AbstractClimate change is regarded as the greatest threat to the World’s ecosystem and hence to the sustainability of human life. Because anthropogenic emissions of greenhouse gasses are held largely responsible for the enhanced greenhouse effect, the international community has committed to reduce emissions, and in particular, to replace fossil fuels with low carbon renewable sources (COP 21 Paris agreement, 2015). Biofuel is a candidate technology, and the concept of growing energy crops represents significant opportunities.
This project aimed to examine the risk that climate change pose to the value of growing energy crops. The concern is that climate change could reduce yield sufficiently for the crop to give less energy than expected, and possibly less energy than was put into growing it, further increasing the carbon footprint. Clearly, this situation is unacceptable. In order to assess the overall energy balance and carbon footprint, farm practices; fertilizer application and tillage management were accounted in the overall life cycle assessment. Thus, this thesis reports the first fully integrated framework for the assessment of the impact of climate change on growing biofuels under various farm management practices.
Climate change impacts on yield varied depending on future GHG scenario pathway and timeline. The LCA results indicate that synthetic fertiliser application contributed the greatest percentage to the total GHG emission, averaging 57.7%of the total GHG emissions, of which 53.4% came from direct and indirect N2O emissions and 4.3% from CO2 emissions as a result of urea application. The remaining 42.3% of emissions came from input production (37.8%) and field operation (4.4%).Although increasing fertiliser application contributes to yield increase, the overuse of chemical fertilisers has a greater negative impact on the environment as the results indicate. In particular, the rate of fertiliser application is optimal at 160 kg per hectare, and generally, this project has determined that yield is more sensitive to fertiliser than to climate change, whilst climate change is the causal driver for the increase in net energy and carbon footprint at most locations.
The integrated framework developed for this project has been validated and tested using maize, but can be applied to other biofuel crops provided that the proposed location has historical weather data, information about soil type and farm management details of the proposed crop type. Given the absolute importance of reducing carbon emissions.
|Date of Award||Jul 2019|
|Supervisor||Les Duckers (Supervisor), Wendy Garner (Supervisor) & Matthew Blackett (Supervisor)|