This study provides an overview of sixty-four proposed post-Kyoto climate policy architectures as identified in recent literature. These architectures have been evaluated using various criteria, including equity, environmental outcomes, efficiency, participation incentives, and institutional design. Despite the importance of such criteria, no universally accepted framework exists to prioritize one over another, reflecting the complexity of constructing a global climate governance regime. Central to this debate is the choice of decision heuristics—specifically, the controversy between "grandfathering" and "per capita" approaches to setting emission targets. The Kyoto Protocol adopted a grandfathering approach, which has been widely criticized by developing countries for failing to account for historical emissions by industrialized nations. In contrast, many developing nations advocate for per capita-based emissions caps to uphold their development rights. However, this has met resistance from developed countries, particularly the United States, Canada, and Australia, who argue it imposes unfair burdens. The lack of consensus on these decision heuristics remains a fundamental obstacle to establishing a binding and equitable post-Kyoto international climate governance regime.