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Feeding 9 Billion People Sustainably

Jonathan Foley, Executive Director of the Cal Academy of Science, @GlobalEcoGuy
On May 13, I attended a talk given by Jonathan Foley at SPUR on the challenges of feeding 9 billion people on Earth sustainably. When I signed up for Twitter in 2012, @GlobalEcoGuy was one of the first accounts I followed that talked about climate change and environmental issues in a very accessible way. In particular, his essay Breaking the Cycle of Climate Inaction identified how we could succeed in tackling climate change when the political process was still gridlocked and each individual's lifestyle choices would amount to very little. I was very much looking forward to this talk, and what follows is my attempted summary of it. A lot of his talk was similar to the Ted Talk he gave in 2010.
For most of human history, we have not had to think about how to use the planet sustainably. There was always so much more planet available and so few people. As late as 1945, there were just 2.3 billion people on Earth.
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Figure 1: World Population Growth. By Tga.D based on Aetheling's work [CC BY-SA 3.0 ( or GFDL (], via Wikimedia Commons
However, we have now hit a major inflection point in human population growth and resource use. Dr. Foley went so far as to call ours "the most important point in history". Between 1960 and 2010:
  • population has doubled
  • the economy septupled, adjusted for inflation
  • food production tripled
  • water use tripled
  • fossil fuel use has quadrupled
We have been lucky enough to be bequeathed by our ancestors a planet rich in natural resources that can sustain our current population. Our challenge now is whether we are going to be good ancestors for future generations.
We are running out of planet. First, we are running out of land. 40% of the land on Earth is being used for agriculture. The remaining land available is the Arctic & Antarctica, desert, and rainforest. Of those three, rainforest land is the only candidate for agricultural expansion. So we are cutting down the rainforest, especially in Brazil and Indonesia.
Deforestation in Rondonia, Brazil
By Jesse Allen and Robert Simmon (NASA Earth Observatory) [Public domain], via Wikimedia Commons
Second, we are running out of water. We currently consume 50% of Earth's available freshwater. 70-90% of that used for agriculture. We can see the effects of that in photos of the Aral Sea. The rivers that feed the sea are being used to irrigate the Kazakh desert for cotton, and we can see that the Sea is almost gone now.
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Figure 3: Aral Sea in 1989 (left) and 2014 (right). By NASA. Collage by Producercunningham. [Public domain], via Wikimedia Commons
Third, we are running out of atmosphere. We have been using it as a dump for all of our air pollution. Of course, this is where carbon emissions and climate change come in:
  • 60% of greenhouse gases (GHG) come from the burning of fossil fuels for energy and transportation
  • 30% of GHG come from agriculture
As an industry, agriculture is actually the biggest source of GHG. The next biggest industry is transportation which only accounts for 15 percent of emissions. Four things contribute to it:
  1. Deforestation for new agricultural land
  2. Methane from cattle raising and rice farming
  3. Nitrous oxide which gets released when too much fertilizer is used
  4. Transportation of food and materials, a very distant fourth. So actually buying local food does not tackle agriculture's carbon impact
For Dr. Foley, in order to tackle climate change, making agriculture more sustainable is the number one priority.
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Figure 4. By US Environmental Protection Agency [Public domain], via Wikimedia Commons
Even without considering climate change, which will definitely exacerbate the problem, producing enough food in the future will be a huge challenge. There are three big challenges ahead:
  1. Meet current demand with the resources we have available. Even today, 1 billion people are food insecure. Dr. Foley this is primarily an economic, political, and institutional issue rather than a production issue though. At the other end, 1 billion people today eat too much food. So the current food system is failing 2 out of every 7 people on the planet.
  2. Meet future demand. By 2050, population will grow by 28%. A naive calculation would conclude that we need to grow food production by 28% too. However, by 2050, 4 billion people will be richer, creating a global middle class, and middle class buyers generally like meat. Some studies claim that we need to double food production by 2050.
  3. Become truly sustainable. Unfortunately, agriculture is an intrusive and extractive activity, so it cannot actually become completely sustainable, but we can make improvements.
