CO 2e Research Articles

Estructura, composición florística y almacenamiento de carbono en bosques nativos del páramo de Anaime, Tolima, Colombia

Los páramos tienen alta importancia ambiental por su alto endemismo, su regulación hídrica y su almacenamiento de carbono. En este trabajo se caracterizó la estructura y composición poblacional de la vegetación arbórea, se estimó el almacenamiento de carbono en biomasa aérea y el potencial de reducción de emisiones por deforestación, y se priorizó los tipos de bosques nativos en los esfuerzos de conservación en la Reserva Natural Semillas de Agua (RNSA) en el páramo de Anaime, Tolima, Colombia. En cada tipo de bosque (achaparrado, maduro y subpáramo), se establecieron nueve parcelas de muestreo de 10 x 15 m, en donde se midieron todos los individuos con un diámetro del tronco a la altura del pecho (dap) ≥ 10 cm. La biomasa aérea se estimó a través de un modelo alométrico multi-especie generado localmente. Las especies importantes, en términos de índice de valor de importancia y de almacenamiento de carbono, fueron Weinmannia auriculata y Miconia sp. El mayor almacenamiento de carbono se alcanzó en los bosques del subpáramo, seguido de los maduros y achaparrados (242 vs 147 vs 25 Mg/ha, respectivamente). Los bosques en la RNSA almacenan 3,2 Tg CO2e en biomasa aérea, de los cuales se podrían perder 0,2-0,5 Tg CO2e en 20 años con una deforestación anual de 0,78 y 0,28%, respectivamente. Estas reducciones de gases de efecto invernadero podrían ser comercializadas en un potencial proyecto REDD+, que ayuden a conservar estas áreas de bosque. Los bosques achaparrados y del subpáramo deberían ser priorizados en los esfuerzos de conservación debido a su diversidad, endemismo y a su gran cantidad de carbono en el caso de los bosques maduros.

NERACA KARBON PRA DAN POST HTI DI BLOK KHUSUS KESATUAN PENGELOLAAN HUTAN TASIK BESAR SERKAP RIAU

Climate change is the current global issue that has been discuss over two decades. In Indonesia context, the total greenhouse gases (GHG) emissions from all sectors including land use change forestry, energy, peat fire, waste, agriculture and industry is 1.377.982,95 Gg CO 2e. The GHG emission only counted by three main gases such as CO 2 , CH 4 and N 2 O. Related to mitigation efforts by private company to reduce these emissions. This study more focus on comparation on how much natural forest can generate CO 2 absorpsion from tree growth and how much plantation plantation company generate CO 2 absorpsion from tree growth and their emission from its operational activities specially on transportation and N addition by synthentic fertilizer. The study conducted in specific block of forest management unit of Tasik Besar Serkap, Riau Province since January 2016 until June 2016. Based on this study, CO 2 absorpsionfrom natural forest is 33.199.866,70 ton CO 2, CO 2 emissionfrom natural forest is 0, CO 2 absorpsion from plantation company 13.366.266,32 ton CO 2, CO 2 emissionfrom synthetic fertilizer is 66.558.58 ton CO 2, and CO 2 emissionfrom transportation for operationalization of plantation company is 16.688,24 ton CO 2. Keyword: GHG emission, CO 2 absorpsion, plantation Company, transportation, synthetic fertilizer

Transición de leña a gas licuado a presión (GLP) en el sur de México, oportunidad para la mitigación del cambio climático en la región menos desarrollada del país

Between 25% and 55% of households in southern Mexico depend on biomass for cooking, which carries serious consequences on the environment, development and health. In spite of the knowledge of these consequences, transition from biomass to modern fuels has remained outside energy and development policies. In the present work, after describing the panorama of fuelwood use in the country and its importance as an energy source, an approach is presented for estimating CO 2 savings achievable by transition to pressurized liquefied gas (LP). These savings can reach 3.14 Mt CO 2e, 26% less than the baseline scenario. At the end we discuss on the transition to modern fuels in Mexico, the barriers that hinder it and the achievements and failures of the distribution of fuelwood saving cookstoves, as the only and most important governmental initiative to alleviate biomass use, comparing it with other priorities in the government's agenda.

