The climate crisis is emerging as an extreme crisis for the entire earth and humanity. Recently, the 6th IPCC report was published, but the forecast results are even more disastrous. Accordingly, the United States, one of the world's strongest developed countries, is doing its best to prepare active countermeasures against the climate crisis in the field of defense. In particular, the United States recognizes the climate crisis as one of the biggest threats to national security, and is designing policies based on this perception. However, in the case of South Korea, there is no continuously policy for responding to the climate crisis in the defense sector. In this study, in order to think about the problems of South Korea's defense climate crisis management policy, a comparative study was conducted with the U.S. defense climate crisis management policy. As a result, specific policies for each field are being conceived and implemented in the U.S. defense climate crisis management policy. However, in the case of South Korea, it was confirmed that there is no recognition of the climate crisis as a threat by the Ministry of National Defense and no specific policy.