A suggestion to assess spilled hydrocarbons as a greenhouse gas source

دراینمقاله،میزانو ارزش انتشارگازهایگلخانه‌ای اکسید‌نیتروس(N2O) و دی‌اکسید‌کربن(CO2)حاصلازتولید حبوبات منتخب ایران (شامل نخود، لوبیا و عدس) با استفاده از مدل GHGE،برایسالزراعی91-90برآورد شده است.نتایج نشان‌داد که استان‌هایفارسوبوشهر، به‌ترتیبباتولیدسالانه271/79 و 004/0 تنN2O، بیشترینوکمترینمیزانتولیدگاز گلخانه‌ایN2Oرا دارامی‌باشند. همچنین استان‌هایلرستانوبوشهر نیز به‌ترتیب باتولیدسالانه83/10327 و33/1‌تنCO2،بیشترینوکمترینمیزانتولیدگاز گلخانه‌ایCO2را به‌خود اختصاص داده‌اند. مجموعهزینه‌هایزیست‌محیطی انتشار گازهای گلخانه‌ای N2O و CO2 کلکشورنیزحدود705/32‌میلیاردریالبرآوردگردید. باتوجهبه یافته‌ها، مدیریت کودهای نیتروژنه مصرفی در مزارعوتوسعهسیاست‌کاهشمیزانانتشاربه‌همراه مالیات زیست‌محیطی انتشار گازهای گلخانه‌ای بر سطوح مختلف تولید پیشنهاد شده ‌است. واژه‌های کلیدی: اکسید‌نیتروس، دی‌اکسید‌کربن، حبوبات، گازهای گلخانه‌ای

انتشار گازهای گلخانه‌ای و اثرات آن بر گرمایش جهانی یکی از چالش‌های جدی کشورهای توسعه‌یافته و درحال‌توسعه محسوب می‌شود. بر اساس پیمان کیوتو، کشورهای مختلف موظف به محاسبه و اعلام میزان انتشار گازهای گلخانه‌ای شدند. بررسی میزان انتشار گازهای گلخانه‌ای کشورهای مختلف این امکان را فراهم می‌آورد تا ضمن ارائه تصویری از سهم کشورها در تولید گازهای گلخانه‌ای، جایگاه ایران نیز در این مجموعه مشخص شود. این مقاله تلاش دارد تا میزان و ارزش انتشار گازهای گلخانه‌ای اکسید نیتروس (N2O) و دی‌اکسید کربن (CO2) حاصل از دانه های روغنی تولیدی منتخب در ایران (سویا، کلزا، ذرت دانه ای و سایر دانه های روغنی) را با استفاده از مدل GHGE، برای سال زراعی 91-90 برآورد نماید. نتایج نشان داد استان‌های خوزستان و زنجان به ترتیب، با تولید سالانه 49/341 و 004/0 تن، بیش ترین و کم ترین میزان تولید گاز گلخانه‌ای N2O را در سطح کشور دارا می‌باشند. همچنین استان‌های گلستان و هرمزگان نیز به ترتیب، با تولید سالانه 47/7841 و 24/0 تن دی‌اکسید کربن بیش ترین و کم ترین میزان تولید گاز گلخانه‌ای CO2 را به خود اختصاص داده‌اند. مجموع هزینه‌های انتشار گازهای گلخانه‌ای N2O و CO2 کل کشور نیز حدود 331/27 میلیارد ریال برآورد گردید. باتوجه به یافته ها، اصلاح و تغییر شیوه‌های مدیریتی کشاورزی نسبت به سطح زیرکشت محصولات زراعی، مدیریت و افزایش کارایی کودهای ازته مصرفی در مزارع و توسعه سیاست‌های کاهش میزان انتشار به‌همراه مالیات زیست-محیطی انتشار گازهای گلخانه ای به سیاست‌گذاران این عرصه پیشنهاد شد.

