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Environmental Research Letters covers all of environmental science, providing a coherent and integrated approach including research articles, perspectives and editorials. Articles are from 2006 to present.

Description

Environmental Research Letters is a free-to-read journal dedicated to bringing together intellectual and professional scientists, economists, engineers and social scientists, as well as the public sector and civil society who are engaged in efforts to understand the state of natural systems and, increasingly, the human footprint on the biosphere.

latest article added on March 2014

ArticleFirst AuthorPublished
Higher subsoil carbon storage in species-rich than species-poor temperate forestsSchleuß, Per-Marten2014

Higher subsoil carbon storage in species-rich than species-poor temperate forests

Keywords

carbon saturation, subsoil, tree diversity, soil organic, particle size fractionation

Abstract

Forest soils contribute ca. 70% to the global soil organic carbon (SOC) pool and thus are an important element of the global carbon cycle. Forests also harbour a large part of the global terrestrial biodiversity. It is not clear, however, whether tree species diversity affects SOC. By measuring the carbon concentration of different soil particle size fractions separately, we were able to distinguish between effects of fine particle content and tree species composition on the SOC pool in old-growth broad-leaved forest plots along a tree diversity gradient (1-, 3- and 5-species). Variation in clay content explained part of the observed SOC increase from monospecific to mixed forests, but we show that the carbon concentration per unit clay or fine silt in the subsoil was by 30–35% higher in mixed than monospecific stands indicating a significant species identity or species diversity effect on C stabilization. Underlying causes may be differences in fine root biomass and turnover, in leaf litter decomposition rate among the tree species, and/or species-specific rhizosphere effects on soil. Our findings may have important implications for forestry offering management options through preference of mixed stands that could increase forest SOC pools and mitigate climate warming

Authors

Schleuß, Per-Marten, Heitkamp, Felix, Leuschner, Christoph, Fender, Ann-Catrin and Jungkunst, Hermann F

Year Published

2014

Publication

Environmental Research Letters

Locations
DOI

10.1088/1748-9326/9/1/014007

This article contributed by:

Original

Mapping of soil organic carbon stocks for spatially explicit assessments of climate change mitigation potentialVågen, Tor-Gunnar2013

Mapping of soil organic carbon stocks for spatially explicit assessments of climate change mitigation potential

Keywords

East Africa, cumulative mass, mapping, remote sensing, soil carbon stocks

Abstract

Current methods for assessing soil organic carbon (SOC) stocks are generally not well suited for understanding variations in SOC stocks in landscapes. This is due to the tedious and time-consuming nature of the sampling methods most commonly used to collect bulk density cores, which limits repeatability across large areas, particularly where information is needed on the spatial dynamics of SOC stocks at scales relevant to management and for spatially explicit targeting of climate change mitigation options. In the current study, approaches were explored for (i) field-based estimates of SOC stocks and (ii) mapping of SOC stocks at moderate to high resolution on the basis of data from four widely contrasting ecosystems in East Africa. Estimated SOC stocks for 0–30 cm depth varied both within and between sites, with site averages ranging from 2 to 8 kg m−2. The differences in SOC stocks were determined in part by rainfall, but more importantly by sand content. Results also indicate that managing soil erosion is a key strategy for reducing SOC loss and hence in mitigation of climate change in these landscapes. Further, maps were developed on the basis of satellite image reflectance data with multiple R-squared values of 0.65 for the independent validation data set, showing variations in SOC stocks across these landscapes. These maps allow for spatially explicit targeting of potential climate change mitigation efforts through soil carbon sequestration, which is one option for climate change mitigation and adaptation. Further, the maps can be used to monitor the impacts of such mitigation efforts over time.

