Human appropriation of land use for agriculture has long been the primary determinant of the level of global biodiversity. However, over the past fifty years technological change in the agricultural sector has enabled the accommodation of larger populations without greater land use requirements. The current situation is singular, in that the population will continue to expand over the coming century, but in combination with very substantial fertility decline. This will result in substantial increases in the dependent population, at the same time that there is a reduction in the supply of labour. What does this imply for land use in the coming century? We demonstrate in an endogenous growth model how this combination of peak population and declining fertility could result in technological regression in agriculture, due to the myriad pressures on the labor supply, and the reversal of the longstanding trend toward reduced land use in agriculture. In this sense, the long term future for biodiversity is not so bright.