New techniques for monitoring greenhouse gas (GHG) emissions are
urgently needed in multiple spatial scales, to find ways to effectively mitigate emissions
and for sustainable policy-making. This paper focuses on a novel facility-scale
monitoring technique which uses sequential multi-beam open-path laser spectroscopy
measurements and wind field data to infer spatio-temporal distributions of GHG
emission sources. The problem of mapping and quantifying the GHG source is
considered as a non-stationary, three-dimensional (3D) tomography problem in which
the GHG source is reconstructed simultaneously with the temporally evolving 3D
concentration of the GHG. The tomographic reconstruction problem is highly rank
deficient due to the practically realizable limited-angle setup of sensors. However,
the proposed approach for the reconstruction takes advantage of the non-stationarity
of the inverse problem – we model the temporal evolution of the 3D concentration
distribution and the contribution of the source to it by a convection-diffusion model in
which the wind field data is incorporated. The reconstruction problem is formulated in
the framework of Bayesian state estimation, using laser spectroscopy observations and
the evolution model. Particularly, Kalman smoother estimates are computed. In this
paper, the 3D tomographic reconstruction of GHG concentration and source is tested
both with numerical simulation studies and with experimental field data. The results
demonstrate the feasibility of the approach for mapping and quantifying various types
of GHG sources and for quantifying their uncertainties in multiple wind conditions.

Estimation of net greenhouse gas balance using crop- and soil-based approaches: Two case studies

Globally, agriculture is directly responsible for 14% of annual greenhouse gas(GHG) emissions and induces an additional 17% through land use change, mostlyin developing countries (Vermeulen et al 2012). Agricultural intensification andexpansion in these regions is expected to catalyze the most significant relativeincreases in agricultural GHG emissions over the next decade (Smith et al 2008,Tilman et al 2011). Farms in the developing countries of sub-Saharan Africa andAsia are predominately managed by smallholders, with 80% of land holdingssmaller than ten hectares (FAO 2012). One can therefore posit that smallholderfarming significantly impacts the GHG balance of these regions today and willcontinue to do so in the near future.However, our understanding of the effect smallholder farming has on theEarth’s climate system is remarkably limited. Data quantifying existing andreduced GHG emissions and removals of smallholder production systems areavailable for only a handful of crops, livestock, and agroecosystems (Herrero et al2008, Verchot et al 2008, Palm et al 2010). For example, fewer than fifteenstudies of nitrous oxide emissions from soils have taken place in sub-SaharanAfrica, leaving the rate of emissions virtually undocumented. Due to a scarcity ofdata on GHG sources and sinks, most developing countries currently quantifyagricultural emissions and reductions using IPCC Tier 1 emissions factors.However, current Tier 1 emissions factors are either calibrated to data primarilyderived from developed countries, where agricultural production conditions aredissimilar to that in which the majority of smallholders operate, or from data thatare sparse or of mixed quality in developing countries (IPCC 2006). For the mostpart, there are insufficient emissions data characterizing smallholder agricultureto evaluate the level of accuracy or inaccuracy of current emissions estimates.Consequentially, there is no reliable information on the agricultural GHG budgetsfor developing economies. This dearth of information constrains the capacity totransition to low-carbon agricultural development, opportunities for smallholdersto capitalize on carbon markets, and the negotiating position of developingcountries in global climate policy discourse.Concerns over the poor state of information, in terms of data availability andrepresentation, have fueled appeals for new approaches to quantifying GHGemissions and removals from smallholder agriculture, for both existing conditionsand mitigation interventions (Berry and Ryan 2013, Olander et al 2013).Considering the dependence of quantification approaches on data and the currentdata deficit for smallholder systems, it is clear that in situ measurements must bea core part of initial and future strategies to improve GHG inventories and

Evaluation of Greenhouse Gas Emission from Animal Manure Using the Closed Chamber Method for Gas Fluxes

In addition to greenhouse gas (GHG) emissions by sources, GHG removal by sinks is essential in achieving the net zero target by 2050. Both the GHG sources and sinks are influenced by local and remote socioeconomic activities through international trade. However, the impacts of international trade on global net GHG emissions remain unknown. This study estimates net GHG emissions of nations from the consumption perspective, considering both GHG sources and sinks influenced by human activities. Results show that 26% of global net GHG emissions were embodied in international trade. GHG footprints in tropical nations would be significantly underestimated if only sources are considered and sink changes are neglected, especially in Indonesia (counting 65% of its GHG footprints) and Africa (44%). After considering sink changes, the consumption of processed foods and animal products exerted larger impacts on GHG footprints of tropical nations, which is mainly attributed to emissions from forest conversion; and the GHG leakage through international trade from tropical nations (e.g., Indonesia) to other nations (e.g., India and the United States) was more prominent. These results highlight the importance of sink changes in assessing GHG footprints. They can offer new insights into expediting the achievement of the net zero target.

