Increasing of green house gases (GHG) emissions in the atmosphere is raising global concern. This is because these emissions have led to a shift of temperatures, unpredictable weather patterns and sporadic rainfall that has caused heavy floods, among other adverse impacts. As a result, many countries are pursuing various policies and strategies to help mitigate and adapt to climate change. This will require an understanding of the processes that contribute to it. This compendium will therefore introduce learners to the basic science of climate change by focusing on an understanding of global change, concept of climate change, causes of climate change, vulnerability to, and impact of climate change, generation of climate change data, and international dialogues, processes and mechanisms on climate change.