6.7A - Growing Resource Demands
Growing demand for food, fuel and other resources globally has led to contrasting regional trends in land-use cover (deforestation, afforestation, conversion of grasslands to farming) affecting terrestrial carbon stores with wider implications for the water cycle and soil health.
The burning of fossil fuels is not the only human activity that is disturbing the biological carbon and hydrological cycles. There are others related to the growing global demand for food, fuel and other resources, all of which the outcome of continuing global population growth and economic development.
Deforestation
The clearance of forests both for their timber and for the land they occupy. In the latter case, the land is mainly cultivated to provide grazing for livestock or to produce cash crops. However, it is not all bad news, as afforestation and reforestation is under way in temperate latitudes. This is helping to offset the loss of tropical rainforest 'services', but n the case of afforestation much is taking place on what was agricultural land.
There has been a net gain in more than 500,000 ha of forest area in China for 1990-2015, as well as gains of 250,000-500,000 ha in the USA and India. A net gain of 50,000-250,000 was experienced in Russia, Turkey, Iran, Italy, France and Spain.
There was little change in the rest of Europe, northern Africa and the Middle East and the remainder of Central Asia. However, there were losses in South America, Central Africa, and Australia, and losses of more than 500,000 ha in Brazil and Indonesia.
There has been a net gain in more than 500,000 ha of forest area in China for 1990-2015, as well as gains of 250,000-500,000 ha in the USA and India. A net gain of 50,000-250,000 was experienced in Russia, Turkey, Iran, Italy, France and Spain.
There was little change in the rest of Europe, northern Africa and the Middle East and the remainder of Central Asia. However, there were losses in South America, Central Africa, and Australia, and losses of more than 500,000 ha in Brazil and Indonesia.
Grassland conversion
Temperate and tropical grasslands have also become heavily exploited by agriculture. Both grassland types have suffered as a result of overexploitation. The simple act of ploughing leads to an immediate loss of both carbon dioxide and moisture, as well as a change in runoff characteristics.
Urbanisation
No land-use conversion is greater than that associated with urbanisation. Much space has already been taken over and many ecosystems completely destroyed by the insatiable demand for space needed to accommodate a rapidly rising urban population and their widening range of economic activities. Of all forms of development, none is having a more disruptive impact on the carbon and water cycles than urbanisation. Towns and cities are focal points of both GHG emissions and intense water demand.
Clearly, these changes vary from place to place and as a consequence so does their overall impact on carbon stores, soil health and the water cycle. In some locations, the impact is considerable, in others it is minimal if at all.
Clearly, these changes vary from place to place and as a consequence so does their overall impact on carbon stores, soil health and the water cycle. In some locations, the impact is considerable, in others it is minimal if at all.