Net ecosystem carbon and greenhouse gas budgets in fiber and cereal cropping systems

Agriculture is one of the biggest sources of greenhouse gases. Rice production has been identified as one of the major sources of greenhouse gases, especially methane. However, data on the contributions of rice towards greenhouse gas emissions in tropical Africa are limited. In Zimbabwe, as in most of Sub-Saharan Africa, there are very few studies that have explored greenhouse gas emissions from agricultural lands. This study reports the first dataset on greenhouse gas emissions from intermittently flooded rice paddies in Zimbabwe. The objective of this study was to quantify greenhouse gas emissions from dambo rice under different tillage treatments, which were conventional tillage, no tillage, tied ridges, tied fallows, and mulching. Average soil nitrous oxide emissions were 5.9, 0.2, 5.4, 5.2 and 7.8 μg·m-2·hr-1 for tied fallows, conventional tillage, tied ridges, mulching and no tillage respectively. Average methane emission was 0.35 mg·m-2·hr-1 and maximum as 1.62 mg·m-2·hr-1. Average methane emissions for the different tillage systems were 0.20, 0.18, 0.45, 0.52 and 0.38 mg·m-2·hr-1 for tied fallows, conventional tillage, tied ridges, mulching and no tillage respectively. Carbon dioxide emissions were 98.1, 56.0, 69.9, 94.8 and 95.5 mg·m-2·hr-1 for tied fallows, conventional tillage, tied ridges, mulching and no tillage respectively. The estimated emissions per 150 day cropping season were 1.4, 3.6 and 0.6 kg·ha-1 for methane, carbon dioxide and nitrous oxide respectively. We concluded that intermittently saturated dambo rice Paddys are a potential source of greenhouse gases which is important to global greenhouse gas budgets, thus, they deserve more careful study.

A new methodology for organic soils in national greenhouse gas inventories: Data synthesis, derivation and application

Agriculture is a significant source of anthropogenic greenhouse gas (GHG) emissions, and beef cattle are particularly emissions intensive. GHG emissions are typically expressed as a carbon dioxide equivalent (CO2e) ‘carbon footprint’ per unit output. The 100-year Global Warming Potential (GWP100) is the most commonly used CO2e metric, but others have also been proposed, and there is no universal reason to prefer GWP100 over alternative metrics. The weightings assigned to non-CO2 GHGs can differ significantly depending on the metric used, and relying upon a single metric can obscure important differences in the climate impacts of different GHGs. This loss of detail is especially relevant to beef production systems, as the majority of GHG emissions (as conventionally reported) are in the form of methane (CH4) and nitrous oxide (N2O), rather than CO2. This paper presents a systematic literature review of harmonised cradle to farm-gate beef carbon footprints from bottom-up studies on individual or representative systems, collecting the emissions data for each separate GHG, rather than a single CO2e value. Disaggregated GHG emissions could not be obtained for the majority of studies, highlighting the loss of information resulting from the standard reporting of total GWP100 CO2e alone. Where individual GHG compositions were available, significant variation was found for all gases. A comparison of grass fed and non-grass fed beef production systems was used to illustrate dynamics that are not sufficiently captured through a single CO2e footprint. Few clear trends emerged between the two dietary groups, but there was a non-significant indication that under GWP100 non-grass fed systems generally appear more emissions efficient, but under an alternative metric, the 100-year global temperature potential (GTP100), grass-fed beef had lower footprints. Despite recent focus on agricultural emissions, this review concludes there are insufficient data available to fully address important questions regarding the climate impacts of agricultural production, and calls for researchers to include separate GHG emissions in addition to aggregated CO2e footprints.

