Until about 1960, developed nations were responsible for most of this consumption. Since then, however, industrialization in the newly developing nations has resulted in greater reliance on resource- intensive and highly polluting production processes. Cultural factors also influence how populations affect the environment. For example, cultural variations in attitudes toward wildlife and conservation influence environmental conservation strategies, because public support for various policy interventions will reflect societal values. During the past three centuries, the amount of Earth's cultivated land has grown by more than 450 percent, increasing from 2.65 million square kilometers to 15 million square kilometers.
Data exclude the countries of the former Soviet Union.
These types of land-use changes have several ecological impacts. Converting land to agricultural use can lead to soil erosion, and the chemicals often used in fertilizers can also degrade soil. Deforestation is also associated with soil erosion and can lessen the ability of soil to hold water, thereby increasing the frequency and severity of floods. Human-induced changes in land use often result in habitat fragmentation and loss, the primary cause of species decline. In fact, if current rates of forest clearing continue, one-quarter of all species on Earth could be lost within the next 50 years.