D rought “is the death of the earth,” wrote the poet T. S. Eliot. A lack of water withers crops, kills trees, and dries up streams and lakes. Humans have long tried to cope by migrating to wetter regions or inventing new ways of moving water to where it is needed, including by pumping it out of the ground. But as human populations grow, climate change takes hold, and groundwater supplies shrink, droughts pose an increasingly complex challenge to people and the environment. This special issue examines the science and social impacts of droughts—past, present, and future. Review articles assess our current knowledge of the causes of drought and consequences for forests and soils, how drought relates to political conditions, and options for improving drought resistance in crops. Additionally, three News Features highlight drought’s infl uence on the rise and fall of an ancient South American empire, California’s ef orts to restore its depleted groundwater, and researchers’ methods for predicting the famines that droughts sometimes bring. Drought is defi ned by the absence of life-giving water. Some scholars believe that the forbidding presence of a drought that struck the United Kingdom in 1921 helped inspire Eliot’s repeated allusions to water and drought in his poetry. That year, less than 260 millimeters of precipitation—one of the lowest levels ever recorded—fell in parts of England, prompting the writer to refl ect on a natural force that has long shaped our planet.

From a monarch mystery unlocked with the help of Indigenous people to an environmental disaster averted by a chemist who was not afraid of a fight, this year's finalists for the AAAS/Subaru (SB&F) Prize for Excellence in Science Books highlight how diverse perspectives, grit, and a healthy dose of hope are essential to the effective practice of science. Read on for reviews of the finalists written by the staff of the Science family of journals, with help from a few friends.

From a monarch mystery unlocked with the help of Indigenous people to an environmental disaster averted by a chemist who was not afraid of a fight, this year's finalists for the Science Books and Films (SB&F) Prizes for Excellence in Science Books highlight how diverse perspectives, grit, and a healthy dose of hope are essential to the effective practice of science. Read on for reviews of the finalists written by the staff of the Science family of journals, with help from a few friends.

From cryptic ciphers and wall-climbing robots to dinosaur digs and visits to the planetarium, this year's finalists for the Science Books and Films (SB&F) Prizes for Excellence in Science Books are packed with fun facts, easy-to-do experiments, and plenty of creepy-crawly creatures. Sponsored by Subaru and the American Association for the Advancement of Science (AAAS, the publisher of Science ), the SB&F competition celebrates high-quality science books for young readers. Read on for reviews of the finalists, written by the staff of the Science family of journals, with help from a few friends.

From cryptic ciphers and wall-climbing robots to dinosaur digs and visits to the planetarium, this year's finalists for the Science Books and Films (SB&F) Prizes for Excellence in Science Books are packed with fun facts, easy-to-do experiments, and plenty of creepy-crawly creatures. Sponsored by Subaru and the American Association for the Advancement of Science (AAAS, the publisher of Science), the SB&F competition celebrates high-quality science books for young readers. Read on for reviews of the finalists, written by the staff of the Science family of journals, with help from a few friends.

Mountain pine beetle infections are becoming more intense as weather warms in coniferous forests, like this one in central British Columbia. Infected trees die slowly, resulting in a forest full of various levels of colorful dieback. PHOTO: TOM NEVESELY/ALL CANADA PHOTOS/CORBIS

