Summarize the ways in which human activities have affected the world's deserts, grasslands, forests, and mountains.

Grassland:

Conversion to croplands, release of CO2 to atmosphere from burning grasslands, overgrazing by livestock and oil production and off road vehicles in arctic tundra

Desert:

Large deserts cities, destruction of soil and underground habitat by off road vehicles, soil salinization from irrigation, depletion of groundwater land disturbance and pollution from mineral extraction

Forests:

Clearing for agriculture, livestock grazing, timber urban development, conversion of diverse forests to tree plantations and damage from off road vehicle and Pollution of forests streams

Mountains:

Agriculture and timber and mineral extraction, hydroelectric dam and reservoir, increasing tourism air pollution from urban areas, soil damage from off road vehicles and water supply threatened by glacial melting