Based on the analytical framework of securitization, this article argues that cooperation between China and the United States on climate change will not lose momentum despite President Trump’s seemingly passive stance. A securitization process on the climate issue has been ongoing in China since President Xi Jinping took office and proposed the Overall National Security Outlook (ONSO). Climate security was thus integrated into China’s political discourse as a key component of ecological and common security, leading to a period of China-U.S. cooperation during the Obama administration. Similarly, in the United States, climate policy has been cemented in security planning and assessment of various federal agencies. The U.S. security sector seems to be largely unaffected by the White House decision to withdraw from the Paris Agreement. A growing number of Americans treat climate change as a security threat and many U.S. states and cities, in collaboration with business leaders, have taken on a role in international climate diplomacy. Combined with existing intergovernmental collaborative projects, robust market forces and innovative local initiatives will continue to push China-U.S. climate cooperation forward. As a necessary step to sustain its ties with the United States on climate issues, the Chinese government needs to propose a renewed bilateral framework on energy and environment cooperation under the China-U.S. Comprehensive Economic Dialogue.