Global Warming Commitment Research Articles

Clean cooking and the SDGs: Integrated analytical approaches to guide energy interventions for health and environment goals

Development and implementation of clean cooking technology for households in low and middle income countries (LMICs) offer enormous promise to advance at least five Sustainable Development Goals (SDGs): 3. Good health and well-being; 5. Gender equality; 7. Affordable and clean energy; 13. Climate action; 15. Life on land. Programs are being implemented around the world to introduce alternative cooking technologies, and we are well on the way to achieving the goal set by the Global Alliance for Clean Cookstoves to reach 100 million homes with cleaner and more efficient cooking methods by 2020. Despite evidence that household air pollution (HAP) from solid fuel combustion is responsible for 3–4 million early deaths per year, many cookstove programs are motivated and/or financed by climate change mitigation schemes and deploy alternative stoves that use solid fuels such as wood and charcoal. However, recent studies have demonstrated that improved biomass-burning stoves typically only incrementally improve air quality and yield modest or minimal health benefits. Likewise, their contributions to climate change mitigation and other SDGs may be limited. Evidence indicates that cleaner fuels, such as liquefied petroleum gas (LPG), ethanol and biogas, offer greater potential benefits not only to health, but also greater progress towards climate goals and other relevant SDGs. We present a modeled estimate of these potential gains for a diverse group of 40 LMICs. Our model suggests that cookstove programs using LPG stoves and fuel will yield greater reductions in both Disability Adjusted Life Years and Global Warming Commitment in these countries than those using improved biomass stoves. Cost and infrastructure requirements for clean fuels such as LPG are widely recognized constraints. In view of these constraints we present an analytical method to simultaneously consider health and climate needs at the national level for the same 40 countries in the context of estimated LPG expansion potentials. Comparative analyses integrating priorities across SDGs at the national and regional levels may guide more practical and effective household energy development choices going forward.

In-Use Emissions and Estimated Impacts of Traditional, Natural- and Forced-Draft Cookstoves in Rural Malawi.

Emissions from traditional cooking practices in low- and middle-income countries have detrimental health and climate effects; cleaner-burning cookstoves may provide “co-benefits”. Here we assess this potential via in-home measurements of fuel-use and emissions and real-time optical properties of pollutants from traditional and alternative cookstoves in rural Malawi. Alternative cookstove models were distributed by existing initiatives and include a low-cost ceramic model, two forced-draft cookstoves (FDCS; Philips HD4012LS and ACE-1), and three institutional cookstoves. Among household cookstoves, emission factors (EF; g (kg wood)−1) were lowest for the Philips, with statistically significant reductions relative to baseline of 45% and 47% for fine particulate matter (PM2.5) and carbon monoxide (CO), respectively. The Philips was the only cookstove tested that showed significant reductions in elemental carbon (EC) emission rate. Estimated health and climate cobenefits of alternative cookstoves were smaller than predicted from laboratory tests due to the effects of real-world conditions including fuel variability and nonideal operation. For example, estimated daily PM intake and field-measurement-based global warming commitment (GWC) for the Philips FDCS were a factor of 8.6 and 2.8 times higher, respectively, than those based on lab measurements. In-field measurements provide an assessment of alternative cookstoves under real-world conditions and as such likely provide more realistic estimates of their potential health and climate benefits than laboratory tests.

Unavoidable Global Warming Commitment and Its Food Security Implications

Unavoidable Global Warming Commitment and Its Food Security Implications

Greenhouse Gas Emission Reductions from Domestic Anaerobic Digesters Linked with Sustainable Sanitation in Rural China

Anaerobic digesters provide clean, renewable energy (biogas) by converting organic waste to methane, and are a key part of China's comprehensive rural energy plan. Here, experimental and modeling results are used to quantify the net greenhouse gas (GHG) reduction from substituting a household anaerobic digester for traditional energy sources in Sichuan, China. Tunable diode laser absorption spectroscopy and radial plume mapping were used to estimate the mass flux of fugitive methane emissions from active digesters. Using household energy budgets, the net improvement in GHG emissions associated with biogas installation was estimated using global warming commitment (GWC) as a consolidated measure of the warming effects of GHG emissions from cooking. In all scenarios biogas households had lower GWC than nonbiogas households, by as much as 54%. Even biogas households with methane leakage exhibited lower GWC than nonbiogas households, by as much as 48%. Based only on the averted GHG emissions over 10 years, the monetary value of a biogas installation was conservatively estimated at US$28.30 ($16.07 ton(-1) CO(2)-eq), which is available to partly offset construction costs. The interaction of biogas installation programs with policies supporting improved stoves, renewable harvesting of biomass, and energy interventions with substantial health cobenefits are discussed.