Life cycle assessment of CO 2 sequestration in magnesium silicate rock – A comparative study

This paper addresses the energy and environmental implications of sequestrating CO 2 from a coal power plant using magnesium silicate rock. An accounting type life cycle assessment (LCA) of the mineralization method under development at Åbo Akademi University (ÅAU), Finland, is presented and the results are compared with the process developed at the National Energy Technology Laboratory (NETL), formerly Albany Research Council (ARC) in the US. The ÅAU process is a multi-staged route where CO 2 is sequestered via a process that first produces magnesium hydroxide, Mg(OH) 2 from Mg silicate. The Mg(OH) 2 produced is later reacted with CO 2 in a high temperature gas/solid pressurized fluidized bed (FB) reactor, forming pure, stable and environmentally benign MgCO 3 product. This study addresses the following important issues; (a) the material and energy requirements of sequestering 1 ton of CO 2 (t-CO 2) in mineral silicate, (b) the overall environmental burdens associated with CO 2 sequestration using serpentinite mineral, (c) the priorities and opportunities for reduction of energy requirements and environmental impacts associated with mineralizing CO 2, and (d) comparison of LCA results of the ÅAU mineralization process route with that of the mineralization process developed by NETL. Exergy calculations show that with heat recovery mineralizing 1 t-CO 2 using the ÅAU process requires 3.6 GJ/t-CO 2 while that of the NETL needs 3.4 GJ/t-CO 2. Applying results of exergy analysis in the life cycle inventory (LCI) models of the ÅAU and the NETL processes leads to 517 kg CO 2e and 683 kg CO 2e of greenhouse gas emissions (in CO 2 equivalents) respectively, for every ton of CO 2 mineralized in serpentinite.

Offsetting greenhouse gas emissions through biological carbon sequestration in North Eastern Australia

The Kyoto Protocol recognises trees as a sink of carbon and a valid means to offset greenhouse gas emissions and meet internationally agreed emissions targets. This study details biological carbon sequestration rates for common plantation species Araucaria cunninghamii (hoop pine), Eucalyptus cloeziana, Eucalyptus argophloia, Pinus elliottii and Pinus caribaea var hondurensis and individual land areas required in north-eastern Australia to offset greenhouse gas emissions of 1000 t CO 2e. The 3PG simulation model was used to predict above and below-ground estimates of biomass carbon for a range of soil productivity conditions for six representative locations in agricultural regions of north-eastern Australia. The total area required to offset 1000 t CO 2e ranges from 1 ha of E. cloeziana under high productivity conditions in coastal North Queensland to 45 ha of hoop pine in low productivity conditions of inland Central Queensland. These areas must remain planted for a minimum of 30 years to meet the offset of 1000 t CO 2e.

Financial feasibility of increasing carbon sequestration in harvested wood products in Mississippi

Longer forest rotation ages can potentially increase accumulation of carbon in harvested wood products due to a larger proportion of sawlogs that can be used for manufacturing durable wood products such as lumber and plywood. This study quantified amounts of carbon accumulated in wood products harvested from loblolly pine ( Pinus taeda L.) stands grown in Mississippi by extending rotation ages traditionally used to manage these stands for timber. The financial viability of this approach was examined based on carbon payments received by landowners for sequestering carbon in standing trees and harvested wood products. Results indicated a potential to increase carbon accumulated in wood products by 16.11 metric tons (t) of carbon dioxide equivalent (CO 2e) per hectare (ha) for a rotation increase of 5 years and 67.07 tCO 2e/ha for a rotation increase of 65 years. Carbon prices of $50/tCO 2e and $110/tCO 2e would be required to provide a sufficient incentive to forest landowners to extend rotations by 5 and 10 years, respectively. With 2.8 million ha of loblolly pine stands in Mississippi, this translates to a possible increase in wood products carbon of 45 million tCO 2e and 80 million tCO 2e for harvest ages increased by 5 and 10 years, respectively. Higher carbon prices lengthened rotation ages modestly due to low present values of carbon accumulated with long rotations.