[Changing Climates Special Issue Index][1]![Figure][2] Wet to dry.Kenya's Lake Magadi, now alkaline and mostly dry, once teemed with freshwater fish; a core drilled here will reveal ancient climate swings.CREDIT: © STEVE BLOOM IMAGES/ALAMYAnthropogenic climate change is now a part of our reality. Even the most optimistic estimates of the effects of contemporary fossil fuel use suggest that mean global temperature will rise by a minimum of 2°C before the end of this century and that CO2 emissions will affect climate for tens of thousands of years. A key goal of current research is to predict how these changes will affect global ecosystems and the human population that depends on them. This special section of Science focuses on the current state of knowledge about the effects of climate change on natural systems, with particular emphasis on how knowledge of the past is helping us to understand potential biological impacts and improve predictive power.Four News stories focus on past and future impacts of climate change and the techniques that researchers are using to study them. Gibbons examines the role of climate variability in hominin evolution in Africa, and Pennisi profiles an effort to use sediment cores to document that variability. Kintisch explores whether coastal wetlands will be able to outclimb rising seas. And Pennisi offers a snapshot on the use of historical photographs to study climate impacts.Four Reviews discuss recent research on the current and future effects of climate change as informed by our understanding of changing climates in the paleorecord. Diffenbaugh and Field review the physical conditions that are likely to shape the impacts of climate change on terrestrial ecosystems, showing that they will face rates of change unprecedented in the past 65 million years. Norris and colleagues review the Cenozoic history of oceanic change; despite some short-lived past analogs, the oceans will also experience more rapid change than ever before. Turning to ecology, Blois and colleagues discuss how climate changes can affect biotic interactions and how these insights might inform our understanding of future interactions. Moritz and Agudo discuss the prospects for species survival, weighing the evidence for persistence versus catastrophic decline.Three Reviews focus on more specific impacts of climate change. Its influence on infectious disease is considered by Altizer and colleagues, who use examples from a wide range of host-pathogen systems to assess whether we are close to a predictive understanding of climate-disease interactions and their potential future shifts. Wheeler and von Braun assess the prospects for human food security, with particular attention to potential impacts on food supply in the world's more impoverished countries . Finally, Post and colleagues take a regional focus, reviewing the ecological consequences of current sea ice decline in the polar regions, the part of the world where the reality of changing climate is perhaps at its most stark. [1]: http://www.sciencemag.org/site/special/climate2013/index.xhtml [2]: pending:yes

[Changing Climates Special Issue Index][1] ![Figure][2] Wet to dry. Kenya's Lake Magadi, now alkaline and mostly dry, once teemed with freshwater fish; a core drilled here will reveal ancient climate swings. CREDIT: © STEVE BLOOM IMAGES/ALAMY Anthropogenic climate change is now a part of our reality. Even the most optimistic estimates of the effects of contemporary fossil fuel use suggest that mean global temperature will rise by a minimum of 2°C before the end of this century and that CO2 emissions will affect climate for tens of thousands of years. A key goal of current research is to predict how these changes will affect global ecosystems and the human population that depends on them. This special section of Science focuses on the current state of knowledge about the effects of climate change on natural systems, with particular emphasis on how knowledge of the past is helping us to understand potential biological impacts and improve predictive power. Four News stories focus on past and future impacts of climate change and the techniques that researchers are using to study them. Gibbons examines the role of climate variability in hominin evolution in Africa, and Pennisi profiles an effort to use sediment cores to document that variability. Kintisch explores whether coastal wetlands will be able to outclimb rising seas. And Pennisi offers a snapshot on the use of historical photographs to study climate impacts. Four Reviews discuss recent research on the current and future effects of climate change as informed by our understanding of changing climates in the paleorecord. Diffenbaugh and Field review the physical conditions that are likely to shape the impacts of climate change on terrestrial ecosystems, showing that they will face rates of change unprecedented in the past 65 million years. Norris and colleagues review the Cenozoic history of oceanic change; despite some short-lived past analogs, the oceans will also experience more rapid change than ever before. Turning to ecology, Blois and colleagues discuss how climate changes can affect biotic interactions and how these insights might inform our understanding of future interactions. Moritz and Agudo discuss the prospects for species survival, weighing the evidence for persistence versus catastrophic decline. Three Reviews focus on more specific impacts of climate change. Its influence on infectious disease is considered by Altizer and colleagues, who use examples from a wide range of host-pathogen systems to assess whether we are close to a predictive understanding of climate-disease interactions and their potential future shifts. Wheeler and von Braun assess the prospects for human food security, with particular attention to potential impacts on food supply in the world's more impoverished countries . Finally, Post and colleagues take a regional focus, reviewing the ecological consequences of current sea ice decline in the polar regions, the part of the world where the reality of changing climate is perhaps at its most stark. [1]: http://www.sciencemag.org/site/special/climate2013/index.xhtml [2]: pending:yes

Science is driven by data. New technologies have vastly increased the ease of data collection and consequently the amount of data collected, while also enabling data to be independently mined and reanalyzed by others. And society now relies on scientific data of diverse kinds; for example, in responding to disease outbreaks, managing resources, responding to climate change, and improving transportation. It is obvious that making data widely available is an essential element of scientific research. The scientific community strives to meet its basic responsibilities toward transparency, standardization, and data archiving. Yet, as pointed out in a special section of this issue (pp. 692–729), scientists are struggling with the huge amount, complexity, and variety of the data that are now being produced.