How are we doing so far? Up until this point, we have depended in large part on our capacity to improve yields. A lot of this was thanks to Norman Borlaug and the Green Revolution. But has the Green Revolution reached its limit? There is evidence now that agricultural yields have stagnated or collapsed in 30-40% of cereal-growing areas since 2000. Companies pushing genetically modified crops like to claim that they are a way to continue increasing yield. However, European and U.S. agricultural yields are about the same even though Europe has a ban on genetically modified crops. Given the difficulties of yield, we cannot grow our way out of the problem.
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Figure 5: Crop Yields in Developing Countries. Notice the flattening of yield per hectare since the beginning of 2000. By Brian0918 at en.wikipedia [Public domain], via Wikimedia Commons
How can we increase food availability while cutting environmental damage? Dr. Foley offered five starting points:
  1. Stop deforestation. Cleared rainforest is not being used to feed more of the 1 billion without access to food. Instead, it is being used to feed the wealthy. Where rainforest has been cleared in Brazil, it has been used for pastures, so biologically rich areas are being decimated to support just a couple animals, or for soybeans, which gets exported to China to feed pigs. 50% of deforestation occurs in Brazil and India, and all of that land is being used to raise livestock, grow soy, harvest timber, or produce palm oil. Foley even declared the production of palm oil was the number 1 issue today in terms of maintaining biodiversity.
  2. Deliver more food on less land. Yields in Africa, Central America, E Africa and E Europe are quite low, relative to a region like the U.S. midwest, which is among the most productive areas in the world. The soil needs nutritional supplements like fertilizer and compost
  3. Deliver More Food with Less Water and Fewer Chemicals. Most irrigation machines in the U.S. spray water droplets into the air across wide swaths of area. Dr. Foley called them "evaporation machines". He cited Israel as an example of a country that is extremely efficient at water use. On chemicals, we often use too much fertilizer, or we use it at bad times. Midwest farmers fertilize their fields in the fall, even though winter will dump snow and probably run-off half of it.
  4. Rethink Diets and Biofuels. We are growing food that does not feed people directly. Only 10-20% of the crop production in the Midwest goes directly to food. 87% of Minnesota's agriculture feeds animals and cars. We can shift our diets away from inefficient crops and animals. Beef is among the worst in this regard. The kilocalorie efficiency of beef is just 3%!
  5. Stop food waste. Dr. Foley wants to see more innovation from Silicon Valley on this. How can we message to consumers when food has actually gone bad? Can we get better about tracking food packaging so that it does not get lost and wasted? 30-40% of food right now is lost
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Figure 6: An example of an "evaporation machine". Paulkondratuk3194 at en.wikipediaCC-BY-SA-3.0; Released under the GNU Free Documentation License.
Some other factoids from Dr Foley's talk that were interesting:
  • Israel is among the most efficient countries on earth when it comes to water use. The primary reason for that is that they use drip irrigation almost exclusively.
  • Drought in California is probably going to become a more common thing because warm years will become more frequent and higher temperatures means less snow in the mountains.
  • We now farm more fish than we catch in the ocean. While this sounds good, it turns out farming can actually be a food negative. This is because two of the most popular farmed sea animals, shrimp and salmon, are carnivorous, so to feed them we actually need to catch other fish from the ocean. He mentioned Tilapia as a fish that is an herbivore.
  • Most palm oil is manufactured and distributed by just a couple of companies, like Cargill, Bunge, and Wilmar. Wilmar alone accounts for almost half of palm oil trade globally. Environmental groups like Greenpeace and the Nature Conservancy have therefore been able to make some progress by targeting just a couple of companies to convince them to change how they source palm oil. The Rainforest Action Network currently tracks the progress of just 20 major snack food companies at Grist had a good story about how consistent pressure and negotiation with Wilmar led them to make a commitment to obtain palm oil only from 100% sustainable means. The rest of the industry soon followed.
  • There is some good news on the meat front. Apparently the U.S. hit peak meat consumption 15 years ago. Beef consumption peaked in the 1980s.
  • 79% of irrigation water is used for rice, wheat, and maize. Of the remaining, 93% is used for cotton, soy, and sugarcane.
Ray et al. 2012 Nature Communications
Cassidy et al 2013 Environ. Res. Lett.
Foley et al. 2005 Science
Foley et al. 2011 Nature
Tilman et al. 2011 PNAS