Carbon footprint of sugar produced from sugarcane in eastern Thailand

Carbon footprint (CFP) of sugar produced from sugarcane in eastern Thailand was estimated from greenhouse gas emissions (CO 2, CH 4, and N 2O) during the sugarcane cultivation and milling process. The use of fossil fuels, chemical and organic fertilizer and sugarcane biomass data during cultivation were collected from field surveys, questionnaires and interviews. Sugar mill emissions, fossil fuel utilization and greenhouse gas emission from wastewater treatments were included. The results show that sugar production has a carbon footprint of 0.55 kg CO 2e kg −1 sugar. This carbon footprint was a sum of 0.49 kg CO 2e kg −1 sugar from sugarcane cultivation and 0.06 kg CO 2e kg −1 sugar from the milling process. For the cultivation part, most of the GHGs emissions were from fertilizer, fossil fuel use and biomass burning. The CFP in eastern Thailand is sensitive to the type of data selected for calculation and of variations of farm inputs during sugarcane cultivation. There was no significant difference of CFP among farm sizes, although small farms tended to give a relatively higher CFP than that of medium and large farms.

Contributing to local policy making on GHG emission reduction through inventorying and attribution: A case study of Shenyang, China

Cities consumed 84% of commercial energy in China, which indicates cities should be the main areas for GHG emissions reduction. Our case study of Shenyang in this paper shows how a clear inventory analysis on GHG emissions at city level can help to identify the major industries and societal sectors for reduction efforts so as to facilitate low-carbon policy-making. The results showed total carbon emission in 2007 was 57 Mt CO 2 equivalents (CO 2e), of which 41 Mt CO 2e was in-boundary emissions and 16 Mt CO 2e was out-of-boundary emissions. The energy sector was dominant in the emission inventory, accounting for 93.1% of total emissions. Within energy sector, emissions from energy production industry, manufacturing and construction industry accounted for 88.4% of this sector. Our analysis showed that comparing with geographical boundary, setting system boundary based on single process standard could provide better information to decision makers for carbon emission reduction. After attributing electricity and heating consumption to final users, the resident and commercial sector became the largest emitter, accounting for 28.5% of total emissions. Spatial analysis of emissions showed that industrial districts such as Shenbei and Tiexi had the large potential to reduce their carbon emissions. Implications of results are finally discussed.

Uncertainty of 21st century growing stocks and GHG balance of forests in British Columbia, Canada resulting from potential climate change impacts on ecosystem processes

Over the coming decades, climate change will increasingly affect forest ecosystem processes, but the future magnitude and direction of these responses is uncertain. We designed 12 scenarios combining possible changes in tree growth rates, decay rates, and area burned by wildfire with forecasts of future harvest to quantify the uncertainty of future (2010–2080), timber growing stock, ecosystem C stock, and greenhouse gas (GHG) balance for 67 million ha of forest in British Columbia, Canada. Each scenario was simulated 100 times with the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3). Depending on the scenario, timber growing stock over the entire land-base may increase by 14% or decrease by 9% by 2080 (a range of 2.8 billion m 3), relative to 2010. However, timber growing stock available for harvest was forecast to decline in all scenarios by 26–62% relative to 2010 (a range of 1.2 billion m 3). Forests were an annual GHG source in 2010 due to an ongoing insect outbreak. If half of the C in harvested wood was assumed to be immediately emitted, then 0–95% of simulations returned to annual net sinks by 2040, depending on scenario, and the cumulative (2010–2080) GHG balance ranged from a sink of −4.5 Pg CO 2e (−67 Mg CO 2e ha −1) for the most optimistic scenario, to a source of 4.5 Pg CO 2e (67 Mg CO 2e ha −1) for the most pessimistic. The difference in total ecosystem carbon stocks between the most optimistic and pessimistic scenarios in 2080 was 2.4 Pg C (36 Mg C ha −1), an average difference of 126 Tg CO 2e yr −1 (2 Mg CO 2e yr −1 ha −1) over the 70-year simulation period, approximately double the total reported anthropogenic GHG emissions in British Columbia in 2008. Forests risk having reduced growing stock and being GHG sources under many foreseeable scenarios, thus providing further feedback to climate change. These results indicate the need for continued monitoring of forest responses to climatic and global change, the development of mitigation and adaptation strategies by forest managers, and global efforts to minimize climate change impacts on forests.

