In the wake of the one-child policy of 1979, China experienced an unprecedented rise in the sex ratio at birth (ratio of male to female births). In cohorts born between 1980 and 2000, there were 22 million more men than women. Some 10.4 percent of these additional men will fail to marry, based on simulations presented here that assess how different scenarios for the sex ratio at birth affect the probability of failure to marry in 21st century China. Three consequences of the high sex ratio and large numbers of unmarried men are discussed: the prevalence of prostitution and sexually transmitted infections, the economic and physical well-being of men who fail to marry, and China's ability to care for its elderly, with a particular focus on elderly males who fail to marry. Several policy options are suggested that could mitigate the negative consequences of the demographic squeeze.

Changes in land use and land cover (LULC) have important and fundamental interactions with the global climate system. Top‐down global scale projections of land use change have been an important component of climate change research; however, their utility at local to regional scales is often limited. The goal of this study was to develop an approach for projecting changes in LULC based on land use histories and demographic trends. We developed a set of stochastic, empirical‐based projections of LULC change for the state of California, for the period 2001–2100. Land use histories and demographic trends were used to project a “business‐as‐usual” (BAU) scenario and three population growth scenarios. For the BAU scenario, we projected developed lands would more than double by 2100. When combined with cultivated areas, we projected a 28% increase in anthropogenic land use by 2100. As a result, natural lands were projected to decline at a rate of 139 km2 yr−1; grasslands experienced the largest net decline, followed by shrublands and forests. The amount of cultivated land was projected to decline by approximately 10%; however, the relatively modest change masked large shifts between annual and perennial crop types. Under the three population scenarios, developed lands were projected to increase 40–90% by 2100. Our results suggest that when compared to the BAU projection, scenarios based on demographic trends may underestimate future changes in LULC. Furthermore, regardless of scenario, the spatial pattern of LULC change was likely to have the greatest negative impacts on rangeland ecosystems.

The Policy Research Working Paper Series disseminates the findings of work in progress to encourage the exchange of ideas about development issues. An objective of the series is to get the findings out quickly, even if the presentations are less than fully polished. The papers carry the names of the authors and should be cited accordingly. The findings, interpretations, and conclusions expressed in this paper are entirely those of the authors. They do not necessarily represent the views of the International Bank for Reconstruction and Development/World Bank and its affiliated organizations, or those of the Executive Directors of the World Bank or the governments they represent. Policy Research Working Paper 5351Fertility decline has fueled a sharp increase in the proportion of 'missing girls' in China, so an increasing share of males will fail to marry, and will face old age without the support normally provided by wives and children. This paper shows that historically, China has had nearly-universal marriage for women and a very competitive market for men. Lower-educated men experience higher rates of bachelorhood while women favor men with better prospects, migrating if needed from poorer to wealthier areas. The authors examine the This paper-a product of the Poverty and Inequality Team, Development Research Group-is part of a larger effort in the department to study socio-political processes and development outcomes. Policy Research Working Papers are also posted on the Web at http://econ.worldbank.org. The authors may be contacted at "Monica Das Gupta"

Because sex ratios at birth have risen sharply in China in recent decades, an increasing proportion of men will be unable to find a bride, and will face old age without the support of a wife and children. We project the proportions of never-married men and their geographical distribution in China in the coming decades. Our projections assume that two tendencies in current marriage patterns will persist: that women will continue to migrate to wealthier areas, and to prefer men with better prospects. We find that, by 2030, more than 20 per cent of men in China aged 30–39 will never have married, and that the proportion will be especially high among poor men in low-income provinces that are least able to provide social protection programmes. The projected geographic concentration of bachelors could be socially disruptive, and the results suggest a need to expand the coverage and central financing of social protection programmes.

The Policy Research Working Paper Series disseminates the findings of work in progress to encourage the exchange of ideas about development issues. An objective of the series is to get the findings out quickly, even if the presentations are less than fully polished. The papers carry the names of the authors and should be cited accordingly. The findings, interpretations, and conclusions expressed in this paper are entirely those of the authors. They do not necessarily represent the views of the International Bank for Reconstruction and Development/World Bank and its affiliated organizations, or those of the Executive Directors of the World Bank or the governments they represent. Policy Research Working Paper 5351Fertility decline has fueled a sharp increase in the proportion of 'missing girls' in China, so an increasing share of males will fail to marry, and will face old age without the support normally provided by wives and children. This paper shows that historically, China has had nearly-universal marriage for women and a very competitive market for men. Lower-educated men experience higher rates of bachelorhood while women favor men with better prospects, migrating if needed from poorer to wealthier areas. The authors examine the This paper-a product of the Poverty and Inequality Team, Development Research Group-is part of a larger effort in the department to study socio-political processes and development outcomes.