The paper examined climate change and human security in Rivers State, Nigeria. The security environment in Rivers State has degenerated in the last few decades. The old security challenge has assumed a devastating dimension, while new threats such as climate change have propped up. The concept of human security is about people-centred security, an unconventional aspect of national security, which was previously focused on protection from external aggression and protection of sovereignty but now includes social, economic, and environmental problems that threaten global security. At present, human security is viewed from the angle of freedom that the citizens of a nation enjoy a peaceful and safe environment. However, the change in weather conditions has become a serious threat to human security. The effects of climate change include health challenges, high temperature, flooding and erosion, poor agricultural harvests, among others. The investigation was informed on the fact that greenhouse gas emissions emanating from anthropogenic activities have adverse effects on the inhabitants of Rivers State. The study aims at interrogating the cause and effects of climate change in Rivers State. The study adopted a qualitative method of data gathering technique. The paper unravelled that climate change has serious effects on human security emanating from flooding, poor agricultural harvest, health challenges, among others. The paper recommends the government should intervene in the adaptation of climate change to sustain the Rivers State inhabitants.