By 2050, the Earth’s population will likely have swelled from seven to nine billion people. To fill all those stomachs — while accounting for shifting consumption patterns, climate change, and a finite amount of arable land and potable water — some experts say food production will have to double. How can we make the numbers add up? Experts say higher yielding crop varieties and more efficient farming methods will be crucial. So will waste reduction. Experts urge cities to reclaim nutrients and water from the waste stream and preserve farmland. Poor countries, they say, can improve crop storage and packaging, and rich nations could cut back on resource-intensive foods like meat.