A hidden trove of historical crop yield data from Africa shows that corn - long believed to tolerate hot temperatures - is a likely victim of global warming.

Stanford agricultural scientist David Lobell and researchers at the International Maize and Wheat Improvement Center (CIMMYT) report in the inaugural issue of Nature Climate Change next week that a clear negative effect of warming on maize - or corn - production was evident in experimental crop trial data conducted in Africa by the organization and its partners from 1999 to 2007.

Led by Lobell, the researchers combined data from 20,000 trials in sub-Saharan Africa with weather data recorded at stations scattered across the region. They found that a temperature rise of a single degree Celsius would cause yield losses for 65 percent of the present maize-growing region in Africa - provided the crops received the optimal amount of rainfall. Under drought conditions, the entire maize-growing region would suffer yield losses, with more than 75 percent of areas predicted to decline by at least 20 percent for 1 degree Celsius of warming.

"The pronounced effect of heat on maize was surprising because we assumed maize to be among the more heat-tolerant crops," said Marianne Banziger, co-author of the study and deputy director general for research at CIMMYT."

"Essentially, the longer a maize crop is exposed to temperatures above 30 C, or 86 F, the more the yield declines," she said. "The effect is even larger if drought and heat come together, which is expected to happen more frequently with climate change in Africa, Asia or Central America, and will pose an added challenge to meeting the increasing demand for staple crops on our planet."

Similar sources of information elsewhere in the developing world could improve crop forecasting for other vast regions where data has been lacking, according to Lobell, who is lead author of the paper describing the study.

"Projections of climate change impacts on food production have been hampered by not knowing exactly how crops fair when it gets hot," Lobell said. "This study helps to clear that issue up, at least for one important crop."

While the crop trials have been run for many years throughout Africa, to identify promising varieties for release to farmers, nobody had previously examined the weather at the trial sites and studied the effect of weather on the yields, said Lobell, who is an assistant professor of environmental earth system science and fellow at Stanford's Program on Food Security and the Environment.

"These trials were organized for completely different purposes than studying the effect of climate change on the crops," he said. "They had a much shorter term goal, which was to get the overall best-performing strains into the hands of farmers growing maize under a broad range of conditions."

The data recorded at the yield testing sites did not include weather information. Instead, the researchers used data gathered from weather stations all over sub-Saharan Africa. Although the stations were operated by different organizations, all data collection was organized by the World Meteorological Organization, so the methods used were consistent.

Lobell then took the available weather data and interpolated between recording stations to infer what the weather would have been like at the test sites. By merging the weather and crop data, the researchers could examine climate impacts.

"It was like sending two friends on a blind date - we weren't sure how it would go, but they really hit it off," Lobell said.

Previously, most research on climate change impacts on agriculture has had to rely on crop data from studies in the temperate regions of North America and Europe, which has been a problem.

"When you take a model that has been developed with data from one kind of environment, such as a temperate climate, and apply it to the rest of the world, there are lots of things that can go wrong" Lobell said, noting that much of the developing world lies in tropical or subtropical climates.

But he said many of the larger countries in the developing world, such as India, China and Brazil, which encompass a wide range of climates, are running yield testing programs that could be a source of comparable data. Private agribusiness companies are also increasingly doing crop testing in the tropics.

"We're hoping that with this clear demonstration of the value of this kind of data for assessing climate impacts on crops that others will either share or take a closer look themselves at their data for various crops," Lobell said.

"I think we may just be scratching the surface of what can be achieved by combining existing knowledge and data from the climate and agriculture communities. Hopefully this will help catalyze some more effort in this area."

Lobell is a Center Fellow at the 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.

The work was funded by the Rockefeller Foundation

President Obama's vision of a "world free of nuclear weapons" -- first enunciated in Prague in April 2009 -- has been derided by his critics as a utopian fantasy that will have no influence on the nuclear strategies of other nations.

But in a special issue of The Nonproliferation Review, entitled Arms, Disarmament, and Influence: International Responses to the 2010 Nuclear Posture Review, 13 prominent researchers from around the world examined foreign governments' policy responses to Obama's 2010 Nuclear Posture Review (NPR), the landmark document published a year and a day after his Prague speech.

They found that many nations, though not all, had been "strongly influenced by Washington's post-Prague policy and nuclear posture developments," which reduced the role of nuclear weapons in U.S. national strategy, and assured non-nuclear nations that the U.S. would never use nuclear arms against them provided they remained in compliance with their obligations under the Nuclear Non-Proliferation Treaty.

