Given the globalization and connectedness of the world, threats to the security of the United States can originate anywhere, a lesson the country learned in the tragedy of September 11. There are several types of threat that can only be countered through global networks.
The first type of global threat is one of epidemic disease. An example was the SARS crisis of 2003–2004. When a new disease evolves, it can be transmitted around the world quickly as people travel by airplane. The key to preventing the spread of such diseases is global reporting and international collaboration of scientists to work on vaccines and cures. The World Health Organization and the United States Centers for Disease Control and Prevention work together productively on such issues.
Another major threat is terrorism. Like epidemic disease, this is a global threat, with groups spawned by grievances across the globe sometimes attacking their own countries but also attacking other countries they consider sources of their grievances. Discovering and preventing terrorist attacks often relies on global intelligence sharing. International cooperation can monitor travels and communications of persons of interest.
Global climate change has been identified as a major threat to United States security. It disrupts everything from disease patterns to food supplies, increases global migration as areas become uninhabitable, and increases the frequency of extreme weather events. According to the Worldwide Threat Assessment of the US Intelligence Community,
global environmental and ecological degradation, as well as climate change, are likely to fuel competition for resources, economic distress, and social discontent through 2019 and beyond.
Global climate change can only be addressed through global cooperation and innovative solutions.