This issue marks the beginning of Science9s coverage of two prominent anniversaries. Charles Robert Darwin, originator of modern evolutionary theory, was born 200 years ago next month. His book setting forth this theory, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, was published 150 years ago in November. These anniversaries have special resonance for scientists worldwide, and the general public too, in that Darwin wrote specifically for a broad audience. As The Times (London) wrote in 1909 in honor of his first centenary, To no other man has it been given to effect a revolution in human thought so large, so pervading, so sudden, and yet so enduring. Darwin taught mankind to see all things in a new light, not only the mysteries of nature, great and small, the mysteries of existence and the innumerable objects of research, but the common things of everyday life.

![Figure][1] CREDIT: GRAND TOUR/CORBIS In art, restoration involves recapturing an object's aesthetic value. In ecology, the stakes are arguably much higher: Our planet's future may depend on the maturation of the young discipline of ecological restoration. In this issue, we sample restoration projects around the world and consider the state of the science of this emerging field. The goal of restoration ecology is not necessarily to restore an ecosystem to a pristine, prehuman ideal, but a long-term view is still important. In the opening Perspective, Jackson and Hobbs (p. [567][2]) highlight paleoecology as a component of restoration science. Two more Perspectives focus on aspects of terrestrial ecosystems that are vital to the success of restoration. Harris (p. [573][3]) considers the role of the soil microbial community: the bacteria and fungi that degrade organic matter and provide nutrients to the system. Dixon (p. [571][4]) highlights the role of pollinators, whose activities are essential to natural and restored plant communities. The struggle to balance ecosystem complexity and economic reality is the theme of three News features: two that examine efforts to restore functional forest ecosystems in southern China (p. [556][5]) and Borneo (p. [557][6]) and a third that probes the ecological consequences of burgeoning rubber plantations in Southeast Asia (p. [564][7]). How successful is restoration? In a Perspective, Palmer and Filoso (p. [575][8]) caution that it is unlikely to lead to the full recovery of the biodiversity and ecosystem services of undisturbed systems. A meta-analysis by Rey Benayas et al. , published on Science Express this week, confirms this view but shows that well-done restoration consistently enhances biodiversity and ecosystem services. In another Perspective, Norton (p. [569][9]) considers the limits to restoration posed by invasive species, and a News story examines the success of a national program targeting invasives in South Africa (p. [562][10]). Also on Science Express this week, Schulte et al. report an unprecedented restoration of oysters in the Chesapeake Bay in the eastern United States, which bodes well for the health of the entire estuarine ecosystem. Coral reefs, meanwhile, are under attack from human insults and climate change; a News feature (p. [559][11]) gives an overview of important efforts to restore damaged reefs. Finally, in a Research Article, Worm et al. (p. [578][12]) review current efforts to restore marine ecosystems and fisheries, concluding that making fisheries sustainable is an achievable goal. Restoration ecology is a relatively new science—the Society for Ecological Restoration International ([www.ser.org/default.asp][13]) celebrates its 21st birthday this year—but in its short life it has assumed a major role in sustainable development efforts across the globe. [1]: pending:yes [2]: /lookup/doi/10.1126/science.1172977 [3]: /lookup/volpage/325/573?iss=5940 [4]: /lookup/volpage/325/571?iss=5940 [5]: /lookup/doi/10.1126/science.325_556 [6]: /lookup/doi/10.1126/science.325_557 [7]: /lookup/volpage/325/564?iss=5940 [8]: /lookup/doi/10.1126/science.1172976 [9]: /lookup/volpage/325/569?iss=5940 [10]: /lookup/volpage/325/562?iss=5940 [11]: /lookup/volpage/325/559?iss=5940 [12]: /lookup/volpage/325/578?iss=5940 [13]: http://www.ser.org/default.asp

