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In 2019, New York State passed aggressive new climate legislation to reduce greenhouse gas (GHG) emissions and laid out major changes for how emissions are reported. One change is the inclusion of emissions from outside of the boundaries of the State if they are associated with energy use within NY; the traditional inventory considered emissions only within the State. The new legislation also mandated that methane emissions be compared with carbon dioxide over a 20-year time frame rather than the 100-year time frame previously used by NY and still used by virtually all other governments globally. This reflected the desire of NY's policymakers for a tool that evaluates emissions from the standpoint of energy consumption and that more heavily weighs the role of methane as an agent of warming over the next few decades. This paper compares emissions based on the new approach for GHG reporting with the traditional inventory. The traditional inventory is driven almost entirely by carbon dioxide emissions. As of 2015, these carbon dioxide emissions had declined by 15% since 1990 due to an 88% decrease in coal consumption and a 27% decrease in consumption of petroleum products, although consumption of natural gas had increased by 57%. Methane emissions increased by almost 30% between 1990 and 2015, largely due to the increased consumption of natural gas. According to the new GHG reporting rules, methane contributed 28% of all fossil-fuel emissions in 1990 and 37% in 2015. Total GHG emissions remained virtually unchanged from 1990 to 2015. [ABSTRACT FROM AUTHOR]

Extensive grazing systems in the tropics have large greenhouse gas (GHG) emissions. Here an integrated cropping, livestock farming and saline pond aquaculture system is described which also reduces GHG emissions in tropical farming. The system was developed in the 1980s in the central Philippines and is re-evaluated in terms of its potential to reduce emissions from livestock production, particularly in wet and wet-dry tropical regions. The estimated cumulative annual GHG emission savings amount to 12.9 tonne CO2-e per head of cattle exiting the integrated feedlot system after 300 days. Use of silage from crop by-products and implementation of a feed-lot programme enabled immediate and significant reductions of GHG emissions over extensive cattle grazing. Integration with a saline animal waste processing pond allowed production of natural feed products, cyanobacteria algal mat for use in aquaculture, as crop fertiliser and soil amendment or in the silage manufacture process. Fish production from ponds receiving the harvested algal mat resulted in an annual average of 3300 kg/ha compared to an average 700 kg/ha in inorganic fertilised ponds. The unitised ratios for the integrated system were respectively: 1 ha sugarcane: 4 head of cattle: 0.13 ha saline waste processing pond. Stoichiometrically, bio-processing of waste material in saline ponds provides a novel solution to GHG emissions from feedlots. It uses a multi-step process dominated by cyanobacteria mats in which all the captured liquid and solid waste is passed through fermentation and a mixed aerobic and anaerobic photosynthesis/photosynthesis and mixed aerobic/anaerobic sulphate reduction pathway to use organic wastes and also reduce GHG emissions. Sulphate is reduced and sequestered as iron sulphide eliminating the potential for harmful sulphide emissions. Calcium carbonate precipitation in the cyanobacteria mats results in significant sequestration of carbon. The process produces organic feed matter with a three-fold increase in nitrogen levels arising from nitrogen fixation in the treatment pond. [ABSTRACT FROM AUTHOR]

The development of potential metrics for comparing black carbon (BC) to carbon dioxide has been requested within legislation in the United States and has been discussed at the United Nations Framework Convention on Climate Change Conference of the Parties in Poznan: therefore, it is important to further investigate the advantages and drawbacks to using such a metric. For context, we summarize the various proposed CO2 equivalent metrics and the rationales for developing them. We use BC marginal abatement curves to examine the implications of using 100-year global warming potentials to include BC in greenhouse gas (GHG) trading regimes. This idealized study demonstrates the impacts on emissions of CO2, and radiative forcing over time. Finally, we address the drawbacks of trading poorly quantified short-lived emissions with GHGs despite different physical interactions with the climate system. While the case for reducing BC for both health and climate benefits is compelling, there are reasons for limiting the use of BC metrics to illustrative analyses, such as identifying which BC mitigation actions would provide the greatest climate benefits, rather than using these metrics for trading with GHGs. Indeed, market-based mechanisms in general may not be appropriate for BC regulation at this time. [ABSTRACT FROM AUTHOR]

Non-CO2 greenhouse gases, included in the Kyoto Protocol, are methane (CH4), nitrous oxide (N2O), hexafluorocarbons (HFC), perfluorinated compounds (PFC) and sulphur hexafluoride (SF6). Together they account for about 25% of the present global greenhouse gas emissions. Reductions in emissions of these gases have occurred in the industrialised countries, and they contribute to the efforts to reach the target of 5% greenhouse gas emission reduction as agreed in the Kyoto Protocol for these countries. Globally however, greenhouse gas emissions continue to increase as do the concentrations of these gases in the atmosphere. The relation between emissions and concentrations is not clear for all non-CO2 greenhouse gases. This especially holds for methane. This article discusses the contribution of non-CO2 greenhouse gases to global climate forcing within the causal chain approach of the DPSIR schema (Drivers, Pressures, State, Impact and Response) as a background for the studies presented in this special issue. Although considerable reductions in non-CO2 greenhouse gas emissions are expected in the first commitment period under the Climate Convention (Kyoto Protocol), it is argued that further substantial emission reductions in subsequent commitment periods for the most important non-CO2 greenhouse gases (CH4 and N2O) are difficult to achieve. [ABSTRACT FROM AUTHOR]