scholarly journals Temporal and spatial decoupling of CO<sub>2</sub> and N<sub>2</sub>O soil emissions in a Mediterranean riparian forest

2017 ◽  
Author(s):  
Sílvia Poblador ◽  
Anna Lupon ◽  
Santiago Sabaté ◽  
Francesc Sabater
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Riparian Forest ◽  
Ghg Emissions ◽  
Microbial Processes ◽  
Spatial Gradient ◽  
N2o Emissions ◽  
Nitrification And Denitrification ◽  
Riparian Soils

Abstract. Riparian zones play a fundamental role in regulating the amount of carbon (C) and nitrogen (N) that is exported from catchments. However, C and N removal via soil gaseous pathways can influence local budgets of greenhouse gases (GHG) emissions and contribute to climate change. Over a year, we quantified soil effluxes of carbon dioxide (CO2) and nitrous oxide (N2O) from a Mediterranean riparian forest in order to understand the role of these ecosystems on catchment GHG emissions. In addition, we evaluated the main soil microbial processes that produce GHG (mineralization, nitrification, and denitrification) and how changes in soil properties can modify the GHG production over time and space. Mediterranean riparian soils emitted large amounts of CO2 to the atmosphere (1.2–10 g C m−2  d−1), but were powerless sources of N2O (0.001–0.2 mg N m−2 d−1) due to low denitrification rates. Both CO2 and N2O emissions showed a marked (but antagonistic) spatial gradient as a result of variations in soil moisture across the riparian zone. Deep groundwater tables fueled large soil CO2 effluxes near the hillslope, while N2O emissions were higher in the wet zones adjacent to the stream channel. However, both CO2 and N2O emissions peaked after spring rewetting events, when optimal conditions of soil moisture, temperature, and N availability favor microbial respiration, nitrification, and denitrification. Overall, our results highlight the role of riparian soils as hotspots of GHG emissions, and suggest that future alterations in hydrologic regimes can affect the microbial processes that produce GHG as well as the contribution of these systems to climate change.

scholarly journals Soil water content drives spatiotemporal patterns of CO<sub>2</sub> and N<sub>2</sub>O emissions from a Mediterranean riparian forest soil

2017 ◽  
Vol 14 (18) ◽  
pp. 4195-4208 ◽  
Author(s):  
Sílvia Poblador ◽  
Anna Lupon ◽  
Santiago Sabaté ◽  
Francesc Sabater
Keyword(s):  
Climate Change ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Riparian Forest ◽  
Ghg Emissions ◽  
Microbial Processes ◽  
N2o Emissions ◽  
Nitrification And Denitrification

Abstract. Riparian zones play a fundamental role in regulating the amount of carbon (C) and nitrogen (N) that is exported from catchments. However, C and N removal via soil gaseous pathways can influence local budgets of greenhouse gas (GHG) emissions and contribute to climate change. Over a year, we quantified soil effluxes of carbon dioxide (CO2) and nitrous oxide (N2O) from a Mediterranean riparian forest in order to understand the role of these ecosystems on catchment GHG emissions. In addition, we evaluated the main soil microbial processes that produce GHG (mineralization, nitrification, and denitrification) and how changes in soil properties can modify the GHG production over time and space. Riparian soils emitted larger amounts of CO2 (1.2–10 g C m−2 d−1) than N2O (0.001–0.2 mg N m−2 d−1) to the atmosphere attributed to high respiration and low denitrification rates. Both CO2 and N2O emissions showed a marked (but antagonistic) spatial gradient as a result of variations in soil water content across the riparian zone. Deep groundwater tables fueled large soil CO2 effluxes near the hillslope, while N2O emissions were higher in the wet zones adjacent to the stream channel. However, both CO2 and N2O emissions peaked after spring rewetting events, when optimal conditions of soil water content, temperature, and N availability favor microbial respiration, nitrification, and denitrification. Overall, our results highlight the role of water availability on riparian soil biogeochemistry and GHG emissions and suggest that climate change alterations in hydrologic regimes can affect the microbial processes that produce GHG as well as the contribution of these systems to regional and global biogeochemical cycles.

