non-CO2 Greenhouse Gases Research Articles

An overview of non-CO2 greenhouse gases

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.

The potential of blue energy for reducing emissions of CO2 and non-CO2 greenhouse gases

Salinity gradient power (or blue energy) is a renewable energy source mentioned in the literature since the 1950s. It refers to the production of electricity by mixing of two solutions with different salt concentrations, for example river and sea water. The global potential of salinity power has been estimated in the 1970s as substantial, but the state of membrane technology at that time – crucial for energy recovery – did not permit the practical use of this resource. More recently, the interest in salinity power has been growing because of the need for carbon neutral, renewable sources of electricity. This study aims to assess the potential of salinity-gradient power for reducing emissions of CO2 and non-CO2 greenhouse gases. First, we discuss the global technical potential for blue energy, i.e. the maximum amount of energy that could be retrieved at the current state of technology. We focus on rivers as source of fresh water and seas as source of saline water. The analysis is based on global datasets of annual river discharges for more than 5000 world rivers. The resulting estimates of global and regional potentials for salinity gradient power are used to estimate the potential for reducing greenhouse gases, assuming that salinity power would reduce the need for fossil fuels. The results are shown for global totals, regional totals and selected rivers.

Emission mitigation potentials and costs for non-CO2 greenhouse gases in Annex-I countries according to the GAINS model

The GAINS model allows for estimation of costs and potentials for greenhouse gas (GHG) mitigation by individual GHGs. In this article, the GAINS model is used to assess mitigation potentials for non-CO2 GHGs in 2020 for all countries covered in the Annex-I of the Kyoto protocol. Mitigation measures for methane, nitrous oxide or fluorinated gases and their costs are identified and mitigation potentials and costs are compared with other available studies. Differences in the structure of economic sectors between countries are important determinants for the differences in the respective contribution of non-CO2 GHGs. For some countries, a successful application of mitigation options clearly hampers the potential still available for future reductions. While a number of options exist to reduce CO2 even at negative costs (∼25% of the overall reduction potential), this is not the case for non-CO2 gases. Non-CO2 gases, however, provide considerable potential in the very low cost range (less than 10 €/t CO2-eq), in particular as they are affected by options to abate CO2 as well. In the range for very cheap options, non-CO2 gases cover about 36% of the reduction potential, a fraction which is decreasing for the higher cost range, to about 26% for a carbon price of 100 €/t CO2-eq. These figures have been calculated for the total of Annex-I countries, assuming a social discount rate of 4%.

The role of non-CO2 greenhouse gases in cost-effective strategies to reduce pollution by dairy cattle in the Czech Republic

Agriculture is an important source of greenhouse gases, including methane (CH4) and nitrous oxide (N2O). In addition, it is a source of compounds contributing to other environmental problems such as acidification, terrestrial and aquatic eutrophication, tropospheric ozone formation, and human health problems. These compounds include, for instance, ammonia (NH3), nitrogen oxides (NOx), and particulate matter (PM) volatile organic compounds or nitrate (). In this article, we address the question how we can reduce the overall environmental impact (OEI) of agriculture at least costs, and what the role of non-CO2 greenhouse gases in these optimal solutions is. We present results of the DAIRY model, an optimization model for the Czech dairy production sector. The model distinguishes between nine study regions defined according environmental and agriculture characteristics and calculates emissions, their potential impact and OEI at regional and national level. We show that in cost-effective scenarios the model tends to select measures to reduce emissions contributing to climate change and aquatic eutrophication first. This is in contrast with current policies in the Czech Republic, which is aiming at reduction of emissions causing acidification and eutrophication. We also show that reducing greenhouse gas emissions plays a modest role in optimal strategies to reduce the OEI of dairy production.

The Influence of Nutrients and Non-CO2 Greenhouse Gas Emissions on the Ecological Footprint of Products

The ecological footprint (EF) commonly neglects the influence of other stressors than land use and CO2 emissions on the land area required for human activities. This study analyzes the relevancy of including nutrients and non-CO2 greenhouse gases in the EF assessment of products. The analysis was based on environmental information for 1,925 goods and services. Our findings suggest that within specific product categories, i.e., waste treatment processes, bio-based energy, agricultural products and chemicals, adding non-CO2 greenhouse gases and nutrient emissions can have a dominant influence on the EF results.

