I highlight new and emerging threats to tropical forests, the world's most biologically diverse ecosystems. The drivers of tropical forest destruction and key perils to biodiversity have changed over the past decade and will continue to evolve in the future. Industrial drivers of forest conversion, such as logging, large-scale soy and cattle farming, oil-palm plantations, and oil and gas development, have escalated in importance, buoyed by rapid globalization, economic growth, and rising standards of living in developing nations. Biofuels are likely to grow rapidly as a driver of future forest destruction. Climate change is similarly emerging as a potentially serious driver of change in the tropics, and many species, including certain amphibians, primates, and plants, are being harmed by emerging pathogens. In general, old-growth forests are vanishing rapidly and being replaced by fragmented, secondary, and selectively logged forests, particularly in impoverished tropical countries. Road expansion continues apace and is increasingly imperiling the world's last tropical frontiers. Human population growth, especially in developing nations, remains an important underlying threat to forests. These various environmental dangers often operate in concert, magnifying their impacts and posing an even greater threat to tropical forests and their biodiversity.