It has become quite evident that more effective global environmental governance will be needed to adequately address climate change. The devil lies in the details. A new environmental regime must be constructed with institutional capacities designed to respond to global-scale collective action problems in general and the specific challenges of climate change in particular. To begin to define exactly what those capacities would look like, we provide a diagnostic profile of the current environmental regime’s failure. We group the elements of institutional failure into three categories: (i) political economy considerations, (ii) negotiation roadblocks, and (iii) structural deficiencies with regards to ensuring adherence to shared commitments (i.e. lack of discipline on free riding). Ultimately, we propose a robust, yet lean, Global Environmental Organization (GEO) that would function with support from other international bodies, most notably the World Trade Organization (WTO).