Manfred Lenzen and colleagues suggest that 30% of species globally may be threatened by the international trade in commodities (Nature 486, 109–112; 2012). We feel that this estimate is too conservative.

The scale and magnitude of damage to biodiversity resulting from the recent sharp rise in trade volume will probably take decades to realize (F. Essl et al. Proc. Natl Acad. Sci. USA 108, 203–207; 2011). Exports worldwide increased by 119% between 1990 and 2011 (see go.nature.com/au5chf), notably from 'megadiverse' countries such as China, Brazil, India and Indonesia. These countries are also major exporters of commodities such as biofuel, which has a huge detrimental impact on tropical and subtropical biodiversity.

The real threat to biodiversity is underestimated by analysing only globally threatened species, because these are largely outnumbered by regionally threatened species (M. Winter et al. Proc. Natl Acad. Sci. USA 106, 21721–21725; 2009).

Both of these considerations need to be included in attempts to quantify biodiversity damage from international trade. For example, although the Forest Stewardship Council certification process does include the impacts of trade, it does not consider time lags that may worsen biodiversity damage (www.fsc.org).