Authors

Vågen, Tor-Gunnar and Winowiecki, Leigh A

Year Published

2013

Publication

Environmental Research Letters

Locations
DOI

10.1088/1748-9326/8/1/015011

This article contributed by:

Original

Shifts in plant dominance control carbon-cycle responses to experimental warming and widespread droughtHarte, John2006

Shifts in plant dominance control carbon-cycle responses to experimental warming and widespread drought

Keywords

carbon, climate, drought, vegetation, feedback

Abstract

Global climate change is predicted to increase the intensity and frequency of future drought, which in turnmay be expected to induce a range of biogeochemical climate feedbacks. A combination of model simulations and observational studies of a recent wide-scale drought, suggested that the drought induced substantial terrestrial ecosystem carbon loss, but hypothesizedmechanisms could not be evaluated via comparison to a control. Here, we investigated carbon-cycle responses to climate changes by combining results from a controlled 15-year ecosystem warming experiment in montane grassland with observational data from before and during the recent drought. We found that both experimentalwarming and real-world drought induced substantial soil carbon loss in our study system, and that the same mechanism, a drying-induced shift in plant species composition and an associated decline in community productivity, provides a common explanation for these declines in soil carbon.

Authors

Harte, John, Saleska, Scott and Shih, Tiffany

Year Published

2006

Publication

Environmental Research Letters

Locations
DOI

10.1088/1748-9326/1/1/014001

This article contributed by:

