Glacier response to current climate change and future scenarios in the northwestern Italian Alps

We analyze longtime series of annual snout positions of several valley glaciers in the northwestern Italian Alps, together with a high-resolution gridded dataset of temperature and precipitation available for the last 50 years. Glacier snout fluctuations are on average negative during this time span, albeit with a period of glacier advance between about 1970 and 1990. To determine which climatic variables best correlate with glacier snout fluctuations, we consider a large set of seasonal predictors, based on our climatic dataset, and determine the most significant drivers by a stepwise regression technique. This in-depth screening indicates that the average glacier snout fluctuations strongly respond to summer temperature and winter precipitation variations, with a delay of 5 and 10 year, respectively. Snout fluctuations display also a significant (albeit weak) response to concurrent (same year) spring temperature and precipitation conditions. A linear regressive model based on these four climatic variables explains up to 93 % of the variance, which becomes 89 % when only the two delayed variables are taken into account. When employed for out-of-sample projections, the empirical model displays high prediction skill, and it is thus used to estimate the average glacier response to different climate change scenarios (RCP4.5, RCP8.5, A1B), using both global and regional climate models. In all cases, glacier snout fluctuations display a negative trend, and the glaciers of this region display an accelerated retreat, leading to a further regression of the snout position. By 2050, the retreat is estimated to be between about 300 and 400 m with respect to the current position. Glacier regression is more intense for the RCP8.5 and A1B scenarios, as it could be expected from the higher severity of these emission pathways.     

Characterization of chlordecone-tolerant fungal populations isolated from long-term polluted tropical volcanic soil in the French West Indies

The insecticide chlordecone is a contaminant found in most of the banana plantations in the French West Indies. This study aims to search for fungal populations able to grow on it. An Andosol heavily contaminated with chlordecone, perfused for 1 year in a soil–charcoal system, was used to conduct enrichment cultures. A total of 103 fungal strains able to grow on chlordecone-mineral salt medium were isolated, purified, and deposited in the MIAE collection (Microorganismes d'Intérêt Agro-Environnemental, UMR Agroécologie, Institut National de la Recherche Agronomique, Dijon, France). Internal transcribed spacer sequencing revealed that all isolated strains belonged to the Ascomycota phylum and gathered in 11 genera: Metacordyceps, Cordyceps, Pochonia, Acremonium, Fusarium, Paecilomyces, Ophiocordyceps, Purpureocillium, Bionectria, Penicillium, and Aspergillus. Among predominant species, only one isolate, Fusarium oxysporum MIAE01197, was able to grow in a liquid culture medium that contained chlordecone as sole carbon source. Chlordecone increased F. oxysporum MIAE01197 growth rate, attesting for its tolerance to this organochlorine. Moreover, F. oxysporum MIAE01197 exhibited a higher EC₅₀ value than the reference strain F. oxysporum MIAE00047. This further suggests its adaptation to chlordecone tolerance up to 29.2 mg l^?1. Gas chromatography–mass spectrometry (GC-MS) analysis revealed that 40 % of chlordecone was dissipated in F. oxysporum MIAE01197 suspension culture. No chlordecone metabolite was detected by GC-MS. However, weak amount of ¹⁴CO₂ evolved from ¹⁴C₁₀-chlordecone and ¹⁴C₁₀-metabolites were observed. Sorption of ¹⁴C₁₀-chlordecone onto fungal biomass followed a linear relationship (r ²?=?0.99) suggesting that it may also account for chlordecone dissipation in F. oxysporum MIAE01197 culture.     

Farming adaptation to environmental change in coastal Bangladesh: shrimp culture versus crop diversification

Farming in coastal Bangladesh includes rice/shrimp and rice/non-rice cropping systems. The former has been highly profitable but has exacerbated salinization of soil and water. We evaluate the relative profitability, riskiness, and sustainability of the two cropping systems, using data from two coastal villages in Khulna District. Shrimp cultivation was initially very rewarding. However, over 12–15 years, the cropping system experienced declining profitability, increased salinity, and adverse impacts on rice cropping and the local environment. From 2009, farmers adapted the system by changing the pond (gher) infrastructure, adopting delayed planting of a saline-tolerant rice cultivar, flushing out accumulated salt with freshwater during rice cropping, and allowing the soil to dry out after harvesting rice. The budgeting results show that with current management practices, the rice/shrimp system is economically more viable (higher returns to land and labour and less risky) than the rice/non-rice system. Soil analyses showed that while salinity was higher in the gher during the dry season, it was significantly reduced in the wet season and was very similar between the two systems (1–2 dS/m). Hence, as well as being more profitable and less risky, the rice/shrimp system may well be more sustainable than previously observed.     

