Expanding use of archaeology in climate change response by changing its social environment.

Climate science has outlined targets for reductions of greenhouse gas emissions necessary to provide a substantial chance of avoiding the worst impacts of climate change on both natural and human systems. How to reach those targets, however, requires balancing physical realities of the natural environment with the complexity of the human social environment, including histories, cultures, and values. Archaeology is the study of interactions of natural and social environments through time and across space. As well, the field of cultural resources management, which includes archaeology, regularly engages with values such as site significance and allocation of funding that the modern social environment ascribes to its own history. Through these two approaches, archaeology has potential to provide both data for and methods of addressing challenges the global community faces through climate change. To date, however, archaeology and related areas of cultural heritage have had relatively little role in the global climate response. Here, we assess the social environment of archaeology and climate change and resulting structural barriers that have limited use of archaeology in and for climate change with a case study of the US federal government. On this basis, we provide recommendations to the fields of archaeology and climate response about how to more fully realize the multiple potential uses of archaeology for the challenges of climate change.

Timing and causes of mid-Holocene mammoth extinction on St. Paul Island, Alaska.

Relict woolly mammoth (Mammuthus primigenius) populations survived on several small Beringian islands for thousands of years after mainland populations went extinct. Here we present multiproxy paleoenvironmental records to investigate the timing, causes, and consequences of mammoth disappearance from St. Paul Island, Alaska. Five independent indicators of extinction show that mammoths survived on St. Paul until 5,600 ± 100 y ago. Vegetation composition remained stable during the extinction window, and there is no evidence of human presence on the island before 1787 CE, suggesting that these factors were not extinction drivers. Instead, the extinction coincided with declining freshwater resources and drier climates between 7,850 and 5,600 y ago, as inferred from sedimentary magnetic susceptibility, oxygen isotopes, and diatom and cladoceran assemblages in a sediment core from a freshwater lake on the island, and stable nitrogen isotopes from mammoth remains. Contrary to other extinction models for the St. Paul mammoth population, this evidence indicates that this mammoth population died out because of the synergistic effects of shrinking island area and freshwater scarcity caused by rising sea levels and regional climate change. Degradation of water quality by intensified mammoth activity around the lake likely exacerbated the situation. The St. Paul mammoth demise is now one of the best-dated prehistoric extinctions, highlighting freshwater limitation as an overlooked extinction driver and underscoring the vulnerability of small island populations to environmental change, even in the absence of human influence.