![Figure][1] CREDIT: GRAND TOUR/CORBIS In art, restoration involves recapturing an object's aesthetic value. In ecology, the stakes are arguably much higher: Our planet's future may depend on the maturation of the young discipline of ecological restoration. In this issue, we sample restoration projects around the world and consider the state of the science of this emerging field. The goal of restoration ecology is not necessarily to restore an ecosystem to a pristine, prehuman ideal, but a long-term view is still important. In the opening Perspective, Jackson and Hobbs (p. [567][2]) highlight paleoecology as a component of restoration science. Two more Perspectives focus on aspects of terrestrial ecosystems that are vital to the success of restoration. Harris (p. [573][3]) considers the role of the soil microbial community: the bacteria and fungi that degrade organic matter and provide nutrients to the system. Dixon (p. [571][4]) highlights the role of pollinators, whose activities are essential to natural and restored plant communities. The struggle to balance ecosystem complexity and economic reality is the theme of three News features: two that examine efforts to restore functional forest ecosystems in southern China (p. [556][5]) and Borneo (p. [557][6]) and a third that probes the ecological consequences of burgeoning rubber plantations in Southeast Asia (p. [564][7]). How successful is restoration? In a Perspective, Palmer and Filoso (p. [575][8]) caution that it is unlikely to lead to the full recovery of the biodiversity and ecosystem services of undisturbed systems. A meta-analysis by Rey Benayas et al. , published on Science Express this week, confirms this view but shows that well-done restoration consistently enhances biodiversity and ecosystem services. In another Perspective, Norton (p. [569][9]) considers the limits to restoration posed by invasive species, and a News story examines the success of a national program targeting invasives in South Africa (p. [562][10]). Also on Science Express this week, Schulte et al. report an unprecedented restoration of oysters in the Chesapeake Bay in the eastern United States, which bodes well for the health of the entire estuarine ecosystem. Coral reefs, meanwhile, are under attack from human insults and climate change; a News feature (p. [559][11]) gives an overview of important efforts to restore damaged reefs. Finally, in a Research Article, Worm et al. (p. [578][12]) review current efforts to restore marine ecosystems and fisheries, concluding that making fisheries sustainable is an achievable goal. Restoration ecology is a relatively new science—the Society for Ecological Restoration International ([www.ser.org/default.asp][13]) celebrates its 21st birthday this year—but in its short life it has assumed a major role in sustainable development efforts across the globe. [1]: pending:yes [2]: /lookup/doi/10.1126/science.1172977 [3]: /lookup/volpage/325/573?iss=5940 [4]: /lookup/volpage/325/571?iss=5940 [5]: /lookup/doi/10.1126/science.325_556 [6]: /lookup/doi/10.1126/science.325_557 [7]: /lookup/volpage/325/564?iss=5940 [8]: /lookup/doi/10.1126/science.1172976 [9]: /lookup/volpage/325/569?iss=5940 [10]: /lookup/volpage/325/562?iss=5940 [11]: /lookup/volpage/325/559?iss=5940 [12]: /lookup/volpage/325/578?iss=5940 [13]: http://www.ser.org/default.asp

![Figure][1] CREDITS (TOP TO BOTTOM): A. KONINGS; M. LOSOS The diversification and speciation of living organisms are the broad theme for this special section, continuing our celebration of Charles Darwin's 200th birthday. The five Reviews in this section present multiple views on research on diversification at scales ranging from the macroevolutionary to the molecular. Benton (p. [728][2]) examines the extents to which biotic and abiotic factors have shaped species diversity in the fossil record. Gavrilets and Losos (p. 732) use theoretical predictions and empirical data to identify general patterns in the temporal, spatial, and genetic/morphological properties of adaptive radiation. Schluter (p. [737][3]) reviews how research on ecological speciation has shifted in focus from morphological evolution to reproductive isolation, tracing the links between Darwin's ideas and current thinking. Fraser et al. (p. [741][4]) discuss the contentious area of microbial species formation. Finally, using examples from studies of genes and mutations involved in evolutionary change, Stern and Orgogozo (p. 746) illustrate how developmental biology and evolutionary theory might combine to reveal new predictive principles of genetic evolution. The special section is accompanied by evolutionary coverage in all other sections of the magazine. The News section features the second in our series of monthly “origins” essays, on the origins of art and symbolic behavior. The Commentary section includes reviews of new evolutionary books. Science Careers carries a feature on researchers in the museum world, who play a vital role in evolutionary research. In Reports, Krug et al. (p. [767][5]) reveal the legacy of the end-Cretaceous mass extinction for the subsequent diversification of bivalves [see the accompanying Perspective by Crame (p. [720][6])]. With a focus on conservation, Carnaval et al. (p. [785][7]) model spatially explicit evolutionary processes in endemic tree-frog species in the Brazilian Atlantic Forest (the biodiversity hotspot that inspired Darwin during his South American landfall). Forbes et al. (p. 776) reveal how a recent host shift of the fly Rhagoletis pomonella , a model for sympatric speciation, has led to incipient speciation in a parasitoid wasp that attacks the fly. Rowland and Emlen (p. 773) show facultative male trimorphism in dung beetles, a hitherto unsuspected level of intraspecific variation. Tang and Presgraves (p. [779][8]) report a cellular and molecular mechanism of hybrid sterility, which has a key role in speciation in Drosophila . And in Science Express, there is an echo of another of Darwin's central interests: Anderson et al. show that a melanism mutation has been selected for in gray wolves, most likely after a hybridization event with domestic dogs. This is a sample, not a survey. Research on speciation and diversification is itself expanding and diversifying. Evolutionary topics have been covered more frequently in Science in the first decade of the 21st century than in any previous one (and an order of magnitude more than in the years of the Modern Synthesis in the mid-20th century). This reflects not only the continuing efforts to understand and document the selective forces leading to speciation, but also how genetic research is homing in on the molecular and cellular mechanisms that enable diversification to occur. Darwin, we hope, would be thrilled. [1]: pending:yes [2]: /lookup/doi/10.1126/science.1157719 [3]: /lookup/doi/10.1126/science.1160006 [4]: /lookup/doi/10.1126/science.1159388 [5]: /lookup/doi/10.1126/science.1164905 [6]: /lookup/doi/10.1126/science.1169410 [7]: /lookup/doi/10.1126/science.1166955 [8]: /lookup/doi/10.1126/science.1169123

