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.


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.

Navigate This Article