Impacts

Competition for agricultural land

The amount of land that could be dedicated to energy biomass is limited as most of the suitable land is in use for agriculture, human settlement, covered by forests, or locked up in protected areas (FAO, 2003). Therefore, energy biomass plantations may compete with the existing agricultural land uses and/or may lead to the use of the remaining natural landscape that should be kept under conservation.

A study from the University of Florida suggests that to replace the entire US gasoline supply would require 60% of all available cropland (Moreira, 2005). It is also estimated that up to 13% of the European Union agricultural land would be needed to produce the 5.75% target of biofuel share in Europe’s energy consumption (Biofuels Research Advisory Council, 2006).

The consequence of energy biomass plantations expanding into the natural landscape will obviously lead to direct biodiversity loss due to habitat destruction and fragmentation. Further biodiversity loss would occur if unsustainable agricultural practices (e.g. overuse of chemical inputs that may lead to eutrophication and water pollution, tillage that can result in soil erosion or compaction) are used when establishing and managing the planted biomass. However, Perlack et al. (1992) and Cook and Beyea (2000) reported that displacing annual crops with perennial grassy crops, considered as a second generation feedstock, could reduce pesticide and net fertilizer use, and lead to greater animal biodiversity as habitat is improved and natural ecosystems functions are restored.

Other issues related to agriculture include: (i) monoculture of the more energy efficient crops (sugar cane, oil palm) may eventually be preferred over crop rotations, which may result in the simplification of agro-ecosystems associated with a decrease in crop and farm biodiversity; (ii) the emergence of genetically engineered energy crops for better yield and energy efficiency could result in cross-pollination in the wild, thereby affecting biodiversity.

Competition with other land uses/ecosystem services

Given the limited amount of suitable land, energy biomass may also expand into riparian areas, set-aside land, or tree lines which all play an important ecological role. Wetlands biodiversity could also be at risk being drained to plant energy crops. However, planting energy biomass could rehabilitate marginal and degraded lands.

Deforestation

In addition to the potential loss of forest due to land clearing for agriculture, the growing interest for cellulosic biomass (second generation feedstock) may increase the existing pressure on forests from fuelwood harvesting (particularly in developing countries) and worsens the already alarming loss of biodiversity in these ecosystems. Moreover, harvesting forest resources to produce biofuel can work against the goal of greenhouse gas reduction as between 25 and 30% of the greenhouse gases released into the atmosphere each year (1.6 billion tones) is caused by deforestation. Cook and Beyea (2000) reported that forest or tree plantation for biofuel production can have beneficial impact on biodiversity as long as it does not replace natural stands and especially if it replace row crops or help restoring degraded lands (bird populations recovery and understory vegetation favoring habitat for small mammals). Moreover, the negative impact of forest harvesting can be mitigated through the use of the residues from logging which can constitute about 60% of the total harvested tree left in forests (Parikka, 2004).

Increasing in price of food crops

As the global demand for food is ever-increasing, agricultural land use changes to energy biomass production may have the following negative consequences:
  • Force farmers to clear additional lands for food production or grazing;
  • Result in increase in food prices as a consequence of using food crops to produce ethanol which may force indigenous people to rely more intensively on food from the wild, thus having negative impact on biodiversity.

Water-related impacts

Expansion of the production of biomass for biofuel production may require increased need for water, especially for crops with high water demand. Water is already scarce in many areas and constitutes the major resource constraint on further agricultural expansion. This aspect is a serious concern in that biodiversity loss from inland water is occurring faster than for any other major biome and the pressures on water resources are already rapidly escalating through the direct drivers of food production and urbanization.

Water use and pollution in the processing phase of biofuels production also need some considerations. Water pollution can be caused by untreated oil palm mill effluent that contains chemicals (European Commission, 2006). The conversion of biomass to fluid fuels consumes little water compared to the evapotranspiration losses in energy crops production. However the effluent production from fermentation processes to produce ethanol may be substantial (Berndes, 2002). Therefore, in addition to water pollution linked to agriculture, further concerns about water pollution and consequent biodiversity loss can arise if water used in the processing technologies is not treated properly before returning to the environment.

References

  • United Nations
  • United Nations Environment Programme