section_path: Human geography/Natural resources and land use
section_name: Natural resources and land use
paragraph_text: Natural resources and land use
  
  Earth has resources that have been exploited by humans. Those termed non-renewable resources, such as fossil fuels, are only replenished over geological timescales. Large deposits of fossil fuels are obtained from Earth's crust, consisting of coal, petroleum, and natural gas. These deposits are used by humans both for energy production and as feedstock for chemical production. Mineral ore bodies have also been formed within the crust through a process of ore genesis, resulting from actions of magmatism, erosion, and plate tectonics. These metals and other elements are extracted by mining, a process which often brings environmental and health damage.
  
  Earth's biosphere produces many useful biological products for humans, including food, wood, pharmaceuticals, oxygen, and the recycling of organic waste. The land-based ecosystem depends upon topsoil and fresh water, and the oceanic ecosystem depends on dissolved nutrients washed down from the land. In 2019, 39 million km (15 million sq mi) of Earth's land surface consisted of forest and woodlands, 12 million km (4.6 million sq mi) was shrub and grassland, 40 million km (15 million sq mi) were used for animal feed production and grazing, and 11 million km (4.2 million sq mi) were cultivated as croplands. Of the 12 – 14% of ice-free land that is used for croplands, 2 percentage points were irrigated in 2015. Humans use building materials to construct shelters.