A recent study has concluded that expanding the amount of land in Brazil used to grow sugarcane for ethanol could have serious environmental and social consequences.

It could lead to more pressure on natural rainforest if sugarcane displaces other crops northwards, degraded soil and water supplies, and exploitation of workers in the industry.

Brazil provides an important case-study for policy makers worldwide considering expanding biofuel production. Brazil has invested in producing ethanol from sugarcane since the oil crisis of the 1970s. In 2007, 19 billion litres were produced, a similar quantity to the amount of corn ethanol produced in the US.

The OECD estimates that ethanol production in Brazil will increase to 44 billion litres by the year 2016. This will mean a doubling of the area of land planted with sugarcane to 14 million hectares. Sugarcane requires a period of low rainfall in its growing cycle and is grown mainly in the south-east of the country.

Soya is another major crop in Brazil, covering a much larger area of 23 million hectares. Soya can be grown more easily in tropical conditions. If sugarcane expands into central areas where soya is currently cultivated, it could lead to deforestation further north, with implications for the global carbon balance. It has also been suggested that an increase in sugarcane production could also displace grazing land and increase the rate of deforestation for ranching purposes. Ethanol has been viewed as a promising biofuel, but the negative effects on natural ecosystems and social structures of those working in the industry should be taken into account.

For example:

* Soil degradation caused by erosion and compaction, which reduces soil's ability to filter water

* Deterioration of wetlands, streams, rivers and reservoirs due to silt and sediment

* Transport via silt of pollutants and chemicals

* Banned substances such as organochlorides found in fish and sediments

* Waste water from processing sugarcane depleting oxygen in water systems

* Heavy use of nitrogen fertilisers leading to eutrophication of coastal water and estuaries * Destruction of riparian forests with impact on biodiversity

* Air pollution caused by burning sugarcane straw

Conditions for workers harvesting the crop are also poor. Often employed by gang-leaders as short-term migrant workers from other parts of Brazil, labourers have long working days, low pay and a high death rate, with little protection through labour legislation. The researchers say increasing ethanol production in Brazil is not a necessary or justified response to global warming if it entails the loss of natural resources.

Major changes are needed to ensure expansion is sustainable and socially responsible, including:

* Thorough environmental risk assessments for expansion to new regions such as the centre of Brazil

* improved land-use practices to reduce pollution and soil erosion

* protection of streams and riparian ecosystems

* banning of sugarcane burning

* fair working conditions

* a more constructive approach from international stakeholders and world trade bodies to promote sustainable development in countries where biofuel production is likely to increase

* including environmental value in the price of biofuels to discourage excessive replacement of natural forest, wetlands and pastures by biofuel crops

Source: Martinelli, L. and Filoso, S. (2008). Expansion of sugarcane ethanol production in Brazil: environmental and social challenges. Ecological Applications. 18(4): 885-898. Contact: martinelli@cena.usp.br