Publications

Evaluation of the <scp>ECOSSE</scp> model to predict heterotrophic soil respiration by direct measurements

Summary This paper aims to evaluate the suitability of the ECOSSE model to estimate soil heterotrophic respiration ( R h ) from arable land and short rotation coppices of poplar and willow. Between 2011 and 2013, we measured R h with automatic closed dynamic chambers on root exclusion plots at one site in the UK (willow, mixed commercial genotypes of S alix spp.) and two sites in I taly (arable and poplar, P opulus × C anadensis M oench, O udemberg genotype), and compared these measured fluxes to simulated values of R h with the ECOSSE model. Correlation coefficients ( r ) between modelled and measured monthly R h data were strong and significant, with a range between 0.81 and 0.96 for all three types of vegetation. There was no significant error and bias in the model for any site. The model was able to predict seasonal trends in R h at all three sites even though it occasionally underestimated the flux values during warm weather in spring and summer. Because of the strong correlation between the measured and modelled values, it is unlikely that underestimation of the flux is the result of missing processes in the model. Therefore, further detailed monitoring of R h is needed to modify the model. In this research, a limited set of input data was used to simulate R h at the three sites. Nevertheless, overall results of the model evaluation suggest that the ECOSSE model simulates soil R h adequately under all land uses tested and that continuous and direct measurements (such as automatic chambers installed on root‐exclusion plots) are a useful tool to test model performance to simulate R h at the site level. Highlights Model evaluation is crucial to predict soil carbon balance accurately. Modelled and measured heterotrophic respiration were compared for three land uses. The model performed well statistically for all three vegetation types. Modelled heterotrophic respiration should be evaluated by comparison to continuous measurements.

The role of soil organic matter in maintaining the productivity and yield stability of cereals in China

Using salt-amended soils to calculate a rate modifier for salinity in soil carbon models.

In salt-affected soils, soil organic carbon levels are usually low as a result of poor plant growth; additionally, decomposition of soil organic matter may be decreased. Thus, the CO2 evolution from salt-affected soils is likely to be lower than that from non-saline soils. Carbon models such as Rothamsted Carbon (RothC) that are used to estimate global CO2 emission do not consider the effect of salinity on CO2 emission. Given the large extent of salt-affected soils (19 percent of 20.8 billion hectares of arable land on Earth), this may lead to overestimation of CO2 release. Two laboratory incubation experiments were conducted to assess the effect of soil texture on response of CO2 release to salinity and to calculate a rate modifier for salinity in soil carbon models and study soil carbon dynamics: a sandy loam (18.8% clay) and a sandy clay loam (22.5% clay) in one experiment and a loamy sand (6.3 % clay) and a clay loam (42 % clay) in another experiment. Sodium chloride (NaCl) was used to develop a range of salinities viz. EC1:5 1.0, 2.0, 3.0, 4.0 and 5.0 dS/m. The soils were amended with 2% wheat residues and CO2 emission was measured over 4 months. Cumulative CO2-C/g soil decreased with increased salinity. Cumulative CO2-C expressed as percent of the control soil (without salt addition) showed a lower impact of salinity on organic matter decomposition with increasing clay content. A decrease in particulate organic carbon (POC) associated with incubation was less in the higher saline soils whereas total organic carbon, humus-C and charcoal-C did not change over time and were not significantly affected by salinity. A significant exponential relationship was obtained between EC and the salt rate modifier, suggesting that a new salt rate modifier should be incorporated into RothC in order to accurately model CO2 emissions from salt-affected soils.

Lénergie durable urbaine, lénergie de demain

Au cours des 20 dernières années, les zones urbaines ont connu une croissance impressionnante. Actuellement, plus de 3,5 millions de personnes y vivent (environ la moitié de la population mondiale). Les pays en développement, en particulier, connaissent une évolution rapide avec un déclin des économies rurales au profit des économies urbaines (ONU-HABITAT, ICLEI et PNUE, 2009, p. 7). Si les pays en développement présentent des rythmes et une étendue d’urbanisation très variés, leur défi à relever tient à la difficulté de stabiliser une demande croissante en ressources énergétiques, de construire des ponts, d’assurer l’égalité et l’autonomisation, de diminuer la dégradation de l’environnement, de promouvoir la santé et les moyens de subsistance ainsi que d’élaborer de nouvelles orientations pour le développement (Droege, 2008, p. 1).