Postharvest nitrous oxide emissions from a subtropical oxisol as influenced by summer crop residues and their management

Nitrous oxide (N2O) is the most important non-CO2 greenhouse gas and soil management systems should be evaluated for their N2O mitigation potential. This research evaluated a long-term (22 years) experiment testing the effect of soil management systems on N2O emissions in the postharvest period (autumn) from a subtropical Rhodic Hapludox at the research center FUNDACEP, in Cruz Alta, state of Rio Grande do Sul. Three treatments were evaluated, one under conventional tillage with soybean residues (CTsoybean) and two under no-tillage with soybean (NTsoybean) and maize residues (NTmaize). N2O emissions were measured eight times within 24 days (May 2007) using closed static chambers. Gas flows were obtained based on the relations between gas concentrations in the chamber at regular intervals (0, 15, 30, 45 min) analyzed by gas chromatography. After soybean harvest, accumulated N2O emissions in the period were approximately three times higher in the untilled soil (164 mg m-2 N) than under CT (51 mg m-2 N), with a short-lived N2O peak of 670 mg m-2 h-1 N. In contrast, soil N2O emissions in NT were lower after maize than after soybean, with a N2O peak of 127 g m-2 h-1 N. The multivariate analysis of N2O fluxes and soil variables, which were determined simultaneously with air sampling, demonstrated that the main driving variables of soil N2O emissions were soil microbial activity, temperature, water-filled pore space, and NO3- content. To replace soybean monoculture, crop rotation including maize must be considered as a strategy to decrease soil N2O emissions from NT soils in Southern Brazil in a Autumn.

Regulations Concerning Agriculture and Air Pollution

The main issues related to the atmospheric pollution are the stratospheric ozone depletion, the transboundary air pollution, the troposphere air quality and the climate change. The three last decades have seen the birth of several measures for the atmosphere safeguard. Agricultural activities play a key role in determining, preventing and mitigating atmospheric pollution. The emission to atmosphere of different ozone-depleting substances is regulated by the Montreal Protocol. The role of agriculture activity in ozone depletion is linked to the utilization of methyl bromide as soil sterilant and to the emission of nitrogen oxides and nitrous oxide, from agricultural soils. The Convention on long-range transboundary air pollution regulates the emission of several pollutants, i.e. sulphur dioxide, nitrogen oxides, ammonia, non methane volatile organic compounds, carbon monoxide, heavy metals, persistent organic pollutants, and tropospheric ozone. The agriculture sector is responsible for a large part of the emissions of ammonia and nitrogen oxides, mainly through manure management and nitrogen fertilization, and of most persistent organic pollutants, largely used in the past as insecticides and fungicides. The increase of the greenhouse gases (GHGs) concentration in the atmosphere is under the control of the Kyoto Protocol. Agriculture accounts for 59-63% of global non-CO2 GHGs emissions but at the same time it contributes to the atmospheric CO2 concentration stabilisation through the substitution of fossil fuels by biofuels and the sequestration of C in soil and vegetal biomass. In this paper we provide an outline of the numerous scientific and legislative initiatives aimed at protecting the atmosphere, and we analyse in detail the agriculture sector in order to highlight both its contribution to atmospheric pollution and the actions aimed at preventing and mitigating it.

Irreversible climate change will also change environmental assessment and management

Environmental and management methods and procedures developed for the planet’s present climate will not be effective after irreversible climate change occurs. To quote Rubin (2009, p 17) ‘‘Suddenly the text books seem to be describing some other world than the one we live in.’’ Because the results of climate change cannot be known until they do occur, the focus of new environmental and management methods and procedures is unknown at present, but professionals should be prepared to act when they are known. Anthropogenic greenhouse gas emissions are still rising, and reaching zero discharge of carbon dioxide is not probable as long as fossil fuels (petroleum, coal, natural gas) are a major source of energy. As a consequence, environmental changes that have already occurred are not likely to be reversed. ‘‘The severity of damaging human-induced climate change depends not only on the magnitude of the change but also on the potential for irreversibility . . . the climate change that takes place due to increases in carbon dioxide concentration is largely irreversible for 1,000 years after emissions stop’’ (Solomon et al. 2009, p 1704). ‘‘Global average temperatures increase while CO2 is increasing and then remain approximately constant (within __ 0.58C) until the end of the millennium despite zero further emissions . . . ’’ (Solomon et al. 2009, p 1705). Therefore, humankind is likely to experience climate change for 1000 years after anthropogenic carbon dioxide emissions cease. Nonanthropogenic carbon is in the atmosphere—e.g., drying wetlands, thawing permafrost—and these positive feedback loops are likely to accelerate. Rapid climate change may soon become the norm, and all humankind must adjust to it effectively. Obviously, global problems require global collaborations from the world’s nations. Failure to do so effectively will ensure that climate change continues. The encouraging aspect of collaboration and improvisation is that ‘‘carbon dioxide is the only greenhouse gas whose falloff displays multiple rather than single time constraints . . . Current emissions of major non-CO2 greenhouse gases such as methane or nitrous oxide are significant for climate change in the next few decades or century, but these gases do not persist over time in the same way as carbon dioxide’’ (Solomon et al. 2009, p 1705).