Original

Dust, fertilization and sourcesRemer, Lorraine A2006

Dust, fertilization and sources

Keywords

No keywords available

Abstract

Aerosols, tiny suspended particles in the atmosphere, play an important role in modifying the Earth's energy balance and are essential for the formation of cloud droplets. Suspended dust particles lifted from the world's arid regions by strong winds contain essential minerals that can be transported great distances and deposited into the ocean or on other continents where productivity is limited by lack of usable minerals [1]. Dust can transport pathogens as well as minerals great distance, contributing to the spread of human and agricultural diseases, and a portion of dust can be attributed to human activity suggesting that dust radiative effects should be included in estimates of anthropogenic climate forcing. The greenish and brownish tints in figure 1 show the wide extent of monthly mean mineral dust transport, as viewed by the MODerate resolution Imaging Spectroradiometer (MODIS) satellite sensor. Figure 1. The monthly mean global aerosol system for February 2006 from the MODIS aboard the Terra satellite. The brighter the color, the greater the aerosol loading. Red and reddish tints indicate aerosol dominated by small particles created primarily from combustion processes. Green and brownish tints indicate larger particles created from wind-driven processes, usually transported desert dust. Note the bright green band at the southern edge of the Saharan desert, the reddish band it must cross if transported to the southwest and the long brownish transport path as it crosses the Atlantic to South America. Image courtesy of the NASA Earth Observatory (http://earthobservatory.nasa.gov). Even though qualitatively we recognize the extent and importance of dust transport and the role that it plays in fertilizing nutrient-limited regions, there is much that is still unknown. We are just now beginning to quantify the amount of dust that exits one continental region and the fraction that arrives at another continent [2]. At the deposition end of the chain, it is still unclear how the limited minerals in the dust such as iron are released for uptake by organisms either on land or in the ocean. Not all dust deposited into oceans results in a phytoplankton bloom. The process requires a chemical pathway that mobilizes a fraction of the iron into soluble form. Meskhidze et al [3] show that phytoplankton blooms following dust transport from the Gobi desert in Asia into the Pacific ocean result in a phytoplankton bloom only if the dust is accompanied by high initial SO2-to-dust ratios, suggesting that sulfuric acid coatings on the dust particle mobilize the embedded iron in the dust for phytoplankton uptake. Quantifying transport, deposition and nutrient availability are the latter ends of a puzzle that must begin by identifying and quantifying dust emission at the sources. The emission process is complex at the microscale requiring the right conditions for saltation and bombardment, which makes identification and inclusion of sources in global transport models very difficult. The result is that estimates of annual global dust emissions range from 1000 to 3000 Tg per year [4]. Even as global estimates of dust emissions are uncertain, localizing the sources brings even greater uncertainty. It has been recognized for several years that dust sources are not uniformly distributed over the arid regions of the Earth, but are regulated to topographic lows associated with dried lake deposits [5]. Using aerosol information from satellites, a comprehensive map of the world's source regions shows sources localized to specific areas of the Earth's arid regions [6]. Still these maps suggest broad emission sources covering several degrees of latitude and longitude. In the paper by Koren and co-authors [7] appearing in this issue, one particular dust source, the Bodélé depression in Chad, is analyzed in detail. They find that the specific topography of the depression combined with the prevailing wind direction in the winter provides perfect conditions for aerosol saltation, uplift and transport. The winter Bodélé dust is carried over the populated regions of west Africa where it can be affected by smoke and urban pollution before it continues transport over the Atlantic and towards Amazonia. Although Koren et al do not speculate on the chemical possibilities in their paper, the interaction between the dust and the pollutants provides opportunity for acids to coat the dust particles and to mobilize the iron compounds, creating a highly efficient fertilizing agent for ocean phytoplankton and the biota of the Amazon forest. Koren et al do quantify the dust emission of the Bodélé depression, estimating that this small area produces approximately 50% of the Saharan dust deposited in the Amazon. The findings of Koren and his co-authors suggest that dust emission sources may be highly localized spots in the Earth's deserts that can be mapped precisely by satellites of moderate to fine resolution. Like fire hot spots that localize smoke emission, desert dust hot spots can be identified with great detail. This can provide aerosol transport models with better source emission information and improve estimates that will help in making estimates concerning biogeochemical processes and also estimates of climate forcing and response. References [1] Swap R et al 1992 Saharan dust in the Amazon basin Tellus B 44 133-49 (doi:10.1034/j.1600-0889.1992.t01-1-00005.x) [2] Kaufman Y J, Koren I, Remer L A, Tanré D, Ginoux P and Fan S 2005 Dust transport and deposition observed from the Terra-MODIS space observations J. Geophys. Res. 110 D10S12 (doi:10.1029/2003JD004436) [3] Meskhidze N, Chameides W L and Nenes A 2005 Dust and pollution: a recipe for enhanced ocean fertizilation? J. Geophys. Res. 110 (D3) D03301 (doi:10.1029/2004JD005082) [4] Cakur R V et al 2006 Constraining the magnitude of the global dust cycle by minimizing the difference between a model and observations J. Geophys. Res. 111 D06207 (doi:10.1029/2005JD005791) [5] Ginoux P et al 2001 Sources and distribution of dust aerosol simulated with the GOCART model J. Geophys. Res. 106 20255-74 (doi:10.1029/2000JD000053) [6] Prospero J M, Ginoux P, Torres O, Nicholson S E and Gill T E 2002 Environmental characterization of global sources of atmospheric soil dust identified with the NIMBUS 7 total Ozone Mapping Spectrometer (TOMS) absorbing aerosol product Rev. Geophys. 40 (1) 1002 (doi:10.1029/2000RG000095) [7] Koren I, Kaufman Y J, Washington R, Todd M C, Rudich Y, Martins J V and Rosenfeld D 2006 The Bodélé depression: a single spot in the Sahara that provides most of the mineral dust to the Amazon forest Environ. Res Lett. 1 014005 (doi:10.1088/1748-9326/1/1/014005) Lorraine A Remer received a BS degree in atmospheric science from the University of California, Davis, in 1980, an MS degree in oceanography from the Scripps Institution of Oceanography, University of California, San Diego, in 1983, and a PhD degree, also in atmospheric science from the University of California, Davis, in 1991. She became involved with the MODIS retrievals of atmospheric aerosols in 1991, first as a Research Scientist with Science Systems and Applications, Inc., and subsequently with the National Aeronautics and Space Administration, which she joined in 1998. She is an Associate Member of the MODIS Science Team and a Member of the Global Aerosol Climatology Project Science Team.