Linking local impacts to changes in climate: a guide to attribution

Assessing past impacts of observed climate change on natural, human and managed systems requires detailed knowledge about the effects of both climatic and other drivers of change, and their respective interaction. Resulting requirements with regard to system understanding and long-term observational data can be prohibitive for quantitative detection and attribution methods, especially in the case of human systems and in regions with poor monitoring records. To enable a structured examination of past impacts in such cases, we follow the logic of quantitative attribution assessments, however, allowing for qualitative methods and different types of evidence. We demonstrate how multiple lines of evidence can be integrated in support of attribution exercises for human and managed systems. Results show that careful analysis can allow for attribution statements without explicit end-to-end modeling of the whole climate-impact system. However, care must be taken not to overstate or generalize the results and to avoid bias when the analysis is motivated by and limited to observations considered consistent with climate change impacts.     

The effect of glyphosate on the growth and competitive effect of perennial grass species in semi-natural grasslands

Biodiversity within European semi-natural biotopes in agro-ecosystem is declining, and herbicide drift from neighbouring fields is considered as an important factor for the decline. The aim of the present study was to investigate whether the growth and competitive interactions in a model system of two perennial grass species, Festuca ovina and Agrostis capillaris, are affected by sub-lethal doses of glyphosate in field margins. In a glasshouse experiment with ample nitrogen, the interspecific competitive interactions were found to be significantly affected by glyphosate; the competitive effect of F. ovina on A. capillaris increased and the competitive effect of A. capillaris on F. ovina decreased with increasing doses of glyphosate. Furthermore, the importance of interspecific competition increased with the glyphosate dose. The results of the study of competitive interactions are in agreement with the observed plant community dynamics at the field site where F. ovina was found to be more dominant in plots treated with a relatively high dose of glyphosate. Importantly, the effects of glyphosate on the plant community dynamics critically depended on the effect of glyphosate on the plant competitive interactions. The study concludes that the current practice in the environmental risk assessment of non-target effects of herbicides, where single species are tested in the greenhouse, may be inadequate for assessing the effect of herbicides in semi-natural plant communities. The presented methods can be used for assessing the importance of competitive interactions for the sensitivity of non-target plants to herbicides in risk assessment.     

Acetylcholinesterase in honey bees (Apis mellifera) exposed to neonicotinoids, atrazine and glyphosate: laboratory and field experiments

In Québec, as observed globally, abnormally high honey bee mortality rates have been reported recently. Several potential contributing factors have been identified, and exposure to pesticides is of increasing concern. In maize fields, foraging bees are exposed to residual concentrations of insecticides such as neonicotinoids used for seed coating. Highly toxic to bees, neonicotinoids are also reported to increase AChE activity in other invertebrates exposed to sub-lethal doses. The purpose of this study was therefore to test if the honey bee’s AChE activity could be altered by neonicotinoid compounds and to explore possible effects of other common products used in maize fields: atrazine and glyphosate. One week prior to pollen shedding, beehives were placed near three different field types: certified organically grown maize, conventionally grown maize or non-cultivated. At the same time, caged bees were exposed to increasing sub-lethal doses of neonicotinoid insecticides (imidacloprid and clothianidin) and herbicides (atrazine and glyphosate) under controlled conditions. While increased AChE activity was found in all fields after 2 weeks of exposure, bees close to conventional maize crops showed values higher than those in both organic maize fields and non-cultivated areas. In caged bees, AChE activity increased in response to neonicotinoids, and a slight decrease was observed by glyphosate. These results are discussed with regard to AChE activity as a potential biomarker of exposure for neonicotinoids.     

