If we are to think imperially about global environmental politics we must be clear about what we mean by empire, as use of the term often conflates two distinct trends. If “empire” means the resurgence of muscular American unilateralism, then the principal ramification is the need to understand international environmental cooperation not simply “after hegemony” but in the face of it, with American domestic politics a central consideration. If the term refers instead to broader processes of world economic restructuring that are not reducible to American foreign policy initiatives, then we need to situate global environmental politics in the context of changing global modes of accumulation and regulation. Although the two images of empire are not easily reconciled, some of their implications for the study of global environmental politics are shared. Both suggest the growing importance of studying contentious environmental politics alongside more familiar cooperation-theoretic approaches. Also, both suggest that tensions between the localized and non-localized meanings of the world's forests, rivers, watersheds, and coastlines will be at the center of such contention.