scholarly journals A new look at an old concept: using <sup>15</sup>N<sub>2</sub>O isotopomers to understand the relationship between soil moisture and N<sub>2</sub>O production pathways

SOIL ◽  
2019 ◽  
Vol 5 (2) ◽  
pp. 265-274 ◽  
Author(s):  
Katelyn A. Congreves ◽  
Trang Phan ◽  
Richard E. Farrell
Keyword(s):  
Soil Moisture ◽  
Mitigation Strategies ◽  
Soil Conditions ◽  
Site Preference ◽  
N2o Emissions ◽  
Spectroscopic Techniques ◽  
N2o Production ◽  
Nitrification And Denitrification ◽  
The Relationship ◽  
Source Partitioning

Abstract. Understanding the production pathways of potent greenhouse gases, such as nitrous oxide (N2O), is essential for accurate flux prediction and for developing effective adaptation and mitigation strategies in response to climate change. Yet there remain surprising gaps in our understanding and precise quantification of the underlying production pathways – such as the relationship between soil moisture and N2O production pathways. A powerful, but arguably underutilized, approach for quantifying the relative contribution of nitrification and denitrification to N2O production involves determining 15N2O isotopomers and 15N site preference (SP) via spectroscopic techniques. Using one such technique, we conducted a short-term incubation where N2O production and 15N2O isotopomers were measured 24 h after soil moisture treatments of 40 % to 105 % water-filled pore space (WFPS) were established for each of three soils that differed in nutrient levels, organic matter, and texture. Relatively low N2O fluxes and high SP values indicted nitrification during dry soil conditions, whereas at higher soil moisture, peak N2O emissions coincided with a sharp decline in SP, indicating denitrification. This pattern supports the classic N2O production curves from nitrification and denitrification as inferred by earlier research; however, our isotopomer data enabled the quantification of source partitioning for either pathway. At soil moisture levels < 53 % WFPS, the fraction of N2O attributed to nitrification (FN) predominated but thereafter decreased rapidly with increasing soil moisture (x), according to FN=3.19-0.041x, until a WFPS of 78 % was reached. Simultaneously, from WFPS of 53 % to 78 %, the fraction of N2O that was attributed to denitrification (FD) was modelled as FD=-2.19+0.041x; at moisture levels of > 78 %, denitrification completely dominated. Clearly, the soil moisture level during transition is a key regulator of N2O production pathways. The presented equations may be helpful for other researchers in estimating N2O source partitioning when soil moisture falls within the transition from nitrification to denitrification.

Large contribution from anthropogenic warming to an emerging North American megadrought

Science ◽  
2020 ◽  
Vol 368 (6488) ◽  
pp. 314-318 ◽  
Author(s):  
A. Park Williams ◽  
Edward R. Cook ◽  
Jason E. Smerdon ◽  
Benjamin I. Cook ◽  
John T. Abatzoglou ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
North America ◽  
Relative Humidity ◽  
Climate Models ◽  
Hydrological Modeling ◽  
Drought Severity ◽  
Large Contribution ◽  
Moderate Drought

Severe and persistent 21st-century drought in southwestern North America (SWNA) motivates comparisons to medieval megadroughts and questions about the role of anthropogenic climate change. We use hydrological modeling and new 1200-year tree-ring reconstructions of summer soil moisture to demonstrate that the 2000–2018 SWNA drought was the second driest 19-year period since 800 CE, exceeded only by a late-1500s megadrought. The megadrought-like trajectory of 2000–2018 soil moisture was driven by natural variability superimposed on drying due to anthropogenic warming. Anthropogenic trends in temperature, relative humidity, and precipitation estimated from 31 climate models account for 46% (model interquartiles of 34 to 103%) of the 2000–2018 drought severity, pushing an otherwise moderate drought onto a trajectory comparable to the worst SWNA megadroughts since 800 CE.

