• Authors:
    • Kuhnert, M.
    • Hastings, A.
    • Williams, J. R.
    • Smith, K.
    • Datta, A.
    • Fitton, N.
    • Topp, C. F. E.
    • Smith, P.
  • Source: Nutrient Systems in Agroecosystems
  • Volume: 99
  • Issue: 1-3
  • Year: 2014
  • Summary: Biogeochemical models such as DailyDayCent (DDC) are increasingly used to help quantify the emissions of green-house gasses across different ecosystems and climates. For this use they require parameterisation to represent a heterogeneous region or are site specific and scaled upwards. This requires information on inputs such as climate, soil, land-use and land management. However, each input has an associated uncertainty, which propagates through the model to create an uncertainty in the modelled outputs. To have confidence in model projections, an assessment of how the uncertainty in inputs propagated through the model and its impact on modelled outputs is required. To achieve this, we used a pre-defined uncertainty range of key inputs; temperature, precipitation, clay content, bulk density and soil pH, and performed a sensitivity and uncertainty analysis, using Monte Carlo simulations. This allowed the effect of measurement uncertainty on the modelled annual N2O emissions and crop yields at the Grange field experimental site to be quantified. Overall the range of model estimates simulated was relatively high and while the model was sensitive to each input parameter, uncertainty was driven by the sensitivity to soil pH. This decreased as the N fertiliser application rate increased, as at lower N application rates the model becomes more sensitive to other drivers of N mineralisation such as soil and climate inputs. Therefore, while our results indicate that DDC can provide a good estimate of annual N2O emissions and crop yields under UK conditions, reducing the uncertainty in the input parameters will lead to more accurate simulations.
  • Authors:
    • Pidgeon, N. F.
    • Capstick, S. B.
  • Source: Research Article
  • Volume: 122
  • Issue: 4
  • Year: 2014
  • Summary: It has been argued that public doubts about climate change have been exacerbated by cold weather events seen as a form of disconfirming evidence for anticipated 'warming'. Although a link between perceptions of climate and weather is well-established, such assumptions have not been empirically tested. Here we show, using nationally representative data, that directly following a period of severe cold weather in the UK, three times as many people saw these events as pointing towards the reality of climate change, than as disconfirming it. This we argue was a consequence of these cold winters being incorporated into a conceptualisation of extreme or 'unnatural' weather resulting from climate change. We also show that the way in which people interpret cold weather is associated with levels of pre-existing scepticism about climate change, which is in turn related to more general worldviews. Drawing attention to 'extreme' weather as a consequence of climate change can be a useful communication device, however this is problematic in the case of seasonal cold.
  • Authors:
    • Siegfried, W.
    • Rohr, C.
    • Riemann, D.
    • Retso, D.
    • Pribyl, K.
    • Nordl, O.
    • Litzenburger, L.
    • Limanowka, D.
    • Labbe, T.
    • Kotyza, O.
    • Kiss, A.
    • Himmelsbach, I.
    • Glaser, R.
    • Dobrovolny, P.
    • Contino, A.
    • Camenisch, C.
    • Burmeister, K.
    • Brazdil, R.
    • Bieber, U.
    • Barriendos, M.
    • Alcoforado, M.
    • Luterbacher, J.
    • Gruenewald, U.
    • Herget, J.
    • Seneviratne, S.
    • Wagner, S.
    • Zorita, E.
    • Werner, J.
    • Pfister, C.
    • Wetter, O.
    • Soderberg, J.
    • Spring, J.
  • Source: Climatic Change
  • Volume: 125
  • Issue: 3-4
  • Year: 2014
  • Summary: The heat waves of 2003 in Western Europe and 2010 in Russia, commonly labelled as rare climatic anomalies outside of previous experience, are often taken as harbingers of more frequent extremes in the global warming-influenced future. However, a recent reconstruction of spring-summer temperatures for WE resulted in the likelihood of significantly higher temperatures in 1540. In order to check the plausibility of this result we investigated the severity of the 1540 drought by putting forward the argument of the known soil desiccation-temperature feedback. Based on more than 300 first-hand documentary weather report sources originating from an area of 2 to 3 million km(2), we show that Europe was affected by an unprecedented 11-month-long Megadrought. The estimated number of precipitation days and precipitation amount for Central and Western Europe in 1540 is significantly lower than the 100-year minima of the instrumental measurement period for spring, summer and autumn. This result is supported by independent documentary evidence about extremely low river flows and Europe-wide wild-, forest- and settlement fires. We found that an event of this severity cannot be simulated by state-of-the-art climate models.
  • Authors:
    • McCracken, D. I.
    • Bradbury, R. B.
    • Firbank, L.
    • Stoate, C.
