GEARS End-of-Year Practice Exam

Deforestation disrupts how air, water, and land interact, altering flows among Earth's major spheres. When forests are cleared, the atmosphere is affected first: trees normally take up carbon dioxide and release water vapor through transpiration. With fewer trees, CO2 can accumulate in the air, contributing to warming and changing weather and climate patterns. The local energy balance also shifts, since bare land reflects and absorbs heat differently than forested land, further impacting the atmosphere. The hydrosphere feels the impact as rainfall patterns and soil moisture change. Without the protective cover of trees, rainfall runs off the surface more quickly, increasing soil erosion and delivering more sediment and nutrients into rivers and lakes. This changes water quality, sediment load, and the availability of fresh water downstream, and can alter evaporation and precipitation dynamics in the region. In the geosphere, soil structure and fertility decline as roots are removed and erosion intensifies. Loss of organic matter and topsoil lowers land productivity and can trigger landslides or shifts in landforms over time, demonstrating how surface vegetation ties into the stability and composition of the underlying earth. Cryosphere effects are not the primary outcome of deforestation; the main changes occur across the atmosphere, hydrosphere, and geosphere, with climate-driven influences potentially reaching frozen regions more indirectly over longer timescales.