An approach with a Business-as-Usual scenario projection to 2020 for the Covenant of Mayors from the Eastern Partnership

The methodology for the Covenant of Mayors – East needed to be extended with a business-as-usual projection of the emissions for 2020, from which national coefficients for the previous years are derived. In this way, signatories will be able to do their emission inventories of the present situation, and estimate which their emissions in 2020 will be. Then they will commit to an emission reduction target based on their projections of emissions for 2020 following the business-as-usual scenario. The factors are country-specific, calculated both for CO2 and CO2eq (CO2, CH4, N2O using the GWP100metric) in order to allow signatories to choose the approach they prefer. Moreover an urban dimension is provided, providing a margin on the projections.JRC.H.2-Air and Climat

Seasonal trends and environmental controls of methane emissions in a rice paddy field in Northern Italy

Rice paddy fields are one of the greatest anthropogenic sources of methane (CH4), the third most important greenhouse gas after water vapour and carbon dioxide. In agricultural fields, CH4 is usually measured with the closed chamber technique, resulting in discontinuous series of measurements performed over a limited area, that generally do not provide sufficient information on the short-term variation of the fluxes. On the contrary, aerodynamic techniques have been rarely applied for the measurement of CH4 fluxes in rice paddy fields. The eddy covariance (EC) technique provides integrated continuous measurements over a large area and may increase our understanding of the underlying processes and diurnal and seasonal pattern of CH4 emissions in this ecosystem. For this purpose a Fast Methane Analyzer (Los Gatos Research Ltd.) was installed in a rice paddy field in the Po Valley (Northern Italy). Methane fluxes were measured during the rice growing season with both EC and manually operated closed chambers. Methane fluxes were strongly influenced by the height of the water table, with emissions peaking when it was above 10–12 cm. Soil temperature and the developmental stage of rice plants were also responsible of the seasonal variation on the fluxes. The measured EC fluxes showed a diurnal cycle in the emissions, which was more relevant during the vegetative period, and with CH4 emissions being higher in the late evening, possibly associated with higher water temperature. The comparison between the two measurement techniques shows that greater fluxes are measured with the chambers, especially when higher fluxes are being produced, resulting in 30% higher seasonal estimations with the chambers than with the EC (41.1 and 31.7 gCH4 m−2 measured with chambers and EC respectively) and even greater differences are found if shorter periods with high chamber sampling frequency are compared. The differences may be a result of the combined effect of overestimation with the chambers and of the possible underestimation by the EC technique.JRC.H.7-Climate Risk Managemen

How to develop a Sustainable Energy Action Plan (SEAP) in the Eastern Partnership and Central Asian cities

Since 2010 the Covenant of Mayors (CoM) initiative has come to involve 11 Eastern Partnership and Central Asian countries in the implementation of local sustainable energy policies. The specific situation which characterises these countries compels to adapt the methodology for the preparation of the Sustainable Energy Action Plans which has been developed to address the European context and which has been widely described in the Guidebook "How to develop a Sustainable Energy Action Plan (SEAP)". The present outline aims to complement the above mentioned Guidebook by presenting the main adaptations to the methodology as they are proposed for Eastern Partnership and Central Asian cities. It does this by presenting first an overview of the key principles these signatories should keep in mind when preparing a SEAP, and secondly by indicating the main critical aspects of the methodological adaptation. In this framework Eastern Partnership and Central Asian signatories are given the possibility to commit to an emission reduction target by 2020 based on their projections of emissions for this year following a Business-As-Usual scenario.JRC.F.7-Renewables and Energy Efficienc

Seasonal Trends and Environmental Controls of Methane Emissions in a Rice Paddy Field in Northern Italy

Rice paddy fields are one of the greatest anthropogenic sources of methane (CH4), the third most important greenhouse gas after water vapour and carbon dioxide. In agricultural fields, CH4 is usually measured with the closed chamber technique, resulting in discontinuous series of measurements performed over a limited area, that generally do not provide sufficient information on the short-term variation of the fluxes. On the contrary, aerodynamic techniques have been rarely applied for the measurement of CH4 fluxes in rice paddy fields. The eddy covariance (EC) technique provides integrated continuous measurements over a large area and may increase our understanding of the underlying processes and diurnal and seasonal pattern of CH4 emissions in this ecosystem. For this purpose a Fast Methane Analyzer (Los Gatos Research Ltd.) was installed in a rice paddy field in the Po Valley (Northern Italy). Methane fluxes were measured during the rice growing season with both EC and manually operated closed chambers. Methane fluxes were strongly influenced by the height of the water table, with emissions peaking when it was above 10-12 cm. Soil temperature and the developmental stage of rice plants were also responsible of the seasonal variation on the fluxes. The measured EC fluxes showed a diurnal cycle in the emissions, which was more relevant during the vegetative period, and with CH4 emissions being higher in the late evening, possibly associated with higher water temperature. The comparison between the two measurement techniques shows that greater fluxes are measured with the chambers, especially when higher fluxes are being produced, resulting in 30% higher seasonal estimations with the chambers than with the EC (41.1 and 31.8 g CH4 m-2 measured with chambers and EC respectively) and even greater differences are found if shorter periods with high chamber sampling frequency are compared. The differences may be a result of the combined effect of overestimation with the chambers and of the possible underestimation by the EC technique.JRC.H.2-Air and Climat

