In the last 30 days

• Open/close Geoengineering by cloud seeding: influence on sea ice and climate system

  Philip J Rasch et al  2009 Environ. Res. Lett. 4 045112 Tag this article

  Article References Full text PDF (1.52 MB) View as HTML

  General circulation model computations using a fully coupled ocean–atmosphere model indicate that increasing cloud reflectivity by seeding maritime boundary layer clouds with particles made from seawater may compensate for some of the effects on climate of increasing greenhouse gas concentrations. The chosen seeding strategy (one of many possible scenarios) can restore global averages of temperature, precipitation and sea ice to present day values, but not simultaneously. The response varies nonlinearly with the extent of seeding, and geoengineering generates local changes to important climatic features. The global tradeoffs of restoring ice cover, and cooling the planet, must be assessed alongside the local changes to climate features.

• Open/close Energy implications of bottled water

  P H Gleick and H S Cooley  2009 Environ. Res. Lett. 4 014009 Tag this article

  Article References Full text PDF (388 KB) View as HTML

  As bottled water use continues to expand around the world, there is growing interest in the environmental, economical, and social implications of that use, including concerns about waste generation, proper use of groundwater, hydrologic effects on local surface and groundwater, economic costs, and more. A key concern is how much energy is required to produce and use bottled water. This paper estimates the energy footprint required for various phases of bottled water production, transportation, and use. We do not develop a single comprehensive life-cycle energy estimate because of differences among water sources, bottling processes, transportation costs, and other factors, but we quantify key energy inputs necessary for site-specific assessments. We also apply these inputs to three site-specific examples of the energy required from production to the point of use: local bottled water produced and used in Los Angeles, water bottled in the South Pacific and shipped by cargo ship to Los Angeles, and water bottled in France and shipped in various ways to Los Angeles. For water transported short distances, the energy requirements of bottled water are dominated by the energy used to produce the plastic bottles. Long-distance transport, however, can lead to energy costs comparable to, or even larger than, those of producing the bottle. All other energy costs—for processing, bottling, sealing, labeling, and refrigeration—are far smaller than those for the production of the bottle and transportation. These data can be used to generate specific estimates for different sources, treatments, and delivery options.

• Open/close Mamizu climate policy: an evaluation of Japanese carbon emissions reduction targets

  Roger A Pielke Jr  2009 Environ. Res. Lett. 4 044001 Tag this article

  Article References Full text PDF (614 KB) View as HTML

  This letter evaluates Japan's so-called 'Mamizu' climate policies proposed in mid-2009 in terms of the implied rates of decarbonization of the Japanese economy for short-term and long-term targets. The letter uses the Kaya identity to structure the evaluation, employing both a bottom up approach (based on projections of future Japanese population, economic growth, and technology) and a top down approach (deriving implied rates of decarbonization consistent with the targets and various rates of economic growth). Both approaches indicate that the Japanese economy would have to achieve rates of decarbonization of 2.6% to meet a 2020 target of reducing emissions by 15% below 2005 levels, and 5.0% to meet a 2050 target of an 80% reduction below 2005 levels. A target of 25% below 1990 emissions proposed by the opposition party (which subsequently formed a government following elections in August 2009) implies a rate of decarbonization of 4.6% annually to 2020. The letter argues that international criticism of Japanese Mamizu climate policy proposals as being too weak was unfounded, and if anything, the proposals may have been too ambitious. In either case, climate policy would be strengthened through the support of a diversity of approaches to decarbonization.

• Open/close A second hydrocarbon boom threatens the Peruvian Amazon: trends, projections, and policy implications

  Matt Finer and Martí Orta-Martínez  2010 Environ. Res. Lett. 5 014012 Tag this article