Brazilian greenhouse gas emissions: the importance of agriculture and livestock

Data from the 1990-1994 period presented in the "Brazil's Initial National Communication" document indicated that the country is one of the top world greenhouse gas (GHG) emitters. A large majority of Brazil's GHG emissions come from deforestation mainly of the Amazon biome for agriculture and livestock land uses. This unique inventory is now out of date. Thus, the aims of this review were (i) to update estimates of the GHG emissions for the Brazilian territory, (ii) to estimate the sinks to provide calculations of the GHG net emissions for the 1990-2005 period, (iii) to calculate the actual and estimate shares of agricultural and livestock activities, and (iv) to discuss in light of the new figures and patterns the best mitigation options for Brazil. Total emissions in CO2-eq increased by 17% during the 1994-2005 period. CO2 represented 72.3% of the total, i.e. a small decrease, in favour of non-CO2 GHG, in relation to 1994 when its share was 74.1%. The increase of all GHG excluding Land Use Change and Forestry (LUCF) was 41.3% over the period 1994-2005. Climate Analysis Indicators Tool (CAIT) - World Resources Institute (WRI) estimated a higher increase (48.9%) that classified Brazil at the 69th position. Using our estimates Brazil will fall to the 78th position. But in both cases Brazil increased in clearly lower values than the tendency calculated for China and India, two major emitters, with increases of 88.8% and 62.1%, respectively. Brazil's increase is less than those presented for some countries in Annex 1 that are submitted to a quota of reduction, e.g. Spain with 55.6% of increase and New Zealand with 45.8%. Brazil also is below the average increase shown by non-Annex I countries, estimated to be 61.3%, but above the world average (28.1%). Besides the effort to curb emissions from the energy and deforestation sectors, it is now a top priority to implement a national program to promote mitigation efforts concerning the agricultural and livestock sectors. These mitigation options should not be only focused on emission reductions, but also prone enhancement of the carbon sink. Such a program would be easy to be implemented, because several mitigation strategies have already proven to be efficient, simple to adopt and economically viable.

The 2008 Witch Model: New Model Features and Baseline

WITCH is an energy-economy-climate model developed by the climate change group at FEEM. The model has been extensively used in the past 3 years for the economic analysis of climate change policies. WITCH is a hybrid top-down economic model with a representation of the energy sector of medium complexity. Two distinguishing features of the WITCH model are the representation of endogenous technological change and the game–theoretic set-up. Technological change is driven by innovation and diffusion processes, both of which feature international spillovers. World countries are grouped in 12 regions which interact with each other in a setting of strategic interdependence. This paper describes the updating of the base year data to 2005 and some new features: the inclusion of non-CO2 greenhouse gases and abatement options, the new specification of low carbon technologies and the inclusion of reducing emissions from deforestation and degradation.

The global warming potential—the need for an interdisciplinary retrial

It was about 20 years ago today when Global Warming Potentials (GWP) became established as a method for comparing the climate effects of emissions of different greenhouse gases. Since then they have been going in and out of style. The GWP was originally presented as a climate analogue to the ozone depletion potential, to help assess the climate impacts of switching from chlorofluorocarbons to hydrofluorocarbons (and related molecules) (Rogers and Stephens 1988; Fisher et al. 1990). Interest in its wider utility, and in particular its use to compare the climate impact of emissions of CO2 with non-CO2 greenhouse gases, soon followed (e.g. Lashof and Ahuja 1990; IPCC 1990). The First Assessment Report (FAR) of the Intergovernmental Panel on Climate Change (IPCC 1990) tentatively embraced the concept—as the Convening Lead Author of the relevant chapter in that assessment, I was interested to re-read what we had written way-back-when; in particular, I wanted to see whether, with hindsight, I might have changed anything. I believe that we had many of the necessary caveats in place but I was particularly struck by one statement (where the square brackets are my additions for clarity): “It must be stressed that there is no universally accepted methodology for combining all the relevant factors into a single [metric] . . . A simple approach [i.e. the GWP] has been adopted here to illustrate the difficulties inherent in the concept.” But it seems that the die was cast. The IPCC retained the GWP as a metric of choice. As the Kyoto Protocol is a multi-gas treaty, it requires a method to allow parties to the protocol to place emissions of different gases on a CO2-equivalent scale. The GWP (with a 100 year time horizon) was adopted for this purpose. Indeed, it can be argued that it was the existence of the GWP (or its endorsement by the IPCC) which led to the Kyoto Protocol being a multi-gas treaty—see e.g. Skodvin (1999) for a discussion.

