This chapter serves as an accessible introduction to climate change, catering to readers with limited scientific knowledge but a keen interest in the subject. It consolidates essential climatic information and insights from Earth and atmospheric sciences, delving into topics such as the atmosphere, greenhouse gases, global warming potential, CO 2 equivalent emissions, aerosols, and carbon budget. Moreover, it presents compelling scientific evidence that establishes human activity as the primary driver of recent global warming and illustrates the spatial distribution of this warming. A significant focus of this chapter lies in comprehending the global modes of natural climate variability, unraveling the intricate mechanisms behind fluctuations in the Earth's climate. It provides an overview of the latest advancements in climate models, observations, and reanalyses, as well as key institutions and programs involved in handling climatic datasets. Ultimately, this chapter aims to equip readers with a foundational understanding of climate change by consolidating crucial concepts and developments. It concludes by summarizing the key takeaways from the chapter and offering insights into future directions in climate research. By presenting complex scientific concepts in a reader-friendly manner, this chapter empowers individuals to grasp the basics of climate change and sets the stage for further exploration into more detailed aspects of this critical field.