Sir

Stephen Budiansky has discussed in Correspondence1 how, in the United States, affluence could be good for the environment. He argued that although the US population grew by 90% and the real per capita disposable personal income grew by 177% between 1945 and 1997, the per capita area used for food production, urban areas and other land uses remained unchanged, or even declined.

The per capita land use for food production in the United States (1.69 ha) is slightly lower than in developing countries (sub-Saharan Africa is on average 2 ha), whereas food production is several magnitudes higher. Budiansky cites higher use of fertilizer as the main factor accounting for the higher yields per hectare. Two new reports2,3 give us the opportunity to translate this view into a western European perspective.

Flanders in Belgium is among the richest and most developed regions in the world. Between 1990 and 2000 the population grew by 3%, while the real per capita disposable personal income grew by 60%. In contrast to the United States, the areas for food production and habitation have grown by 5.5% and 24%, respectively, over the past ten years. Compared with the United States (agriculture 1.69 ha; urban and other land use 0.13 ha), land use per capita in Flanders is very low (agriculture 0.14 ha; urban and other land use 0.06 ha). However, because of the high population density, there is only 0.23 ha per capita of Flemish territory available (2.8 ha in the United States). Therefore, about 62% of Flanders is allotted to food production, while 27% is covered by urban areas and other land use, leaving only about 11% for nature (about 30% in the United States).

Budiansky does not discuss the environmental impact that goes beyond land use (see ref. 4 for one example). Agriculture is extremely intensive in Flanders, emitting Europe's highest levels of nutrients into the environment. The OECD nutrient balance database for 2001 (see http://www.oecd.org) shows that during the past decade the nitrogen surplus (from manure) was between 177 kg and 203 kg per ha of total agricultural land. The critical load for grasslands in nature reserves and natural grasslands in agricultural areas was exceeded in all sampled points2. As a consequence, vegetation of nutrient-rich environments gradually replaced that of nutrient-poor environments throughout Flanders3. Over-fertilization is causing species extinction; for example it is one of the main reasons why nearly a third of the area's butterfly species have been wiped out during the past century5. The rate of extinctions is speeding up, with half the remaining species expected to die out during this century.

Although present policy aims to tackle the problem at the source by limiting nutrient emissions, atmospheric nitrogen deposition is barely decreasing, and nutrients will continue to accumulate for some time to come3.