Large contribution of fossil-derived components to aqueous secondary organic aerosols in China

Incomplete understanding of the sources of secondary organic aerosol (SOA) leads to large uncertainty in both air quality management and in climate change assessment. Chemical reactions occurring in the atmospheric aqueous phase represent an important source of SOA mass, yet, the effects of anthropogenic emissions on the aqueous SOA (aqSOA) are not well constrained. Here we use compound-specific dual-carbon isotopic fingerprints (δ13C and Δ14C) of dominant aqSOA molecules, such as oxalic acid, to track the precursor sources and formation mechanisms of aqSOA. Substantial stable carbon isotope fractionation of aqSOA molecules provides robust evidence for extensive aqueous-phase processing. Contrary to the paradigm that these aqSOA compounds are largely biogenic, radiocarbon-based source apportionments show that fossil precursors produced over one-half of the aqSOA molecules. Large fractions of fossil-derived aqSOA contribute substantially to the total water-soluble organic aerosol load and hence impact projections of both air quality and anthropogenic radiative forcing. Our findings reveal the importance of fossil emissions for aqSOA with effects on climate and air quality.

Simulation performance of selected global and regional climate models for temperature and rainfall in some locations in India

Global and regional climate models are reported to have inherent bias in simulating the observed climatology of a region. This bias of climate models is the major source of uncertainties in climate change impact assessments. Therefore, use of bias corrected simulated climate data is important. In this study, the bias corrected climate data for 30 years’ period (1976-2005) from selected common fourGCMs and RCMs for six Indian locations are compared with the respective observed data of India Meteorological Department. The analysis indicated that the RCMs performance is much better than GCMs after bias correction for minimum and maximum temperatures. Also, RCMs performance is better than GCMs in simulating extreme temperatures. However, the selected RCMs and GCMs are found to either over estimate or under estimate the rainfall despite bias correction and also overestimated the rainfall extremes for selected Indian locations. Based on the overall performance of four models for the six locations, it was found that the GFDL_ESM2M and NORESM1-M RCMs performed comparatively better than CSIRO and IPSL models. After bias correction, the RCMs could represent the observed climatology better than the GCMs. And these RCMs viz., GFDL_ESM2M and NORESM1-M can be usedindividually after bias correction in the climate change assessment studies for the selected regions.

Spatiotemporal Variations of Freezing and Thawing Indices During the Past Four Decades in Tibet

Freezing and thawing indices (FI and TI) are commonly used as indicators for climate change assessment and permafrost extent estimation in cold regions. In this study, based on the meteorological daily data (1978–2017) among 34 meteorological stations in Tibet, the temperature in space has been interpolated and FI and TI have been calculated. Finally, spatiotemporal variations have been analyzed and the permafrost area has been estimated. The results showed the mean annual of FI and TI in Tibet are 1241.36 and 1290.22°C⋅day, respectively. A significant downward trend in freezing index (FI) and an upward trend in thawing index (TI) have been reported in the time series, in against, analyzing the spatial distribution showed there is an increasing trend from southeast to northwest for FI while TI was decreased gradually in the same region in Tibet. This research indicates that altitude has a significant influence on the change of FI and TI. With the increase of altitude, FI decreased and TI increased more significantly. The permafrost area was estimated at about 0.59 × 106 km2 in Tibet.

Conceptual Frameworks for Assessing Climate Change Effects on Urban Areas: A Scoping Review

Urban areas are amongst the most adversely affected regions by current and future climate change effects. One issue when it comes to measuring, for example, impacts, vulnerabilities, and resilience in preparation of adaptation action is the abundance of conceptual frameworks and associated definitions. Frequently, those definitions contradict each other and shift over time. Prominently, in the transition from the IPCC AR (International Panel on Climate Change Assessment Report) 4 to the IPCC AR 5, a number of conceptual understandings have changed. By integrating common concepts, the literature review presented intends to thoroughly investigate frameworks applied to assess climate change effects on urban areas, creating an evidence base for research and politically relevant adaptation. Thereby, questions concerning the temporal development of publication activity, the geographical scopes of studies and authors, and the dominant concepts as applied in the studies are addressed. A total of 50 publications is identified following screening titles, abstracts, and full texts successively based on inclusion and exclusion criteria. Major findings derived from our literature corpus include a recently rising trend in the number of publications, a focus on Chinese cities, an imbalance in favor of authors from Europe and North America, a dominance of the concept of vulnerability, and a strong influence of the IPCC publications. However, confusion regarding various understandings remains. Future research should focus on mainstreaming and unifying conceptual frameworks and definitions as well as on conducting comparative studies.

Atmospheric Greenhouse Gas Reduction Through Deep Ocean Carbon Sequestration “DOCS”

The United Nations, Intergovernmental Panel on Climate Change, Assessment Report 6 (UN IPCC AR6) dated August 7th 2021 describes the urgency of reducing atmospheric greenhouse gasses, carbon dioxide (CO2) in particular, and methane (CH4) in order to limit global warming to a survivable level. AR6 identifies the tight connection between the world’s Gross Domestic Product and anthropogenic fossil fuel consumption that has resulted in the buildup of CO2. It also describes how and why it is going to become more difficult to achieve the desired goals as we get closer to those goals with the present available technologies. The options for fighting global warming are limited, difficult to implement, and with few good options, the decisions that are being made under these circumstances, are of concern. Rather than focusing on the difficult task of eliminating 100% of anthropogenic atmospheric greenhouse gas emissions, the focus herein is on eliminating ≈7% of the atmospheric greenhouse gasses emitted by microbes, and decomposition including wildfires, every year to achieve net zero emissions for our planet.

Assessing the impact of hydropower constructions on functioning of Dniester and Prut rivers ecosystems within the Hydroeconex project

The article reflects on the main issues, research methodologies and achievements of the project HydroEcoNex, a transboundary project carried out by a consortium of research institutes, NGO and a university – Institute of Zoology, International association of river keepers “Eco-Tiras” (Republic of Moldova), ”Dunărea de Jos” University of Galati (Romania), as well as Ukrainian Scientific Center of Ecology of the Sea and Hydrometeorological Center for Black and Azov Seas. Among the main obtained results are the development of a common methodology with various set of indicators for assessing hydropower impact and climate change, assessment of lost ecosystem services, sharing of generated knowledge to students and researchers, endowment of the research laboratories with advanced research equipment.

Comparable sulfate climate impacts by consumption of developed and developing countries

Regional consumption activities supported by domestic production and international trade have led to substantial amounts of aerosols worldwide, yet the resulting impacts on the global climate system remains unknown. Here we quantify for the first time the climate response to aerosols associated with consumption by developing and developed countries, by integrating a most current-generation fully coupled Earth system model, a recent multi-regional input-output table and an updated emission inventory used for climate change assessment. We find that although consumption associated sulfur dioxide emissions of developed countries are only 60% of those of developing countries, they lead to comparable impacts on the global mean surface air temperature (-0.20±0.09 versus -0.18±0.11 K; with 2 standard deviations) and precipitation (-0.017±0.017 versus -0.019±0.019 mm/day). This is because the emissions of developed countries and resulting forcing are more evenly distributed zonally and located at higher latitudes than the emissions of developing countries. Emissions of both developing and developed countries strongly cool the Northern Hemisphere and cause southward movement of the Intertropical Convergence Zone, while emissions of developing countries have stronger temperature and precipitation impacts over the tropical monsoon regions of China and India. This work serves as the first step of a comprehensive assessment of consumption associated climate impacts in support of global concerted action towards sustainable consumption and stabilized climate.