Ali Wayne, Security Fellow with the Truman National Security Project, has ranked the 13 defining moments of 2016 in a recent article in War on the Rocks. Among them was the monumental development in climate change mitigation, the Paris Agreement. In September 2016, the two biggest contributors to global carbon emissions, United States and China, agreed to ratify the agreement in an unprecedented move to combat climate change.

“#5: The United States and China ratified last December’s COP21 agreement. Their joint step on September 3 was a landmark achievement. Accounting for some 40 percent of global emissions of greenhouse gases, the two countries must work together for collective action against climate change to have any hope. Given the growing intensity and multiplicity of strategic mistrust between Washington and Beijing, climate cooperation offers a rare proof of concept that the world’s two foremost powers can collaborate to address the world’s central challenges. Orville Schell observed last July that ‘[t]he threat of climate change presents both countries with, paradoxically, a fortuitous area of common interest that could catalyze the ‘new kind of major-power relationship’ that Mr. Xi has called for.’

Another potential area of cooperation between the United States and China involves the Middle East, whose cataclysmic reordering is unlikely to resolve itself for several generations. While the former’s dependence on crude oil from the region is diminishing, the latter’s reliance is projected to increase for the next two decades or so. The most immediate focus of their partnership should be to safeguard crucial maritime chokepoints from regional convulsions — especially the Strait of Hormuz, through which approximately 30 percent of the world’s seaborne-traded oil passes.”

Read the full list here.

Ali Wyne is a nonresident fellow with the Atlantic Council’s Brent Scowcroft Center on International Security and a security fellow with the Truman National Security Project.