A Bayesian belief network framework to predict SOC dynamics of alternative management scenarios

Understanding the key drivers that affect a decline of soil organic carbon (SOC) stock in agricultural areas is of major concern since leading to a decline in service provision from soils and potentially carbon release into the atmosphere. Despite an increasing attention is given to SOC depletion and degradation processes, SOC dynamics are far from being completely understood because they occur in the long term and are the result of a complex interaction between management and pedo-climatic factors. In order to improve our understanding of SOC reduction phenomena in the mineral soils of Veneto region, this study aimed to adopt an innovative probabilistic Bayesian belief network (BBN) framework to model SOC dynamics and identify management scenarios that maximise its accumulation and minimise GHG emissions. Results showed that the constructed BBN framework was able to describe SOC dynamics of the Veneto region, predicting probabilities of general accumulation (11.0%) and depletion (55.0%), similar to those already measured in field studies (15.3% and 50%, respectively). A general enhancement in the SOC content was observed where a minimum soil disturbance was adopted. This outcome suggested that management strategies of conversion from croplands to grasslands, no tillage and conservation agriculture are the most promising management strategies to reverse existing SOC reduction dynamics. Moreover, measures implying SOC stocks were also those providing major benefits in terms of GHGs reduction emissions. Finally, climate change scenarios slightly affected management practice. Advancements in our BBN framework might include more detailed classes at higher resolution as well as any socio-cultural or economic aspect that should improve the evaluation of prediction scenarios

Equilibrium responses of global net primary production and carbon storage to doubled atmospheric carbon dioxide: sensitivity to changes in vegetation nitrogen concentration

We ran the terrestrial ecosystem model (TEM) for the globe at 0.5° resolution for atmospheric CO2 concentrations of 340 and 680 parts per million by volume (ppmv) to evaluate global and regional responses of net primary production (NPP) and carbon storage to elevated CO2 for their sensitivity to changes in vegetation nitrogen concentration. At 340 ppmv, TEM estimated global NPP of 49.0 1015 g (Pg) C yr−1 and global total carbon storage of 1701.8 Pg C; the estimate of total carbon storage does not include the carbon content of inert soil organic matter. For the reference simulation in which doubled atmospheric CO2 was accompanied with no change in vegetation nitrogen concentration, global NPP increased 4.1 Pg C yr−1 (8.3%), and global total carbon storage increased 114.2 Pg C. To examine sensitivity in the global responses of NPP and carbon storage to decreases in the nitrogen concentration of vegetation, we compared doubled CO2 responses of the reference TEM to simulations in which the vegetation nitrogen concentration was reduced without influencing decomposition dynamics (“lower N” simulations) and to simulations in which reductions in vegetation nitrogen concentration influence decomposition dynamics (“lower N+D” simulations). We conducted three lower N simulations and three lower N+D simulations in which we reduced the nitrogen concentration of vegetation by 7.5, 15.0, and 22.5%. In the lower N simulations, the response of global NPP to doubled atmospheric CO2 increased approximately 2 Pg C yr−1 for each incremental 7.5% reduction in vegetation nitrogen concentration, and vegetation carbon increased approximately an additional 40 Pg C, and soil carbon increased an additional 30 Pg C, for a total carbon storage increase of approximately 70 Pg C. In the lower N+D simulations, the responses of NPP and vegetation carbon storage were relatively insensitive to differences in the reduction of nitrogen concentration, but soil carbon storage showed a large change. The insensitivity of NPP in the N+D simulations occurred because potential enhancements in NPP associated with reduced vegetation nitrogen concentration were approximately offset by lower nitrogen availability associated with the decomposition dynamics of reduced litter nitrogen concentration. For each 7.5% reduction in vegetation nitrogen concentration, soil carbon increased approximately an additional 60 Pg C, while vegetation carbon storage increased by only approximately 5 Pg C. As the reduction in vegetation nitrogen concentration gets greater in the lower N+D simulations, more of the additional carbon storage tends to become concentrated in the north temperate-boreal region in comparison to the tropics. Other studies with TEM show that elevated CO2 more than offsets the effects of climate change to cause increased carbon storage. The results of this study indicate that carbon storage would be enhanced by the influence of changes in plant nitrogen concentration on carbon assimilation and decomposition rates. Thus changes in vegetation nitrogen concentration may have important implications for the ability of the terrestrial biosphere to mitigate increases in the atmospheric concentration of CO2 and climate changes associated with the increases

The impact of climate-related extreme events on public health workforce and infrastructure – how can we be better prepared?