SADC’s response to climate change – the role of harmonised law and policy on mitigation in the energy sector

2014 ◽  
Vol 25 (1) ◽  
pp. 26-32 ◽  
Author(s):  
M. Barnard
Keyword(s):  
Climate Change ◽  
Global Climate Change ◽  
Global Climate ◽  
Action Plan ◽  
Ghg Emissions ◽  
Energy Sector ◽  
Literature Study ◽  
Member States ◽  
Law And Policy

The negligible levels of energy-related GHG emissions attributable to the Southern African sub-region translates into the sub-region contributing relatively little towards global climate change. Notwithstanding, the member states comprising the Southern African Development Community (SADC) are among the most vulnerable to the trans boundary effects of global climate change. Existing SADC climate change policy documents highlight the important role of the energy sector in climate change mitigation. Furthermore, various international, African Union and SADC legal instruments stress the crucial role of harmonised law and policy as climate change adaptive measure. It is the central hypothesis of this paper that harmonised sub-regional law and policy aimed at regulating SADC member states’ mitigation efforts in the energy sector is a crucial climate change adaptive strategy. This hypothesis is based on the mandates for the formulation of a SADC climate change action plan and for mitigation in the energy sector. These mandates are contained in the texts of the SADC-CNGO Climate Change Agenda, 2012 and the Southern Africa Sub - Regional Framework on Climate Change, 2010 respectively. It is the main aim of this paper to investigate recent developments in the formulation of harmonised SADC law and policy on climate change in general and law and policy pertaining to mitigation in the energy sector specifically. In achieving the stated aim, themes to be investigated by means of a literature study are those of energy-related greenhouse gas emissions and global climate change and harmonised sub-regional policy on mitigation in the energy sector as adaptive measure in the SADC.

scholarly journals Revisiting the relationship between soil moisture and N<sub>2</sub>O production pathways by measuring <sup>15</sup>N<sub>2</sub>O isotopomers

2019 ◽  
Author(s):  
Kate A. Congreves ◽  
Trang Phan ◽  
Richard E. Farrell
Keyword(s):  
Soil Moisture ◽  
Pore Space ◽  
Mitigation Strategies ◽  
Soil Conditions ◽  
Site Preference ◽  
N2o Emissions ◽  
Spectroscopic Techniques ◽  
N2o Production ◽  
Nitrification And Denitrification ◽  
The Relationship

Abstract. Understanding the production pathways of potent greenhouse gases, such as nitrous oxide (N2O), is essential for accurate flux prediction and for developing effective adaptation and mitigation strategies in response to climate change. Yet, there remain surprising gaps in our understanding and precise quantification of the underlying production pathways – such as the relationship between soil moisture and N2O production pathways. A powerful, but arguably underutilized, approach for quantifying the relative contribution of nitrification and denitrification to N2O production involves determining 15N2O isotopomers and 15N site preference (SP) via spectroscopic techniques. Using one such technique we conducted a short-term incubation to precisely quantify the relationship between soil moisture and N2O production pathways. For each of three soils, microcosms were arranged in a complete random design with four replicates; each microcosm consisted of air-dried soil packed into plastic petri dishes wherein moisture treatments were established for water contents equivalent to 45 to 105 % water-filled pore space (WFPS). The microcosms were placed in 1-L jars and sealed; headspace samples were collected after 24-h and analyzed for total N2O concentrations using gas chromatography, and for 15N2O isotopomers using cavity ring-down spectroscopy. Relatively low N2O fluxes and high SP values indicted nitrification during dry soil conditions, whereas at higher soil moisture, peak N2O emissions coincided with a sharp decline in SP indicating denitrification. This pattern supports the classic N2O production curves from nitrification and denitrification as inferred by earlier research; however, our isotopomer data enabled the quantification of source partitioning for either pathway thereby providing clarity on N2O sources during the transition from nitrification to denitrification. At soil moisture levels  78 %, denitrification completely dominated. Clearly, the soil moisture levels during transition is a key regulation of N2O production pathways.

scholarly journals THE ROLE OF IPCC ON SUSTAINABLE DEVELOPMENT IN AGRICULTURE

2017 ◽  
pp. 173-180
Author(s):  
Mahesh Patel ◽  
J.G. Rangiya ◽  
K.J Patel
Keyword(s):  
Climate Change ◽  
Sustainable Development ◽  
Global Climate Change ◽  
Land Surface ◽  
Sea Water ◽  
Global Climate ◽  
Land Use Changes ◽  
Ghg Emissions ◽  
Warming World

