**1. Introduction**

Planet Earth is a highly complex and truly unique celestial body, fine-tuned to sustain life within a very narrow range of tolerances [1, 2]. Within this narrow band of environmental parameters, our civilization emerged over the past several thousand years. As we discovered ways in which to harness the energy stored within our planet, from burning wood, to coal, to petroleum products, we began to increasingly change the environment we live in [3, 4]. The resultant slow but persistent climate change (CC) is beginning to manifest itself across multiple domains of human existence, from rising sea levels, to wind disasters and forest fires, to the emergence of new invasive species [5–8]. This chapter will discuss the impact of CC on various domains of human health and well-being, with specific focus on their relationship to international health security (IHS). Given the vastness of this important topic area, our goal will be to provide an overview of the most pressing issues and most relevant subdomains (**Figure 1**). However, it is simply not feasible to cover this entire subject within a single book chapter, thus limiting the current manuscript to a bullet-point synopsis.

### **Figure 1.**

*Word cloud demonstrating the most common and dominant themes within this chapter. The highly complex nature of the issue of climate change and its relationship to human health is clearly evident.*
