Global change: state of the science

Only recently, within a few decades, have we realized that humanity significantly influences the global environment. In the early 1980s, atmospheric measurements confirmed basic concepts developed a decade earlier. These basic concepts showed that human activities were affecting the ozone layer. Later measurements and theoretical analyses have clearly connected observed changes in ozone to human-related increases of chlorine and bromine in the stratosphere. As a result of prompt international policy agreements, the combined abundances of ozone-depleting compounds peaked in 1994 and ozone is already beginning a slow path to recovery. A much more difficult problem confronting humanity is the impact of increasing levels of carbon dioxide and other greenhouse gases on global climate. The processes that connect greenhouse gas emissions to climate are very complex. This complexity has limited our ability to make a definitive projection of future climate change. Nevertheless, the range of projected climate change shows that global warming has the potential to severely impact human welfare and our planet as a whole. This paper evaluates the state of the scientific understanding of the global change issues, their potential impacts, and the relationships of scientific understanding to policy considerations.     

Climate risk insurance in Pacific Small Island Developing States: possibilities,challenges and vulnerabilities—a comprehensive review

Climate change has become one of the most compelling fields of empirical research over the last couple of decades, partly due to its socio-economic impacts. Using a meta-analysis of 235 peer-reviewed articles published between January 2010 and July 2020, this paper appraises climate change adaptation (CCA) research in Nepal and draws lessons for future adaptation planning. The number of research is observed to have increased significantly in recent years (2015–2020) although there is no consistent pattern over the review period and at the thematic level. Findings submit that the agriculture and food security has the highest number of publications (37%) followed by gender equality and social inclusion (18%) and forest, biodiversity and watershed management (16%). There are no studies found in rural and urban settlement theme. Geographic distribution of CCA studies revealed that over 40% studies were carried out from central Nepal, while no study was conducted in ten districts of eastern and western Nepal. The study focus was also discrete, and the perception and attitude and impact assessment of climate change were common agendas; however, the drivers of change and options for adaptation were understudied. CCA with multipronged initiatives provide a broader understanding of dynamics and governance of climate change that not only affects rural livelihoods, but also influences regional and global environments and biodiversity.

     

Implementation of water safety plan for a large-piped water supply system

A water safety plan for the city of Nagpur was developed by the National Environmental Engineering Research Institute (NEERI) and Nagpur Municipal Corporation (NMC). Possible hazards were identified through field visits. Based on this, an improvement plan was drawn up to suggest corrective actions and a time frame for implementation. The findings of this study are being used to modify or repair components of the water supply system and upgrade management procedures. This paper highlights the lessons learnt during implementation of the WSP and the key challenges faced.     

Functional and phylogenetic diversity as predictors of biodiversity--ecosystem-function relationships

How closely does variability in ecologically important traits reflect evolutionary divergence? The use of phylogenetic diversity (PD) to predict biodiversity effects on ecosystem functioning, and more generally the use of phylogenetic information in community ecology, depends in part on the answer to this question. However, comparisons of the predictive power of phylogenetic diversity and functional diversity (FD) have not been conducted across a range of experiments. To address how phylogenetic diversity and functional trait variation control biodiversity effects on biomass production, we summarized the results of 29 grassland plant experiments where both the phylogeny of plant species used in the experiments is well described and where extensive trait data are available. Functional trait variation was only partially related to phylogenetic distances between species, and the resulting FD values therefore correlate only partially with PD. Despite these differences, FD and PD predicted biodiversity effects across all experiments with similar strength, including in subsets that excluded plots with legumes and that focused on fertilization experiments. Two- and three-trait combinations of the five traits used here (leaf nitrogen percentage, height, specific root length, leaf mass per unit area, and nitrogen fixation) resulted in the FD values with the greatest predictive power. Both PD and FD can be valuable predictors of the effect of biodiversity on ecosystem functioning, which suggests that a focus on both community trait diversity and evolutionary history can improve understanding of the consequences of biodiversity loss.     

Biodiversity conservation through a traditional beliefs system in Indian Himalaya: a case study from Nakuleshwar sacred grove