  • Source: Agriculture Ecosystems & Environment
  • Volume: 166
  • Year: 2013
  • Summary: Here, we review the delivery of ecosystem services from Enclosed Farmland in the UK, and explore how the expected demands for ecosystem services might be met in the future. Most Enclosed Farmland is managed for agriculture; the UK is 60% self-sufficient in foods. Pollinators are in serious decline, but little is known of trends of predators of crop pests. Effects of agriculture on water quality and climate regulation are negative but improving; GHG emissions fell by 20% between 1990 and 2008. Recent declines in numbers of some farmland birds and in plant species richness have been halted, though not reversed. Enclosed Farmland provides considerable leisure and cultural value. Effective delivery of multiple ecosystem services requires improved understanding of how ecosystem services are generated, and of their economics and governance. Food production can be integrated with the delivery of other ecosystem services by promoting a diversity of farming systems and allocating land to different ecosystem services according to its suitability. Approaches include, minimising negative environmental impacts of food production through technology; mitigating environmental harm by managing areas for environmental benefit, from patches within fields to much larger areas; and developing markets and regulations for environmental protection.
  • Authors:
    • De Nocker, L.
    • Aertsens, J.
    • Gobin, A.
  • Source: Land Use Policy
  • Volume: 31
  • Year: 2013
  • Summary: Purpose: This paper aims at indicating the potential of agricultural measures in sequestering carbon as an option for climate change mitigation. The related value for society is estimated. Principle results: Agricultural practices like agroforestry, introducing hedges, low and no tillage and cover crops have an important potential to increase carbon sequestration. The total technical potential in the EU-27 is estimated to be 1566 million tonnes CO2-equivalent per year. This corresponds to 37% of all CO2-equivalent emissions in the EU in 2007. The introduction of agroforestry is the measure with the highest potential, i.e. 90% of the total potential of the measures studied. Taking account only of the value for climate change mitigation, the introduction of agroforestry is estimated to have a value of 282 euro/ha in 2012 that will gradually increase to 1007 euro/ha in 2030. Major conclusions: This implies that there is a huge potential which represents an important value for society in general and for the agricultural sector in specific. At the European level, only in the last few years policy makers have recognized the important benefits of agroforestry. In their rural development programmes some European countries now support farmers to introduce agroforestry. But still the current level of support is only a small fraction of the societal value of agroforestry. If this value would be fully recognized by internalizing the positive externality, we expect that agroforestry will be introduced to a very large extent in the next decades, in Europe and the rest of the world, and this will importantly change the rural landscapes. (C) 2012 Elsevier Ltd. All rights reserved.
  • Authors:
    • Hunter, C.
    • Slee, B.
    • Feliciano, D.
    • Smith, P.
  • Source: Environmental Science & Policy
  • Volume: 25
  • Year: 2013
  • Summary: Challenging greenhouse gas (GHG) emission reduction targets were set in Scotland by the Climate Change (Scotland) Act in June 2009. The national objective is to reduce GHG emissions by 42% by 2020 and 80% by 2050 compared to 1990 levels. The GHG emission reduction targets apply both to the traded and non-traded sectors, thus including the rural land use sector. In North East Scotland, rural land uses cover the majority of the land area, with agriculture and forestry representing about 86% and sporting land about 10% of the total area. The objectives of this study were to provide guidance for the development of a regional GHG inventory to estimate methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) emissions from rural land uses in North East of Scotland, to compare with that of the United Kingdom (UK), and discuss the advantages of regional GHG inventories for rural land uses. The study mainly followed the guidance of the IPCC (Intergovernmental Panel on Climate Change) Revised Guidelines for National Greenhouse Gas Inventories and adapts these to the region level. Data available for North East Scotland allowed an assessment of annual GHG emissions from livestock and grassland, cropland management and sporting land, as well as carbon sequestered by forests, between 1999 and 2010. Estimated GHG emissions of 1420 ktCO(2)e from livestock, grassland and cropland management obtained in this study for 2009 compare well with estimates for the same region from larger-scale inventories. The methodology described, including the steps undertaken for data collection, the shortcomings found and strategies to overcome these, could be applied to other UK or European regions.
  • Authors:
    • Cao, Y.
    • Drake, B.
    • Elliott, J.
    • Firbank, L. G.
    • Gooday, R.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 173
  • Year: 2013
  • Summary: Several influential reports have suggested that one of the most appropriate responses to expected food shortages and ongoing environmental degradation is sustainable intensification, i.e. the increase of food production with at worst no increase in environmental harm, and ideally environmental benefit. Here we sought evidence of sustainable intensification among British farmers by selecting innovative arable, dairy, mixed and upland farms and analysing their own data on yields, inputs and land use and management for 2006 and 2011. The evidence was obtained by interview, and was interpreted in terms of the ecosystem services of food production (GJ ha(-1), where area took into account estimated area to grow any imported animal feeds), regulation of climate, air and water quality (modelled emissions of GHGs (CO(2)e ha(-1)), ammonia (kg ha(-1)) and nitrate loss (kg ha(-1))) and biodiversity (using an index based on the presence of habitats and management). Several farms have increased both food production and other ecosystem services over this time by increasing yields, using resources more efficiently and/or enhancing biodiversity, and sometimes by reducing livestock numbers and increasing cropping. The motivation has been to improve farm profitability through increasing food production, reducing input costs and accessing public payments through agri-environment schemes and generating renewable energy. Such sustainable intensification was not achieved by farmers who increased meat or milk yields. Sustainable intensification can be achieved when the correct drivers are in place to influence the actions of individual farmers. Also, it is possible to indicate sustainable intensification by using a small number of high-level indicators derived from data that farmers already hold, though such an approach may not capture the impacts of farmer innovative practices.
