The 2015 United Nations Paris Agreement on Climate reinforces actions to conserve and enhance forests as carbon reservoirs. A decade after sub-national demonstration projects to reduce emissions from deforestation and forest degradation (REDD+) commenced, we examine why many REDD+ schemes appear to have fuelled social conflict while having limited success in addressing the drivers of forest loss and degradation. Our analysis is two-tiered: first we synthesise findings from a set of ethnographic case studies of REDD+ in Mainland Southeast Asia, conducted by the authors; second, we explore whether the insights from our regional synthesis apply globally, through a comparative review of published qualitative research on REDD+ field experiences. Our results reveal three major implementation dynamics that can undermine REDD+ in practice, which we conceptualise from science and technology studies and critical political ecology as follows: 1) problems with the enrolment of governments, civil society, and local forest users in REDD+ governance; 2) the prevalence of overly simplified codification systems for REDD+ implementation that mismatch targeted societies and landscapes; and 3) the consequent dissonance between REDD+ objectives and outcomes. Together, these problematic dynamics reveal how and why REDD+ so often misses its targets of reducing deforestation and delivering community benefits. In effect, it appears that REDD+ in the course of implementation maps onto local power structures and political economies, rendering it blunt as tool for change. The potential of REDD+ as a ‘solution’ in the global climate regime must therefore be scrutinized, along with other similar mechanisms espoused by the green economy.