In much of maritime Southeast Asia, environmentalism, in its broadest sense of preserving, restoring and improving the natural world, cannot be fully understood without a sense of how animist religions had once conditioned the political and social ecology of the region. The transition to the Anthropocene - "the human epoch" - occurred in tandem with a turn towards monotheism in much of Southeast Asia's uplands, a shift which this book considers as its spiritual dimension. Christianity and Islam became thus implicated in colonial projects that reduced biodiversity and increased carbon emissions in Sumatra and Malaya, two hallmarks of how the Anthropocene has reshaped our planet. Specifically, the process in which conversions to these two religions occurred during the long nineteenth century helped to shape social structures that voided the natural world of enchantment, ushered in a cash economy and relocated power to remake local landscapes into the hands of a urban, distant elite.

This core of this project's enquiry are the changes to religiously mediated encounters with the natural world fostered by intertwining conversions: a turn from animist-inflected worship to modernist monotheism and a shift from nature as kin to nature as commodity. The highlands of North Sumatra in the long 19th century, is well-suited for this study as the region's inhabitants, the Batak, experienced not only two waves of mass religious conversion - the first to Islam, early in the nineteenth century and the second to Christianity towards the end of the century - but also shifts in productive ecology from forest foraging and subsistence agriculture to cash cropping that brought the area into the ambit of the state. Weaving through threads of inter-generational micro-histories, we find a history of conversions that was not as much marked by theological changes in faith as it was with a growing estrangement of religious practices from natural world as a source of everyday blessings. The decline of local communings with nature, led by a shaman class, renders religion increasingly impotent as a bulwark against capitalistic environmental exploitation. The spiritual Anthropocene, then, is as much an epoch of disempowerment for many peoples as it is about humanity's unprecedented power. Understanding this history enables us to critique the present: the limited and non-radical ways in which Christian and Muslim organizations in Indonesia and Malaysia engage with the issue of environmental change.