Читать книгу The Atlas of Food - Erik Millstone - Страница 22

Water Pressure

MANY COUNTRIES already have insufficient fresh water. An increase in population will see many more experiencing water scarcity or water stress by 2050, while climate change will also undoubtedly have an impact on water supplies. A country’s average water supply obscures much regional variation. California’s burgeoning urban population is putting an increasing strain on the state’s limited resources, and in China the wheat-growing north is more water-stressed than its largely rice-growing south. Some countries, such as Egypt, are heavily dependent on water flowing in from another country, increasing their vulnerability. Irrigated crops are crucial to food security, and since 1950 the area under irrigation has doubled. Some methods are very wasteful of water, however, and badly drained irrigation can also lead to increased salinity. But support for farmers to enable them to develop small-scale, low-tech irrigation systems is vital to improving food security in poorer regions. Some countries are able to compensate for a scarcity of water by importing food. In China, much river water in the north is diverted from the fields to more profitable industrial uses, generating currency to pay for imported wheat to offset any shortfall. However, this makes China dependent on the global wheat market, and increases its food insecurity. Many less industrialized countries, especially those in Africa, are much more vulnerable to water stress: when they experience drought they are too poor to buy food elsewhere. Although the effects of climate change on water supplies are difficult to predict with precision, it is possible that the Middle East, Central Asia and southern Europe, already experiencing water stress, will see decreased river flows by the end of this century. Elsewhere, increased temperatures may initially increase glacial melt water flows from mountain ranges, but ultimately the flow may dry up, leading to devastating water shortages in areas such as northeast India, Bangladesh, and China – some of the most intensively farmed areas of the world.

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