Project description:Viruses are non-living, acellular entities, and the most abundant biological agents on earth. They are widely acknowledged as having the capacity to influence global biogeochemical cycles by infecting the bacterial and archaeal populations that regulate carbon and nutrient turnover. Evidence suggests that the majority of viruses in wetlands are bacteriophages, but despite their importance, studies on how viruses control the prokaryotic community and the concomitant impacts on ecosystem function (such as carbon cycling and greenhouse gas flux) in wetlands are rare. Here we investigate virus-prokaryote interactions in freshwater wetland ecosystems in the context of their potential influence on biogeochemical cycling. Specifically, we (1) synthesize existing literature to establish current understanding of virus-prokaryote interactions, focusing on the implications for wetland greenhouse gas dynamics and (2) identify future research priorities. Viral dynamics in freshwater wetlands have received much less attention compared to those in marine ecosystems. However, based on our literature review, within the last 10 years, viral ecology studies on freshwater wetlands have increased twofold. Despite this increase in literature, the potential implication of viral infections on greenhouse gas emission dynamics is still a knowledge gap. We hypothesize that the rate of greenhouse gas emissions and the pool of sequestered carbon could be strongly linked to the type and rate of viral infection. Viral replication mechanism choice will consequently influence the microbial efficiency of organic matter assimilation and thus the ultimate fate of carbon as a greenhouse gas or stored in soils.
Project description:We employ a single-country dynamically-recursive Computable General Equilibrium model to make health-focussed macroeconomic assessments of three contingent UK Greenhouse Gas (GHG) mitigation strategies, designed to achieve 2030 emission targets as suggested by the UK Committee on Climate Change. In contrast to previous assessment studies, our main focus is on health co-benefits additional to those from reduced local air pollution. We employ a conservative cost-effectiveness methodology with a zero net cost threshold. Our urban transport strategy (with cleaner vehicles and increased active travel) brings important health co-benefits and is likely to be strongly cost-effective; our food and agriculture strategy (based on abatement technologies and reduction in livestock production) brings worthwhile health co-benefits, but is unlikely to eliminate net costs unless new technological measures are included; our household energy efficiency strategy is likely to breakeven only over the long term after the investment programme has ceased (beyond our 20 year time horizon). We conclude that UK policy makers will, most likely, have to adopt elements which involve initial net societal costs in order to achieve future emission targets and longer-term benefits from GHG reduction. Cost-effectiveness of GHG strategies is likely to require technological mitigation interventions and/or demand-constraining interventions with important health co-benefits and other efficiency-enhancing policies that promote internalization of externalities. Health co-benefits can play a crucial role in bringing down net costs, but our results also suggest the need for adopting holistic assessment methodologies which give proper consideration to welfare-improving health co-benefits with potentially negative economic repercussions (such as increased longevity).
Project description:China's industrial process-related Greenhouse Gas (GHG) emissions are growing rapidly and are already equivalent to 13-19% of energy-related emissions in the past three decades. Previous studies mainly focused on emissions from fossil fuel combustion, however, there are a broad range of misconceptions regarding the trend and source of process-related emissions. To effectively implement emission reduction policies, it is necessary to compile an accurate accounting of process-related GHG emissions. However, the incompleteness in scope, unsuitable emission factor, and delay in updates in the current emission inventory have led to inaccurate emission estimates and inefficient mitigation actions. Following the methodology provided by Intergovernmental Panel on Climate Change (IPCC), we constructed a time series inventory of process-related GHG emissions for 15 industrial products from 1990-2020 in China. This emission inventory covers more than 90% of China's process-related GHG emissions. In our study, emission factors were adjusted to refer to the industrial production process, technology, and raw material structure in China, which has led to increased accuracy of emission accounting. The dataset can help identify the sources of process-related GHG emissions in China and provide a data base for further policy implications.