The Intergovernmental Panel on Climate Change’s fifth assessment report1 states with confidence that human induced climate change is occurring and that temperatures will continue to rise, even if CO2 emissions were to stop forthwith. The report also acknowledges that climate-related extreme events are increasing in frequency, severity and duration; particularly heavy rainfall events, intensification of cyclones, increases in tidal surge and fires. This poses the question: “Are we prepared?” This is question that public health authorities will need to face but, as health systems are increasingly stressed due to limited resources, increased demand and workforce shortages, being prepared becomes even more challenging. Extreme events place an additional burden on health systems already under pressure due to increased demand for health care services, and as public health resources are offset against the demands in the acute care sector. (For the purposes of this paper, public health services refer to those health and related services that seek to prevent disease and promote health.) The impact on often already overstretched public health services may not be recognised, and additional resourcing and support may not follow. As discussed later, recent Australian experiences indicate that the status quo will not be sufficient to both mount a successful public health response to climate-related extreme events and maintain a strong public health infrastructure

Designing Climate Policy: Lessons from the Renewable Fuel Standard and the Blend Wall

Many policies mandate renewable energy production to combat global climate change. These policies often differ significantly from first-best policy prescriptions. Among the largest renewable energy mandates enacted to date is the Renewable Fuel Standard (RFS), which mandates biofuel consumption far beyond what is feasible with current technology and infrastructure. We critically review the methods used by the Environmental Protection Agency to project near- and long-term compliance costs under the RFS, and draw lessons from the RFS experience to date that would improve the program’s efficiency. The lessons are meant to inform both future RFS rulemaking and the design of future climate policies. We draw two lessons specific to the RFS. First, incorporate uncertainty into rulemaking; second, implement multi-year rules. Multi-year rulemaking allows for longer periods between major regulatory decisions and sends greater certainty to markets. We also provide two more general recommendations: tie waiver authority to compliance costs or include cost containment provisions, and fund research and development of new technologies directly rather than mandating them. Future technological advancement is uncertain, and mandating new technologies has proven to be largely ineffective to date, particularly in fuel markets

DOs and DON'Ts for using climate change information for water resource planning and management: guidelines for study design

Water managers are actively incorporating climate change information into their long- and short-term planning processes. This is generally seen as a step in the right direction because it supplements traditional methods, providing new insights that can help in planning for a non-stationary climate. However, the continuous evolution of climate change information can make it challenging to use available information appropriately. Advice on how to use the information is not always straightforward and typically requires extended dialogue between information producers and users, which is not always feasible. To help navigate better the ever-changing climate science landscape, this review is organized as a set of nine guidelines for water managers and planners that highlight better practices for incorporating climate change information into water resource planning and management. Each DOs and DON'Ts recommendation is given with context on why certain strategies are preferable and addresses frequently asked questions by exploring past studies and documents that provide guidance, including real-world examples mainly, though not exclusively, from the United States. This paper is intended to provide a foundation that can expand through continued dialogue within and between the climate science and application communities worldwide, a two-way information sharing that can increase the actionable nature of the information produced and promote greater utility and appropriate use

Determining the effect of drying time on phosphorus solubilization from three agricultural soils under climate change scenarios

Climate projections for the future indicate that the United Kingdom will experience hotter, drier summers and warmer, wetter winters, bringing longer dry periods followed by rewetting. This will result in changes in phosphorus (P) mobilization patterns that will influence the transfer of P from land to water. We tested the hypothesis that changes in the future patterns of drying–rewetting will affect the amount of soluble reactive phosphorus (SRP) solubilized from soil. Estimations of dry period characteristics (duration and temperature) under current and predicted climate were determined using data from the UK Climate Projections (UKCP09) Weather Generator tool. Three soils (sieved 25°C are predicted in some places and dry periods of 30 to 90 d extremes are predicted. Combining the frequency of projected dry periods with the SRP concentration in leachate suggests that this may result overall in increased mobilization of P; however, critical breakpoints of 6.9 to 14.5 d dry occur wherein up to 28% more SRP can be solubilized following a rapid rewetting event. The precise cause of this increase could not be identified and warrants further investigation as the process is not currently included in P transfer models

