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By Root 2188 0

even halts industrial production. Of the water required for cities and for irrigation, two-thirds depends on groundwater pumped from wells tapping aquifers. However, those aquifers are becoming depleted, permitting seawater to enter them in most coastal areas, and causing land to sink under some cities as the aquifers are becoming emptied. China also already has the world’s worst problem of cessation of river flows, and that problem is becoming much worse because water continues to be drawn from rivers for use. For instance, between 1972 and 1997 there were flow stoppages on the lower Yellow River (China’s second longest river) in 20 out of the 25 years, and the number of days without any flow increased from 10 days in 1988 to the astonishing total of 230 days in 1997. Even on the Yangtze and Pearl Rivers in wetter South China, flow cessation happens during the dry season and impedes ship navigation.

China’s soil problems start with its being one of the world’s countries most severely damaged by erosion (Plate 26), now affecting 19% of its land area and resulting in soil loss at 5 billion tons per year. Erosion is especially devastating on the Loess Plateau (the middle stretch of the Yellow River, about 70% of the plateau eroded), and increasingly on the Yangtze River, whose sediment discharge from erosion exceeds the combined discharges of the Nile and Amazon, the world’s two longest rivers. By filling up China’s rivers (as well as its reservoirs and lakes), sediment has shortened China’s navigable river channels by 50% and restricted the size of ships that can use them. Soil quality and fertility as well as soil quantity have declined, partly because of long-term fertilizer use plus pesticide-related drastic declines in soil-renewing earthworms, thereby causing a 50% decrease in the area of cropland considered to be of high quality. Salinization, whose causes will be discussed in detail in the next chapter (Chapter 13) on Australia, has affected 9% of China’s lands, mainly due to poor design and management of irrigation systems in dry areas. (This is one environmental problem that government programs have made good progress in combating and starting to reverse.) Desertification, due to overgrazing and land reclamation for agriculture, has affected more than one-quarter of China, destroying about 15% of North China’s area remaining for agriculture and pastoralism within the last decade.

All of these soil problems—erosion, fertility losses, salinization, and desertification—have joined urbanization and land appropriation for mining, forestry, and aquaculture in reducing China’s area of cropland. That poses a big problem for China’s food security, because at the same time as its cropland has been declining, its population and per-capita food consumption have been increasing, and its area of potentially cultivatable land is limited. Cropland per person is now only 0.1 hectare, barely half of the world average, and nearly as low as the value for Northwest Rwanda discussed in Chapter 10. In addition, because China recycles very little trash, huge quantities of industrial and domestic trash are dumped into open fields, polluting soil and taking over or damaging cropland. More than two-thirds of China’s cities are now surrounded by trash whose composition has changed dramatically from vegetable leftovers, dust, and coal residues to plastics, glass, metal, and wrapping paper. As my Dominican friends envisioned for their country’s future (Chapter 11), a world buried in garbage will figure prominently in China’s future as well.

Discussions of habitat destruction in China begin with deforestation. China is one of the world’s most forest-poor countries, with only 0.3 acres of forest per person compared to a world average of 1.6, and with forests covering only 16% of China’s land area (compared to 74% of Japan’s). While government efforts have increased the area of single-species tree plantations and thereby slightly increased the total area considered forested, natural forests, especially old-growth forests, have been shrinking.