Greenhouse Gas Mitigation in a Carbon Constrained World: The Role of Carbon Capture and Storage

In a carbon constrained world, at least four classes of greenhouse gas mitigation options are available: Energy efficiency, fuel switching, introduction of carbon dioxide capture and storage along with renewable generating technologies, and reductions in emissions of non-CO2 greenhouse gases. The role of energy technologies is considered crucial in climate change mitigation. In particular, carbon capture and storage (CCS) promises to allow for low-emissions fossil-fuel based power generation. The technology is under development; a number of technological, economic, environmental and safety issues remain to be solved. With regard to its sustainability impact, CCS raises a number of questions: On the one hand, CCS may prolong the prevailing coal-to-electricity regime and countervail efforts in other mitigation categories. On the other hand, given the indisputable need to continue using fossil fuels for some time, it may serve as a bridging technology towards a sustainable energy future. In this paper, we discuss the relevant issues for the case of Germany. We provide a survey of the current state of the art of CCS and activities, and perform an energy-environment-economic analysis using a general equilibrium model for Germany. The model analyzes the impact of introducing carbon constraints with respect to the deployment of CCS, to the resulting greenhouse gas emissions, to the energy and technology mix and with respect to interaction of different mitigation efforts. The results show the relative importance of the components in mitigating greenhouse gas emissions in Germany. For example, under the assumption of a CO2 policy, both energy efficiency and CCS will contribute to climate gas mitigation. A given climate target can be achieved at lower marginal costs when the option of CCS is included. We conclude that, given an appropriate legal and policy framework, CCS, energy efficiency and some other mitigation efforts are complementary measures and should form part of a broad mix of measures required for a successful CO2 mitigation strategy.

Marginal abatement cost estimates for non-CO2 greenhouse gases: lessons from RECLAIM

Recognizing the potential for over- as well as under-estimating the mitigation costs of non-CO2 greenhouse gases in an offset programme, this article examines the accuracy of cost estimates prepared by government agencies for the control of other types of emissions from small/medium sources via an offset programme. Specifically, analogy is made to the control of SOx and NOx controlled by California's Regional Clean Air Incentives Market (RECLAIM) Program. Even allowing for the energy crisis in 2000–2001 that drove up NOx emissions and control costs, it appears that the engineering cost methods used turned out to be generally accurate, defined as ±25%. Although such a finding does not ensure that the same results will apply to the case of non-CO2 GHGs, it certainly reinforces the growing literature on ex ante—ex post cost comparisons of environmental controls.

Nitrous oxide and methane emissions from soil are reduced following afforestation of pasture lands in three contrasting climatic zones

Land use change from agriculture to forestry offers potential opportunities for carbon (C) sequestration and thus partial mitigation of increasing levels of carbon dioxide (CO2) in the atmosphere. The effects of land use change of grazed pastures on in situ fluxes of nitrous oxide (N2O) and methane (CH4) from soil were examined across 3 forest types in Australian temperate, Mediterranean, and subtropical regions, using a network of paired pasture−forest sites, representing 3 key stages of forest stand development: establishment, canopy-closure, and mid to late rotation. During the 12-month study, soil temperature ranged from –6° to 40°C and total rainfall from 487 to 676 mm. Rates of N2O flux ranged between 1 and 100 μg/m2.h in pasture soils and from –5 to 50 μg/m2.h in forest soils; magnitudes were generally similar across the 3 climate zones. Rates of CH4 flux varied from –1 to –50 μg/m2.h in forest soil and from +10 to –30 μg/m2.h in pasture soils; CH4 flux was highest at the subtropics sites and lowest at the Mediterranean sites. In general, N2O emissions were lower, and CH4 consumption was higher, under forest than pasture soils, suggesting that land use change from pasture to forest can have a positive effect on mitigation of non-CO2 greenhouse gas (GHG) emissions from soil as stands become established. The information derived from this study can be used to improve the capacity of models for GHG accounting (e.g. FullCAM, which underpins Australia’s National Carbon Accounting System) to estimate N2O and CH4 fluxes resulting from land use change from pasture to forest in Australia. There is still, however, a need to test model outputs against continuous N2O and CH4 measurements over extended periods of time and across a range of sites with similar land use, to increase confidence in spatial and temporal estimates at regional levels.