  • Authors:
    • Paterson, E.
    • Sim, A.
  • Source: Global Change Biology
  • Volume: 19
  • Issue: 5
  • Year: 2013
  • Summary: Soil organic matter (SOM) mineralization processes are central to the functioning of soils in relation to feedbacks with atmospheric CO 2 concentration, to sustainable nutrient supply, to structural stability and in supporting biodiversity. Recognition that labile C-inputs to soil (e.g. plant-derived) can significantly affect mineralization of SOM ('priming effects') complicates prediction of environmental and land-use change effects on SOM dynamics and soil C-balance. The aim of this study is to construct response functions for SOM priming to labile C (glucose) addition rates, for four contrasting soils. Six rates of glucose (3 atm% 13C) addition (in the range 0-1 mg glucose g -1 soil day -1) were applied for 8 days. Soil CO 2 efflux was partitioned into SOM- and glucose-derived components by isotopic mass balance, allowing quantification of SOM priming over time for each soil type. Priming effects resulting from pool substitution effects in the microbial biomass ('apparent priming') were accounted for by determining treatment effects on microbial biomass size and isotopic composition. In general, SOM priming increased with glucose addition rate, approaching maximum rates specific for each soil (up to 200%). Where glucose additions saturated microbial utilization capacity (>0.5 mg glucose g -1 soil), priming was a soil-specific function of glucose mineralization rate. At low to intermediate glucose addition rates, the magnitude (and direction) of priming effects was more variable. These results are consistent with the view that SOM priming is supported by the availability of labile C, that priming is not a ubiquitous function of all components of microbial communities and that soils differ in the extent to which labile C stimulates priming. That priming effects can be represented as response functions to labile C addition rates may be a means of their explicit representation in soil C-models. However, these response functions are soil-specific and may be affected by several interacting factors at lower addition rates.
  • Authors:
    • Giltrap, D.
    • Hernandez-Ramirez, G.
    • Kim, D.-G.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 168
  • Issue: March
  • Year: 2013
  • Summary: Rising atmospheric concentrations of nitrous oxide (N2O) contribute to global warming and associated climate change. It is often assumed that there is a linear relationship between nitrogen (N) input and direct N2O emission in managed ecosystems and, therefore, direct N2O emission for national greenhouse gas inventories use constant emission factors (EF). However, a growing body of studies shows that increases in direct N2O emission are related by a nonlinear relationship to increasing N input. We examined the dependency of direct N2O emission on N input using 26 published datasets where at least four different levels of N input had been applied. In 18 of these datasets the relationship of direct N2O emission to N input was nonlinear (exponential or hyperbolic) while the relationship was linear in four datasets. We also found that direct N2O EF remains constant or increases or decreases nonlinearly with changing N input. Studies show that direct N2O emissions increase abruptly at N input rates above plant uptake capacity. The remaining surplus N could serve as source of additional N2O production, and also indirectly promote N2O production by inhibiting biochemical N2O reduction. Accordingly, we propose a hypothetical relationship to conceptually describe in three steps the response of direct N2O emissions to increasing N input rates: (1) linear (N limited soil condition), (2) exponential, and (3) steady-state (carbon (C) limited soil condition). In this study, due to the limited availability of data, it was not possible to assess these hypothetical explanations fully. We recommend further comprehensive experimental examination and simulation using process-based models be conducted to address the issues reported in this review. (C) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • Chatterton, J.
    • Graves, A.
    • Kulak, M.
  • Source: Landscape and Urban Planning
  • Volume: 111
  • Issue: March
  • Year: 2013
  • Summary: The production and supply of food currently accounts for 20-30% of greenhouse gas (GHG) emissions in the UK and the government and nongovernmental organisations are seeking to reduce these environmental burdens. Local authorities all over UK establish community farms with the aim to produce more sustainable food for citizens. This study used environmental Life Cycle Assessment (LCA) to quantify the potential savings of food-related GHG emissions that may be achieved with the establishment of an urban community farm, based on a case study recently found in the London Borough of Sutton. The work identified elements of the farm design that require the greatest attention to maximise these savings. The greatest reductions can be achieved by selecting the right crops: (i) providing the highest yields in local conditions and (ii) usually produced in energy-intensive greenhouses or air-freighted to UK from outside Europe. Implications from further development of the farm on the local, unused land were examined, taking into account market requirements. This showed that land used on an urban fringe for food production could potentially reduce greenhouse gas emissions in Sutton by up to 34 t CO(2)e ha(-1) a(-1). Although the percentage of this reduction in total diet emissions is relatively low, the result exceeds carbon sequestration rates for the conventional urban green space projects, such as parks and forests. (C) 2012 Elsevier B.V. All rights reserved.