Assess students' understanding of major carbon reservoirs (atmosphere, oceans, soils, biosphere, fossil fuels) and the fluxes connecting them; evaluate how fossil fuel combustion and deforestation alter these fluxes to raise atmospheric CO2, change ocean uptake, and increase radiative forcing and climate impacts. Tasks may include interpreting box-diagram flux changes, explaining mechanisms, and performing basic quantitative estimates of CO2 transfers and their climatic consequences.