Indeed, the 11 case studies presented "demonstrate that U.S. pronouncements and actions influenced bureaucratic infighting and domestic debates inside a number of important foreign governments, and that some of these governments have adjusted their own policies and actions accordingly."

Read the full report here.

See a presentation about the report here, or listen to a different one here.

Read CISAC co-director Scott Sagan's essay on "Obama's Disarming Influence" in the Bulletin of the Atomic Scientists.  

Read Thomas Fingar's essay on "How China Views U.S. Policy" in the Bulletin of the Atomic Scientists. 

Highlights:

* Russia adopted a nuclear doctrine that was considerably more moderated than it would have been had the United States not pushed ahead with its own policy changes. In the run up to the April 2010 publication of the NPR, Washington "reset" relations with Russia, ended the deployment of missile defense components in Poland and the Czech Republic, and resumed the disarmament negotiations that ultimately led to the ratification of the New START treaty. As a result of this process, and continuous consultation with Russia about the NPR, Moscow narrowed the role of nuclear weapons in its policy and the range of circumstances in which it would consider using them. (page 39)

* "The most important short-term success of Obama's nuclear weapons policy," along with the "Prague Spirit," has been to halt the erosion of the NPT. "Obama's policies helped extract a minimum positive result from the 2010 NPT Review Conference, a favorable outcome compared to the chaos that his predecessor's representatives had created at the 2005 conference." The Obama policy was welcomed as a positive development, which allowed "key players, such as Egypt and Brazil, to strive for compromise, and others, such as Russia and China, not to block it." (page 219)

* The U.S. effort to encourage other governments to reduce the role of nuclear weapons in their policy was successful in the United Kingdom, which adopted a nuclear posture that was very similar to that to the U.S. (page 238)

* Due in large part to the Obama policy, some of the non-nuclear weapons states in NATO began to push for the removal of sub-strategic nuclear weapons from Europe. At the November 2010 NATO summit, members agreed to a new Strategic Concept that called for negotiations with Russia and a linkage between the reduction and eventual elimination of nuclear weapons in NATO Europe to comparable reductions in western Russia. (page 238)

* Obama's new nuclear doctrine was a driving force behind a May 2010 agreement among 189 nations at the Nonproliferation Review Conference to a set of disarmament objectives and steps to reinforce the nuclear non-proliferation regime. (page 238)

* The Obama disarmament initiatives encouraged Indonesia's decision to begin the process of ratifying the Comprehensive Test Ban Treaty. (page 238)

* China continues to view Washington's nuclear doctrine with suspicion. Although Beijing viewed the 2010 NPR favorably compared to its 2001 predecessor, it still found serious cause for concern. This is partly the result of timing: the NPR came out amid a period of rising tension between U.S. and China. It also reflected a tendency among Chinese leaders to view virtually all U.S. doctrine and actions as part of a concerted effort to constrain its rise. In this view, the NPR would foster comparisons between nuclear decreases in Russia and the U.S., and increases in China, and be used as leverage to force Beijing to engage in an expensive conventional arms race. In keeping with this China-centric view, Chinese officials were also concerned about the U.S. military's continued development of missile defense capabilities. (page 243)

* Many non-nuclear weapons states--such as Egypt, Brazil, and South Africa--emphasize their opposition to any constraints being placed on their right to enjoy the benefits of civilian nuclear energy. Some of their opposition is "due to post-colonial sensitivity about any apparent inequality in the terms of international agreements that divide the world into 'haves' and 'have-nots.'" Others are engaged in bargaining, waiting to see what nuclear-weapons states will do regarding disarmament before offering to accept more constraints on nuclear technology development. Some governments also appear to be engaged in "hedging behavior--protecting their ability to enrich uranium or reprocess plutonium" to be closer to acquiring nuclear weapons in the future, should they choose to do so. This may be disappointing for Washington policymakers, but it should not be surprising. After all, the U.S. employs a similar "hedging strategy" in its management of its own nuclear stockpile. As a result, it is imperative to begin discussions of how to reduce the danger of both kinds of nuclear hedging behavior. (page 255)

* The Obama administration must continue "to ensure there is consistency and discipline in the messages" emanating from the military and the government bureaucracy. Some foreign governments viewed the NPR's guarantees as mere rhetoric. "Such a skeptical view is encouraged whenever a senior US military officer makes statements that reflect a lack of understanding or lack of discipline regarding nuclear use policy." Even after the NPR was released, a top U.S. general insisted that the United States had not altered its "calculated ambiguity" policy. (page 258)

The special issue of the Nonproliferation Review was coordinated by Scott D. Sagan, co-director of the Center for International Security and Cooperation at Stanford University, and Jane Vaynman, a PhD candidate at the Department of Government at Harvard University, and a National Security Studies Fellow at the Weatherhead Center for International Affairs. The journal is published by the James Martin Center for Nonproliferation Studies at the Monterey Institute of International Studies, and it is edited by Stephen Schwartz.