  Article References Full text PDF (1.53 MB) View as HTML

  The Peruvian Amazon is home to extraordinary biological and cultural diversity, and vast swaths of this mega-diverse region remain largely intact. Recent analysis indicates, however, that the rapid proliferation of oil and gas exploration zones now threatens the region's biodiversity, indigenous peoples, and wilderness areas. To better elucidate this dynamic situation, we analyzed official Peruvian government hydrocarbon information and generated a quantitative analysis of the past, present, and future of oil and gas activities in the Peruvian Amazon. We document an extensive hydrocarbon history for the region—over 104 000 km of seismic lines and 679 exploratory and production wells—highlighted by a major exploration boom in the early 1970s. We show that an unprecedented 48.6% of the Peruvian Amazon has been recently covered by oil and gas concessions, up from just 7.1% in 2003. These oil and gas concessions overlap 17.1% of the Peruvian Amazon protected area system and over half of all titled indigenous lands. Moreover, we found that up to 72% of the Peruvian Amazon has been zoned for hydrocarbon activities (concessions plus technical evaluation agreements and proposed concessions) in the past two years, and over 84% at some point during the past 40 years. We project that the recent rapid proliferation of hydrocarbon zones will lead to a second exploration boom, characterized by over 20 000 km of new seismic testing and construction of over 180 new exploratory wells in remote, intact, and sensitive forest areas. As the Peruvian Amazon oil frontier rapidly expands, we conclude that a rigorous policy debate is urgently needed in order to avoid the major environmental impacts associated with the first exploration boom of the 1970s and to minimize the social conflict that recently led to deadly encounters between indigenous protesters and government forces.

• Open/close Aerosol–cloud interactions—a challenge for measurements and modeling at the cutting edge of cloud–climate interactions

  Peter Spichtinger and Daniel J Cziczo  2008 Environ. Res. Lett. 3 025002 Tag this article

  Article References Full text PDF (25 KB)

  Research in aerosol properties and cloud characteristics have historically been considered two separate disciplines within the field of atmospheric science. As such, it has been uncommon for a single researcher, or even research group, to have considerable expertise in both subject areas. The recent attention paid to global climate change has shown that clouds can have a considerable effect on the Earth's climate and that one of the most uncertain aspects in their formation, persistence, and ultimate dissipation is the role played by aerosols. This highlights the need for researchers in both disciplines to interact more closely than they have in the past. This is the vision behind this focus issue of Environmental Research Letters.

  Certain interactions between aerosols and clouds are relatively well studied and understood. For example, it is known that an increase in the aerosol concentration will increase the number of droplets in warm clouds, decrease their average size, reduce the rate of precipitation, and extend the lifetime. Other effects are not as well known. For example, persistent ice super-saturated conditions are observed in the upper troposphere that appear to exceed our understanding of the conditions required for cirrus cloud formation. Further, the interplay of dynamics versus effects purely attributed to aerosols remains highly uncertain. The purpose of this focus issue is to consider the current state of knowledge of aerosol/cloud interactions, to define the contemporary uncertainties, and to outline research foci as we strive to better understand the Earth's climate system.

  This focus issue brings together laboratory experiments, field data, and model studies. The authors address issues associated with warm liquid water, cold ice, and intermediate temperature mixed-phase clouds. The topics include the uncertainty associated with the effect of black carbon and organics, aerosol types of anthropogenic interest, on droplet and ice formation. Phases of water which have not yet been fully defined, for example cubic ice, are considered. The impact of natural aerosols on clouds, for example mineral dust, is also discussed, as well as other natural but highly sensitive effects such as the Wegener–Bergeron–Findeisen process.

  It is our belief that this focus issue represents a leap forward not only in reducing the uncertainty associated with the interaction of aerosols and clouds but also a new link between groups that must work together to continue progress in this important area of climate science.

  Focus on Aerosol–Cloud Interactions Contents

  The global influence of dust mineralogical composition on heterogeneous ice nucleation in mixed-phase clouds
  C Hoose, U Lohmann, R Erdin and I Tegen

  Ice formation via deposition nucleation on mineral dust and organics: dependence of onset relative humidity on total particulate surface area
  Zamin A Kanji, Octavian Florea and Jonathan P D Abbatt

  The Explicit-Cloud Parameterized-Pollutant hybrid approach for aerosol–cloud interactions in multiscale modeling framework models: tracer transport results
  William I Gustafson Jr, Larry K Berg, Richard C Easter and Steven J Ghan

  Cloud effects from boreal forest fire smoke: evidence for ice nucleation from polarization lidar data and cloud model simulations
  Kenneth Sassen and Vitaly I Khvorostyanov

  The effect of organic coating on the heterogeneous ice nucleation efficiency of mineral dust aerosols
  O Möhler, S Benz, H Saathoff, M Schnaiter, R Wagner, J Schneider, S Walter, V Ebert and S Wagner