Recognizing the pressing global problem of climate change, the IPCC was formed in 1988 as an apex source to holistically address the issue. It strives to critically congregate best scientific, technical and socio-economic data on global climate change to produce various papers and reports which become standard works of reference (UNEP, 2004). IPCC has contributed extensively to unleash the mitigation potential from the perspective of agriculture, correlating it with climate change policy, environmental quality and ultimately, sustainable development (Working group II, 2007). Agriculture lands form 40- 50% of the earth’s land surface and contribute to 10-12% of the Greenhouse gas (GHG) emissions. In this sector, by improved crop, soil, water, livestock and water management, the mitigation of climate change can be approached in a cost-effective way than other sectors. Hence this paper dwells into the significant role of IPCC to progress towards sustainable development in agriculture sector. It would discuss about how agriculture management activities would decrease GHG emissions and increase carbon sequestration (Technical group V, 2002). In the warming world, precipitation is skewed, sea level is rising, glaciers are melting, acidic levels in oceans are rising and dissolved oxygen in sea water is declining (IPCC, 2014). Hence major river floods are likely, which is a threat to the food production. This paper would highlight the need to limit effects of climate change to achieve sustainable development as the focus, and would further discuss social equity and poverty eradication. It would explore adaptation and mitigation methods to enumerate short and long-term goals to combat climate change from reinvented livestock and crop systems, beneficial land use changes, improved fertilizers and advanced technological perspectives (IPCC, 1990). It would enforce the learnings from IPCC’s contributions enumerating how agriculture must have a high synergy with sustainable development to address global climate change.

scholarly journals Growing our future: Assessing the outcome of afforestation programs in Ontario, Canada

2021 ◽  
Vol 97 (02) ◽  
pp. 179-190
Author(s):  
Georgina K. Magnus ◽  
Elizabeth Celanowicz ◽  
Mihai Voicu ◽  
Mark Hafer ◽  
Juha M. Metsaranta ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Change Mitigation ◽  
Carbon Sink ◽  
Ghg Emissions ◽  
Mitigation Strategies ◽  
Spatially Explicit ◽  
Auxiliary Data ◽  
Carbon Budget Model ◽  
Change Mitigation

The United Nations Framework Convention on Climate Change (UNFCCC) requires its signatories, including Canada, to estimate and report their annual greenhouse gas (GHG) emissions and removals. Forests are an important natural resource as they slow the accumulation of atmospheric carbon through the process of carbon sequestration. Due to the role of forests as carbon sinks, governments consider afforestation projects as feasible climate change mitigation strategies. This article outlines a spatially-explicit approach to validating afforestation data in Ontario, Canada. Validation is a user-supervised process that uses satellite imagery, remote sensing tools, and other auxiliary data to confirm the presence of seedlings planted through Forests Ontario’s 50 Million Tree program. Of the 12 466 hectares assessed, 83% is identified as afforested, 6% is not afforested and 10% is not determined. The area classified as successful afforestation is used as input for the Generic Carbon Budget Model (GCBM), to simulate afforestation effects on carbon stocks. Our findings show the afforestation activities will create a small carbon sink by 2060. From this project, it is evident that spatial validation of afforestation data is feasible, although the collection of additional standardized auxiliary data is recommended for future afforestation projects, if carbon benefits are to be reported.

scholarly journals The Role of Soil N2O Emissions in Agricultural Green Total Factor Productivity: An Empirical Study from China around 2006 when Agricultural Tax Was Abolished

Agriculture ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 150 ◽  
Author(s):  
Xiaocang Xu ◽  
Lu Zhang ◽  
Linhong Chen ◽  
Chengjie Liu
Keyword(s):  
Total Factor Productivity ◽  
Regional Difference ◽  
Production Efficiency ◽  
Ghg Emissions ◽  
Analytical Framework ◽  
Important Variable ◽  
N2o Emissions ◽  
Factor Productivity ◽  
The Impact