Authors:

Irma Argüello is founder and chair of the NPSGlobal Foundation, a private nonprofit initiative that focuses on improving global security and reducing risks stemming from WMD proliferation.

Ralph A. Cossa is President of the Pacific Forum CSIS in Honolulu. He is senior editor of the Forum's quarterly electronic journal, Comparative Connections. 

Ambassador Nabil Fahmy is the founding Dean of the School of Global Affairs and Public Policy at the American University in Cairo. He is also the Chair of the James Martin Center for Nonproliferation Studies' Middle East Project.

Thomas Fingar is the Oksenberg-Rohlen Distinguished Fellow and Senior Scholar in the Freeman Spogli Institute for International Studies at Stanford University.

Brad Glosserman is Executive Director of the Pacific Forum CSIS in Honolulu. Mr. Glosserman is co-editor of Comparative Connections, the Pacific Forum's quarterly electronic journal, and writes, along with Ralph Cossa, the regional review.

S. Paul Kapur is associate professor in the Department of National Security Affairs at the U.S. Naval Postgraduate School and a faculty affiliate at Stanford University's Center for International Security and Cooperation.

Mustafa Kibaroglu is an Assistant Professor at Bilkent University.

Michael Krepon is the co-founder of the Stimson Center, a Washington-based think tank specializing in national and international security problems. 

Harald Müller is executive director of Peace Research Institute Frankfurt and Professor at International Relations at Goethe University Frankfurt.

Pavel Podvig is an independent analyst based in Geneva, Switzerland, where he manages the research project Russian Nuclear Forces.

Scott D. Sagan is the Caroline S.G. Munro Professor of Political Science, co-director of Stanford's Center for International Security and Cooperation, and a Senior Fellow at the Freeman Spogli Institute. He also serves as the co-chair of the American Academy of Arts and Science's Global Nuclear Future Initiative.

Scott Snyder is Director of the Center for U.S.-Korea Policy at The Asia Foundation, Senior Associate at Pacific Forum CSIS, and Adjunct Senior Fellow for Korean Studies at the Council on Foreign Relations.

Jane Vaynman is a PhD candidate at the Department of Government at Harvard University and a National Security Studies Fellow at the Weatherhead Center for International Affairs.

^{The Center for International Security and Cooperation (CISAC), part of the Freeman Spogli Institute for International Studies (FSI), is an interdisciplinary university-based research and training center addressing some of the world's most difficult security problems with policy-relevant solutions. The Center is committed to scholarly research and to giving independent advice to governments and international organizations.}

Go out there and change the world.
- Tim Draper, Draper Fisher Jurvetson

"Whatever the world looks like now, it will change," said Tim Draper, founder and managing director of Draper Fisher Jurvetson (DFJ), during the keynote session at the March 1 Entrepreneurship in the Global Marketplace seminar, organized by the Stanford Program on Regions of Innovation and Entrepreneurship (SPRIE) with sponsorship from Alibaba.com, the first in a series of seminars by the Schwarzenegger Emerging Entrepreneur Initiative. Concluding his remarks, Draper urged the overflow audience: "Go out there and change the world."

Draper and the nine other participants shared different perspectives on entrepreneurship, but a key message underlying all of the presentations was that the world is a dynamic, rapidly changing place where entrepreneurs can succeed by anticipating and responding to global trends. In doing so, many suggested, it is also possible to change the world—for the better. The participants all concurred that China is one of the key places in the world—now and in the future—to do business, representing a challenging but a vast frontier of opportunity.

Global demographic trends are a major factor that venture capitalists consider when making investments. Addressing the worldwide aging phenomenon, which is particularly acute in Asia-Pacific countries such as Japan and China, Draper explained how DFJ has invested in a company that manufactures videogame-like devices designed to improve cognition, noting the growing market for such devices that help keep cognitive health apace with a longer life span. Hans Tung, a partner with the Shanghai-based venture capital firm Qiming Ventures, described how his firm is tracking the large segment of China's population living in small cities away from commercial hubs. These members of the populace, who prefer to shop online where they can find a wider selection of goods than in their local shopping malls, are quickly becoming a driving force in China's e-commerce market.

