Date of this Version
Annu. Rev. Energy Environ. 1991. 16:401-31
Biomass could be a renewable source of energy and chemicals that would not add CO2 to the atmosphere. It will become economically competitive as its cost decreases relative to energy costs, and biotechnology is expected to accelerate this trend by increasing biomass productivity. Pressure to slow global warming may also make biomass more attractive. Substantial dependence on biomass would entail massive changes in land use, risking serious reductions in biodiversity through destruction of habitat for native species. Forests could be managed and harvested more intensively, and virtually all arable land unsuitable for high-value agriculture or silviculture might be used to grow energy crops. We estimate that it would require an area equal to that farmed in 1988, about 130 million hectares, just to supply the United States with transportation fuel. Planning at micro to macro scales will be crucial to minimize the ecological impacts of producing biomass. Cropping and harvesting systems will need to provide the spatial and temporal diversity characteristic of natural ecosystems and successional sequences. To maximize habitat value for interior-dependent species, it will be essential to maintain the connectivity of the habitat net work, both within biomass farms and to surrounding undisturbed areas. Incorporation of these ecological values will be necessary to forestall costly environmental restoration, even at the cost of submaximal biomass productivity. Since it is doubtful that all managers will take the longer view, some sort of intervention will very likely be necessary. Given concerns about global warming, both bioenergy proponents and conservationists have an incentive to work together.