  Enhanced formation of cubic ice in aqueous organic acid droplets
  Benjamin J Murray

  Quantification of water uptake by soot particles
  O B Popovicheva, N M Persiantseva, V Tishkova, N K Shonija and N A Zubareva

  Meridional gradients of light absorbing carbon over northern Europe
  D Baumgardner, G Kok, M Krämer and F Weidle

  MAID: a model to simulate UT/LS aerosols and ice clouds
  H Bunz, S Benz, I Gensch and M Krämer

  Single-parameter estimates of aerosol water content
  S M Kreidenweis, M D Petters and P J DeMott

  Supersaturations, microphysics and nitric acid partitioning in a cold cirrus cloud observed during CR-AVE 2006: an observation–modelling intercomparison study
  I V Gensch, H Bunz, D G Baumgardner, L E Christensen, D W Fahey, R L Herman, P J Popp, J B Smith, R F Troy, C R Webster, E M Weinstock, J C Wilson, T Peter and M Krämer

  Connecting hygroscopic growth at high humidities to cloud activation for different particle types
  H Wex, F Stratmann, T Hennig, S Hartmann, D Niedermeier, E Nilsson, R Ocskay, D Rose, I Salma and M Ziese

  Modeling of the Wegener–Bergeron–Findeisen process—implications for aerosol indirect effects
  T Storelvmo, J E Kristjánsson, U Lohmann, T Iversen, A Kirkevåg and Ø Seland

  Droplet nuclei in non-precipitating clouds: composition and size matter
  Cynthia H Twohy and James R Anderson

  A laboratory investigation of the relative humidity dependence of light extinction by organic compounds from lignin combustion
  Melinda R Beaver, Rebecca M Garland, Christa A Hasenkopf, Tahllee Baynard, A R Ravishankara and Margaret A Tolbert

  Cirrus cloud formation and ice supersaturated regions in a global climate model
  Ulrike Lohmann, Peter Spichtinger, Stephanie Jess, Thomas Peter and Herman Smit

  Notes on state-of-the-art investigations of aerosol effects on precipitation: a critical review
  A P Khain

• Open/close A new emission inventory for nonagricultural open fires in Asia from 2000 to 2009

  Yu Song et al  2010 Environ. Res. Lett. 5 014014 Tag this article

  Article References Full text PDF (426 KB) View as HTML

  Open fires play a significant role in atmospheric pollution and climatic change. This work aims to develop an emission inventory for nonagricultural open fires in Asia using the newly released MODIS (Moderate Resolution Imaging Spectroradiometer) burned area product (MCD45A1), as the MODIS sensor cannot efficiently detect field crop residue burning. Country-level or province-specific biomass density data were used as fuel loads. Moisture contents were taken into account when calculating combustion factors for grass fuel. During the nine fire years 2000–2008, both burned areas and fire emissions clearly presented spatial and seasonal variations. Extensive nonagricultural open fires were concentrated in the months of February and March, while another peak was between August and October. Indonesia was the most important contributor to fire emission, which was largely attributable to peat burning. Myanmar, India, and Cambodia together contributed approximately half of the total burned area and emission. The annual emissions for CO ₂, CO, CH ₄, NMHC _s, NO _x , NH ₃, SO ₂, BC, OC, PM _2.5, and PM ₁₀ were 83 (69–103), 6.1 (4.6–8.2), 0.38 (0.24–0.57), 0.64 (0.36–1.0), 0.085 (0.074–0.10), 0.31 (0.17–0.48), 0.030 (0.024–0.037), 0.023 (0.020–0.028), 0.27 (0.22–0.33), 2.0 (1.6–2.6), and 2.2 (1.7–2.9) Tg yr ^{− 1}, respectively. This inventory has a daily temporal resolution and 500 m spatial resolution, and covers a long period, from April 2000 to February 2009. It could be used in global and regional air quality modeling.

