The chapters in this section provide a summary of what we have learned from the Arctic Messenger about ongoing changes in the state of the Arctic environment and of the significance of such changes not only to the Arctic itself but also to the global ecosystem. The choice of themes is personal and not all are covered with the same degree of detail. The main criterion I used to select a theme is the notion of an anthropogenic (human) activity causing an adverse environmental impact at a far-distant location. Consequently, I have not included such possible themes as chronic and acute oil spills. This is not a statement about the environmental damages that can be caused by such incidents but is a recognition that such spills do not generally result in circumpolar, hemispheric or global effects.