Policy brief: Climate trend and global crop production since 1980

Global warming is likely already taking a toll on world wheat and corn production, according to a new study led by Stanford University researchers. But the United States, Canada and northern Mexico have largely escaped the trend.

"It appears as if farmers in North America got a pass on the first round of global warming," said David Lobell, an assistant professor of environmental Earth system science and center fellow at the Program on Food Security and the Environment at Stanford University. "That was surprising, given how fast we see weather has been changing in agricultural areas around the world as a whole."

Lobell and his colleagues examined temperature and precipitation records since 1980 for major crop-growing countries in the places and times of year when crops are grown. They then used crop models to estimate what worldwide crop yields would have been had temperature and precipitation had typical fluctuations around 1980 levels.

The researchers found that global wheat production was 5.5 percent lower than it would have been had the climate remained stable, and global corn production was lower by almost 4 percent. Global rice and soybean production were not significantly affected.

The United States, which is the world's largest producer of soybeans and corn, accounting for roughly 40 percent of global production, experienced a very slight cooling trend and no significant production impacts.

Outside of North America, most major producing countries were found to have experienced some decline in wheat and corn (or maize) yields related to the rise in global temperature. "Yields in most countries are still going up, but not as fast as we estimate they would be without climate trends," Lobell said.

Lobell is the lead author of the paper, Climate Trends and Global Crop Production Since 1980, published May 5 online in Science Express.

Russia, India and France suffered the greatest drops in wheat production relative to what might have been with no global warming. The largest comparative losses in corn production were seen in China and Brazil.

Total worldwide relative losses of the two crops equal the annual production of corn in Mexico and wheat in France. Together, the four crops in the study constitute approximately 75 percent of the calories that humans worldwide consume, directly or indirectly through livestock, according to research cited in the study.

"Given the relatively small temperature trends in the U.S. Corn Belt, it shouldn't be surprising if complacency or even skepticism about global warming has set in, but this study suggests that would be misguided," Lobell said.

Since 1950, the average global temperature has increased at a rate of roughly 0.13 degrees Celsius per decade. But over the next two to three decades average global temperature is expected to rise approximately 50 percent faster than that, according to the report of the Intergovernmental Panel on Climate Change. With that rate of temperature change, it is unlikely that the crop-growing regions of the United States will continue to escape the rising temperatures, Lobell said.

"The climate science is still unclear about why summers in the Corn Belt haven't been warming. But most explanations suggest that warming in the future is just as likely there as elsewhere in the world," Lobell said.

"In other words, farmers in the Corn Belt seem to have been lucky so far."

This is the first study to come up with a global estimate for the past 30 years of what has been happening, Lobell said.

To develop their estimates, the researchers used publicly available global data sets from the United Nations Food and Agriculture Organization and from the University of Delaware, University of Wisconsin, and McGill University.

The researchers also estimated the economic effects of the changes in crop yield using models of commodity markets.

"We found that since 1980, the effects of climate change on crop yields have caused an increase of approximately 20 percent in global market prices," said Wolfram Schlenker, an economist at Columbia University and a coauthor of the paper in Science.

He said if the beneficial effects of higher carbon dioxide levels on crop growth are factored into the calculation, the increase drops down to 5 percent.

"Five percent sounds small until you realize that at current prices world production of these four crops are together worth nearly $1 trillion per year," Schlenker said. "So a price increase of 5 percent implies roughly $50 billion per year more spent on food."

Rising commodity prices have so far benefited American farmers, Lobell and Schlenker said, because they haven't suffered the relative declines in crop yield that the rest of the world has been experiencing.

"It will be interesting to see what happens over the next decade in North America," Lobell said. "But to me the key message is not necessarily the specifics of each country. I think the real take-home message is that climate change is not just about the future, but that it is affecting agriculture now. Accordingly, efforts to adapt agriculture such as by developing more heat- and drought-tolerant crops will have big payoffs, even today. "

Justin Costa-Roberts, an undergraduate student at Stanford, is also a coauthor of the Science paper. David Lobell is a researcher in Stanford's Program on Food Security and the Environment, a joint program of Stanford's Woods Institute for the Environment and Freeman Spogli Institute for International Studies. Schlenker is an assistant professor at the School of International and Public Affairs and at the Department of Economics at Columbia.

