Climate change could be to blame for many of the wars in China during the past millennium, says an article published recently in Human Ecology. The study, the first quantitative examination of the link between conflict and temperature changes, is a milestone in climate change research.

David Zhang and co-authors compared the 899 wars that occurred in eastern China between A.D. 1000 and 1911 with climatic data for the same period. They found that warfare frequency in eastern China—particularly in that region’s southern part—correlated strongly with temperature oscillations. Warfare ratios in the cold phases were twice as high as in the warm phases. Furthermore, almost all dynastic changes and warfare peaks coincided with cold phases.

“In general, rebellion was the dominant category of war,” write the authors. “The rebellions were predominantly peasant uprisings induced by famine and heavy taxation, since farmers were always the first to suffer from declining agricultural production.”

The authors surmise that by affecting agriculture, cooler temperatures disrupted food supply, especially in the ecologically vulnerable northern part of eastern China. Food scarcity could have triggered rebellions or forced people to migrate, further exacerbating food shortages in certain areas. Migration could also have generated tension between groups, producing local conflicts—especially when China was populated by nomadic tribes that could move freely. The authors also hypothesize that food scarcity may have encouraged opposing Chinese armies to conduct cross-border raids on each other’s crops. However, additional, more detailed analysis of the pathways leading from cooler temperatures to conflict in eastern China is needed.

It is unclear whether the correlation observed by Zhang in eastern China will hold true for other parts of the world. We should also be careful not to use this one study to draw premature connections to today’s unprecedented climate change. However, we hope additional quantitative studies will be carried out; they would be solid contributions to the research on climate and security, which currently suffers from a scarcity of empirical data.

The President’s Emergency Plan for AIDS Relief (PEPFAR), a $15 billion commitment, is set to expire at the end of fiscal year 2008. This critical boost in U.S. AIDS funding has helped millions of individuals infected with HIV, and in so doing, has improved developing nations’ health and education systems and decreased violence against women. In an original podcast by the Environmental Change and Security Program and the Global Health Initiative, UNAIDS Executive Director Dr. Peter Piot discusses how reauthorizing PEPFAR at increased levels of funding, expanding AIDS prevention programs, and coordinating global efforts to combat HIV/AIDS under U.S. leadership could amplify the effectiveness and sustainability of the global AIDS response.

Click here for the Wilson Center, “PEPFAR Reauthorization and the Global AIDS Response” event summary.

Climate and security links are definitely in vogue these days. Some of the work on these connections has been measured and nuanced; some has been less judicious. I want to flag a recently published rich resource that falls in the former category and avoids the hyperbole that characterizes the latter.

The academic journal Political Geography–admittedly not a publication on every policymaker’s desk–devotes its current issue to climate change and conflict. The six pieces feature the most recent work of some longtime environmental security contributors such as Australian geographer Jon Barnett and Norwegian peace researcher Nils Petter Gleditsch. The articles were first presented at a June 2005 conference in Oslo convened by Gleditsch’s International Peace Research Institute, Oslo (PRIO) and geographer Karen O’Brien’s Global Environmental Change and Human Security Project (GECHS). Visit this space again soon for a more detailed analysis of the contributions.

The world could face a global food crisis in the next 50 years, said experts at a recent UN-backed conference in Iceland on sustainable development. Their calculus is simple: In the coming half century, there will be more people on the planet, but rapid land degradation will make it difficult to produce commensurate increases in food. Warmer temperatures and more frequent floods, caused by climate change, will diminish soil fertility in many parts of the world—particularly in developing countries. As 800 million people are already at risk for hunger today, population growth alone is likely increase global food insecurity.

The expansion of biofuels could potentially exacerbate food shortages. A major UN report on biofuels warns that as more fields are devoted to producing corn, palm oil, sugar cane, and other agricultural products for use as biofuels, the amount of food that is produced for human consumption could decrease.

Climate change’s effects on marine ecosystems could also contribute to a food crisis. Changes in water temperature and salinity can damage coral reefs, which scientists estimate support between one-quarter and one-third of all marine life. In addition, a recent study published in Nature shows that phytoplankton—single-celled ocean plants that form the base of the marine food chain—are growing more slowly as the water at Earth’s mid and low latitudes becomes warmer. As the supply of phytoplankton becomes limited, fish have less food to eat, and at the end of the chain, human beings suffer from a scarcity of fish—a particularly dire situation in communities where fish is a primary source of food.