Guidance for the Performance Evaluation of Three-Dimensional Air Quality Modeling Systems for Particulate Matter and Visibility

ABSTRACT

Guidance for the performance evaluation of three-dimensional air quality modeling systems for particulate matter and visibility is presented. Four levels are considered: operational, diagnostic, mechanistic, and probabilistic evaluations. First, a comprehensive model evaluation should be conducted in at least two distinct geographical locations and for several meteorological episodes. Next, streamlined evaluations can be conducted for other similar applications if the comprehensive evaluation is deemed satisfactory. In all cases, the operational evaluation alone is insufficient, and some diagnostic evaluation must always be carried out. Recommendations are provided for designing field measurement programs that can provide the data needed for such model performance evaluations.     

Study of the Relationship of Distant SO2 Emissions to Dallas-Fort Worth Winter Haze

ABSTRACT

A study was conducted to estimate the changes in wintertime visual air quality in Dallas-Fort Worth (DFW) that might occur due to proposed reductions in SO₂ emissions at two steam electric generating plants in eastern Texas, each over 100 km from the city. To provide information for designing subsequent investigations, the haze was characterized broadly during the first year of the study. Meteorological data acquired then demonstrated that, during haze episodes, emissions from only one of the two plants were likely to be transported directly to DFW. Therefore, the second year of the study was centered on just one of the power plants. Air quality was then characterized within the urban area and at rural locations that would be upwind and downwind of the plant during transport to DFW. An instrumented aircraft measured plume dispersion and the air surrounding the plume on selected days. A mathematical model was used to predict the change that would occur in airborne particulate matter concentrations in DFW if SO₂ emissions were reduced to reflect the proposed limitations. The contribution of particles in the atmosphere to light extinction was estimated, and simulated photographs were produced to illustrate the visibility changes. The study concluded that the proposed emission reductions would, at most, subtly change perceived wintertime visibility.     

A Thermal Desorption Procedure for Determining Residual Blowing Agent (CFC-11) in Rigid Foam

A method for measuring the cell gas content in rigid foams has been developed. A unique foam extraction device and a thermal desorption system were developed to expedite gas extraction and analysis. CFC-11 found by this method was in excellent agreement with the calculated value in a commercially formulated foam (7.1 versus 7.8 percent). Average method precision (i.e., relative standard deviation) from processing nine foam samples (in duplicate) was 1.9 percent. The method has also been successfully applied to foams containing non-GFC blowing agents.     

Distribution of Hg,As and Se in material and flue gas streams from preheater–precalciner cement kilns and vertical shaft cement kilns in China

The aim of this study was to evaluate the behavior of Hg, As, and Se in cement production. Two types of cement plants were studied, including the vertical shaft kiln (VSK) and preheater–precalciner kiln (PPK) processes. Determination of Hg, As, and Se in the main material and gas streams were performed. It was found that recycling of particulate matter captured by an air pollution control device caused a significant enrichment of Hg and As inside both processes. The total quantity of Hg entering the process and the quantity emitted to the atmosphere were found to be 10–109 and 6.3–38 mg, respectively, per ton of clinker produced. The average Hg emission was calculated to be around 41% of the total mercury input. The emissions found complied with the European Union (EU) limit and exceeded partly the U.S. limit. Furthermore, it was found that oxidized mercury was the dominant species in the PPK process, whereas the reduced form was dominant in the VSK process, due to the oxidizing and reducing gas conditions, respectively. Regarding the distribution of As and Se, the major amounts were bound to the solid materials, that is, cement clinker and particulate matter. Based on cement production data in China in 2013, the annual emissions of Hg and As were estimated to be in the range of 8.6–52 and 4.1–9.5 tons, respectively.

Implications: There are fairly limited studies on Hg, As, and Se measurements from cement manufacturing facilities in China, and even more limited studies on the behavior in vertical shaft kilns. The needs for increased emission reduction efforts in energy-intensive industries are globally recognized, and an improved understanding of the processes ongoing in a cement kilns system is decisive. Since the processes are complex and almost impossible to recreate in the laboratory, field measurements are indeed important. The findings in the present study were solely based on field measurements and the data are considered to be valuable for the further development of emission reduction technology.