Authors

Remer, Lorraine A

Year Published

2006

Publication

Environmental Research Letters

Locations
    DOI

    10.1088/1748-9326/1/1/011001

    This article contributed by:

    Original

    Learning from the Brazilian biofuel experienceWang, Michael2006

    Learning from the Brazilian biofuel experience

    Keywords

    No keywords available

    Abstract

    In the article `The ethanol program in Brazil' 1 ref1 José Goldemberg summarizes the key features of Brazil's sugarcane ethanol programthe most successful biofuel program in the world so far. In fact, as of 2005, Brazil was the world's largest producer of fuel ethanol. In addition to providing 40% of its gasoline market with ethanol, Brazil exports a significant amount of ethanol to Europe, Japan, and the United States. The success of the program is attributed to a variety of factors, including supportive governmental policies and favorable natural conditions (such as a tropical climate with abundant rainfall and high temperatures). As the article points out, in the early stages of the Brazilian ethanol program, the Brazilian government provided loans to sugarcane growers and ethanol producers (in most cases, they are the same people) to encourage sugarcane and ethanol production. Thereafter, ethanol prices were regulated to ensure that producers can economically sustain production and consumers can benefit from using ethanol. Over time, Brazil was able to achieve a price for ethanol that is lower than that for gasoline, on the basis of energy content. This lower cost is largely driving the widespread use of ethanol instead of gasoline by consumers in Brazil. In the United States, if owners of E85 flexible-fuel vehicles (FFVs) are expected to use E85 instead of gasoline in their FFVs, E85 will have to be priced competitively against gasoline on an energy-content basis. Compared with corn-based or sugar beet-based ethanol, Brazil's sugarcane-based ethanol yields considerably more favorable results in terms of energy balance and reductions in greenhouse gas emissions. These results are primarily due to (i) the dramatic increase of sugarcane yield in Brazil in the past 25 years and (ii) the use of bagasse instead of fossil fuels in ethanol plants to provide the heat needed for ethanol plant operations and to generate electricity for export to electric grids. Advancements in technology associated with both sugarcane farming and ethanol production have definitely played an important role in yielding the significant benefits associated with sugarcane ethanol. The United States produced about 4 billion gallons of ethanol from corn in 2005. Production was expected to increase to about 5 billion gallons by 2006. Corn-based ethanol achieves moderate reductions in greenhouse gas emissions. In the long run, the great potential of fuel ethanol lies in its production from cellulosic biomass, which is abundant in many regions of the world and can yield much greater reductions in greenhouse gas emissions and energy benefits. Figure 1 presents reductions in greenhouse emissions of several ethanol production pathways that were evaluated at the Argonne National Laboratory. Bagasse, a cellulosic biomass type already available in sugarcane ethanol plants, will certainly offer an opportunity for economically co-producing cellulosic ethanol and sugarcane ethanol in existing sugarcane ethanol plants. IMG http://ej.iop.org/images/1748-9326/1/1/011002/img1.gif Greenhouse gas emissions per million Btu of gasoline and ethanol produced and used Figure 1. Greenhouse gas emissions per million Btu of gasoline and ethanol produced and used. Despite the encouraging progress of Brazil's ethanol program some issues will still need to be addressed. Figure 4 of 1 ref1 shows a significant drop in ethanol production in the 2000/2001 season. A steady supply of ethanol will be a key factor for the success of a fuel ethanol program. Consumers are not going to tolerate fluctuations in ethanol production. Instead, they will turn to conventional fuels for fueling their FFVs as a result of supply fluctuations, which can be detrimental to the success of the ethanol program. In addition to this, other environmental effects of biofuels in general, and sugarcane ethanol in particular, need to be assessed. Some have debated and speculated that Brazil's sugarcane ethanol program has caused (i) soil erosion and biodiversity problems by converting rainforests into sugarcane plantations and (ii) local air pollution problems as a result of burning in plantations before harvest. Also, as interest in biofuels heightens worldwide, environment-conscious practices are needed to avoid adverse environmental effects of biofuel production and use. For instance, if feedstock production (sugarcane in Brazil, corn in the United States, and palm oil in Malaysia for biodiesel production) moves into virgin or marginal land, carbon in both soil and vegetation could be decreased and diminish the benefits associated with biofuels, and cause other environmental problems, such as soil erosion. Societies need to pay close attention to these potential detrimental environmental effects to ensure that biofuel production will, indeed, be on a sustainable path. US Government References 1 Goldemberg J 2006 The ethanol program in Brazil Environ. Res Lett. 1 014008 doi:10.1088/1748-9326/1/1/014008 http://dx.doi.org/10.1088/1748-9326/1/1/014008 IMG http://ej.iop.org/images/1748-9326/1/1/011002/wangimg2.jpg Photo of Michael Wang Michael Wang has been working in the Center for Transportation Research of Argonne National Laboratory since 1991. He is the manager of the Systems Assessment Section in the center which evaluates energy and emission effects of advanced vehicle technologies and new transportation fuels. He developed the GREET (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) model, with which he has conducted several major studies for government agencies and industries. Since 1996, he has examined energy and emission benefits of bio-ethanol. His results for bio-ethanol have been cited by many. Michael Wang received his PhD in environmental science from University of California at Davis.