According to scientists at the Iceland forum, competition over scarce resources could lead to conflict. Studies on the relationship between environmental degradation and conflict indicate that such conflicts are likely to be intrastate and of low intensity. Scientists suggesting that food scarcity could trigger classic interstate wars, such as James Lovelock, who predicts that China and Russia will clash to exploit Siberia’s new fertile soils, are in the minority.

Yet policymakers should not be indifferent to food scarcity in developing countries merely because it is not likely to cause global-scale conflicts. Indeed, if the developing world faces more famines and malnutrition in the coming years, pressure on Western governments will be high to intervene.

Former Senate Majority Leader Bill Frist, who was a practicing surgeon before his political career, announced last week that he would return to medicine—in a big way. The New York Times reports that Frist will lead Save the Children’s new “Survive to Five” initiative. This program aims to reduce the number of children—estimated at nearly 10 million annually worldwide—who die before they turn five years old. Save’s website describes five solutions to the five biggest contributing factors to child mortality. By applying these solutions—all of them proven, and most of them very inexpensive—they hope to save as many as 6 million children every year.

The Times mentions that other American politicians, such as Jimmy Carter and Bill Clinton, have dedicated much of their post-political lives to global health, with excellent results. Perhaps even more encouraging is that some current world leaders are addressing these issues as well. Last month, British Prime Minister Gordon Brown and German Chancellor Angela Merkel vowed “urgent action” on health issues in developing countries. Their International Health Partnership, which began on September 5, will address child mortality, as well as maternal mortality and HIV/AIDS prevention and education.

The Times notes that Frist is playing a key role in a similar campaign with the Bill and Melinda Gates Foundation, along with former rival Senator Tom Daschle—although it doesn’t mention that while majority leader, Frist broke with political tradition by campaigning against his counterpart. It is encouraging that they have put political differences behind them and are working together on a new campaign that could save and improve the lives of millions of children around the world. Hopefully, they will be successful in persuading Americans and their elected officials that child mortality is not only unacceptable and preventable, but that reducing it is a worthy use of taxpayer dollars.

This effort may seem daunting, given that less than one-half of one percent of the U.S. budget goes to international assistance. Frist was successful in ushering through the President’s Emergency Plan for AIDS Relief (PEPFAR), which dedicated $15 billion over five years to fighting AIDS, principally in Africa. This was a major victory for global health, but there is room in the budget and the priorities of American leaders for more global health programs—especially if PEPFAR is doubled, as is now being considered, to $30 billion over the next 5 years. Campaigns to reduce childhood mortality do not face the political scrutiny of HIV/AIDS programs such as PEPFAR, but it will still be important that Frist and others involved allow science-based medicine to dictate funding priorities; one of PEPFAR’s main failings is that it has caved to ideology in placing an unadvisedly large emphasis on abstinence education.

Frist and his colleagues certainly have a difficult battle against child mortality ahead of them. But Frist—a surgeon, politician, and businessman—has an impressive range of skills and an equally enviable Rolodex of supporters to call upon.

Climate change has been altering the world’s geography so rapidly that cartographers can hardly keep up. The prestigious Times Comprehensive Atlas of the World was last published in 2003, and in preparation for the release of the 12th edition this year, coastlines, lakes, forests, and cities have had to be redrawn.

The Aral Sea in Central Asia has shrunk by 75 percent in 40 years, while Lake Chad in Africa is only 5 percent of its 1963 size. Furthermore, during certain times of the year, the Rio Grande, Colorado, Yellow, and Tigris rivers fail to reach the sea.

The 12th edition of the atlas contains approximately 20,000 updates. Naturally, not all the updates are consequences of climate change: 3,500 are simply name changes, and not every geographic update is the result of climate change. Also, not all the geographic changes occurred during the last four years—some happened earlier, but are only now being noticed by mapmakers, who are becoming increasingly aware of climate change-related geographical changes.

Some changes were previously unknown because they were happening in isolated parts of the world. In India, for instance, official records list 102 islands in the Sunderbans, where the Ganges and Brahmaputra rivers empty into the Bay of Bengal. Those islands are inhabited by 1.8 million people. However, after a six-year study, scientists have been able to map only 100 islands, finding that the other two had been swallowed up by the sea, said Sugata Hazra, director of Calcutta’s School of Oceanography Studies at Jadavpur University. Scientists estimate that the submersion of the two islands rendered approximately 10,000 people homeless.