The decision in 2006 to abolish the agricultural tax, which had lasted for thousands of years, contributed to the prosperity of agriculture, and with it the growing importance of soil N2O emissions in China. However, most of the previous literature ignored soil N2O emissions due to their too small share in total agricultural greenhouse gas (GHG) emissions. This paper attempts to take soil N2O emissions as an important variable in the measurement of agricultural green total factor productivity (AGTFP), which incorporates environmental pollution into the analytical framework of agricultural production efficiency. Three impressive results were found. Firstly, soil N2O emissions play an increasingly important role in agricultural GHG emissions. The proportion of soil N2O emissions in agricultural GHG emissions increased from 4.52% in 1998 to 4.83% in 2006, and then to 5.36% in 2016. Secondly, the regional difference of soil N2O emissions in AGTFP is visible. In 2016, although soil N2O emissions accounted for a small proportion (about 5%) of the total agricultural GHG emissions in China, the AGTFP including soil N2O emissions was much lower than that excluding soil N2O emissions, especially in areas with high agricultural and population density. Finally, over time, soil N2O emissions have had an increasing effect on AGTFP. Compared with 1998–2006, the impact of excluding soil N2O emissions on AGTFP in 2007–2016 was more evident than that including soil N2O emissions.

Achieving a low carbon transition in Japan, the role of motor vehicle lifetime

2016 ◽  
Author(s):  
Shigemi Kagawa ◽  
Daisuke Nishijima ◽  
Yuya Nakamoto
Keyword(s):  
Climate Change ◽  
New Technologies ◽  
Motor Vehicle ◽  
Global Climate ◽  
Ghg Emissions ◽  
Low Carbon ◽  
Policy Tool ◽  
Using Data

In order to achieve climate change mitigation goals, reducing greenhouse gas (GHG) emissions from Japan’s household sector is critical. Accomplishing a transition to low carbon and energy efficient consumer goods is particularly valuable as a policy tool for reducing emissions in the residential sector. This case study presents an analysis of the lifetime of personal vehicles in Japan, and considers the optimal scenario in terms of retention and disposal, specifically as it relates to GHG emissions. Using data from Japan, the case study shows the critical importance of including whole-of-life energy and carbon calculations when assessing the contributions that new technologies can make towards low carbon mobility transitions. While energy-efficiency gains are important, replacing technologies can overlook the energy and carbon embedded in the production phase. Without this perspective, policy designed to reduce GHG emissions may result in increased emissions and further exacerbate global climate change.

scholarly journals Climate change mitigation and adaptation in agriculture: the case of the olive

2018 ◽  
Vol 9 (4) ◽  
pp. 633-642 ◽  
Author(s):  
G. Montanaro ◽  
V. Nuzzo ◽  
C. Xiloyannis ◽  
B. Dichio
Keyword(s):  
Climate Change ◽  
Climate Change Mitigation ◽  
Management Practices ◽  
Ghg Emissions ◽  
Tree Biomass ◽  
Climatic Impact ◽  
Soil C ◽  
Mitigation And Adaptation ◽  
Change Mitigation

Abstract Agriculture might serve as a mitigation solution through carbon (C) sequestration in soil, in tree biomass and reducing greenhouse gas (GHG) emissions. Increased C is beneficial for some soil structures and functions, improving the use of water and in turn the crop adaptation. This study reports on the synergy between mitigation and adaptation in agriculture through the paradigm of the olive (Olea europaea). Through data on net ecosystem productivity and soil respiration, the role of olive groves to store C in tree biomass (from 0.36 to 2.78 t CO2 ha−1 yr−1) and into soil (∼8.5 t CO2 ha−1 yr−1) is reviewed. The influence of some management practices on that role is also discussed. The overall climatic impact of olive fruit and oil production has been evaluated also considering GHG emissions by field operations (e.g., pruning, mulching of cover crop, fertilization, harvest, etc.) and by the extraction and bottling of oil. Soil C as interface between climate change mitigation and adaptation has been delineated, linking C-induced improvements in soil properties to increased water storage and reduced run-off and erosion. The outcomes may strengthen the environmental role of agriculture and promote synergistic mitigation and adaptation policies assisting in soil and water resources conservation.

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