Global Climate Change Diplomacy Act This bill requires the Department of State to take specified actions to address global climate change. Specifically, the State Department must establish and staff Climate Change Officer positions, the holders of which shall be assigned to U.S. embassies, consulates, or diplomatic missions. Each officer shall provide climate change mitigation expertise, engage with international entities concerned with addressing climate change, and facilitate U.S. engagement in bilateral and multilateral cooperation on climate change. Each chief of mission in a foreign country must take certain climate change-related actions, including (1) developing a strategy to improve and increase studying, mitigating, and adapting to climate change; and (2) certifying that considerations related to climate change are incorporated in activities, management, and operations of the U.S. embassy or other diplomatic post under the director of the chief of mission. The State Department must also establish a curriculum at its Foreign Service Institute to provide employees with specialized climate change training, and it must ensure that embassy personnel responsible for contracts, grants, or acquisitions are trained on evaluating such agreements for considerations related to sustainability and climate change.