Summary: As the Arctic warms at three times the global rate, there are growing concerns about the impacts of climate change on barren-ground caribou populations, and the Indigenous people that rely on caribou for subsistence. Investigators have speculated that the climate-driven ‘greening of the Arctic’ would benefit caribou populations, but paradoxically, many have declined in recent years. This pattern has raised questions about the influence of changing summer habitat conditions on caribou and how populations may be impacted in the future. The short Arctic summer provides caribou with important forage resources but is also the time they are exposed to intense harassment by insects, factors which are both being altered by longer, warmer growing seasons. Additionally, the summer ranges of barren-ground caribou often overlap with areas targeted for energy development, compounding concerns about the resilience of caribou to changing conditions. To understand the influence of climate-driven summer habitat conditions and human development on caribou in Arctic Alaska, the USGS is working with a variety of federal, state, tribal and international partners. This talk will discuss our recent findings about the influence of summer habitat and development on the behavior and demography of barren-ground caribou in Alaska, and how we are forecasting shifts in caribou distributions in response to future climate change scenarios.