Avoid constructing wind farms on peat

Including trace gas fluxes in estimates of the carbon mitigation potential of UK agricultural land

Abstract. A number of changes in agricultural land‐management show some potential as carbon mitigation options. However, research has focused on CO 2 ‐carbon mitigation and has largely ignored potential effects of land management change on trace gas fluxes. In this paper, we attempt for the first time, to assess the impact of these changes on fluxes of the important agricultural greenhouse gases, methane and nitrous oxide, in the UK. The estimates presented here are based on limited evidence and have a great (unquantifiable) uncertainty associated with them, but they show that the relative importance of trace gas fluxes varies enormously among the scenarlos. In some, such as the application of sewage sludge, woodland regeneration and bioenergy production scenarios, the inclusion of estimates for trace gas fluxes makes only a small (&lt;10%) difference to the CO 2 ‐C mitigation potential. In the animal manure and agricultural extensification scenarios, including estimates of trace gas fluxes has a large impact, increasing the CO 2 ‐C mitigation potential by up to 50%. In the no‐till scenario, the carbon mitigation potential decreases significantly due to a sharp increase in N 2 O emissions under no‐till. When these land‐management options are combined for the whole agricultural land area of the UK, including trace gases has an impact on estimated mitigation potentials, and depending upon assumptions for the animal manure scenario, the total mitigation potential either decreases by about 10% or increases by about 30%, potentially shifting the mitigation potential of the scenario closer to the EU's 8% Kyoto target for reduction of CO 2 ‐carbon emissions (12.52 Tg C yr −1 for the UK).

Recasting Economics As If the Climate and Global Ecology Really Mattered

Climate change mitigation options in the rural land use sector: Stakeholders’ perspectives on barriers, enablers and the role of policy in North East Scotland

Impacts of land use, population, and climate change on global food security

Abstract In recent years, global hunger has begun to rise, returning to levels from a decade ago. Climate change is a key driver behind these recent rises and is one of the leading causes of severe food crises. When coupled with population growth and land use change, future climate variability is predicted to have profound impacts on global food security. We examine future global impacts of climate variability, population, and land use change on food security to 2050, using the modeling framework FEEDME (Food Estimation and Export for Diet and Malnutrition Evaluation). The model uses national food balance sheets (FBS) to determine mean per capita calories, hence incorporating an assumption that minimum dietary energy requirements (MDER) remain constant. To account for climate variability, we use two Representative Concentration Pathway (RCP) scenarios from the Intergovernmental Panel on Climate Change (IPCC), alongside three Shared Socio‐economic Pathway (SSP) scenarios incorporating land use and population change within the model. Our results indicate that SSP scenarios have a larger impact on future food insecurity, in particular because of projected changes in population. Countries with a projected decrease in population growth had higher food security, while those with a projected rapid population growth tended to experience the worst impacts on food security. Although climate change scenarios had an effect on future crop yields, population growth appeared to be the dominant driver of change in undernourishment prevalence. Therefore, strategies to mitigate the consequences of projected population growth, including improved maternal health care, increasing equality of access to food at the national level, closing the yield gap, and changes in trade patterns, are essential to ensuring severe future food insecurity is avoided.

Bioenergy and climate change mitigation: an assessment

Abstract Bioenergy deployment offers significant potential for climate change mitigation, but also carries considerable risks. In this review, we bring together perspectives of various communities involved in the research and regulation of bioenergy deployment in the context of climate change mitigation: Land‐use and energy experts, land‐use and integrated assessment modelers, human geographers, ecosystem researchers, climate scientists and two different strands of life‐cycle assessment experts. We summarize technological options, outline the state‐of‐the‐art knowledge on various climate effects, provide an update on estimates of technical resource potential and comprehensively identify sustainability effects. Cellulosic feedstocks, increased end‐use efficiency, improved land carbon‐stock management and residue use, and, when fully developed, BECCS appear as the most promising options, depending on development costs, implementation, learning, and risk management. Combined heat and power, efficient biomass cookstoves and small‐scale power generation for rural areas can help to promote energy access and sustainable development, along with reduced emissions. We estimate the sustainable technical potential as up to 100 EJ : high agreement; 100–300 EJ : medium agreement; above 300 EJ : low agreement. Stabilization scenarios indicate that bioenergy may supply from 10 to 245 EJ yr −1 to global primary energy supply by 2050. Models indicate that, if technological and governance preconditions are met, large‐scale deployment (&gt;200 EJ ), together with BECCS , could help to keep global warming below 2° degrees of preindustrial levels; but such high deployment of land‐intensive bioenergy feedstocks could also lead to detrimental climate effects, negatively impact ecosystems, biodiversity and livelihoods. The integration of bioenergy systems into agriculture and forest landscapes can improve land and water use efficiency and help address concerns about environmental impacts. We conclude that the high variability in pathways, uncertainties in technological development and ambiguity in political decision render forecasts on deployment levels and climate effects very difficult. However, uncertainty about projections should not preclude pursuing beneficial bioenergy options.