Transport sector electrification in a hydropower resource rich developing country: Energy security, environmental and climate change co-benefits

This paper analyzes the co-benefits of transport sector electrification in terms of reductions of greenhouse gas and local environmental emissions, improvement in energy security and employment generation during 2015–2050 in the case of Nepal—a developing country with large hydropower potential. A bottom up energy system model of Nepal based on the MARKAL framework was developed to assess the effects of meeting a part of the land transport service demand through electrified mass transport system and electric vehicles. The present study shows that if the share of electricity based transport services is to grow from 10% in 2015 to 35% by 2050, the hydropower generation capacity would have to increase by 495 MW by 2050 as compared to the base case, while the annual electricity generation in 2050 would have to increase by 7.86 TWh. As a result, the cumulative total imported energy would decrease by 14.6% in the 35% transport electrification scenario as compared to the base case during 2015–2050. In addition, the cumulative greenhouse gas emissions would be reduced by 12.9% (74.7 million tons CO 2e) in the same scenario during 2015–2050.

Decarbonization of the U.S. electricity sector: Are state energy policy portfolios the solution?

State governments have taken the lead on U.S. energy and climate policy. It is not yet clear, however, whether state energy policy portfolios can generate results in a similar magnitude or manner to their presumed carbon mitigation potential. This article seeks to address this lack of policy evidence and contribute empirical insights on the carbon mitigation effects of state energy portfolios within the U.S. electricity sector. Using a dynamic, long-term electricity dispatch model with U.S. power plant, utility, and transmission and distribution data between 2010 and 2030, this analysis builds a series of state-level policy portfolio scenarios and performs a comparative scenario analysis. Results reveal that state policy portfolios have modest to minimal carbon mitigation effects in the long run if surrounding states do not adopt similar portfolios as well. The difference in decarbonization potential between isolated state policies and larger, more coordinated policy efforts is due in large part to carbon leakage, which is the export of carbon intensive fossil fuel-based electricity across state lines. Results also confirm that a carbon price of $50/metric ton CO 2e can generate substantial carbon savings. Although both policy options – an energy policy portfolio or a carbon price – are effective at reducing carbon emissions in the present analysis, neither is as effective alone as when the two strategies are combined.

Lowering carbon footprint of durum wheat by diversifying cropping systems

Improving cropping systems may help mitigate greenhouse gas emissions. This study determined the carbon footprint of durum wheat ( Triticum turgidum L.) produced in diverse cropping systems. Durum was grown in rotation systems which had different combinations of oilseed, pulse, and cereal crops at five site-years in Saskatchewan, Canada. Total greenhouse gas emissions from the decomposition of crop residues along with various production inputs were used for the estimation of carbon footprint. On average, emissions from the decomposition of crop straw and roots accounted for 25% of the total emissions, those from the production, transportation, storage, and delivery of fertilizers and pesticides to farm gates and their applications 43%, and emissions from farming operations 32%. Durum wheat preceded by an oilseed crop ( Brassica napus or Brassica juncea) the previous year had carbon footprint of 0.33 kg CO 2e kg −1 of grain, or 7% lower than durum in cereal–cereal–durum system. Durum preceded by a biological N-fixing crop ( Cicer arietinum chickpea, Lens culinaris lentil, or Pisum sativum pea) the previous year lowered its carbon footprint by 17% compared with durum preceded by a cereal crop. Durum produced in a pulse–pulse–durum system had carbon footprint 0.27 kg CO 2e kg −1 of grain, 34% lower than durum grown in cereal–cereal–durum systems. Diversifying cropping systems with oilseeds and biological N-fixers significantly lowered carbon footprint of durum wheat.

