An overview of non-CO2 greenhouse gases

Major US electric utility climate pledges have the potential to collectively reduce power sector emissions by one-third

In the Netherlands, several measures were implemented to curb the emissions of non-CO2 greenhouse (NCG) gases in the period 1990–2003. Without the implementation of these reduction measures, emissions of NCG gases in 2003 would have been 11 million tonnes of CO2-eq. higher. Policies which were already in place before specific NCG gas policies were introduced, are predominantly responsible for the reductions achieved so far. Roughly 80% of the achieved reductions in the Netherlands can be attributed to these policies, and 20% to a specific Dutch Reduction Plan on NCG gases that was introduced in 2000. Our analysis shows that the policies in place in the period 1990–2003 were very economical from the government point of view: almost half of the emission reductions can be achieved against costs below 5 euro per tonne CO2-eq. Whereas, for example, the cost-effectiveness of government CO2 reduction programmes in the housing sector ranged from 4 to over 300 euro per tonne of CO2-eq. in the period 1995–2002.

Finland has set a legally binding goal of achieving “carbon neutrality” by 2035 and net-negative greenhouse gas emissions thereafter. The scientific background for this goal is based on an interpretation of what a nationally fair share of global carbon budget compatible with 1.5 °C warming is. This national carbon budget includes also non-CO2 greenhouse gas (GHG) emissions and is thus stricter than the original, global CO2-only carbon budget. Finland’s pathway to carbon neutrality relies not only on emission reductions but also on carbon sinks in the land use, land-use change and forestry (LULUCF) sector. The net sink in the LULUCF sector, as estimated in the national greenhouse gas inventory, is interpreted as negative emissions. This assumption is problematic, as part of the LULUCF sink is considered natural sink in the conceptual framework behind the global carbon budget estimates and assuming it entirely anthropogenic leads to underestimation of the net CO2 emissions.   Here we present an analysis and revision of the Finnish net greenhouse gas emission pathway with two major improvements. First, we extend the carbon budget framework to nationally allowed warming to be able to account explicitly also for national non-CO2 GHG emissions. The global allowed warming until 2050 from future GHG emissions is calculated as the sum of the remaining warming to 1.5 °C, the global decreasing warming impact of past non-CO2 GHG emissions by 2050, and future warming due to reduced aerosols by 2050. We use the fair share used previously for allocating national carbon budget to calculate national allowed warming contribution until 2050 and subtract non-CO2 GHG contribution based on a Finnish carbon neutrality scenario and simulations with a simple climate model FaIR 2.1. The remaining allowed warming is then used to calculate the national CO2-only carbon budget.   The second improvement is to consider the recent advancements in disentangling natural and anthropogenic carbon fluxes in the LULUCF sector. National results from a recent global study indicate that the Finnish LULUCF sector has been a carbon sink due to the natural sink induced by CO2 fertilization and climate change. The large natural sink is expected to decrease especially in the most stringent global emission reduction scenarios.    The preliminary results indicate that Finland’s currently planned pathway is not compatible with its national fair share of allowed warming compatible with the 1.5-degree target, and more stringent emission reductions coupled with strengthening of the land sink and other forms of negative emissions are very likely needed.

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Climate change: the political situation.

Changes in Non-CO2 Greenhouse Gas Emissions From Livestock Production, Meat Consumption and Trade in China

Liquid biofuels such as ethanol and biodiesel are considered important renewable replacements for petroleum fuels such as gasoline and diesel. Biomass-based energy carriers are traditionally treated as inherently carbon neutral, so that only the fossil-based carbon dioxide (CO2) and other non-CO2 greenhouse gas (GHG) emissions associated with their production are counted when assessing their global warming impact. This accounting convention is embedded by construction in lifecycle assessment (LCA) models, which on a direct basis (i.e., excluding economically induced effects) often find that biofuels from efficient industrial agricultural production systems reduce GHG emissions relative to their fossil fuel counterparts. LCA modeling can be subjected to an independent empirical test that bounds a biofuel's potential GHG reduction within the dynamics of the terrestrial carbon cycle. Such a test can be performed using annual basis carbon (ABC) accounting, which entails spatially and temporally explicit analysis of the direct GHG exchanges between the atmosphere and a physical vehicle-fuel system. An ABC case study of a corn ethanol biorefinery and the farmland that supplies it shows that using the ethanol it produced instead of gasoline provided no significant reduction in GHG emissions, in contrast to an LCA result that found a 40% GHG reduction for the same facility. ABC accounting reveals that the renewable ethanol so produced was not carbon neutral when substituting for gasoline, and sensitivity analysis indicates that its net GHG emissions impacts are likely to higher than those of petroleum gasoline in practice.

