Options for the Future
The demands of human populations for food and possibly energy from agriculture are likely to be sustained, over the next few decades at least. This will be driven by continued population growth and increased food consumption associated with economic growth in developing countries, and increased use of bioenergy as an alternative to fossil fuels in an attempt to minimize the impact of climate change. Conserving biodiversity will continue to be a challenge, while pressure to commit more land to agriculture will remain an enduring reality. The greatest uncertainty is probably the extent to which climate change will exacerbate these problems by reducing agricultural productivity, as a result increasing the demand for land for agriculture; and by directly driving species to extinction. This chapter will define the issues and possible solutions. Key aspects of these challenges to be covered include the need to focus on strategies to minimize food energy competition both at the biomass and land-use levels. The areas in which science can contribute need to be systematically evaluated. Historically food production has increased to meet or exceed popula-
tion growth and associated demand for food. In the second half of the 20th century this was achieved in the ‘Green Revolution’ that combined new higher yielding genotypes with the use of increased inputs such as fertilizers, but with very little change in the area being cultivated. In the last decade the view has emerged that this technology has reached its limits with a slowing in the rate of growth of food production (Fedoroff and Brown, 2004). Some people argue that scientists are to blame for the growth in
human populations because they developed more efficient agriculture that has kept pace so far with the growth in populations. The alternative to not developing the capacity to feed a growing population would be limiting growth by starvation. Surely the ethics of scientists and the community at large must be to support human life, while highlighting the strain population growth places on global sustainability? However, the ‘Green Revolution’ has not been without significant problems. A consistent criticism is that the technology has made farmers in developing countries more dependent on high cost nutrient inputs. The reality is that the new plant cultivars tend to yield more regardless of fertilizer use, but do respond very well when additional nutrients are used. Loss of biodiversity in agriculture due to the dominance of high-yielding crop cultivars that encourage the growth of monocultures is another continuing concern. Plant breeders are now able to directly tackle this problem by deliberately introducing more diverse material into their programmes. Modern DNA analysis tools assist in maximizing diversity in cultivated plants by allowing deliberate selection of new cultivars or parental lines for use in breeding that are as genetically different as possible from other cultivars in cultivation. This needs to continue as a very active process to balance the relentless pressure on agriculture to maximize performance by selecting the very best performing genes or genotypes. These deficiencies do not detract from the key role this technology has played in feeding the human population and protecting biodiversity by minimizing the footprint of agriculture, but they do dictate a need for continued efforts to address the unintended problems that result. Climate change and the costs and limits of fossil fuels have provided a
strong incentive to explore the potential for efficient energy crops. However, competition for land with food crops and biodiversity conservation are potentially serious negative impacts of biofuel production. This suggests the urgent need to focus biofuel crop production on species that are highly efficient and do not compete directly with food crops for land or water. The ideal species for these applications have not been identified for most production environments worldwide. Time has probably been wasted on attempts to adapt or use food crops rather than undertake the testing required to reliably identify and in many cases domesticate new species as biofuel crops from the many plant species available (see Chapter 11). The long-term priority for biomass production will probably be to replace fossil fuels in applications other than transport fuels. Biofuels provide a partial or possibly a complete solution for transport in the short term (next few decades). However, they will only make a net positive contribution if their production and use is managed better than it is at present. New technologies will be needed to supply energy for transport in the long term.