The work was supported by a grant from the Rockefeller Foundation.

Sugarcane - a principal crop for biofuel - reduces the local air temperature compared to pasturelands or fields growing soybeans or maize, according to a new study from researchers at Stanford University and the Carnegie Institution for Science. But sugarcane's effect on temperature is a "double-edged machete," as it increases ambient temperatures compared with natural vegetation.

These small local changes should be taken into consideration in studies of global climate change, the researchers said.

The researchers looked at changes in vegetation in the Brazilian Cerrado - a vast tropical savanna lying south of the Amazon basin - large areas of which have been converted from natural vegetation to agriculture in recent decades.

Increasingly, these existing agricultural areas are now being converted to sugarcane for use in biofuel production. Brazil is now second only to the United States in ethanol production, much of which is used domestically.

What the effect on global climate would be if sugarcane farming were to expand significantly is not yet clear, said David Lobell, an assistant professor in environmental Earth system science at Stanford and center fellow at the Program on Food Security and the Environment.

"The temperature changes are happening locally, where the land-use change is happening," Lobell said. "It does not seem to spill over into other countries, for example, at least as far as we can tell right now."

But Lobell said sugarcane growing in the Cerrado is definitely expanding and given that the region encompasses approximately 1.9 million square kilometers (733,000 square miles) - an area larger than Alaska - the potential exists for a globally significant effect.

Using maps and data from hundreds of satellite images, the researchers calculated the temperature, the amount of water given off and how much light was reflected rather than absorbed for each of the different types of vegetation. They found that compared to land cultivated with other annual crops, sugarcane reduced the local air temperature by an average of 0.93 degrees Celsius (1.67 F).

But compared to the natural vegetation of the Cerrado - mainly grass and shrubs - the sugarcane fields warmed the ambient air by 1.55 C (2.79 F).

Lobell said the bulk of the temperature difference is due to evapotranspiration - the moisture released to the air through the leaves of the plants and the soil. Most of the land put into sugarcane had previously been converted from natural vegetation to pastureland, said Scott Loarie, a postdoctoral researcher at Carnegie. "If someone has a farm that once was natural vegetation, that transition to pasture and annual crops caused local warming," he said. "So now as the farm is going to sugarcane, by comparison it is cooling temperatures locally."

Their research, Direct Impacts on Local Climate of Sugarcane Expansion in Brazil, is described in the current issue of Nature Climate Change.

This local cooling does not necessarily mean that the global climate is cooling as a result. It depends in part on what happens with the agriculture that was displaced by the sugarcane, Loarie said. For example, if cattle used to graze on a tract of land and some Amazon forest is cut down to provide new pasture for them, net carbon emissions will actually increase.

"You might not make any difference as far as cooling the world globally at all; in fact, you might make the world marginally warmer," he said.

"The global implications of these local effects were not a part of this study, and any discussion of mitigating global climate should consider the potential for these land use cascades."

One of the important aspects of the study, Lobell said, is that it demonstrates how satellite data can be used in real time to understand the effects of environmental changes. Most research studying the impact of biofuel use on climate has been done with computer modeling.

"I think the coolest thing about this study is you actually can see these temperature effects happening already," Lobell said. "In terms of the more general point about bio energy, I think it is another good example of why looking only at greenhouse gases is not the full picture."

Another takeaway from the study, Loarie said, is that the temperature findings support the existing rule of thumb that biofuel crops are best located on land that is already used for agriculture. That general guideline stems from the fact that there is less carbon released to the atmosphere by converting land where the existing vegetation contains low amounts of carbon, such as pasture or crops, than by cutting down the dense, carbon-rich forests in the Amazon.

