In this year's book, we have assembled the latest information on these new environmental threats, and have also described some of the surprising and potentially dangerous connections between these problems. One chapter, for example, examines the far-reaching effects that climate change may have on natural ecosystems, while another shows how dependent humanity is on the "services" provided by those ecosystems--from the pollination of crops to the maintenance of safe water supplies. and citizen activists, a strong international agreement can lead to surprisingly rapid progress.