Final answer:
The "ultimate international commons" refers to globally shared resources like the atmosphere, oceans, and biodiversity, which require international cooperation for management and protection, as no single nation can solve these cross-border environmental issues alone.
Step-by-step explanation:
The term "ultimate international commons" refers to shared global resources that are not confined within a single country's borders and hence require collective management and preservation. Examples of these resources are the atmosphere, the oceans (for fish and fishing), and biodiversity. These resources can be threatened by activities such as overfishing or pollution. To protect them, international cooperation is essential because no single nation can resolve these issues alone due to their global nature.
International agreements and organizations like the International Commission for the Conservation of Atlantic Tunas (ICCAT) are examples of how nations attempt to manage the international commons. However, the effectiveness of these entities is often challenged by issues like lack of enforceability and the temptation for nations to free-ride, taking advantage of the commons while contributing little to their preservation.
Environmental protection efforts have increased globally, yet international externalities like global warming and the loss of biodiversity continue to be major challenges that can only be addressed through global cooperative efforts.