Sacred groves are well recognized in the world in terms of biodiversity conservation. The present study was conducted in the Nakuleshwar sacred grove, in the valley of Thal kedar hill in the Kumaon region of Pithoragarh district in Indian Himalaya, in appreciation of its role in biodiversity conservation. The study aimed at the documentation and inventory of the sacred grove, its phytodiversity, threats and conservation in the Himalayan region, and to achieve this, systematic field surveys were conducted during 2007?C2010 covering all four seasons. A total of 83 species from 71 genera and 50 families were identified, of which 43 species are flowering plants, including 7 trees, 7 shrubs, 4 climbers and 25 herbs, and 40 species are non-flowering plants of which lichens are represented by 12 species from 8 genera, bryophytes 6 species from 5 genera, and pteridophytes 7 species from 9 genera, while gymnosperms are represented by a single species. Acer oblongum, Cinnamomum tamala, Cedrus deodara, Coriaria nepalensis act as keystone species in the grove. Ophiopogon inermis is a common herb during the rainy season while Goodyera hemsleyana (Orchid) is a new distribution record for the western Himalaya. A total of 43 species from 38 genera are used ethnobotanically by local people for various ailments. Mahonia nepaulensis, Asparagus adscendens, Thalictrum foliolosum, Cinnamomum tamala and Berberis asiatica are highly exploited species and need to be conserved. Climatic conditions of the grove are moderate and the floristic patch of the grove is completely different from the plant diversity of the surrounding area and matches with the diversified floral wealth of comparatively higher altitudes. Due to anthropogenic pressure, this grove is facing new threats of degradation, hence needing special attention.     

Past climate, future perspective: an exploratory analysis using climate proxies and drought risk assessment to inform water resources management and policy in Maine, USA

In recent decades, significant progress has been made toward reconstructing the past climate record based on environmental proxies, such as tree rings and ice core records. However, limited examples of research that utilizes such data for water resources decision-making and policy exist. Here, we use the reconstructed record of Palmer Drought Severity Index (PDSI), dating back to 1138AD to understand the nature of drought occurrence (severity and duration) in the state of Maine. This work is motivated by the need to augment the scientific basis to support the water resources management and the emerging water allocation framework in Maine (Maine Department of Environmental Protection, Chapter 587). Through a joint analysis of the reconstructed PDSI and historical streamflow record for twelve streams in the state of Maine, we find that: (a) the uncertainties around the current definition of natural drought in the Chapter 587 (based on the 20th century instrumental record) can be better understood within the context of the nature and severity of past droughts in this region, and (b) a drought index provides limited information regarding at-site hydrologic variations. To fill this knowledge gap, a drought index-based risk assessment methodology for streams across the state is developed. Based on these results, the opportunities for learning and challenges facing water policies in a changing hydroclimate are discussed.     

Arsenic toxicity in crop plants: physiological effects and tolerance mechanisms

Heavy metals are toxic substances released into the environment, contributing to a variety of toxic effects on living organisms in food chain by accumulation and biomagnifications. Certain pollutants such as arsenic (As) remain in the environment for an extensive period. They eventually accumulate to levels that could harm physiochemical properties of soils and lead to loss of soil fertility and crop yield. Arsenic, when not detoxified, may trigger a sequence of reactions leading to growth inhibition, disruption of photosynthetic and respiratory systems, and stimulation of secondary metabolism. Plants respond to As toxicity by a variety of mechanisms including hyperaccumulation, antioxidant defense system, and phytochelation. Arbuscular mycorrhizae symbiosis occurs in almost all habitats and climates, including disturbed soils. There is growing evidence that arbuscular mycorrhizae fungi may alleviate metal/metalloid toxicity to host plant. Here, we review (1) arsenic speciation in the environment and how As is taken up by the roots and metabolised within plants, and (2) the role of arbuscular mycorrhizae in alleviating arsenic toxicity in crop plants.     

Use of total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol as an independent biomarker to classify smoking status

Biomarkers of exposure to tobacco smoke are needed. The objective of this study was to develop total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) as a biomarker of tobacco smoke independent of serum cotinine. Data from National Health and Nutrition Examination Survey were used to estimate cut-off points on NNAL scale to differentiate participants in various classes of smoking status. A cut-off of 13.4 pg/mL for NNAL differentiated smokers from nonsmokers with a specificity and sensitivity of 92%. NNAL can be used as an independent biomarker of exposure to tobacco smoke with high specificity and sensitivity.     

Trends in concentrations of selected dioxins and furans across various stages of kidney function for US adults

Environmental Science and Pollution Research - Exposure to dioxins and furans has the potential to affect kidney function and could be associated with chronic kidney disease. Data for US adults...     

Solid waste management of temple floral offerings by vermicomposting using Eisenia fetida

Recycling of temple waste (TW) mainly comprising of floral offerings was done through vermitechnology using Eisenia fetida and its impact on seed germination and plant growth parameters was studied by comparing with kitchen waste (KW) and farmyard waste (FYW) vermicompost (VC). The worm biomass was found to be maximum in TW VC compared to KW and FYW VCs at both 40 and 120 days old VCs. Physico-chemical analysis of worm-worked substrates showed better results in TW VC especially in terms of electrical conductivity, C/N, C/P and TK. 10% TW VC–water extract (VCE) showed stimulatory effect on germination percentage of chickpea seeds while KW and FYW VCE proved effective at higher concentration. Variation in growth parameters was also observed with change in the VC–soil ratio and TW VC showed enhanced shoot length, root length, number of secondary roots and total biomass at 12.5% VC compared to KW and FYW VC.