Blue revolution for food security under carbon neutrality: A case from the water-saving and drought-resistance rice

More than 275 million people are deriving their sustenance and livelihood needs from forests and causing forest degradation due to unsustainable harvest of forest produce. India is committed to achieve sustainable development of forests. The inadequate finance, capacity and research are key issues for sustainable development of forests in India. The consumption of wood and wood-based products has been considered for the estimation of emissions from forestry sector. The carbon sequestration has been estimated on the basis of productivity of forests and tree outside forests. The forestry sector in India will be a net source of Green House Gases (GHGs) till 2051 if policies and programs of forestry sector are implemented at the current pace and commitment. The forestry sector will also be net source of GHG till 2051 if the policies and programs suggested above are implemented moderately but the intensity of emissions will be low. The forestry sector may become net sink of GHG’s only if policies and programs are implemented aggressively with full commitment. The aggressive implementation of policies and programs will not only improve the quality of forests but also improve the quality of the life of the forest dependent communities by providing them a sustained livelihood which in turn benefit environment. The political commitment is very low for the forestry sector in India. If this continue in future, it would not be possible to achieve the scenario based on aggressive scenario. The Intended Nationally Determined Contributions (INDCs) for forestry sector announced by the Government of India on 2nd October, 2015 are extremely difficult to achieve.

Globally, greenhouse gas (GHG) reduction is a serious concern. To evaluate whether turfs serve as a GHG sink or source, GHG budget assessments for life cycle are required. However, previous studies have only focused on the use of turfs. To bridge these gaps in literature, this study investigated GHG (CO2, N2O, and CH4) emissions from the disposal of grass clippings and soil GHG fluxes in turfs. Additionally, GHG budgets in the turf production phase were assessed. Finally, inclusive GHG budgets from turf production to disposal of grass clippings for four turf uses (soccer stadium, golf course, office, and urban park) were assessed. Grass clippings were disposed in three forms (incineration, leaving as-is, and biochar). We found that GHG emissions from incineration and leaving 1 t-fresh weight (FW) of grass clippings were 0.711 and 0.207 t-CO2e, respectively. Contrastingly, the GHG emissions from the biochar yield from 1 t-FW of grass clippings were −0.200 t-CO2e. Further, annual soil GHG fluxes in newly established Zoysia and Kentucky bluegrass turfs were calculated at 0.067 and 0.040 tCO2e･ha-1･yr-1, respectively. As the turf grass in production fields sequester large amounts of CO2, GHG budgets in turf production phase were estimated at approximately −20 t-CO2e･ha-1･yr-1. Inclusive GHG budget assessment from turf production to disposal of grass clippings showed that turfs only in the urban parks served as a GHG sink and this ability was comparable to CO2 sequestration in forests. To enhance the ability of GHG sinks and to promote changes from a GHG source to GHG sink, our study revealed the importance of reduction of GHG emissions from energy and resource uses (especially fertilizers and gasoline) for turf management.

Agricultural practices contribute significant levels of greenhouse gas (GHG) emissions. Methods to measure net global warming potential (GWP) and greenhouse gas intensity (GHGI) that account for all sources and sinks of GHG emissions in agroecosystems are still evolving. Sources of GHGs include soil CO 2 , N 2 O, and CH 4 emissions and CO 2 emissions associated with farm operations, N fertilization, and other chemical inputs. Sinks of GHGs include CH 4 uptake, soil C sequestration, and crop residue returned to the soil. This chapter discusses the methods of measuring net GWP and GHGI using two approaches: In the soil organic C (SOC) method, net GWP and GHGI are calculated by using N 2 O and CH 4 emissions (or CH 4 uptake), as well as CO 2 emissions from farm operations, N fertilization, and other chemical inputs as GHG sources and C sequestration rate (ΔSOC) as GHG sink. In the soil respiration method, soil respiration (excluding root respiration) is included as another GHG source, and the previous year's crop residue returned to the soil instead of ΔSOC is included as GHG sink in addition to the above parameters. Advantages and drawbacks of each method of calculating net GWP and GHGI are also discussed.