A free, self-paced textbook in 8 chapters. Read a chapter, then drill it with the 100 companion flashcards using spaced repetition.
Earth's atmosphere is divided into five main layers stacked from lowest to highest: the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. Most weather occurs in t...
Wind is generated by differences in air pressure, which arise from uneven heating of Earth's surface. Air naturally flows from high-pressure regions to low-pressure regions, settin...
Climatologists classify the world into five major climate zones using the Köppen system: tropical (A), dry (B), temperate (C), continental (D), and polar (E). Tropical climates fea...
The greenhouse effect is a natural process in which certain atmospheric gases trap outgoing infrared radiation, warming Earth's surface above what it would otherwise be. The four m...
Carbon continuously cycles through Earth's atmosphere, biosphere, oceans, and geosphere. The main steps include photosynthesis, in which plants and algae absorb CO₂; respiration, i...
Beyond everyday weather, Earth's atmosphere and oceans produce powerful recurring phenomena. The El Niño–Southern Oscillation (ENSO) is a coupled ocean-atmosphere cycle that altern...
Rising greenhouse gas concentrations reshape the planet through interconnected impacts. One of the most visible is sea level rise, driven by the thermal expansion of warming ocean...
Responding to climate change requires both mitigation — actions to reduce or prevent greenhouse gas emissions — and adaptation — adjustments that minimize harm from climate impacts...