Rising sea levels—which threaten to submerge some 12 additional islands in the Sunderbans—are sometimes perceptible to the human eye. In Bangladesh, many islands disappear each year, forcing populations to migrate from island to island and to live in extremely precarious conditions. As Shahidul Mullah, who lives with his family on a small island in Bangladesh, told Spiegel Online, “When I moved here, we still had three fields in front of the house. Now there are only two. I’m afraid the water will take another piece away from me this year.”

Last week, policymakers, business leaders, and farmers gathered in Oslo at the second annual African Green Revolution Conference to discuss ways to increase agricultural productivity in Africa. The conference, inspired by former UN Secretary-General Kofi Annan’s July 2004 call to revolutionize African farming, and co-sponsored by two Norwegian public development organizations and two transnational companies, focused on how partnerships between the public and private sectors can offer valuable opportunities for agricultural development. Pedro Sanchez of Columbia University’s Earth Institute cited Malawi, which last year managed to turn a 40 percent grain deficit into a 25 percent surplus, as the first successful African Green Revolution country. Yet other attendees warned that this growth had been achieved partially at the expense of environmental degradation—particularly deforestation—and urged agricultural development programs in Africa to strive for growth that will be sustainable in the long-term.

Also last week: Representatives from 158 countries met in Vienna for a weeklong UN conference on reducing greenhouse gas emissions. The delegates agreed that industrialized nations should aim for a non-binding target of reducing their emissions by between 25 and 40 percent of 1990 levels by 2020. This goal is expected to serve as a loose framework for the major UN-sponsored international climate talks that will be held in Bali, Indonesia this December. At the conference, China rejected criticism that it has not been doing enough to combat climate change, arguing that its one-child policy, by preventing 300 million births over the past three decades, has also kept the country’s levels of greenhouse gas emissions significantly lower than they would have otherwise been.

They say that a good man is hard to find. But in some countries, the opposite is true: a good woman is hard to find—because it’s hard to find women at all. According to a recent article by the BBC, the Chinese city of Lianyungang has eight men for every five women. Ninety-nine cities in China have gender ratios as high as 125 (125 men for every 100 women, or a 5:4 ratio).

But China is not alone. India has a gender ratio of 113, and the ratio in Asia as a whole is 104.4. In the United States, by contrast, the rate is 97, meaning that there are more women than men.

Gender imbalances are caused by cultural and economic preferences for male children, which contribute to sex-selective abortion and female infanticide. Over 60 million girls are “missing” in Asia as a result of these practices.

Furthermore, some government policies may intensify these gender preferences. China’s one-child policy, for example, may cause concern among parents, particularly in rural areas, that having a female child endangers their family’s future. Government policies intended to combat skewed gender ratios, such as bans on prenatal ultrasounds for the purpose of determining the baby’s sex and bans on sex-selective abortion, have proven ineffective.

Unbalanced gender ratios have consequences that reach beyond just the mothers and children involved. According to Valerie Hudson, high gender ratios leave many men without prospects for marriage, which may mean these men have fewer incentives to contribute peacefully to society. The men with the slimmest prospects for marriage are likely to be unemployed, poor, and uneducated, so they are already at increased risk for violent behavior. Hudson cites statistical evidence showing links between high gender ratios and higher rates of violent crime, drug use, trafficking, and prostitution.

Hudson and co-author Andrea den Boer cover these links in greater detail in their book Bare Branches: The Security Implications of Asia’s Surplus Male Population. In the 11th issue of the Environmental Change and Security Report, Richard Cincotta takes issue with some of the statistical methods that Hudson and den Boer use. He argues that what is important is not nationwide gender ratios, but the number of “marriage-age men” (25-29 years old) and “marriage-age women” (20-24).

While there may be some debate over whether the relationship between gender ratios and violent behavior is a causal one, there is little doubt about what causes the gender imbalances in the first place. An end to preferences for female children will be beneficial not only to girls and women, but to societies as a whole.

Photo Credit: A subway in China, courtesy of flickr user 俊玮 戴.