Why are terrorism, globalization, diseases, and climate change multifaceted in terms of how they are defined as policy problems? Specifically, how are they viewed as economic, political, security, and/or environmental policy problems?

A good way to unpack this question is to start with terrorism and see how it is connected with other issues. On one hand, it might seem as if terrorism is an isolated security threat, but on the other hand, if one studies it more deeply, one sees that it is connected to other factors affecting the global economy.
Diseases and climate change both increase poverty and worsen living conditions in many countries. Climate change causes droughts and the spread of certain pests and plant diseases. This means that young men who previously would have worked in the fields now flock to cities looking for jobs—which often do not exist. Their frustration with the lack of economic prospects can make them vulnerable to recruitment by terrorist groups, especially if those group offer wages or the opportunity to extort money or food.
People in poor countries may attempt to migrate to rich countries but may lack skills for many jobs and knowledge of the local language. They are then likely to end up clustered in slums alienated from their local societies, and they are then also vulnerable to recruitment by terrorists.