It is China's e-commerce and other Internet firms—fueled by the explosion of Internet users—that carry increasingly significant weight in China's domestic and the global economy. Duncan Clark, a visiting scholar at SPRIE, presented related findings from SPRIE's China 2.0: The Rise of a Digital Superpower research initiative, which is led by Marguerite Gong Hancock, associate director of SPRIE. China 2.0, explores the conditions generating such rapid growth of the Internet, and investigates questions surrounding the possible global implications of it. Clark noted that as China's three largest Internet firms—search engine Baidu, instant-messaging service Tencent, and e-commerce portal Taobao—expand, domestic competition will not only intensify, but move further into the global economic arena. The "big three" firms are already ranked among the top 20 Internet sites in the world based on site traffic. According to Clark, the key question in the future for U.S. companies will be how to partner with Chinese companies in order to insure their own growth.

Riding the global wave of innovation and entrepreneurship, Jonathan Ross Shriftman, co-founder of Solé Bicycle Company, and Ryder Fyrwald, vice president of global operations at the Kairos Society, have discovered opportunities to effect positive change despite a global climate of intense economic competition. Shriftman, a recent University of Southern California (USC) graduate, described the lessons that he has learned through his company's quest to manufacture low-cost, quality fixed-gear bicycles that provide a stylish, alternate form of transportation. Despite funding and language challenges, Shriftman and his partner succeeded in connecting with a manufacturer in China through Alibaba.com, and have sold nearly 800 bicycles to date. Fyrwald, who is still an undergraduate at USC's Marshall School of Business, explained the philosophy behind the Kairos Society, an international network of student entrepreneurs who seek to solve world issues through entrepreneurship and innovation. He cited the example of WaterWalla, a company that has developed, among other technologies, a low-cost water purification device for use by urban slum dwellers.

From the perspective of seasoned venture capitalists Draper and Tung and emerging entrepreneurs Shriftman and Fyrwald, the message at Entrepreneurship in the Global Marketplace was clear: the way to succeed in a rapidly changing world is to react promptly—and creatively—to global trends. And, as Shriftman suggested, it is possible to "do well by doing good," and change the world in a positive way.

The breadth of [Shorenstein] APARC's work is truly impressive... I look forward to making full use of the resources and opportunities afforded me through the visiting fellowship.

-Dr. Siyan Yi

How can Stanford University contribute to improved health policy in the low-income countries of Asia? In addition to our formal degree-granting and research programs, mentorship of young scholars can play a role in strengthening the evidence base and analytic skills undergirding health policy for the millions of Asians who live on only a few dollars a day.

The Asia Health Policy Program (AHPP) is delighted to announce the inauguration of a fellowship program for young health policy experts from developing countries in Asia. The first Developing Asia Health Policy Fellow will be Dr. Siyan Yi from Cambodia. He holds a medical doctor degree from the University of Health Sciences in Cambodia as well as a doctoral degree in international health sciences from the Graduate School of Medicine at the University of Tokyo. Dr. Karen Eggleston, director of AHPP, will be his primary sponsoring faculty member.

Dr. Yi's research has centered largely on epidemiological methods. This has included, for example, work on surveys in Cambodia on adolescent risky sexual behaviors, substance abuse, and depression; a health promotion project in primary schools; sexual behaviors among people living with HIV/AIDS; and HIV risk behaviors among tuberculosis patients. Currently, he is involved in hospital- and community-based research projects in several developing countries as well as in Japan.

Cambodia has recently created a School of Public Health and is facing an increasing burden of chronic disease, while the burden from infectious diseases such as tuberculosis remains significant. Since Dr. Yi's research interests lie in health promotion and risky behaviors, he could someday be instrumental in helping to set policies to address the public health challenges Cambodia will face.  

Dr. Yi will join the Walter H. Shorenstein Asia-Pacific Research Center (Shorenstein APARC) in autumn 2011 for a nine-month fellowship to immerse in the academic environment and to develop additional skills to contribute to improved health policy in Cambodia. He notes that "the breadth of [Shorenstein] APARC's work is truly impressive... I look forward to making full use of the resources and opportunities afforded me through the visiting fellowship."