(ĭrō'zhӘn), general term for the processes by which the surface of the earth is constantly being worn away. The principal agents are gravity, running water, near-shore waves, ice (mostly glaciers), and wind. All running water gathers and transports particles of soil or fragments of rock (formed by weathering ), and every stream carries, in suspension or rolling along its bottom, material received from its tributaries or detached from its own banks. These transported particles strike against the bedrock of the stream channel, literally grinding it away and eventually settle out along the channel or find their way to the sea. The Mississippi River is being reduced by erosion at the rate of 1 ft (30 cm) in about 9,000 years. Seacoasts are eroded by ocean waves, which detach loose or nonresistant material. Waves wear the rock by both the force of their own impact and the abrasive action of the detritus they carry. Global warming , by increasing sea levels, accelerates coastal erosion and…