Berkeley and Stanford - Climate change could increase the likelihood of civil war in sub-Saharan Africa by over 50 percent within the next two decades, according to a new study led by a team of researchers at University of California, Berkeley, Stanford University, New York University and Harvard University, and published in today's (Monday, Nov. 23) online issue of the journal Proceedings of the National Academy of Sciences (PNAS).

The study provides the first quantitative evidence linking climate change and the risk of civil conflict. It concludes by urging accelerated support by African governments and foreign aid donors for new and/or expanded policies to assist with African adaptation to climate change.

"Despite recent high-level statements suggesting that climate change could worsen the risk of civil conflict, until now we had little quantitative evidence linking the two," said Marshall Burke, the study's lead author,  a graduate student at UC Berkeley's Department of Agricultural and Resource Economics, and research associate at the Program on Food Security and the Environment. "Unfortunately, our study finds that climate change could increase the risk of African civil war by over 50 percent in 2030 relative to 1990, with huge potential costs to human livelihoods."

"We were definitely surprised that the linkages between temperature and recent conflict were so strong," said Edward Miguel, professor of economics at UC Berkeley and faculty director of UC Berkeley's Center for Evaluation for Global Action. "But the result makes sense. The large majority of the poor in most African countries depend on agriculture for their livelihoods, and their crops are quite sensitive to small changes in temperature.  So when temperatures rise, the livelihoods of many in Africa suffer greatly, and the disadvantaged become more likely to take up arms."

Understanding the causes and consequences of civil strife in much of the African continent has been a major focus of the social sciences for decades, said Miguel, given the monumental suffering has resulted from it.

In the study, the researchers first combined historical data on civil wars in sub-Saharan Africa with rainfall and temperature records across the continent. They found that between 1980 and 2002, civil wars were significantly more likely in warmer-than-average years, with a 1 degree Celsius increase in temperature in a given year raising the incidence of conflict across the continent by nearly 50 percent.

Building on this historical relationship between temperature and conflict, the researchers then used projections of future temperature and precipitation change to quantify future changes in the likelihood of African civil war. Based on climate projections from 20 global climate models, the researchers found that the incidence of African civil war could increase 55 percent by 2030, resulting in an additional 390,000 battle deaths if future wars are as deadly as recent wars.

All climate models project rising temperatures in coming decades, said David Lobell, study co-author and an assistant professor of environmental earth system science at Stanford and center fellow at Stanford's Program on Food Security and the Environment, a joint program of the Freeman Spogli Institute for International Studies and the Woods Institute for the Environment.

"On average, the models suggest that temperatures over the African continent will increase by a little over 1 degree Celsius by 2030," he added. "Given the strong historical relationship between temperature rise and conflict, this expected future rise in temperature is enough to cause big increases in the likelihood of conflict."

To confirm that this projection was not the result of large effects in just a few countries or due to overreliance on a particular climate model, the researchers recalculated future conflict projections using alternate data.  "No matter what we tried - different historical climate data, different climate model projections, different subsets of the conflict data - we still found the same basic result," said Lobell.

It's easy to think of climate change as a long way off, said the researchers, but their study shows how sensitive many human systems are to small increases in temperature, and how fast the negative impacts of climate change could be felt.

"Our findings provide strong impetus to ramp up investments in African adaptation to climate change, for instance by developing crop varieties less sensitive to extreme heat and promoting insurance plans to help protect farmers from adverse effects of the hotter climate," said Burke.

Applying findings from this study could prove useful to policy makers at the upcoming Copenhagen negotiations in December in determining both the speed and magnitude of response to climate change, the authors said.

"If the sub-Saharan climate continues to warm and little is done to help its countries better adapt to high temperatures, the human costs are likely to be staggering," said Burke.

Growing up I always wanted one thing around this time of year: a ride with Santa. Yes, a sky-high journey with that burly, bearded Claus who reportedly could offer children a chance to see the world differently. It seemed like an adventure to me, one that would surely offer a more thorough understanding of Christmas.

As summer recedes and December approaches it appears that my wish was granted this past summer while riding shotgun to and from a farm near the small town of Ashland, Nebraska alongside a man who seemed to a twenty-year-old everything I imagined Santa Claus to be at age seven. For five weeks in the company of a farm operator I had the opportunity to broaden my understanding of commercial food production and the managerial complexity, associated risk, and arrant talent involved in much of agriculture today.

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Our driving conversations soon carried over into late mornings and afternoons—anytime when the space for conversation transpired. “The marketplace is fiercely competitive,” he would say to explain the indistinct security governmental support for crop production provides. Daily, his business was subject to environmental and market persuasions. Although federal insurance policies and subsidies were valuable for his business, he was still one of many farmers who jockeyed within a bullish and bearish economy. Prior to hedging his crops, for example, he had to contemplate the eminent yield successes on farms in Iowa in addition to this summer’s drought-induced crop loss in Argentina. But he also could not forget about policy makers in China and Europe who through their governmental measures influence world demand and supply of staple grains. These conversations depicted the realities of an interdependent food market around the globe and helped me distinguish applications of macro-agricultural studies.

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Familiarizing myself with the farm’s operations did not come without mistakes, however. I will never forget the dexterous and visionary employees who taught me not just that wearing shorts while working on a farm is equivalent to modeling a Speedo at a consulting interview, but more importantly how complicated producing food is with advanced mechanized systems. Whether it be welding an auger for grain transfer, converting a piece of scrap metal into a rotating laptop computer harness for the cattle chute, or actually building a propane-powered irrigation pump, the competency of those with whom I worked was remarkable. I learned untold lessons and skills from colleagues, reminding me that a cattle pen could also be an educational setting. 

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I could spend many more months in Ashland refining my tractor driving capabilities and acquiring more knowledge of agricultural management and economics. I wish I could witness the crops reach adulthood and the combines combing those matured fields during the autumn months. Yet, I am grateful for the time I had there, and what I learned will help guide me as I continue to navigate through complex issues facing U.S. agriculture and international food security.

This year I will still anticipate Christmas and its enduring celebrity, but I will rest in bed just a bit more calmly on Santa’s night. My conversations in a Toyota truck this summer and the knowledge gained from the entire experience in Nebraska have sated my sleigh-riding hunger and enhanced my studies of food’s complexities. This farm experience was that kind of ride for me, allowing me to evaluate the impact of U.S. commercial farmers within a global agricultural network, admire those who cultivate what we eat, and seek a deeper understanding of food as a livelihood and resource.

Ever wanted to see the North Pole? Try Nebraska.

Development of new crop varieties that are more heat and drought tolerant will be critical for successful adaptation to a warmer world. A recent 3 day meeting of international climate and crop experts at Stanford University focused on specific needs and promising approaches for improving crops. A meeting synopsis and recommended priorities can be found in a summary report, Climate Extremes and Crop Adaptation.