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With a population set to hit 9 billion human beings by 2050, the world needs to grow more food —without cutting down forests and jungles, which are the climate's huge lungs.
The solution, according to one soil management scientist, is Big Data.
Kenneth Cassman, an agronomist at the University of Nebraska, Lincoln, recently unveiled a new interactive mapping tool that shows in fine-grain detail where higher crop yields are possible on current arable land.
"By some estimates, 20 to 30 percent of greenhouse gas emissions are associated with agriculture and of that a large portion is due to conversion of natural systems like rainforests or grassland savannahs to crop production, agriculture," Cassman told NBC News at a conference in suburban Seattle.
The only practical way to stop the conversion of wild lands to farmland is grow more food on land already dedicated to agriculture, he said. Currently, the amount of farmland used to produce rice, wheat, maize and soybean, he noted, is expanding at a rate of about 20 million acres a year.
Cassman and colleagues unveiled the Global Yield Gap and Water Productivity Atlas in October at the Water for Food conference. The atlas was six years and $6 million in the making and contains site-specific data on soil, climate and cropping systems to determine potential yield versus actual yield farm by farm in nearly 20 countries around the world. Projects are ongoing to secure data for 30 more countries.
Mind the gap
Once farmers are aware of their gaps, they can prioritize investments to close them, such as spending on fertilizer, a new irrigation system or different crop varieties. When scaled up to a global view, a seed company can look at the map and see where drought routinely curbs yields, for example, and target research, development and marketing of drought-tolerant varieties on those regions.
The tool is likely to be especially helpful to major agribusiness companies such as Syngenta and Monsanto, which were major sponsors of the conference where the atlas was unveiled, said Danielle Nierenberg, president of Food Tank, a Washington-based advocacy for sustainable agriculture.
"That is not necessarily a bad thing, but if information isn't getting down to the 500 million family farmers around the world who are producing most of the world's food, more than 50 percent of the world's food, then I don't see the point. Those farmers have to make a profit too and feed their families," she said.
Atlas in action
A key initiative going forward is to teach smallholder farmers how to use the atlas, Cassman said. Until now, the tool has largely rested with agricultural researchers who have validated its promise of delivering information that can help grow more food on existing farmland.
At the Water for Food conference, for example, agricultural researcher Zvi Hochman with Australia's Commonwealth Scientific and Industrial Research Organization described how he used the atlas to compare his country's wheat yields with those in similar climate zones around the world. A colleague noted overlap with Argentina, where yields are higher.
To figure out the difference in yield, Hochman dug into the data and learned that Argentinean farmers grow wheat and corn on the same fields each year. He then explored scenarios for growing two crops a year in Australia. That's "a system," he said, "that is not currently practiced by most farmers." A winning strategy for Australia, he concluded, is to grow lentils after wheat in years with sufficient water.
Likewise, Kindie Tesfaye, a researcher with the International Maize and Wheat Improvement Center in Ethiopia, described how he used the atlas to determine that by closing the yield gap a feasible 50 percent in Ethiopia, the country could grow enough cereals to feed 205 million people by 2050, which is greater than the United Nation's projected growth in population to about 174 million.
To close the gap by that much, he added, more research is needed to understand "the biophysical and the socioeconomic constraints that are leading to these yield gaps." That is, the atlas is a first step, a road map to boosting yields.
"It allows us to be able to pinpoint where the big gaps are and to start to gather the pieces of the puzzle to say, well, why is it that we have the yield gaps in those particular points," Robert Lenton, the founding director of the Water for Food Institute at the University of Nebraska, said during a press briefing at the conference.
Closing the gaps
One key breakthrough is the global boom in natural gas, according to Cassman. Its abundance and thus lower cost, he said, makes natural-gas-derived fertilizers and energy for pumping water accessible and available in a way they were not just seven years ago. As a result, for the first time in at least 40 years, he said, the value of crops grown is rising faster due to insatiable demand than the cost of inputs.
"In closing yield gaps in many parts of the world, particularly sub-Saharan Africa, the biggest constraints are nutrients and water," he said. "And if the cost of accessing external resources to alleviate those constraints on your farm, if that's decreasing relative to the value of what you produce, then at least the economic incentive to use those inputs becomes greater. And it wasn't that way in the past."
Cheap natural gas, he said, increases the economic incentive to use those inputs and grow more food. And enough food to meet the demand for more meat and sugar in an increasingly wealthy world, he said, is necessary to alleviate poverty, stabilize population and curb climate change.
"Indirectly, if we don't have access to reasonable supplies of energy then you don't reduce poverty fast enough to stabilize human population at 9.6 (billion) and you zoom past it and then your challenge for climate change and land clearing become exorbitantly larger," Cassman said. "I think that is what people are missing in the connections."
The need to close yield gaps is reinforced by a study released Monday in Nature Climate Change on the challenge of implementing a forest conservation policy. If non-forested areas aren't protected as well, the study found, agriculture will expand into grasslands and other areas that also store carbon, leading to carbon emissions that essentially offset those gained by saving the forests.
A more robust policy is to globally protect native forests and non-forested areas such as grasslands, according to study lead author Alexander Popp at the Potsdam Institute for Climate Impact Research in Germany.
"That would mean this loss of potential land for agricultural expansion, which has to be compensated for by increasing yield," he told NBC News.