The problem of bioethanol's 'dirty footprint' in Alagoas state in Brazil (Nature 469, 299; 2011) is real and deserves attention. But the historical background bears clarification.

The loss of Atlantic rainforest in Alagoas to sugar cane began well before the 35-year-old national sugar-cane ethanol programme was introduced. Sugar-cane plantations and mills were established in the state in the early seventeenth century, starting on the coastal plains and then moving inland (A. L. S. Santos et al. Campo-Território 2, 19–37; 2007). The state's forests have been logged for shipbuilding and other uses since the eighteenth century (W. Dean With Broadax and Firebrand Univ. California Press; 1995).

The authors' implication that Alagoas's forests are no longer a biodiversity hotspot is misleading. The entire Brazilian Atlantic Forest is listed as a hotspot precisely because of the huge areas that have been lost. Combined with the forest's richness of endemic plants, this fulfils the two criteria for a biodiversity hotspot (N. Myers et al. Nature 403, 853–858; 2000).