Climate Change National Security Strategy Act of 2019 This bill requires the impacts of climate change to be identified and considered in the development and implementation of national security policies and plans. Specifically, the bill requires the National Security Advisor and the Office of Science and Technology Policy to jointly establish an interagency Climate and National Security Working Group, which must develop an action plan on climate-related impacts on national security interests. Further, specified federal departments and agencies must each develop a plan that ensures that such impacts are identified and considered in the development and implementation of relevant national security doctrine, policies, and plans. The plans must be updated at least annually.