![Figure][1] CREDIT: DLILLC/CORBIS Forests have had a pervasive influence on the evolution of terrestrial life and continue to provide important feedbacks to the physical environment, notably climate. Today, studies of the world's forests are taking place against a backdrop of unprecedented change, largely resulting either directly or indirectly from human activity. In this special issue, we focus particularly on the future of forests in light of these changes. Current research on the relationships of forests and climate are considered in a Review by Bonan (p. [1444][2]), which provides an overview of how climate and forests are connected through physical, chemical, and biological processes that affect the carbon cycle, the hydrologic cycle, atmospheric composition, and the flow of solar energy and heat through the Earth system. In this video presentation, Jerry Franklin, Review author Gordon Bonan, and Perspective author Valerie Kapos discuss the importance of understanding the influence of forests on climate and some of the challenges of global forest governance. For scientists interested in forest dynamics (the turnover of individual trees and species over time), long-term forest plots are yielding field data on processes that take place over time scales longer than a research career. Until recently, though, the development of predictive models of forest dynamics lagged behind observation. In a Perspective, Purves and Pacala (p. [1452][3]) explain how advances in the mathematics of forest modeling and the ecological understanding of forest communities are generating exciting new possibilities for mapping future trajectories of forests over times from decades to centuries. At longer time scales, pollen and macrofossil records, along with genetic data, have revealed past movements of species as climates changed, which in turn provide pointers to the direction of future change, as discussed by Petit et al. in a Perspective (p. [1450][4]). Three further Perspectives deal with aspects of sustainable forest management. Miles and Kapos (p. [1454][5]) consider the question of incentives for “avoided deforestation” in the context of the recent Bali conference on climate change; Canadell and Raupach (p. [1456][6]) discuss how carbon sequestration can protect against the effects of climate change; and Chazdon (p. [1458][7]) considers how forests and their ecosystem services can be restored on degraded lands. In another Perspective, Agrawal et al. (p. [1460][8]) spotlight some recent trends in forest governance and ownership, which in effect define the limits and opportunities for sustainability. The three News reports take a look at how humans have reshaped wooded landscapes across the globe. Stokstad (p. [1436][9]) takes stock of a large-scale assessment of Amazonian biodiversity in regenerating forests and tree farms. Koenig (p. [1439][10]) examines the precariousness of the extensive rainforests in the Democratic Republic of the Congo. Morell (p. [1442][11]) reports on the success of preservation efforts in China's Hengduan Mountain Region, one of the richest temperate forest ecosystems. Forests and trees have been intimately bound up with the emergence and cultural development of our own species. Their future, and that of human society, depends ever more on how humans treat them in the coming decades. [1]: pending:yes [2]: /lookup/doi/10.1126/science.1155121 [3]: /lookup/doi/10.1126/science.1155359 [4]: /lookup/doi/10.1126/science.1155457 [5]: /lookup/doi/10.1126/science.1155358 [6]: /lookup/doi/10.1126/science.1155458 [7]: /lookup/doi/10.1126/science.1155365 [8]: /lookup/doi/10.1126/science.1155369 [9]: /lookup/doi/10.1126/science.320.5882.1436 [10]: /lookup/doi/10.1126/science.320.5882.1439 [11]: /lookup/doi/10.1126/science.320.5882.1442