The impact of global warming on food prices and hunger could be large over the next 20 years, according to a new Stanford University study. Researchers say that higher temperatures could significantly reduce yields of wheat, rice and maize - dietary staples for tens of millions of poor people who subsist on less than $1 a day. The resulting crop shortages would likely cause food prices to rise and drive many into poverty.  

But even as some people are hurt, others would be helped out of poverty, says Stanford agricultural scientist David Lobell.

Lobell discussed the results of his research on Feb 19 at the annual meeting of the American Association for the Advancement of Science in San Diego.

"Poverty impacts depend not only on food prices but also on the earnings of the poor," said Lobell, a center fellow at Stanford's Program on Food Security and the Environment (FSE). "Most projections assume that if prices go up, the amount of poverty in the world also will go up, because poor people spend a lot of their money on food. But poor people are pretty diverse. There are those who farm their own land and would actually benefit from higher crop prices, and there are rural wage laborers and people that live in cities who definiztely will be hurt."

Lobell and his colleagues recently conducted the first in-depth study showing how different climate scenarios could affect incomes of farmers and laborers in developing countries.

Household incomes

In the study, Lobell, former FSE researcher Marshall Burke and Purdue University agricultural economist Thomas Hertel focused on 15 developing countries in Asia, Africa and Latin America. Hertel has developed a global trade model that closely tracks the consumption and production of rice, wheat and maize on a country-by-country basis. The model was used to project the effects of climate change on agriculture within 20 years and the resulting impact on prices and poverty.

Using a range of global warming forecasts, the researchers were able to project three different crop-yield scenarios by 2030:

• "Low-yield" - crop production is toward the low end of expectations.
• "Most likely" - projected yields are consistent with expectations.
• "High-yield" - production is higher than expected.

"One of the limitations of previous forecasts is that they don't consider the full range of uncertainties - that is, the chance that things could be better or worse than we expect," Lobell said. "We provided Tom those three scenarios of what climate change could mean for agricultural productivity. Then he used the trade model to project how each scenario would affect prices and poverty over the next 20 years.

"The impacts we're talking about are mainly driven by warmer temperatures, which dry up the soil, speed up crop development and shut down biological processes, like photosynthesis, that plants rely on," he added. "Plants in general don't like it hotter, and in many climate forecasts, the temperatures projected for 2030 would be outside the range that crops prefer."

Results

The study revealed a surprising mix of winners and losers depending on the projected global temperature. The "most likely" scenario projected by the International Panel on Climate Change is that global temperatures will rise 1.8 degrees Fahrenheit (1 degree Celsius) by 2030. In that scenario, the trade model projected relatively little change in crop yields, food prices and poverty rates

But under the "low-yield" scenario, in which temperatures increase by 2.7 F (1.5 C), the model projects a 10 to 20 percent drop in agricultural productivity, which results in a 10 to 60 percent rise in the price of rice, wheat and maize. Because of these higher prices, the overall poverty rate in the 15 countries surveyed was expected to rise by 3 percent.

However, an analysis of individual countries revealed a far more complicated picture. In 11 of the 15 countries, poor people who owned their own land and raised their own crops actually benefited from higher food prices, according to the model. In Thailand, for example, the poverty rate for people in the non-agricultural sector was projected to rise 5 percent, while the rate for self-employed farmers dropped more than 30 percent - in part because, as food supplies dwindled, the global demand for higher-priced crops increased.

"If prices go up and you're tied to international markets, you could be lifted out of poverty quite considerably," Lobell explained. "But there are a lot of countries, like Bangladesh, where poor people are either in urban areas or in rural areas but don't own their own land. Countries like that could be hurt quite a lot. Then there are semi-arid countries - like Zambia, Mozambique and Malawi - where even if prices go up and people own land, productivity will go down so much that it can't make up for those price increases. In the 'low-yield' scenario, those countries would see higher poverty rates across all sectors."

Under the "high-yield" scenario, in which global temperatures rise just 0.9 F (0.5 C), crop productivity increased. The resulting food surplus led to a 16 percent drop in prices, which could be detrimental to farm owners. In Thailand, the poverty rate among self-employed farmers was projected to rise 60 percent, while those in the non-agriculture sector saw a slight drop in poverty. In Zambia, Mozambique, Malawi and Uganda, poverty in the non-farming sector was projected to decline as much as 5 percent.

Risk management

Lobell said that, although the likelihood of the "low-yield" or "high-yield" scenario occurring is only 5 percent, it is important for policymakers to consider the full range of possibilities if they want to help countries adapt to climate change and ultimately prevent an increase in poverty and hunger. 

"It's like any sort of risk management or insurance program," he said. "You have to have some idea of the probability of events that have a big consequence. It's also important to keep in mind that any change, no matter how extreme, will benefit some households and hurt others."

The Program on Food Security and the Environment at Stanford is an interdisciplinary research and teaching program that generates policy solutions to the persistent problems of global hunger and environmental damage from agricultural practices worldwide. The program is jointly run by Stanford's Woods Institute for the Environment and the Freeman Spogli Institute for International Studies.

Eric Brewer is Professor of Computer Science at the University of California Berkeley where he leads the Technology and Infrastructure for Emerging Regions (TIER) research group.

Eric spoke about the role for technology in effective development strategies at the base of the pyramid.

The history of development to date has been characterized by large agencies funding big projects with strings attached, usually in the form of debt or demands for political allegiance. These kinds of projects are hampered by their scale and the requirement to work with corrupt governments. They typically include little role for new technology as projects move slowly and lack the expertise to facilitate this.

Outside the sphere of traditional development, technology is having a major impact on economic prosperity. The mobile phone revolution, driven by bottom up demand, provides enormous advantages to any worker operating in a large radius. A taxi driver given a mobile phone, for example, will increase his revenue by 60% on average. Other bottom-up businesses have seen major success. The Village Phone scheme, which runs as a franchise model with capital coming from microfinance, now covers the majority of Bangladeshi villages. A village phone lady will make on average two times the income she would have done from farming.

However, the mobile phone remains a largely urban phenomenon since cellular networks require a certain density of users before they can economically justify the installation of a base station. The availability of an internet connection is crucial for the viability of businesses and services in rural areas.  WiFi-based Long Distance networks (WiLDNet) are emerging as a potential low-cost alternative to traditional connectivity solutions for rural regions. Unlike mesh networks, which use omni-directional antennas to cater to short ranges, WiLD networks are comprised of point-to-point wireless links that use directional antennas with line of sight over long distances.

Eric's Berkeley research team has partnered with Aravind Eye Hospital in Theni in the southern India state of Tamil Nadu to use this technology to address the problem of blindness in the region, 70% of which is treatable. The long-distance wireless network they have installed is allowing eye specialists to interview and examine patients in five remote clinics via high-quality video conferencing. 25,000 patients have recovered sight using this system and it is set to expand to 50 centers covering 2.5 million people.

Eric's team has also worked on software that addresses local educational needs in developing regions. In poorly resourced schools, students will often be sharing a mouse and computer screen with a group of others. Metamouse gives each student their own mouse to use; when answering questions all users must agree on a location before progressing. This encourages collaboration between students and has had impressive results in boys in particular, with a 50% improvement in scoring compared to each user having their own PC.