What is desertification, and name two human activities that contribute to it.

• A. Desertification is the degradation of land in arid and semiarid regions; contributing activities include overgrazing and deforestation.
• B. Desertification is the spreading of deserts due to volcanic eruptions; contributing activities include snowfall and urbanization.
• C. Desertification refers to desert areas becoming more productive due to irrigation.
• D. Desertification only occurs in tropical rainforests due to pollution.

Answer: (A)

Desertification is the long-term degradation of land in arid and semiarid regions, where soil becomes less fertile, vegetation cover declines, and productivity falls due to losses in soil structure and moisture. Two human activities that drive this process are overgrazing and deforestation. Overgrazing removes vegetation and compact soils, so rainfall runs off instead of soaking in, organic matter declines, and topsoil is easily eroded. Deforestation strips away tree roots and canopy that protect soil, increasing wind and water erosion, reducing soil moisture retention, and speeding the inland spread of degraded land. These changes diminish the land’s ability to support vegetation and people. Other descriptions given aren’t accurate: desertification isn’t caused by volcanic eruptions spreading deserts, it isn’t simply about deserts becoming more productive through irrigation, and it isn’t limited to tropical rainforests.