Loarie said that while the study clearly showed that planting sugarcane moves the temperature closer to what it would have been if the natural vegetation had not been removed from the land, that doesn't mean the land is any closer to its natural state in other respects.

"Converting pasture to sugarcane is definitely not ecological restoration," said Chris Field, a professor of biology and of environmental Earth system science, who was involved in the research.

"Still, the direct effect on climate is potentially important enough to play a role in future decisions about land use and land management in large parts of the tropics," he said.

The study was funded by the Stanford University Global Climate and Energy Project.

Greg Asner, a professor, by courtesy, of environmental Earth system science, is a coauthor of the paper. Lobell is also a center fellow at both the Freeman Spogli Institute for International Studies and the Woods Institute for the Environment. Field is also a senior fellow at the Precourt Institute for Energy and at the Woods Institute, and director of the Department of Global Ecology at the Carnegie Institution.

February 10th marked the launch of the Program on Food Security and the Environment's Global Food Policy and Food Security Symposium Series. Setting the stage for the two-year series were Jeff Raikes, CEO of the Bill & Melinda Gates Foundation, and Greg Page, CEO and Chairman of Cargill Inc. As CEOs from the largest foundation and the largest agricultural firm in the world they provided important perspectives on global food security in these particularly volatile times. Full video and clips of the event are now available - Improving Food Security in the 21st Century: What are the Roles for Firms and Foundations.

Jeff Raikes: A Perspective from the Bill & Melinda Gates Foundation

Catalytic philanthropy

The Gates Foundation, through its Agricultural Development Initiative, has been a leader in addressing global food security issues. The Foundation allocates 25% of its resources to global development and to addressing the needs of the 1 billion people who live in extreme poverty ($1/day). 70-75% of those people live in rural areas and are dependent on subsistence agriculture for their livelihoods.

The Gates Foundation is driven by the principle: how can it invest its resources in ways that can leverage performance and address market failures? Its approach embodies a novel concept driven by both private sector motives and public responsibilities. Raikes describes this as catalytic philanthropy.

"The Foundation identifies where its investments can create an innovation, a new intervention that can really raise the quality of lives for people," said Raikes. "If successful, it can be scaled up and sustained by the private sector if we can show that there is a profit opportunity or the public sector if we can show that this is a better way to improve the overall quality of society through investment in public dollars."

Image Photo credit: Michael Prince

In the realm of agriculture, allocating resources across the agricultural value chain has proven to be the most effective approach. As an example of this strategy, Raikes talked about a farmer-owned, Gates-supported dairy chilling plant in Kenya. The cooling facility provided the storage necessary to provide a predictable price at which to sell farmers' milk. This price knowledge and market access gave farmers the confidence to invest in better technology and better dairy cattle. The plant also provided artificial insemination services and extension services to teach farmers how to get greater amounts of milk from the cattle.

"I love the concept. I also love the numbers," said Raikes. "In just two or three years there were now 3,000 farmers in a 25 kilometer radius that were able to access this dairy chilling plant and able to sell their milk."

In addition to improving incomes, Raikes remarked that very consistently what he hears is when farmers are able to improve their incomes the first thing they do with the money is invest in the education of their children.

Upcoming challenges to food security

During the next 40 years or so, global food production must double to accommodate a growing and richer population. Climate change and water scarcity contribute to this challenge. The places that will suffer the most severe weather are also the places where the poorest farmers live. 95% of sub-Saharan agriculture is rain fed with very little irrigation.

"If we are going to be able to feed the world we are going to have to figure out how to achieve more crop per drop," cautioned Raikes. "This includes trying to breed crop varieties that will better withstand water shortages. Early results show that you can get as much as a 20% increase in yield or more under stressed conditions when you have varieties that are bred for that need."

These challenges are compounded by the current economic crisis that is putting pressure on budgets in both donor and developing countries. In 2009, the G20 committed 22 billion dollars to agricultural development in recognition of the importance of agricultural development to food security. However, of the 22 billion promised, 224 million dollars went to five countries in the first round of grants in June. By November, when 21 additional countries submitted their proposals, just 97 million dollars were available to be dispersed and 17 countries were turned away empty handed.