Climate and Health Relevant Emissions from in-Use Indian Three-Wheelers Fueled by Natural Gas and Gasoline

Auto-rickshaws in India use different fuels and engine technologies, with varying emissions and implications for air quality and climate change. Chassis dynamometer emission testing was conducted on 30 in-use auto-rickshaws to quantify the impact of switching from gasoline to compressed natural gas (CNG) in spark-ignition engines. Thirteen test vehicles had two-stroke CNG engines (CNG-2S) and 17 had four-stroke CNG engines (CNG-4S), of which 11 were dual-fuel and operable on a back-up gasoline (petrol) system (PET-4S). Fuel-based emission factors were determined for gaseous pollutants (CO(2), CH(4), NO(X), THC, and CO) and fine particulate matter (PM(2.5)). Intervehicle variability was high, and for most pollutants there was no significant difference (95% confidence level) between "old" (1998-2001) and "new" (2007-2009) age-groups within a given fuel-technology class. Mean fuel-based PM(2.5) emission factor (mean (95% confidence interval)) for CNG-2S (14.2 g kg(-1) (6.2-26.7)) was almost 30 times higher than for CNG-4S (0.5 g kg(-1) (0.3-0.9)) and 12 times higher than for PET-4S (1.2 g kg(-1) (0.8-1.7)). Global warming commitment associated with emissions from CNG-2S was more than twice that from CNG-4S or PET-4S, due mostly to CH(4) emissions. Comprehensive measurements and data should drive policy interventions rather than assumptions about the impacts of clean fuels.

Models to predict emissions of health-damaging pollutants and global warming contributions of residential fuel/stove combinations in China.

Residential energy use in developing countries has traditionally been associated with combustion devices of poor energy efficiency, which have been shown to produce substantial health-damaging pollution, contributing significantly to the global burden of disease, and greenhouse gas (GHG) emissions. Precision of these estimates in China has been hampered by limited data on stove use and fuel consumption in residences. In addition limited information is available on variability of emissions of pollutants from different stove/fuel combinations in typical use, as measurement of emission factors requires measurement of multiple chemical species in complex burn cycle tests. Such measurements are too costly and time consuming for application in conjunction with national surveys. Emissions of most of the major health-damaging pollutants (HDP) and many of the gases that contribute to GHG emissions from cooking stoves are the result of the significant portion of fuel carbon that is diverted to products of incomplete combustion (PIC) as a result of poor combustion efficiencies. The approximately linear increase in emissions of PIC with decreasing combustion efficiencies allows development of linear models to predict emissions of GHG and HDP intrinsically linked to CO2 and PIC production, and ultimately allows the prediction of global warming contributions from residential stove emissions. A comprehensive emissions database of three burn cycles of 23 typical fuel/stove combinations tested in a simulated village house in China has been used to develop models to predict emissions of HDP and global warming commitment (GWC) from cooking stoves in China, that rely on simple survey information on stove and fuel use that may be incorporated into national surveys. Stepwise regression models predicted 66% of the variance in global warming commitment (CO2, CO, CH4, NOx, TNMHC) per 1 MJ delivered energy due to emissions from these stoves if survey information on fuel type was available. Subsequently if stove type is known, stepwise regression models predicted 73% of the variance. Integrated assessment of policies to change stove or fuel type requires that implications for environmental impacts, energy efficiency, global warming and human exposures to HDP emissions can be evaluated. Frequently, this involves measurement of TSP or CO as the major HDPs. Incorporation of this information into models to predict GWC predicted 79% and 78% of the variance respectively. Clearly, however, the complexity of making multiple measurements in conjunction with a national survey would be both expensive and time consuming. Thus, models to predict HDP using simple survey information, and with measurement of either CO/CO2 or TSP/CO2 to predict emission factors for the other HDP have been derived. Stepwise regression models predicted 65% of the variance in emissions of total suspended particulate as grams of carbon (TSPC) per 1 MJ delivered if survey information on fuel and stove type was available and 74% if the CO/CO2 ratio was measured. Similarly stepwise regression models predicted 76% of the variance in COC emissions per MJ delivered with survey information on stove and fuel type and 85% if the TSPC/CO2 ratio was measured. Ultimately, with international agreements on emissions trading frameworks, similar models based on extensive databases of the fate of fuel carbon during combustion from representative household stoves would provide a mechanism for computing greenhouse credits in the residential sector as part of clean development mechanism frameworks and monitoring compliance to control regimes.

Global warming potential, global warming commitment and other indexes as characteristics of the effects of greenhouse gases on Earth's climate