Geological suitability and capacity of CO2 storage in the Jiyang Depression, East China

Carbon dioxide capture and storage (CCS) is an effective technology to reduce carbon dioxide (CO2) emissions in China. In this paper, the authors considered storage opportunities offered by oil reservoirs and deep saline aquifers in the Jiyang Depression, in east China. Based on detailed geological analysis and assessment of CO2 storage suitability, the Dongying Sag and Linyi‐Shanghe areas of the Huimin Sag within the Jiyang Depression appear promising for CO2 storage. Following more detailed characterization, the second and third members of the Shahejie Formation located in these two areas appear the most promising for CO2 storage. Within the areas identified as having potential for storage, 55 primary and 62 secondary recommended storage units were defined, with a total theoretical capacity of 5.02 × 108 tonnes (t) CO2. This represents storage of CO2 emissions from large‐scale sources in the Jiyang Depression for more than 30 years at current emission rates

Environmental benefits of improved water and nitrogen management in irrigated sugar cane : a combined crop modelling and life cycle assessment approach

The application of irrigation water and nitrogen (N) fertilizer in excess of crop demand reduces profitability and has multiple detrimental impacts on the environment. N dynamics in agroecosystems are extremely complex, and mechanistic crop models are most often required to quantify the impact of improved management practices on reducing fertilizer N losses. In this study, Life Cycle Assessment (LCA) methodology and mechanistic modelling was used to quantify the environmental benefits of improved management of water and fertilizer N by sugarcane farmers in a case study in Pongola, South Africa. A baseline scenario, representing farmer intuition-based irrigation scheduling management, and two additional scenarios in which water, and water and N were more rationally managed, were compared. Results show that improved water and N management can lead to a 20% reduction in non-renewable energy consumption per functional unit (FU), with sustained or even increased yields. Total GHG emissions can potentially be reduced by 25% through more efficient water and N management. Limiting the rates of fertilizer N applied, made possible by decreasing N leaching through improved irrigation scheduling, resulted in the highest reductions for both impact categories. While total water consumption was very similar between the scenarios, more efficient use of rainfall was achieved through accurate scheduling, reducing blue water requirements. Through the simultaneous consideration of multiple environmental impacts, combining mechanistic crop modelling and LCA shows potential to identify improved management practices as well as to establish environmental stewardship incentives.L'application d'eau d'irrigation et d'engrais azotés (N) en excès par rapport à la demande des cultures réduit la profitabilité et a de multiples impacts négatifs sur l'environnement. La dynamique de l'azote dans les agrosystèmes est extrèmement complexe, et des modèles de culture mécanistes sont souvent nécessaires pour quantifier l'impact de pratiques de gestion améliorées sur la réduction des pertes en azote. Cette étude utilise la méthodologie de l'Analyse du Cycle de Vie (ACV) combinée à la modélisation mécaniste pour quantifier les bénéfices environnementaux d'une gestion améliorée de l'eau et des fertilisants azotés par des producteurs de canne à sucre, dans une étude de cas à Pongola, Afrique du Sud. Un scénario de base représente les pratiques courantes et intuitives des producteurs en termes d'irrigation, et deux scénarios supplémentaires représentent des pratiques de gestion plus rationnelles de l'eau, et de l'eau et des engrais, respectivement. Les résultats montrent qu'une meilleure gestion de l'eau et de l'azote peut générer une réduction de 20% de la consommation en énergie non-renouvelable, avec des rendements maintenus voire améliorés. Les émissions totales de GES peuvent potentiellement être réduites de 25%. La réduction des applications d'engrais, rendue possible par le moindre lessivage de l'azote sous irrigation raisonnée, résulte en de fortes réductions de ces deux catégories d'impacts. La consommation totale en eau est similaire entre scénario de base et scénarios de meilleure gestion de l'eau; cependant l'utilisation de l'eau de pluie est plus efficiente avec les irrigations raisonnées, réduisant ainsi les besoins d'extraction de la ressource. Par la prise en compte simultanée d'impacts environnementaux multiples, la combinaison de l'ACV et de la modélisation mécaniste de culture montre un potentiel pour identifier les pratiques améliorées et pour développer un accompagnement en éco-conception de systèmes.http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1531-03612016-04-30hb201