1.5 Human–Environmental Interaction

Natural resources are materials from nature that people use, like water, soil, forests, fish, minerals and fossil fuels. Renewable resources can be replaced naturally within a human lifetime, like solar energy, wind and timber if it is replanted. Nonrenewable resources form far too slowly to replace, like oil, coal and natural gas.

Land use is how people use an area of land: farming, housing, industry, parks or transportation. Land use reflects both the environment and the culture and economy of the people there. Flat, fertile river valleys tend to be farmed; steep slopes may be forested or terraced.

Sustainability means using resources in ways that meet people's needs today without making it harder for future generations to meet theirs. That idea was popularized by the United Nations' 1987 Brundtland Report. Unsustainable use includes overfishing, pumping groundwater faster than rain refills it, and clearing forests faster than they regrow.

Sustainability has environmental, economic and social sides. A policy that protects a forest but leaves local families with no income won't last, so geographers look at all three.

Environmental determinism was the claim that the physical environment, especially climate, determines how a society develops. In the late 1800s and early 1900s, geographers such as Ellen Churchill Semple and Ellsworth Huntington argued that people in temperate climates were naturally more energetic and advanced than people in tropical ones.

Geographers rejected this idea. It ignored human choice, technology, trade and history, and it was used to justify racism, colonialism and the idea that some peoples should rule others. You should know it so you can explain why it was abandoned, not as a valid explanation.

Possibilism says the environment sets limits and offers possibilities, but people decide how to respond, using their culture and technology. The French geographer Paul Vidal de la Blache is closely tied to this view.

Examples are everywhere. The Netherlands, with about a quarter of its land below sea level, built dikes, pumps and polders (land reclaimed from the sea) to farm and live there. Farmers in the Andes and in the Philippine Cordilleras carved terraces into steep mountainsides to grow crops. Air conditioning and large water projects allowed big desert cities like Phoenix and Dubai to grow.

• Clearing forests for farms and ranches, which can increase erosion and reduce biodiversity.
• Irrigation, which can make dry land productive but can also drain rivers or leave salt in the soil.
• Urban growth, which covers land with pavement and increases flooding from runoff.
• These impacts show the relationship runs both ways: the environment shapes options, and people reshape the environment.