Publications

Developing countries face many challenges when constructing national inventories of greenhouse gas (GHG) emissions, such as lack of activity data, insufficient measurements for deriving country-specific emission factors, and a limited basis for assessing GHG mitigation options. Emissions from agricultural production are often significant sources in developing countries, particularly soil nitrous oxide, and livestock enteric and manure methane, in addition to wetland rice methane. Consequently, estimating GHG emissions from agriculture is an important part of constructing developing country inventories. While the challenges may seem insurmountable, there are ways forward such as: (a) efficiently using resources to compile activity data by combining censuses and surveys; (b) using a tiered approach to measure emissions at appropriately selected sites, coupled with modeling to derive country-specific emission factors; and (c) using advanced software systems to guide compilers through the inventory process. With a concerted effort by compilers and assistance through capacity-building efforts, developing country compilers could produce transparent, accurate, complete, consistent and comparable inventories, as recommended by the IPCC (Intergovernmental Panel on Climate Change). In turn, the resulting inventories would provide the foundation for robust GHG mitigation analyses and allow for the development of nationally appropriate mitigation actions and low emission development strategies.

The reliability of calculation methods for the carbon emission savings to be achieved in Scotland by replacing power generated from fossil fuels (and other more conventional sources) with that produced by large-scale wind farm developments is a cause for concern, largely in relation to wind farms sited on peatlands. Scottish Government policy is to deliver renewable energy without environmental harm, and to meet biodiversity objectives including the conservation of designated wildlife sites and important habitats such as peatlands. The implications for carbon emissions of developing a wind farm are, therefore, just one aspect of the suite of considerations that the planning system takes into account. This paper presents a simple methodology for prospectively calculating the potential carbon emission savings to be realised by developing wind farms on peatland, forestland or afforested peatland. The total carbon emission savings of an individual wind farm are estimated by accounting emissions from the power source that will be replaced by wind power against: loss of carbon due to production, transportation, erection, operation and dismantling of the wind farm components (the infrastructure overhead); loss of carbon due to backup power generation; loss of carbon stored in peat and forest; loss of carbon-fixing potential of peatland and forest; and carbon savings due to habitat improvement. Most of the carbon losses are determined by national infrastructure, but those from peat soil and plants are influenced by site selection and management practices. The extent of drainage around each constructed element of the wind farm is a major factor for greenhouse gas emissions. Consideration of an example site with a low extent of drainage, where management practices that minimise net carbon losses (e.g. undrained floating roads, habitat improvement and site restoration on decommissioning) were used indicates that emissions from the soil and plants may cancel out as little as < 6% of the potential carbon savings, even on peatland. However, if the soil had a high extent of drainage and management practices that minimise carbon losses were abandoned, greenhouse gas emissions from the soil and plants could amount to 77% of the wind farm’s gross carbon savings; in other words, even though the development would not be a net cost in terms of greenhouse gas emissions, it would not provide much benefit. Thus, the development of wind farms on peat as opposed to mineral soils incurs a much greater risk that the potential net saving of greenhouse gas emissions will be significantly reduced by poor site management practice. This means that good site selection and management is of the utmost importance if wind farms are to be developed on peatlands.

Abstract Growing bioenergy crops such as Miscanthus has the potential to mitigate atmospheric carbon dioxide emissions by the replacement of fossil fuels and by storing carbon (C) in the soil due to land use change. Here we compare direct measurements of soil organic C fractions made in Carlow (Ireland) to model predictions made by RothC and a cohort model. Our results show that when Miscanthus is grown on land previously under arable agriculture, the soil organic C will increase to a level above that of native pasture, as Miscanthus organic material is shown to have a slow decomposition rate. In addition we demonstrate that for measured organic C, fractions of different lability are similar to the C pools used in RothC. Using the model predictions from RothC and Miscanthus yields from MISCANFOR, we predict that in Ireland, changing the land use from arable to Miscanthus plantations has the potential to store between 2 and 3 Mg C ha −1 y −1 depending on the crop yield and the initial soil organic C level.

Rice (Oryza sativa L.) is cultivated as a major crop in most Asian countries and its production is expected to increase to meet the demands of a growing population. This is expected to increase greenhouse gas (GHG) emissions from paddy rice ecosystems, unless mitigation measures are in place. It is therefore important to assess GHG mitigation potential whilst maintaining yield. Using the process-based ecosystem model DayCent, a spatial analysis was carried out in a rice harvested area in Bangladesh for the period 1996 to 2015, considering the impacts on soil organic carbon (SOC) sequestration, GHG emissions and yield under various mitigation options. An integrated management (IM, a best management practice) considering reduced water, tillage with residue management, reduced mineral nitrogen fertilizer and manure, led to a net offset by, on average, −2.43 t carbon dioxide equivalent (CO2-eq.) ha−1 year−1 (GHG removal) and a reduction in yield-scaled emissions intensity by −0.55 to −0.65 t CO2-eq. t−1 yield. Under integrated management, it is possible to increase SOC stocks on average by 1.7% per year in rice paddies in Bangladesh, which is nearly 4 times the rate of change targeted by the “4 per mille” initiative arising from the Paris Climate Agreement.

<p>Rice cultivation has high water consumption and emits large quantities of greenhouse gases. Therefore, rice fields provide great potential to mitigate GHG emissions by modifications to cultivation practices or external inputs. Previous studies showed differences for impacts of alternated wetting and drying (AWD) practices for above-ground and below-ground biomass, which might have long term impacts on soil organic carbon stocks. The objective of this study is to parameterise and evaluate the model ECOSSE for rice simulations based on data from an Italian rice test site where the effects of different water management practices and 12 common European cultivars, on yield and GHG emissions, were investigated. Special focus is on the differences of the impacts on the greenhouse gas emissions for AWD and continuous flooding (CF). The model is calibrated and tested for field measurements and is used for model experiments to explore climate change impacts and long-term effects. Long term carbon storage is of particular interest since it is a suitable mitigation strategy. As experiments showed different impacts of management practices on the below ground biomass, long term model experiments are used to estimate impacts on SOC of the different practices. The measurements also allow an analysis of the impacts of different cultivars and the uncertainty of model approaches using a single data set for calibration.</p>