Barlborough Hall, Derbyshire

Abstract This article examines the architectural evolution of Barlborough Hall from its construction in 1583 to the present day, using a number of previously unpublished documents, mostly from the Locker-Lampson Collection. It also discusses a painting in the British Library which indicates that the house was once prefaced by ranges of forecourt buildings, and it outlines the various alterations made to the house and garden between 1696 and 1714, identifying the architect responsible for at least some of these changes as John Hallam. The most important source of new information is an album of drawings by Lindley, Woodhead &amp; Hurst of 1815, which records the building in detail before further alterations completed in 1825. These drawings also permit reconstructions of the likely design and appearance of the original house. The relatively minor additions in the mid-nineteenth century and the alterations made to the building since it became a school in 1938 are also outlined.

Stiring soil C pools out of equilibrium in response to climate and land-use changes

Evaluation of the ECOSSE Model for Estimating Soil Respiration from Eight European Permanent Grassland Sites

This study used the ECOSSE model (v. 5.0.1) to simulate soil respiration (Rs) fluxes estimated from ecosystem respiration (Reco) for eight European permanent grassland (PG) sites with varying grass species, soils, and management. The main aim was to evaluate the strengths and weaknesses of the model in estimating Rs from grasslands, and to gain a better understanding of the terrestrial carbon cycle and how Rs is affected by natural and anthropogenic drivers. Results revealed that the current version of the ECOSSE model might not be reliable for estimating daily Rs fluxes, particularly in dry sites. The daily estimated and simulated Rs ranged from 0.95 to 3.1 g CO2-C m−2, and from 0.72 to 1.58 g CO2-C m−2, respectively. However, ECOSSE could still be a valuable tool for predicting cumulative Rs from PG. The overall annual relative deviation (RD) value between the cumulative estimated and simulated annual Rs was 11.9%. Additionally, the model demonstrated accurate simulation of Rs in response to grass cutting and slurry application practices. The sensitivity analyses and attribution tests revealed that increased soil organic carbon (SOC), soil pH, temperature, reduced precipitation, and lower water table (WT) depth could lead to increased Rs from soils. The variability of Rs fluxes across sites and years was attributed to climate, weather, soil properties, and management practices. The study suggests the need for additional development and application of the ECOSSE model, specifically in dry and low input sites, to evaluate the impacts of various land management interventions on carbon sequestration and emissions in PG.

Using long-term experiments to estimate the potential for carbon sequestration at the regional level - an examination of five European scenarios

Resolving controversies surrounding carbon sinks from carbonate weathering

Carbon sequestration potential of tree planting in China

China's large-scale tree planting programs are critical for achieving its carbon neutrality by 2060, but determining where and how to plant trees for maximum carbon sequestration has not been rigorously assessed. Here, we developed a comprehensive machine learning framework that integrates diverse environmental variables to quantify tree growth suitability and its relationship with tree numbers. Then, their correlations with biomass carbon stocks were robustly established. Carbon sink potentials were mapped in distinct tree-planting scenarios. Under one of them aligned with China's ecosystem management policy, 44.7 billion trees could be planted, increasing forest stock by 9.6 ± 0.8 billion m³ and sequestering 5.9 ± 0.5 PgC equivalent to double China's 2020 industrial CO₂ emissions. We found that tree densification within existing forests is an economically viable and effective strategy and so it should be a priority in future large-scale planting programs.

Considering agriculture in IPCC assessments

A new scheme for initializing process-based ecosystem models by scaling soil carbon pools