    Authors

    Wang, Michael

    Year Published

    2006

    Publication

    Environmental Research Letters

    Locations
      DOI

      10.1088/1748-9326/1/1/011002

      This article contributed by:

      Original

      Images of the energy futureMason, Arthur2006

      Images of the energy future

      Keywords

      energy forecasting, foresight planning, history of ideas

      Abstract

      This letter draws attention to the aesthetic fascination for images of the energy future and the role of knowledge about the future in organizing energy policy and planning. Envisioning the energy future, once intertwined with notions of progress, has become synonymous with conceptions of risk while efforts to manage risk are an open-ended, future-oriented project. I argue that today’s images of the energy future reflect a change in US energy prediction over the past 30 years that can be traced to the birth of a system of energy forecasting on the basis of a narrow organization of experience to the 1970s energy crisis.

      Authors

      Mason, Arthur

      Year Published

      2006

      Publication

      Environmental Research Letters

      Locations
        DOI

        10.1088/1748-9326/1/1/014002

        This article contributed by:

        Original

        Can there be science-based precaution?Weiss, Charles2006

        Can there be science-based precaution?

        Keywords

        precaution, science-based, risk management, standard of proof, reasonable belief, adaptive management, utility function, attitude toward risk, cost/benefit, legal principle, trade law, genetically modified crops

        Abstract

        'Science-based precaution' is possible in logic if not in politics, and should be a normal part of risk management. It should balance the risks and benefits of innovation, or equivalently, specify the price one is willing to pay to avoid risk. The Precaution Principle states that the absence of scientific proof does not preclude precautionary action—or, in its stronger version, that it requires such action. This principle is a useful counterweight to the insistence on rigorous scientific proof, but focuses on costs and risks to the exclusion of benefits. It expresses 'look before you leap', but not 'nothing ventured, nothing gained'. To facilitate adaptive management, we propose a complementary principle: 'precautionary action should not unreasonably interfere with innovation that promises major benefits, until its dangers and benefits are well understood'. In international trade law, we propose that scientific evidence presented in support of discriminatory measures that would otherwise violate the world trade regime—such as the de facto European Union moratorium on importing genetically modified crops—be required to suffice to support a 'reasonable belief' of danger to human health or the environment.