Dual Isotope and Isotopomer Measurements for the Understanding of N2O Production and Consumption during Denitrification in an Arable Soil

The aim of our research was to obtain information on the isotopic fingerprint of nitrous oxide (N2O) associated with its production and consumption during denitrification. An arable soil was preincubated at high moisture content and subsequently amended with glucose (400 kg C ha-1) and KNO3 (80 kg N ha-1) and kept at 85% water-filled pore space. Twelve replicate samples of the soil were incubated for 13 days under a helium-oxygen atmosphere, simultaneously measuring gas fluxes (N2O, N2 and CO2) and isotope signatures (d18O-N2O, d15Nbulk-N2O, d15Na, d15Nß and 15N site preference) of emitted N2O. The maximum N2O flux (6.9 ± 1.8 kg N ha-1 day-1) occurred 3 days after amendment application, followed by the maximum N2 flux on day 4 (6.6 ± 3.0 kg N ha-1 day-1). The d15Nbulk was initially -34.4¿ and increased to +4.5¿ during the periods of maximum N2 flux, demonstrating fractionation during N2O reduction, and then decreased. The d18O-N2O also increased, peaking with the maximum N2 flux and remaining stable afterwards. The site preference (SP) decreased from the initial +7.5 to -2.1¿ when the N2O flux peaked, and then simultaneously increased with the appearance of the N2 peak to +8.6¿ and remained stable thereafter, even when the O2 supply was removed. We suggest that this results from a non-homogenous distribution of NO in the soil, possibly linked to the KNO3 amendments to the soil, causing the creation of several NO pools, which affected differently the isotopic signature of N2O and the N2O and N2 fluxes during the various stages of the process. The N2O isotopologue values reflected the temporal patterns observed in N2O and N2 fluxes. A concurrent increase in 15N site preference and d18O of N2O was found to be indicative of N2O reduction to N2.JRC.H.2-Air and Climat

Effect of antecedent soil moisture conditions on emissions and isotopologue distribution of N2O during denitrification

The present study determined the influence of initial moisture conditions on the production and consumption of nitrous oxide (N2O) during denitrification and on the isotopic fingerprint of soil-emitted N2O. Sieved arable soil was pre-incubated at two different moisture contents: pre-wet at 75% and pre-dry at 20% water-filled pore space. After wetting to 90% water-filled pore space the soils were amended with glucose (400 kg C ha-1) and KNO3 (80 kg N ha-1) and incubated for 10 days under a He/O2-atmosphere. Antecedent moisture conditions affected denitrification. N2+N2O fluxes and the N2O to N2 ratio were higher in soils which were pre-incubated under dry conditions, probably because mobilization of organic C during the pre-treatment enhanced denitrification. Gaseous N fluxes showed similar time patterns of production and reduction of N2O in both treatments, where N2O fluxes where initially increasing and maximised 3 to 4 days after fertilizer application, and N2 fluxes where delayed by 1 to 2 days. Time courses of ¿15Nbulk-N2O and ¿18O-N2O exhibited in both treatments increasing trends until maximum N2-fluxes occurred, reflecting isotope fractionation during intense NO3- reduction. Later this trend slowed down in the pre-dry treatment, while ¿18O-N2O was constant and ¿15Nbulk-N2O decreased in the pre-wet treatment. We explain these time patterns by non-homogenous distribution of NO3- and denitrification activity, resulting from application of NO3- and glucose to the surface of the soil. We assume that several process zones were thus created, which affected differently the isotopic signature of N2O and the N2O and N2 fluxes during the different stages of the process. We modelled the ¿15Nbulk-N2O using process rates and associated fractionation factors for the pre-treated soils, which confirmed our hypothesis. The site preference (SP) initially decreased while N2O reduction was absent, which we could not explain by the N-flux pattern. During the subsequent increase in N2 flux, SP and ¿18O-N2O increased concurrently, confirming that this isotope pattern is indicative for N2O reduction to N2. The possible effect of the antecedent moisture conditions of the soil on N2O emissions were shown to be important.JRC.DDG.H.2-Climate change and air qualit

The uncertain climate footprint of wetlands under human pressure

Significant climate risks are associated with a positive carbon-temperature feedback in northern latitude carbon-rich ecosystems, making an accurate analysis of human impacts on the net greenhouse gas balance of wetlands a priority. Here, we provide a coherent assessment of the climate footprint of a network of wetland sites based on simultaneous and quasi-continuous ecosystem observations of CO2 and CH4 fluxes. Experimental areas are located both in natural and managed wetlands, and cover a wide range of climatic regions, ecosystem types and management practices. Based on direct observations we predict that sustained CH4 emissions in natural ecosystems are in the long term (i.e. several centuries), typically offset by CO2 uptake, though with large spatio-temporal variability. Using a space-for-time analogy across ecological and climatic gradients we represent the chronosequence from natural to managed conditions in order to quantify the "cost" of CH4 emissions for the benefit of net carbon sequestration. With a sustained pulse-response radiative forcing model, we found a significant increase in atmospheric forcing due to land management, in particular for wetland converted to cropland. Our results quantify the role of human activities on the climate footprint of northern wetlands and call for development of active mitigation strategies for managed wetlands and new IPCC guidelines accounting for both sustained CH4 emissions and cumulative CO2 exchange.JRC.H.7-Climate Risk Managemen