Energy-related activities are a major contributor of greenhouse gas (GHG) emissions. A growing body of knowledge clearly depicts the links between human activities and climate change. Over the last century the burning of fossil fuels such as coal and oil and other human activities has released carbon dioxide (CO2) emissions and other heat-trapping GHG emissions into the atmosphere and thus increased the concentration of atmospheric CO2 emissions. The main human activities that emit CO2 emissions are (1) the combustion of fossil fuels to generate electricity, accounting for about 37% of total U.S. CO2 emissions and 31% of total U.S. GHG emissions in 2013, (2) the combustion of fossil fuels such as gasoline and diesel to transport people and goods, accounting for about 31% of total U.S. CO2 emissions and 26% of total U.S. GHG emissions in 2013, and (3) industrial processes such as the production and consumption of minerals and chemicals, accounting for about 15% of total U.S. CO2 emissions and 12% of total ...

Article 2 of the United Nations Framework Convention on Climate Change (UNFCCC) calls for stabilization of greenhouse gas (GHG) concentrations at levels that prevent dangerous anthropogenic interference (DAI) in the climate system. However, some of the recent policy literature has focused on dangerous climatic change (DCC) rather than on DAI. DAI is a set of increases in GHGs concentrations that has a non-negligible possibility of provoking changes in climate that in turn have a non-negligible possibility of causing unacceptable harm, including harm to one or more of ecosystems, food production systems, and sustainable socio-economic systems, whereas DCC is a change of climate that has actually occurred or is assumed to occur and that has a non-negligible possibility of causing unacceptable harm. If the goal of climate policy is to prevent DAI, then the determination of allowable GHG concentrations requires three inputs: the probability distribution function (pdf) for climate sensitivity, the pdf for the temperature change at which significant harm occurs, and the allowed probability (“risk”) of incurring harm previously deemed to be unacceptable. If the goal of climate policy is to prevent DCC, then one must know what the correct climate sensitivity is (along with the harm pdf and risk tolerance) in order to determine allowable GHG concentrations. DAI from elevated atmospheric CO2 also arises through its impact on ocean chemistry as the ocean absorbs CO2. The primary chemical impact is a reduction in the degree of supersaturation of ocean water with respect to calcium carbonate, the structural building material for coral and for calcareous phytoplankton at the base of the marine food chain. Here, the probability of significant harm (in particular, impacts violating the subsidiary conditions in Article 2 of the UNFCCC) is computed as a function of the ratio of total GHG radiative forcing to the radiative forcing for a CO2 doubling, using two alternative pdfs for climate sensitivity and three alternative pdfs for the harm temperature threshold. The allowable radiative forcing ratio depends on the probability of significant harm that is tolerated, and can be translated into allowable CO2 concentrations given some assumption concerning the future change in total non-CO2 GHG radiative forcing. If future non-CO2 GHG forcing is reduced to half of the present non-CO2 GHG forcing, then the allowable CO2 concentration is 290–430 ppmv for a 10% risk tolerance (depending on the chosen pdfs) and 300–500 ppmv for a 25% risk tolerance (assuming a pre-industrial CO2 concentration of 280 ppmv). For future non-CO2 GHG forcing frozen at the present value, and for a 10% risk threshold, the allowable CO2 concentration is 257–384 ppmv. The implications of these results are that (1) emissions of GHGs need to be reduced as quickly as possible, not in order to comply with the UNFCCC, but in order to minimize the extent and duration of non-compliance; (2) we do not have the luxury of trading off reductions in emissions of non-CO2 GHGs against smaller reductions in CO2 emissions, and (3) preparations should begin soon for the creation of negative CO2 emissions through the sequestration of biomass carbon.

Although CO2 emissions stand for most of greenhouse gas (GHG) emissions, the contribution of mitigation efforts based on non-CO2 emissions is still a field that needs to be explored more thoroughly. Extending abatement opportunities to non-CO2 could reduce overall mitigation costs but it could also exert a negative pressure on agricultural output. This paper offers insights about the first effect while provides a preliminary discussion for the second. We investigate the role of non-CO2 GHGs in climate change mitigation in Europe using a computable general equilibrium (CGE) model. We develop a specific modelling framework extending the model with non-CO2 GHGs as an additional mitigation alternative. These modifications allow us to analyse the implications for the European Union (EU) of including non-CO2 GHG emissions in its cap and trade system. We distinguish two targets on all GHG emissions for 2020, a reduction by 20% and 30% with respect to 1990 levels. Within each reduction cap, we consider two mitigation opportunities by means of a carbon tax levied on: 1) CO2 emissions only, and 2) All GHGs emissions (both CO2 and non-CO2 GHG). Results show that a multi-gas mitigation policy would slightly decrease policy costs compared to the CO2 only alternative.

