of agriculture. He says that even in the United States, converting plant material into animal material (e.g., feeding cows corn) yields very low returns. The conversion from grains to milk is about 40 percent, he says, which is “remarkably good.” Eggs yield about 22 percent, pork and chicken about 10, and “for every 100 calories of corn that we could eat, you’ll get about 3 on a plate of boneless beef.”

“Eighty-seven percent of the farmland in Minnesota is growing something for non-human consumption, mainly animal feed,” Foley says. Using some of that land for direct human consumption is one way to get more for less.

Changes in consumption patterns may necessarily have to follow. Greater demand for meat products means less plant-based foods will be available for human consumption. This is already a challenge and it’s getting even bigger as a global middle class emerges for this first time – driven by higher incomes  in Chi(continued)