The impact of various parameters on the carbon footprint of milk production in New Zealand and Sweden

The carbon footprint (CF) of milk production was analysed at the farm gate for two contrasting production systems; an outdoor pasture grazing system in New Zealand (NZ) and a mainly indoor housing system with pronounced use of concentrate feed in Sweden (SE). The method used is based on the conceptual framework of lifecycle assessment (LCA), but only for greenhouse gas (GHG) emissions. National average data were used to model the dairy system in each country. Collection of inventory data and calculations of emissions were harmonised to the greatest extent possible for the two systems. The calculated CF for 1 kg of energy corrected milk (ECM), including related by-products (surplus calves and culled cows), was 1.00 kg carbon dioxide equivalents (CO 2e) for NZ and 1.16 kg CO 2e for SE. Methane from enteric fermentation and nitrous oxide emissions from application of nitrogen (as fertiliser and as excreta dropped directly on the field) were the main contributors to the CF in both countries. The most important parameters to consider when calculating the GHG emissions were dry matter intake (DMI), emission factor (EF) for methane from enteric fermentation, amount of nitrogen applied and EF for direct nitrous oxide emissions from soils. By changing one parameter at a time within ‘reasonable’ limits (i.e. no extreme values assumed), the impact on the total CF was assessed and showed changes of up to 15%. In addition, the uncertainty in CF estimates due to uncertainty in EF for methane from enteric fermentation and nitrous oxide emissions (from soil and due to ammonia volatilisation) were analysed through Monte Carlo simulation. This resulted in an uncertainty distribution corresponding to 0.60–1.52 kg CO 2e kg −1 ECM for NZ and 0.83–1.56 kg CO 2e kg −1 ECM for SE (in the prediction interval 2.5–97.5%). Hence, the variation within the systems based on the main EF is relatively large compared with the difference in CF between the countries.

The implications of climate policy for the impacts of climate change on global water resources

This paper assesses the implications of climate policy for exposure to water resources stresses. It compares a Reference scenario which leads to an increase in global mean temperature of 4 °C by the end of the 21st century with a Mitigation scenario which stabilises greenhouse gas concentrations at around 450 ppm CO 2e and leads to a 2 °C increase in 2100. Associated changes in river runoff are simulated using a global hydrological model, for four spatial patterns of change in temperature and rainfall. There is a considerable difference in hydrological change between these four patterns, but the percentages of change avoided at the global scale are relatively robust. By the 2050s, the Mitigation scenario typically avoids between 16 and 30% of the change in runoff under the Reference scenario, and by 2100 it avoids between 43 and 65%. Two different measures of exposure to water resources stress are calculated, based on resources per capita and the ratio of withdrawals to resources. Using the first measure, the Mitigation scenario avoids 8–17% of the impact in 2050 and 20–31% in 2100; with the second measure, the avoided impacts are 5–21% and 15–47% respectively. However, at the same time, the Mitigation scenario also reduces the positive impacts of climate change on water scarcity in other areas. The absolute numbers and locations of people affected by climate change and climate policy vary considerably between the four climate model patterns.

Life-cycle greenhouse gas emissions and energy balances of sugarcane ethanol production in Mexico

The purpose of this work was to estimate GHG emissions and energy balances for the future expansion of sugarcane ethanol fuel production in Mexico with one current and four possible future modalities. We used the life cycle methodology that is recommended by the European Renewable Energy Directive (RED), which distinguished the following five system phases: direct Land Use Change (LUC); crop production; biomass transport to industry; industrial processing; and ethanol transport to admixture plants. Key variables affecting total GHG emissions and fossil energy used in ethanol production were LUC emissions, crop fertilization rates, the proportion of sugarcane areas that are burned to facilitate harvest, fossil fuels used in the industrial phase, and the method for allocation of emissions to co-products. The lower emissions and higher energy ratios that were observed in the present Brazilian case were mainly due to the lesser amount of fertilizers applied, also were due to the shorter distance of sugarcane transport, and to the smaller proportion of sugarcane areas that were burned to facilitate manual harvest. The resulting modality with the lowest emissions of equivalent carbon dioxide (CO 2e) was ethanol produced from direct juice and generating surplus electricity with 36.8 kgCO 2e/GJ ethanol. This was achieved using bagasse as the only fuel source to satisfy industrial phase needs for electricity and steam. Mexican emissions were higher than those calculated for Brazil (27.5 kgCO 2e/GJ ethanol) among all modalities. The Mexican modality with the highest ratio of renewable/fossil energy was also ethanol from sugarcane juice generating surplus electricity with 4.8 GJ ethanol/GJ fossil.