Pure and Binary Adsorption of Methane and Nitrogen by Silicalite

Methane is the most important non-CO2 greenhouse gas (GHG) responsible for global warming with more than 10 % of total GHG emissions. The greenhouse warming potential (GWP) of this gas is much higher than carbon dioxide. Therefore, any reduction in methane emissions is really important in atmosphere reconstruction. Nitrogen is needed to be removed from landfill gas to obtain low grade natural gas as a renewable source of energy from garbage, but the separation is really difficult. Adsorption was considered as a possibility for this separation, and silicalite was studied as the adsorbent. The adsorption behavior of methane and nitrogen with this adsorbent was studied by concentration pulse chromatography and constant volume techniques. Ideal separation factors were obtained from the experimental pure adsorption isotherms by using the temperature independent Toth isotherm model. Mixture adsorption isotherms for the binary system of methane and nitrogen at (40, 70, and 100) °C at 1 bar total pressure were determined experimentally. Corresponding x−y diagrams and separation factors were obtained from these data. The thermodynamic consistency tests between pure and binary gas adsorption systems were also carried out. The separation factors obtained with silicalite for the separation applications of methane and nitrogen gases in this work are much better than those obtained for other systems in the literature.

Economic comparison of greenhouse gas mitigation options in Germany

Our objective is to provide a balanced analysis of greenhouse gas mitigation options, across a variety of climate policy scenarios, for Germany. At least four classes of greenhouse gas mitigation options are available: energy efficiency, fuel switching, CO2 capture and storage (CCS), and reductions in emissions of non-CO2 greenhouse gases. These options vary by cost, timing, and our ability to represent them in an economic analysis. We use the Second Generation Model, an economy-wide computable general equilibrium (CGE) model that embodies greenhouse gas mitigation possibilities from the energy system and CCS. Policy scenarios are represented as a response to varying levels of a price for greenhouse gas emissions, either applied economy-wide or targeted at energy-intensive sectors of the economy according to the EU emissions trading scheme. Energy efficiency options are represented in the standard CGE format where non-energy inputs substitute for energy inputs within economic production functions, or system of consumer demand equations, as the price of energy increases relative to other goods. The electric power sector provides substantial opportunities for fuel switching and the deployment of advanced electricity-generating technologies, with and without CO2 capture and storage. Our methodology relies on engineering descriptions of electricity-generating technologies and how their competitive positions vary with a CO2 price or change in fuel price. Further, we allow for reduction of emissions of non-CO2 gases, which adds a set of mitigation opportunities not usually included in energy-economic modeling efforts. A formal decomposition methodology is used to isolate the contribution of each greenhouse gas mitigation option.

Reducing the risk of Atlantic thermohaline circulation collapse: sensitivity analysis of emissions corridors

We present emissions corridors for the 21 st century reducing the risk of collapse of the Atlantic thermohaline circulation (THC) while considering ex- pectations about the socio-economically acceptable pace of emissions reductions. Emissions corridors embrace the range of CO2 emissions that are compatible with normatively defined policy goals or 'guardrails'. They are calculated along the conceptual and methodological lines of the tolerable windows approach. We inves- tigate the sensitivity of the emissions corridors to key uncertain physical quantities (i.e. climate sensitivity and North Atlantic hydrological sensitivity, emissions of non- CO2 greenhouse gases and sulfate aerosols) as well as to the guardrails. Results indicate a large dependency of the width of the emissions corridor on climate and hydrological sensitivity: for low values of the climate and/or hydrological sensitivity, the corridor boundaries are far from being transgressed by business-as-usual emis- sions scenarios for the 21 st century. In contrast, for high values of both quantities already low non-intervention scenarios leave the corridor in the early decades of this century. The width of the CO2 emissions corridor is also affected by the emissions pathway of non-CO2 greenhouse gases and sulfate aerosols, but to a lesser extent. We further find that the choice of the policy goal strongly influences the shape of the emissions corridor. Pursuit of a more ambitious THC target, for instance, tightens the corridor considerably. More strict expectations concerning the socio-economically admissible pace of emissions reduction (expressed in terms of a maximum emissions reduction rate and a transition time towards a de-carbonizing economy) act in the

