Michelle Tigchelaar
Research Associate, University of Washington
Washington, USA


Note from BHP Team: Food first takes center stage in the Big History Project course in Units 6 and 7, when we look at the transition from foraging to farming. Questions abound: What conditions enabled the development of agriculture? What were the effects on human society? Was it actually an improvement over foraging?

It’s only natural that we’d also wonder about the future of food, and feeding the inhabitants of a planet that’s increasingly affected by our human activity. As the population grows, will there be enough food for everyone? Will rising temperatures and water levels affect what crops we grow, and where? Should crops be genetically engineered to address human illnesses? What opportunities and controversies come into question as technological “solutions” are considered?

At Big History, we love reaching out to experts and researchers at the forefront of the very topics BHP classrooms are curious about. Our friend Michelle Tigchelaar is one who’s always eager to share with BHP teachers and classrooms. What follows is her take on the question: How will we feed the world, when the world is changing? Give it a read with students, and then join us for an Exchange with Michelle in the BHP Online Teacher Community from July 10-12!


When you stop to think about it, would you guess we currently grow too much or not enough food for every person on Earth to eat? If you’ve ever seen images of large food riots or hungry children in Africa, you might be inclined to think we don’t grow nearly enough food; but you’d be wrong. While between 1960 and 2000 the number of people on Earth doubled, the amount of food we grow nearly tripled. This happened because of the Green Revolution, which spread the use of high-yield crops, fertilizers, pesticides, and irrigation around the globe.

Remember the fact from the food label on your cereal box that you need about 2,000-2,500 calories per day? We now produce enough food to provide every person on Earth with 2,700 calories! Unfortunately, this food is not distributed evenly: A third of the world population is currently overweight or obese, while nearly 1 billion people are chronically undernourished. This problem of food distribution is not the only challenge we face: more and more people are eating Western diets; in many places, the Green Revolution is causing soil erosion and pollution; global population is continuing to rise; and climate change is making it more difficult to grow food.

How much food will we need in the future?
Demographers–people who study populations and how they’re changing–predict that by 2050, there will be 9 billion people on Earth, up from 7.6 billion today. (Interestingly, one of the main factors determining whether population will actually grow this fast is girls’ education!) But how much food we need to grow is not only set by how many people there are to feed. What we eat is really important too. In the United States and other Western countries, people generally eat more food, and more of it comes from animal products. In rapidly developing countries such as China and Brazil, eating habits are now shifting in the same direction. This Western diet costs a lot more energy, land, and other resources to produce. Beef is an especially costly food: it takes more than 20 pounds of feed to raise 1 pound of beef protein! If these trends in population growth and changing diets continue, the world will need to grow 70 percent more food by 2050.

How will a changing climate affect our ability to grow food?
Human civilization developed in a very stable part of Earth’s climate history: the Holocene. The stability of the Holocene allowed people to settle and thrive, developing agricultural practices well-adapted to the known climate. At the moment, however, we are rapidly exiting this stable climate period: Human activities such as energy production, transportation, construction, and even agriculture are increasing the amount of heat-trapping gases in our atmosphere, causing our planet to warm up. This warming leads to more heat waves, melting of glaciers and rising of sea levels, more heavy rainfall, and more drought.

This global warming is bad news for our crops. Crops only thrive in a narrow range of temperatures, beyond which their yields decrease rapidly. Scientists estimate that for every degree Celsius increase in global mean temperature, yields will decrease by 7.4 percent for corn, 6.0 percent for wheat, and 3.2 percent for rice – the three most-grown crops in the world. If we keep putting heat-trapping gases in the atmosphere at the same rate as today, global temperature will increase by 4 degrees Celsius by the end of the century. There are many compounding challenges, such as the fact that insect pests and bacterial disease do like warmer temperatures, and that in places where glaciers and snowpack are melting, less water will be available for irrigation.

Are the effects of climate change on food production all negative? As you may recall from biology class, plants need sunshine, water, nutrients, and carbon dioxide to grow. Carbon dioxide is one of the heat-trapping gases we are adding to our atmosphere, so plants may get a little boost out of this. Crops are also shifting into areas where they currently don’t grow. We may soon be able to grow wheat in northern Canada and Russia, as the growing season there becomes longer. And in Florida, people are looking to start growing Mediterranean olives instead of the typical oranges. Still, in the warm places on our planet – the tropics, where access to food is already the lowest – impacts on agriculture will be mostly negative. This means the people who contributed least to climate change will be impacted the most.

What can we do about it?
How can we prevent the world from growing hungry (or hungrier) in the future? For the last few decades, plant breeders have been working on developing crops that are resilient in heat and drought; so far, they have not succeeded. In the meantime, when dealing with small changes, farmers might be able to adapt their current practices to a new environment. But the main things we can do to improve food security in the future are: waste less food (about a third of all food is currently wasted!); eat less, in general, and eat less meat, specifically; and combat climate change. Cities and nations around the world are already investing in renewable energy and sustainable farming. Let’s continue the trend.

About the author: Dr. Michelle Tigchelaar is a research associate at the University of Washington, where she studies the impacts of a changing climate on food and society. She loves sharing ideas about climate science with others – whether they’re visitors of the Pacific Science Center in Seattle, union members in Washington State, or Big History Project teachers around the world.

Photo credit: Ubud, Bali Traditional Public Market, ©Edmund Lowe Photography/Getty

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