Sequestering carbon in minimum-tilled clay soils used for irrigated cotton and grain production

Soil organic carbon (SOC) increased throughout a 10-year monitoring period (1998–2008) in an experiment that compared five cotton-based cropping systems. These systems included faba bean, vetch and wheat crops, as well as fallows of up to 10 months. All crops were grown on permanent ridges using minimum tillage. Topsoil (0–30 cm) contained between 40 and 42 t SOC ha −1 in 1998 and increased by 0.28 t C ha −1 yr −1 across the five cropping systems (range 0.18–0.45 t C ha −1 yr −1, or 0.66–1.65 t CO 2e ha −1 yr −1). In 2006 and 2008, SOC was measured to 90 cm depth; this indicated that on average 2.1 t C ha −1 yr −1 (range 1.1–3.8 t C ha −1 yr −1) was sequestered (equivalent to 7.8 t CO 2e ha −1 yr −1). The greatest accretions of C occurred in the subsoil: 14%, 67% and 19% of the sequestered-C was found in the 0–30, 30–60 and 60–90 cm depth intervals, respectively. SOC was 7% higher in the cropping systems that received legume stubble, which had higher N content. Faba bean and vetch stubbles averaged 2.89 and 3.89% N, whereas wheat and cotton stubbles averaged 0.78 and 1.56% N, respectively. Carbon inputs from crop stubble (excluding roots) ranged from 11.8 to 29.6 t C ha −1 over the 10-year period. Sequestered C exceeded the estimated CO 2e emissions typical of irrigated cotton cropping systems.

The contribution of maize cropping in the Midwest USA to global warming: A regional estimate

Agricultural soils emit about 50% of the global flux of N 2O attributable to human influence, mostly in response to nitrogen fertilizer use. Recent evidence that the relationship between N 2O fluxes and N-fertilizer additions to cereal maize are non-linear provides an opportunity to estimate regional N 2O fluxes based on estimates of N application rates rather than as a simple percentage of N inputs as used by the Intergovernmental Panel on Climate Change (IPCC). We combined a simple empirical model of N 2O production with the SOCRATES soil carbon dynamics model to estimate N 2O and other sources of Global Warming Potential (GWP) from cereal maize across 19,000 cropland polygons in the North Central Region (NCR) of the US over the period 1964–2005. Results indicate that the loading of greenhouse gases to the atmosphere from cereal maize production in the NCR was 1.7 Gt CO 2e, with an average 268 t CO 2e produced per tonne of grain. From 1970 until 2005, GHG emissions per unit product declined on average by 2.8 t CO 2e ha −1 annum −1, coinciding with a stabilisation in N application rate and consistent increases in grain yield from the mid-1970’s. Nitrous oxide production from N fertilizer inputs represented 59% of these emissions, soil C decline (0–30 cm) represented 11% of total emissions, with the remaining 30% (517 Mt) from the combustion of fuel associated with farm operations. Of the 126 Mt of N fertilizer applied to cereal maize from 1964 to 2005, we estimate that 2.2 Mt N was emitted as N 2O when using a non-linear response model, equivalent to 1.75% of the applied N.