High- and low-tech solutions

In an effort to alleviate some of this deficit, the Gates Foundation has committed 300 million dollars in six grants that span the value chain. These include investments in science and technology, farm management practices, farmer productivity, and market access as well as the data and policy environment to support the Foundation's work. The grants are intended to support about 5 ½ million farm families in sub-Saharan Africa and South Asia.

"We believe innovative solutions can come from both high-tech and low-tech," said Raikes. "On the high-tech end, submergent genes are allowing rice crops to survive periods of flooding up to 15 days. In areas of rice farming prone to flooding, this can save entire crops traditionally wiped out by such weather disasters."

Image Photo credit IRRI/Ariel Javellana

The sub1gene seeds are now being used by 400,000 farmers and are on track to be used by 20 million rice farmers by 2017. On the low-tech end, the Gates Foundation is providing $2 triple layer bags to farmers to reduce crop loss from pests; an affordable solution that has increased average income per farmer by $150/year.

"We primarily support conventional breeding, but we also support biotechnology breeding. In some cases we think that breeders in Africa and South Asia will want to take advantage of the modern tools we use here in our country to provide better choices for their farmers," explained Raikes.

Reasons for optimism

After years of diminished support, US Agricultural Development assistance to sub-Saharan Africa has gone from about 650 million in 2005 to about 1.5 billion in 2009. In developing countries, the Comprehensive Agricultural Development Program (CADP) in Africa has challenged countries to dedicate 10% of their national budgets to agriculture with the goal of improving annual agricultural growth by 6%. 20 countries have signed on to the CADP compacts, and 10 countries are exceeding the 6% growth target. Finally, since 1990, 1.3 billion people worldwide have lifted themselves out of poverty primarily through improvements in agricultural productivity.

Raikes pointed to Ghana as a success story. Since 1990, casaba production, an important staple food for poor smallholder farmers, has increased fivefold. Tomato production increased six fold. The cocoa sector has been revived and hunger has been cut by 75%.

"The key to success in Ghana was a combination of getting the right developing country policy with the right macroeconomic reform, the right institutional reform, smart public investment, and an overall good policy environment," said Raikes.

Supporting good policy is an important part of the Foundation's food security strategy, and was a strong motivation behind its funding of FSE's Global Food Policy and Food Security Symposium series.

"We see this symposium series as an opportunity to gather policy leaders who will bring new ideas of what will be effective policy approaches and effective economic environments in the countries we care a lot about, in particular sub-Saharan Africa and South Asia," said Raikes.

Raikes concluded his remarks by reminding everyone that the key to improving food security globally is making sure women, who make up at least 70% of the farm labor population, are included in the equation.

Greg Page: Balancing the race to caloric sufficiency with rural sociology

As the largest global agricultural firm, Cargill has an influential role to play in the world of food and agriculture. Cargill is a major supplier of food and crops and a provider of farmer services, inputs, and market access.

Image Photo credit: Olaf Hammelburg

Together with the Gates Foundation, Cargill has reached out and trained 200,000 cocoa farmers in the Ivory Coast, Ghana, and Cameroon. One tribe and one small village at a time the company has helped improve food safety, quality maintenance, and storage; benefiting the farmers, Cargill, and customers further down the supply chain. Cargill has also assisted, through financing and product purchasing, 265,000 farmers in Benin, Burkina Faso, the Ivory Coast, Malawi, Uganda, Zambia, and Zimbabwe.

Can the world feed itself?

A billion people lack sufficient caloric intake on a daily basis. In sub-Saharan Africa, 38% of all children are chronically malnourished, largely the result of inadequate agricultural productivity. While nine of the ten countries that have the highest prevalence of malnourishment are in sub-Saharan Africa, the two countries with the largest absolute number of malnourished people are India and China.

"This points to the difficulty of this problem," said Page. "India exports corn and soybean protein and China has 2.5 trillion dollars of hard currency reserves. These issues aren't necessarily of ability to feed people, but a willingness and commitment to do so."