Although CO2 emissions stand for most of greenhouse gas (GHG) emissions, the contribution of mitigation efforts based on non-CO2 emissions is still a field that needs to be explored more thoroughly. Extending abatement opportunities to non-CO2 could reduce overall mitigation costs but it could also exert a negative pressure on agricultural output. This paper offers insights about the first effect while provides a preliminary discussion for the second. We investigate the role of non-CO2 GHGs in climate change mitigation in Europe using a computable general equilibrium (CGE) model. We develop a specific modelling framework extending the model with non-CO2 GHGs as an additional mitigation alternative. These modifications allow us to analyse the implications for the European Union (EU) of including non-CO2 GHG emissions in its cap and trade system. We distinguish two targets on all GHG emissions for 2020, a reduction by 20% and 30% with respect to 1990 levels. Within each reduction cap, we consider two mitigation opportunities by means of a carbon tax levied on: 1) CO2 emissions only, and 2) All GHGs emissions (both CO2 and non-CO2 GHG). Results show that a multi-gas mitigation policy would slightly decrease policy costs compared to the CO2 only alternative.

Opportunities beyond CO2 for climate mitigation

Greenhouse gas emission reduction and environmental quality improvement from implementation of aerobic waste treatment systems in swine farms

Forecasts indicate that China’s non-carbon dioxide (CO2) greenhouse gas (GHG) emissions will increase rapidly from the 2014 baseline of 2 billion metric tons of CO2 equivalent (CO2e). Previous studies of the potential for mitigating non-CO2 GHG emissions in China have focused on timeframes through only 2030, or only on certain sectors or gases. This study uses a novel bottom-up end-use model to estimate mitigation of China’s non-CO2 GHGs under a Mitigation Scenario whereby today’s cost-effective and technologically feasible CO2 and non-CO2 mitigation measures are deployed through 2050. The study determines that future non-CO2 GHG emissions are driven largely by industrial and agricultural sources and that China could reduce those emissions by 47% by 2050 while enabling total GHG emissions to peak by 2023. Except for F-gas mitigation, few national or sectoral policies have focused on reducing non-CO2 GHGs. Policy, market, and other institutional support are needed to realize the cost-effective mitigation potentials identified in this study.

Accurate and verifiable emission reductions are a function of the degree of transparency and stringency of the protocols employed in documenting project- or program-associated emissions reductions. The purpose of this guide is to provide a background for law and policy makers, urban planners, and project developers working with the many Greenhouse Gas (GHG) emission reduction programs throughout the world to quantify and/or evaluate the GHG impacts of Natural Gas Vehicle (NGVs). In order to evaluate the GHG benefits and/or penalties of NGV projects, it is necessary to first gain a fundamental understanding of the technology employed and the operating characteristics of these vehicles, especially with regard to the manner in which they compare to similar conventional gasoline or diesel vehicles. Therefore, the first two sections of this paper explain the basic technology and functionality of NGVs, but focus on evaluating the models that are currently on the market with their similar conventional counterparts, including characteristics such as cost, performance, efficiency, environmental attributes, and range. Since the increased use of NGVs, along with Alternative Fuel Vehicle (AFVs) in general, represents a public good with many social benefits at the local, national, and global levels, NGVs often receive significant attention in themore » form of legislative and programmatic support. Some states mandate the use of NGVs, while others provide financial incentives to promote their procurement and use. Furthermore, Federal legislation in the form of tax incentives or procurement requirements can have a significant impact on the NGV market. In order to implement effective legislation or programs, it is vital to have an understanding of the different programs and activities that already exist so that a new project focusing on GHG emission reduction can successfully interact with and build on the experience and lessons learned of those that preceded it. Finally, most programs that deal with passenger vehicles--and with transportation in general--do not address the climate change component explicitly, and thus there are few GHG reduction goals that are included in these programs. Furthermore, there are relatively few protocols that exist for accounting for the GHG emissions reductions that arise from transportation and, specifically, passenger vehicle projects and programs. These accounting procedures and principles gain increased importance when a project developer wishes to document in a credible manner, the GHG reductions that are achieved by a given project or program. Section four of this paper outlined the GHG emissions associated with NGVs, both upstream and downstream, and section five illustrated the methodology, via hypothetical case studies, for measuring these reductions using different types of baselines. Unlike stationary energy combustion, GHG emissions from transportation activities, including NGV projects, come from dispersed sources creating a need for different methodologies for assessing GHG impacts. This resource guide has outlined the necessary context and background for those parties wishing to evaluate projects and develop programs, policies, projects, and legislation aimed at the promotion of NGVs for GHG emission reduction.« less