Radiative forcing (RF) is widely used for evaluation of separate radiative active substance effects on climate. For photochemically active greenhouse gases, this effect detachment for the definite radiative active substance content change poses the problem of filtering out of all other chemically connected greenhouse gas effects. Two schemes of RF calculation for such greenhouse gas are proposed and analyzed: the cumulative and the individual ones as the direct generalization of the standard RF definition and the filtering out procedure, respectively. The global warming commitment (GWC) of gas X relative to a standard gas A for time period T is proposed and determined by the same formula, as the well-known global warming potential (GWP) of gas X , but for different integrated radiative forcing (RF). RF X ( t )=Δ F X ( t ) is the net total radiation flux change at the tropopause level caused only by a gas X content variation during the period of integration. In the GWP of a gas X , Δ F X ( t ) and Δ F A ( t ) appear due to instantaneous releases into the atmosphere of the same definite mass (1 kg) of gas X and of a standard gas A . In the GWC, the actually measured or modeled gas content evaluations are used for the estimation of gas X relative input into the current and future greenhouse warming. The GWC of the principal greenhouse gases (GG) are calculated and analyzed for the period before 1995, calculations and analysis being based on the observed GG content evolution. For this period and for the period from now until 2050, the global GG content evolution reconstruction and prediction by means of radiative photochemical atmospheric model are based on two of the well-known IPCC scenarios of GG anthropogenic emissions. The GWCs of CH 4 , N 2 O and chlorofluorocarbons (CFCs) against CO 2 as a standard GG are different from their relative RF and much more accurately reflect the real events in the above mentioned periods than the widely used RF of GG relative to RF of CO 2 , when the character of the GG content evolution during the time period considered is not accounted for. The filtering efficiency of cumulative and individual schemes is estimated.

Emissions of greenhouse gases and other airborne pollutants from charcoal making in Kenya and Brazil

Airborne emissions from charcoal‐making kilns commonly used in Kenya and Brazil were measured during typical operating conditions. Emission factors were determined for carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), carbon monoxide (CO), total nonmethane hydrocarbons, nitrogen oxides (NOx) and total suspended particulates (TSP) along with charcoal production efficiency and charcoal and fuelwood carbon and energy contents. The conversion of wood carbon to charcoal carbon ranged from 37 to 69%, depending on kiln type. Emission factors, expressed as grams of pollutant per kilogram of charcoal produced, for the eight kilns ranged from 543 to 3027 for CO2, 32–62 for CH4, 143–373 for CO, 24–124 for total nonmethane organic compounds, 0.011–0.30 for N2O, 0.0054–0.13 for NOx, and 13–41 for TSP. On average, fuelwood carbon was approximately diverted as follows: 51% to charcoal, 27% to CO2, and 13% to products of incomplete combustion (PIC). Due to the higher global warming potentials (GWPs) of PIC relative to CO2on a carbon atom basis, such kilns can produce rather large net greenhouse gas emissions, even when the wood is harvested renewably. Based on published GWPs for CO2, CH4, and N2O only, we estimate that 0.77–1.63 kg C‐CO2(carbon as carbon dioxide equivalents) is emitted per kilogram of charcoal produced. We estimate that the total primary global warming commitment (GWC) of Kenyan and Brazilian charcoal‐making kiln emissions is about 2.7 and 7.5 million tons (Mt) C‐CO2, respectively. For comparison, the primary GWC from fossil fuel use in the United States is almost 1700 Mt C‐CO2.

Greenhouse Implications of Household Stoves: An Analysis for India

▪ Abstract It is commonly assumed that biomass fuel cycles based on renewable harvesting of wood or agricultural wastes are greenhouse-gas (GHG) neutral because the combusted carbon in the form of CO2is soon taken up by regrowing vegetation. Thus, the two fifths or more of the world's households relying on such fuels are generally not thought to play a significant role in GHG emissions, except where the wood or other biomass they use is not harvested renewably. This review examines this assumption using an emissions database of CO2, CO, CH4, NMHC, N2O, and total suspended particulate emissions from a range of household stoves in common use in India using six biomass fuels, kerosene, liquefied petroleum gas, and biogas. Because typical biomass stoves are thermally inefficient and divert substantial fuel carbon to products of incomplete combustion, their global warming commitment (GWC) per meal is high. Depending on time horizons and which GHGs are measured, the GWC of a meal cooked on a biomass stove can actually exceed that of the fossil fuels, even if based on renewably harvested fuel. Biogas, being based on a renewable fuel and, because it is a gas, being combusted with high efficiency in simple devices, has by far the lowest GWC emitted at the stove per meal and is indicative of the advantage that upgraded fuels made from biomass have in moving toward sustainable development goals. There are a number of policy implications of this work, including revelation of a range of win-win opportunities for international investment in rural energy development that would achieve cost-effective GHG reduction as well as substantial local benefits.

EPA's Scenarios for Future Greenhouse Gas Emissions and Global Warming

risks of global warming regardless of uncertainties about the response of the climate system . Scenario analyses conducted by EPA for a Report to Congress on Policy Options for Stabilizing Global Climate indicate that if no policies to limit greenhouse gas emissions are undertaken , the equivalent of a doubling of carbon dioxide would occur between 2030 and 2040 , and the Earth might be committed to a global warming of 2-4°C(3-7°F)by 2025 and 3-6°C(4-10°F) by 2050. Early application of existing and emergingtechnologies designed among other things, to increase the efficiency of energy use, expand the use of non-fossil energy sources , reverse deforestation, and phase out chlorofluorocarbons , could reduce the globalwarming commitment in 2025 by about one-fourth, and the rate of climatic change during the next century by at least 60%. A global commitment to rapidly reducing greenhouse gas emissions could stabilize the concentrations of these gases by the middle of the next century, perhaps limiting global warming to less than 2 °C (3 °F).