Addressing climate change with a comprehensive US cap-and-trade system

Abstract There is growing impetus for a domestic US climate policy that can provide meaningful reductions in emissions of carbon dioxide (CO2) and other greenhouse gases. I describe and analyse an up-stream, economy-wide CO2 cap-and-trade system which implements a gradual trajectory of emissions reductions (with inclusion over time of non-CO2 greenhouse gases), and includes mechanisms to reduce cost uncertainty. Initially, half of the allowances are allocated through auction and half through free distribution, with the share being auctioned gradually increasing to 100 per cent over 25 years. The system provides for linkage with emission-reduction credit projects in other countries, harmonization over time with effective cap-and-trade systems in other countries and regions, and appropriate linkage with actions taken in other countries, in order to establish a level playing field among domestically produced and imported products.

Emissions in the Platinum Age: the implications of rapid development for climate-change mitigation

Abstract Rapid global economic growth, centred in Asia but now spread across the world, is driving rapid greenhouse-gas emissions growth, making earlier projections unrealistic. This paper develops new, illustrative business-as-usual projections for carbon dioxide (CO2) from fossil fuels and other sources and for non-CO2 greenhouse gases. Making adjustments to 2007 World Energy Outlook projections to reflect more fully recent trends, we project annual emissions by 2030 to be almost double current volumes, 11 per cent higher than in the most pessimistic scenario developed by the Intergovernmental Panel on Climate Change (IPCC), and at a level reached only in 2050 in the business-as-usual scenario used by the Stern Review. This has major implications for the global approach to climate-change mitigation. The required effort is much larger than implicit in the IPCC data informing the current international climate negotiations. Large cuts in developed country emissions will be required, and significant deviations from baselines will be required in developing countries by 2020. It is hard to see how the required cuts could be achieved without all major developing as well as developed countries adopting economy-wide policies.

Nitrous oxide and methane flux in Australian and New Zealand landscapes: measurements, modeling and mitigation

Nitrous oxide (N2O) and methane (CH4) represent around 25% of the increased radiative forcing in the earth’s atmosphere (Houghton et al. 2001). This may be half that represented by carbon dioxide (~50%), but nevertheless important enough to demand greater research into the sinks and sources of CH4 and N2O, the biogeochemical processes and factors involved, and ultimately to explore the management options available to mitigate emissions and enhance the sinks. Unlike carbon dioxide, the vast majority of the increase in the atmospheric concentrations of N2O and CH4 has been mediated by processes that occur naturally; in soils, sediments or animals within the landscape. N2O emissions are principally a product of microbial nitrification and denitrification in the soil (Firestone and Davidson 1989), whilst CH4 may be produced by methanogenic bacteria under anaerobic, anoxic conditions in the soils and sediments (Conrad 1996) and in the course of enteric fermentation by ruminant animals and termites. Predominantly, aerobic soils are an important CH4 sink (Dalal et al. 2008), greatest in well drained and undisturbed soils, such as many native forests (Price et al. 2004). However, human activities can have a profound effect on these processes: deforestation and land-clearing, agricultural intensification and increased use of fertilizers, ruminant animal domestication and livestock production have all contributed to enhanced emissions of N2O and modified exchange of CH4 between the soil and atmosphere. As such, understanding the ecosystem processes that mediate N2O and CH4 exchange between the landscape (soil–plant–animal) and the atmosphere is critical to enable a predictive understanding of how these landscapes will respond to a change in management, land-use or a change in the climate itself. Similarly, only with this process-level understanding can management options be successfully selected and applied to mitigate N2O and CH4 emissions and enhance available sinks. The measurement and understanding of greenhouse gas exchange in northern hemisphere ecosystems can not always be transferred to Australian or New Zealand ecosystems. Soils in Australia have generally very low nutrient concentrations (especially phosphorous) and atmospheric N deposition is very low. New Zealand’s greenhouse gas emissions inventory is dominated by N2O and CH4, because the economy and land management is dominated by agriculture. A Research Forum on ‘Non-CO2 greenhouse gas fluxes in Australian-New Plant Soil (2008) 309:1–4 DOI 10.1007/s11104-008-9674-5