The contribution of carbon-based payments to wetland conservation compensation on agricultural landscapes

This paper evaluates the potential of payments for carbon sequestered through wetland and riparian conservation, to offset the costs of publicly funded wetland conservation programs. In particular, the research focuses on quantifying the value of carbon sequestered in wetland and riparian zones of the Prairie Pothole Region in the province of Saskatchewan. The analysis examines a number of different program design, targeting alternatives and carbon prices and finds that payments for carbon contribute up to 3% (at $5 t −1 CO 2e) and up to 9% (at $15 t −1 CO 2e) of the monetary costs to compensate farmers for adopting wetland and riparian conservation management.

Ecological–economic assessment of aquaculture options: Comparison between abalone monoculture and integrated multi-trophic aquaculture of abalone and seaweeds

Integrated multi-trophic aquaculture (IMTA) possesses ecological and socio-economic advantages, relative to single-species aquaculture. The promotion of a sustainable aquaculture industry requires that decision-makers, ecosystem managers and farmers have sufficient quantitative information associated with its implementation from both public and private perspectives. The present paper applies the Differential Drivers–Pressure–State–Impact–Response (ΔDPSIR) methodological approach to an ecological and economic comparison between mono-aquaculture and IMTA. Data from a South African 240-ton year − 1 abalone farm were used as a case study. Three operation schemes were considered: abalone monoculture in a flow-through system; and two IMTA schemes, which recycle water and replace 10% and 30% of kelp consumption with on-farm-grown seaweed. The analysis indicates a decrease in the aquaculture generated ecological pressures with the incorporation of seaweeds, mainly a reduction in nitrogen discharges into the adjacent coastal ecosystem (by 3.7 to 5.0 tons year − 1 ), a reduction in harvest of natural kelp beds (by 2.2 to 6.6 ha year − 1 ) and a reduction of GHG emissions (by 290 to 350 tons CO 2e year − 1 ). Adopting an IMTA configuration raised farm profits by 1.4 to 5%. The corresponding overall gain from using IMTA in the case study is several folds larger than the net gain in profit, and is estimated between 1.1 and 3.0 million U.S. dollar per annum. This range of values reflects the gains of adopting IMTA on (i) economic value of the aquaculture, i.e. farm's profit, (ii) value of environmental externalities, and (iii) implementation costs. The analysis suggests that the value of the benefits to the public by adopting the IMTA configurations can be larger than the gains in farm's profitability.

The impact of increased biodiesel production on the greenhouse gas emissions from field crops in Canada

Greenhouse gas (GHG) emissions associated with the production of the 21 major field crops in Canada were 16.8 Tg CO 2e of N 2O and 17.2 Tg of fossil fuel CO 2 in 2006. The mean GHG emission intensity on an area basis for these crops was 1.0 Mg of CO 2e per ha. On a dry matter (DM) basis, the mean GHG emission intensity was 0.33 Mg of CO 2e Mg − 1 DM. For western Canada, the GHG emission intensity was 0.35 MgCO 2e Mg − 1 DM and 0.30 MgCO 2e Mg − 1 DM for eastern Canada. The sensitivity of the GHG emissions to crop-specific GHG emission intensities was demonstrated by examining two biodiesel scenarios. The biodiesel share of the diesel fuel blend was 2% in the first scenario (B2) and 5% in the second scenario (B5). The increased feedstock was assumed to come from canola and soybeans. The B2 scenario increased the emission intensity for western Canada to 0.38 MgCO 2e Mg − 1 DM and the B5 scenario to 0.43 MgCO 2e Mg − 1 DM. Neither scenario had any appreciable effect on the magnitude of the emission intensity for eastern Canada. The GHG emissions from the canola-dominated western Canadian field crops were increased by the B2 and B5 fuel blend scenarios. In the soybean-dominated east, the two scenarios resulted in decreased GHG emissions from field crops. Canola-based biodiesel potentially eliminates more petrodiesel CO 2 emissions than soybean biodiesel. However, for both scenarios, the net potential GHG reductions (petrodiesel offset plus change in GHG emissions from field crops) were 2.60 MgCO 2e ha − 1 of additional oilseeds in the east and 0.94 MgCO 2e ha − 1 in the west. The higher meal by-product from soybean oil meant a smaller loss of livestock feed for eastern Canada.