        Authors

        Weiss, Charles

        Year Published

        2006

        Publication

        Environmental Research Letters

        Locations
          DOI

          10.1088/1748-9326/1/1/014003

          This article contributed by:

          Original

          Risks of the oil transitionFarrell, A E2006

          Risks of the oil transition

          Keywords

          energy, climate change, unconventional petroleum, synfuels

          Abstract

          The energy system is in the early stages of a transition from conventionally produced oil to a variety of substitutes, bringing economic, strategic, and environmental risks. We argue that these three challenges are inherently interconnected, and that as we act to manage one we cannot avoid affecting our prospects in dealing with the others. We further argue that without appropriate policies, tradeoffs between these risks are likely to be made so as to allow increased environmental disruption in return for increased economic and energy security. Responsible solutions involve developing and deploying environmentally acceptable energy technologies (both supply and demand) rapidly enough to replace dwindling conventional oil production and meet growing demand for transportation while diversifying supply to improve energy security.

          Authors

          Farrell, A E and Brandt, A R

          Year Published

          2006

          Publication

          Environmental Research Letters

          Locations
            DOI

            10.1088/1748-9326/1/1/014004

            This article contributed by:

            Original

            The Bodélé depression: a single spot in the Sahara that provides most of the mineral dust to the Amazon forestKoren, Ilan2006

            The Bodélé depression: a single spot in the Sahara that provides most of the mineral dust to the Amazon forest

            Keywords

            Sahara, Amazon, dust, aerosols, rainforest, fertilization

            Abstract

            About 40 million tons of dust are transported annually from the Sahara to the Amazon basin. Saharan dust has been proposed to be the main mineral source that fertilizes the Amazon basin, generating a dependence of the health and productivity of the rain forest on dust supply from the Sahara. Here we show that about half of the annual dust supply to the Amazon basin is emitted from a single source: the Bodélé depression located northeast of Lake Chad, approximately 0.5% of the size of the Amazon or 0.2% of the Sahara. Placed in a narrow path between two mountain chains that direct and accelerate the surface winds over the depression, the Bodélé emits dust on 40% of the winter days, averaging more than 0.7 million tons of dust per day

            Authors

            Koren, Ilan, Kaufman, Yoram J, Washington, Richard, Todd, Martin C, Rudich, Yinon, Martins, J Vanderlei and Rosenfeld, Daniel

            Year Published

            2006

            Publication

            Environmental Research Letters

            Locations
            DOI

            10.1088/1748-9326/1/1/014005

            This article contributed by:

            Original

            Talk of the city: engaging urbanites on climate changeMoser, Susanne C2006

            Talk of the city: engaging urbanites on climate change

            Keywords

            climate change, communication, social change, urban residents

            Abstract

            Climate change requires societal engagement on both mitigation and adaptation. With a growing majority of people living in cities, urban dwellers and municipal decision-makers will need to reduce their emissions and other impacts on the regional and global climate while dealing with the unavoidable near-term and potential longer-term impacts of climate change. To facilitate effective societal response to climate change, a busy, distracted, and so far only marginally interested public needs to be engaged on the topic. This poses significant challenges to communication and sustained outreach efforts. This letter draws on critical insights from a three-year multi-disciplinary project that involved academics and practitioners from various disciplines and sectors of (mostly US) society and explored how to communicate climate change in ways that facilitate societal response. The letter raises questions about key audiences, appropriate messengers, framings and messages, reception of climate change information, and the choice of communication mediums and formats to achieve different communication and engagement goals.

            Authors

            Moser, Susanne C

            Year Published

            2006

            Publication

            Environmental Research Letters

            Locations
              DOI

              10.1088/1748-9326/1/1/014006

              This article contributed by:

              Original

              Recent Articles

              Higher Subsoil Carbon Storage in Species-Rich than Species-Poor Temperate Forests

              by Schleuß, Per-Marten, Heitkamp, Felix, Leuschner, Christoph, Fender, Ann-Catrin and Jungkunst, Hermann F

              Forest soils contribute ca. 70% to the global soil organic carbon (SOC) pool and thus are an important element of the global carbon cycle. Forests also harbour a large part of the global terrestrial biodiversity. It is not clear, however, whether tree species diversity affects SOC. By measuring the carbon concentration of different soil particle size fractions separately, we were able to distin...

              published 2014 in Environmental Research Letters

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              published 2014 in Environmental Research Letters