Can the world feed itself? Yes, said Page.

When you break down the number of calories needed per malnourished person per day and convert that to tons of whole grains required to extinguish that hunger you get 30 million tons; 1/6 the amount of grain we converted to fuel globally last year. In the U.S. alone, 40% of our corn goes to ethanol.

"It isn't an issue of caloric famine-it is an issue of economic famine," stated Page. "In other words, this is not a food supply problem, but rather the lack of purchasing power to pay for a diet. An adequate price must be assured to reward the farmer for his efforts and to provide enough money that she can do it again the following year."

Rural sociology premium

What we face is the need to keep smallholders on the farm-despite the fact that they may not be the low-cost producer of foodstuffs-in order to avoid a rural population migration that would be unsustainable. As a result, the challenge the world faces is who is going to pay that rural sociology premium? If it costs more to raise crops on small farms is that burden going to be borne by the urban poor or is there going to be an alternative funding mechanism that allows smallholders to succeed?

Image Photo credit: Cargill

What is the survival price for a smallholder farmer? Page explained that if you wanted a family of four on a farm in sub-Saharan Africa to receive an income commensurate with the average per capita income of the urban population, you would come up with a price near $400 a ton.

"To put this in context, the highest price for maize that has ever been reached here in the United States is about $275 a ton," said Page. "This rural sociology premium to sustain smallholders is not an insignificant amount of money. How do we achieve fairness between the revenue received by the rural smallholder and the price borne by the urban consumer?"

State of disequilibrium - complacency to crisis

Today we are experiencing incredible price volatility where commodity prices are in a continuous state of disequilibrium. Very small changes in production have outsized impacts on price. This is in contrast to the last two and a half decades when the world operated with fairly robust stocks due to crop subsidies in the United States and Western Europe.

"This period of subsidization was when the western world probably did more harm to sub-Saharan Africa and South Asia than any other period in history," said Page. "We refused to allow price to signal to western farmers to produce less. As a result, the world price of grains fell far below the ability of any smallholder to compete. We then shipped those surpluses to developing countries, which then failed to invest in their agriculture for decades."

Today we are lurching from complacency to crisis. The ability of information and market speculation to be transmitted rapidly is affecting purchasing decisions of thousands to millions of consumers. Rising fuel prices, export restrictions, increasing demand for crops for biofuels, and unpredictable weather have all contributed to higher prices. Some of the drivers of price, however, are good things, such as the increase in per capita income and the capacity of more people to have a more dense and nutritious diet.

"Interestingly, the upside of the ethanol and biofuels program is that it brought prices back to a sufficiency that reinvigorated investment in agriculture," noted Page. "On one level I think a very good argument could be made that the biofuels program brought the world further from famine than it ever had been because of the price."

Critical food security factors

Page concluded by summarizing the elements that Cargill believes are critically important to increase food security. The first is the ability to understand the tradeoffs between a fast path to caloric sufficiency and the needs of rural sociology. Second, that crops be grown in the right soil, with the right technology, and relying on free trade so we can harvest competitive advantage to its fullest.

Another critical factor is rural property rights. Smallholders must have the ability to own the land, have access to it, and transfer it to future generations if you want a farmer to reinvest in his farm, said Page.

"Smallholders in developing countries need some degree of revenue certainty and access to a reliable market if we expect them to do what their countries really need them to do, which is raise productivity," explained Page. "Today they are often forced to sell at harvest, often below the cost of production, and lack the storage capabilities and capital to provide crops sufficiently and continuously."

Open, trust-based markets also play a key role in ensuring food security. Governments need to support trade. When Russia, Ukraine, and Argentina turned to embargos as a way to protect domestic food prices open markets were jeopardized and price volatility increased. Finally, there are very important roles for the world's governments in the creation of infrastructure that is vital to provide access to markets.

"I believe fully and completely in the world's capacity to harvest photosynthesis to feed every single person and to do it at prices that can be borne by all," concluded Page.