Project description:Climate-sensitive northern cryosphere inland waters emit greenhouse gases (GHGs) into the atmosphere, yet their total emissions remain poorly constrained. We present a data-driven synthesis of GHG emissions from northern cryosphere inland waters considering water body types, cryosphere zones, and seasonality. We find that annual GHG emissions are dominated by carbon dioxide ([Formula: see text] teragrams of CO2; [Formula: see text]) and methane ([Formula: see text] teragrams of CH4), while the nitrous oxide emission ([Formula: see text] gigagrams of N2O) is minor. The annual CO2-equivalent (CO2e) GHG emissions from northern cryosphere inland waters total [Formula: see text] or [Formula: see text] petagrams of CO2e using the 100- or 20-year global warming potentials, respectively. Rivers emit 64% more CO2e GHGs than lakes, despite having only one-fifth of their surface area. The continuous permafrost zone contributed half of the inland water GHG emissions. Annual CO2e emissions from northern cryosphere inland waters exceed the region's terrestrial net ecosystem exchange, highlighting the important role of inland waters in the cryospheric land-aquatic continuum under a warming climate.
Project description:With the intensification of global warming, wetland greenhouse gas (GHG) emissions have attracted worldwide attention. However, the scientific understanding of wetland GHGs is still limited. To gain a comprehensive and systematic understanding of the current research status and development trends in wetland GHGs. We selected 1627 papers related to wetland GHG research from the Web of Science Core Collection database and used the bibliometric visualization analysis method to reveal the annual publication, main core research forces, research hotspots, and trends in this field. The results showed that the research in this field shows a steady upward trend. United States research institutions and scholars play a key role in this field. The research on "climate change" based on three major wetland GHGs (carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)) has been continuously gaining popularity. In recent years, "water" has become an emerging core topic. More and more studies have focused on enhancing wetland pollutant treatment capacity, improving wetland ecosystem productivity, maintaining water level stability, strengthening blue carbon sink function, exploring remote sensing applications in wetlands, and promoting wetland restoration to reduce GHG emissions. Furthermore, we discussed the influencing factors of the emission of CO2, CH4, and N2O in wetlands and summarized the potential methods to reduce GHG emissions. The findings provide scientific guidance and reference on wetland sustainable development and GHG emission reduction.
Project description:The potential of palm-oil biofuels to reduce greenhouse gas (GHG) emissions compared with fossil fuels is increasingly questioned. So far, no measurement-based GHG budgets were available, and plantation age was ignored in Life Cycle Analyses (LCA). Here, we conduct LCA based on measured CO2, CH4 and N2O fluxes in young and mature Indonesian oil palm plantations. CO2 dominates the on-site GHG budgets. The young plantation is a carbon source (1012 ± 51 gC m-2 yr-1), the mature plantation a sink (-754 ± 38 gC m-2 yr-1). LCA considering the measured fluxes shows higher GHG emissions for palm-oil biodiesel than traditional LCA assuming carbon neutrality. Plantation rotation-cycle extension and earlier-yielding varieties potentially decrease GHG emissions. Due to the high emissions associated with forest conversion to oil palm, our results indicate that only biodiesel from second rotation-cycle plantations or plantations established on degraded land has the potential for pronounced GHG emission savings.
Project description:In recent times, waste management has emerged as a significant environmental challenge, and sewage is among the major contributors due to the rapidly increasing population. Despite sewage treatment plants (STPs) being the solution for the treatment of sewage, they have been identified as sources of greenhouse gas (GHG) emissions. This study aimed to estimate the contribution of STPs to GHG emissions in the state. This was achieved by visiting the sites, filling scientifically designed questionnaires, sample collection as well as computational methods by Intergovernmental Panel on Climate Change. The assessment of direct and indirect emissions from the STPs revealed that emissions were caused by the activated sludge process, electricity consumption, transportation, and sludge storage. Electricity consumption by STPs was responsible for the highest emissions, accounting for 43% of the total emissions, equivalent to 20,823 tCO2 eq. The activated sludge process contributed 31% (14,934 tCO2 eq) of the emissions, while storage of sludge in landfills accounted for 24% (11,359 tCO2 eq). Additionally, transportation contributed 2% (1121 tCO2 eq) of the emissions. In total, the STPs in Himachal Pradesh had the potential to contribute 48,237 tCO2 eq GHG emissions annually. Thus, the study suggests process-level modifications in STPs of Himachal Pradesh to mitigate GHG emissions. This research provides insight into the GHG emissions from STPs and highlights the need for their management to reduce environmental impacts.