• Open/close Life-cycle energy and greenhouse gas emission impacts of different corn ethanol plant types

  Michael Wang et al  2007 Environ. Res. Lett. 2 024001 Tag this article

  Article References Full text PDF (606 KB) View as HTML

  Since the United States began a programme to develop ethanol as a transportation fuel, its use has increased from 175 million gallons in 1980 to 4.9 billion gallons in 2006. Virtually all of the ethanol used for transportation has been produced from corn. During the period of fuel ethanol growth, corn farming productivity has increased dramatically, and energy use in ethanol plants has been reduced by almost by half. The majority of corn ethanol plants are powered by natural gas. However, as natural gas prices have skyrocketed over the last several years, efforts have been made to further reduce the energy used in ethanol plants or to switch from natural gas to other fuels, such as coal and wood chips. In this paper, we examine nine corn ethanol plant types—categorized according to the type of process fuels employed, use of combined heat and power, and production of wet distiller grains and solubles. We found that these ethanol plant types can have distinctly different energy and greenhouse gas emission effects on a full fuel-cycle basis. In particular, greenhouse gas emission impacts can vary significantly—from a 3% increase if coal is the process fuel to a 52% reduction if wood chips are used. Our results show that, in order to achieve energy and greenhouse gas emission benefits, researchers need to closely examine and differentiate among the types of plants used to produce corn ethanol so that corn ethanol production would move towards a more sustainable path.

• Open/close Economic and environmental evaluation of compressed-air cars

  Felix Creutzig et al  2009 Environ. Res. Lett. 4 044011 Tag this article

  Article References Full text PDF (603 KB) View as HTML

  Climate change and energy security require a reduction in travel demand, a modal shift, and technological innovation in the transport sector. Through a series of press releases and demonstrations, a car using energy stored in compressed air produced by a compressor has been suggested as an environmentally friendly vehicle of the future. We analyze the thermodynamic efficiency of a compressed-air car powered by a pneumatic engine and consider the merits of compressed air versus chemical storage of potential energy. Even under highly optimistic assumptions the compressed-air car is significantly less efficient than a battery electric vehicle and produces more greenhouse gas emissions than a conventional gas-powered car with a coal intensive power mix. However, a pneumatic–combustion hybrid is technologically feasible, inexpensive and could eventually compete with hybrid electric vehicles.

• Open/close Monitoring and estimating tropical forest carbon stocks: making REDD a reality

  Holly K Gibbs et al  2007 Environ. Res. Lett. 2 045023 Tag this article

  Article References Full text PDF (614 KB) View as HTML

  Reducing carbon emissions from deforestation and degradation in developing countries is of central importance in efforts to combat climate change. Key scientific challenges must be addressed to prevent any policy roadblocks. Foremost among the challenges is quantifying nations' carbon emissions from deforestation and forest degradation, which requires information on forest clearing and carbon storage. Here we review a range of methods available to estimate national-level forest carbon stocks in developing countries. While there are no practical methods to directly measure all forest carbon stocks across a country, both ground-based and remote-sensing measurements of forest attributes can be converted into estimates of national carbon stocks using allometric relationships. Here we synthesize, map and update prominent forest biomass carbon databases to create the first complete set of national-level forest carbon stock estimates. These forest carbon estimates expand on the default values recommended by the Intergovernmental Panel on Climate Change's National Greenhouse Gas Inventory Guidelines and provide a range of globally consistent estimates.

• Open/close Environmental assessment of passenger transportation should include infrastructure and supply chains

  Mikhail V Chester and Arpad Horvath  2009 Environ. Res. Lett. 4 024008 Tag this article

  Article References Full text PDF (1.12 MB) View as HTML

  To appropriately mitigate environmental impacts from transportation, it is necessary for decision makers to consider the life-cycle energy use and emissions. Most current decision-making relies on analysis at the tailpipe, ignoring vehicle production, infrastructure provision, and fuel production required for support. We present results of a comprehensive life-cycle energy, greenhouse gas emissions, and selected criteria air pollutant emissions inventory for automobiles, buses, trains, and airplanes in the US, including vehicles, infrastructure, fuel production, and supply chains. We find that total life-cycle energy inputs and greenhouse gas emissions contribute an additional 63% for onroad, 155% for rail, and 31% for air systems over vehicle tailpipe operation. Inventorying criteria air pollutants shows that vehicle non-operational components often dominate total emissions. Life-cycle criteria air pollutant emissions are between 1.1 and 800 times larger than vehicle operation. Ranges in passenger occupancy can easily change the relative performance of modes.