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The United Nations Climate Change Conference COP 28 recently took place in Dubai, marking an important milestone in assessing progress towards the goals of the Paris Agreement. The conference revealed slow progress in climate action, prompting nations to collectively commit to accelerating efforts. Transitioning from fossil fuels to renewable energy sources was a key focus. The conference also addressed the need for climate empowerment, the social dimension of climate change, and the health impacts of climate change. COP 28 adopted the operationalization of a loss and damage fund for developing countries, but progress on net-zero trajectories and climate finance fell short. The conference endorsed a declaration on the connection between climate change and human health, as well as cleaner energies for the aviation sector. The impact of aircraft emissions on the environment was highlighted, emphasizing the need for further research and action. COP 29, to be held in Azerbaijan, will likely address topics such as fulfilling commitments in the Paris Agreement, climate finance, and the effectiveness of Nationally Determined Contributions. Binding commitments and accelerated actions are seen as necessary for progress. [Extracted from the article]

Effects of aerosols such as black carbon (BC) on climate and buildup of the monsoon over the Indian Ocean are insufficiently quantified. Uncertain contributions from various natural and anthropogenic sources impede our understanding. Here, we use observations over 5 y of BC and its isotopes at a remote island observatory in northern Indian Ocean to constrain loadings and sources during little-studied monsoon season. Carbon-14 data show a highly variable yet largely fossil (65 ± 15%) source mixture. Combining carbon-14 with carbon-13 reveals the impact of African savanna burning, which occasionally approach 50% (48 ± 9%) of the total BC loadings. The BC mass-absorption cross-section for this regime is 7.6 ± 2.6 m²/g, with higher values during savanna fire input. Taken together, the combustion sources, longevity, and optical properties of BC aerosols over summertime Indian Ocean are different than the more-studied winter aerosol, with implications for chemical transport and climate model simulations of the Indian monsoon. [ABSTRACT FROM AUTHOR]

Comprehensive characterization of turbulent fluxes and land‐atmosphere interactions at a semi‐arid region in the Deccan Plateau of peninsular India is presented using 2‐year eddy covariance measurements. Contrary to previously reported results over the Indian region, surface energy partitioning is more into sensible heat flux than latent heat flux, even during the monsoon season. Irrespective of the seasons, the soil moisture and its response to rainfall drive the land‐atmosphere interactions and along with the net radiation, play crucial roles in deciding the surface fluxes and its partitioning. Time series comparison with ERA5 reanalysis data reveals the inadequate representation of land‐atmosphere interactions in ERA5 reanalysis over the peninsular Indian region, particularly the intensity and duration of rainfall and the feedbacks of soil moisture to the atmosphere. The surface energy balance closure improves by ∼3% when the soil heat storage term is considered and is the highest when the height and scatter of the roughness elements around the measurement site are the lowest. The influence of rainfall on energy balance closure is lower as compared to land surface heterogeneity. The present study also fills an existing gap of validating the surface fluxes and its partitioning in ERA5 reanalysis in the tropics and will provide deeper insights on the land‐atmosphere interactions in tropical semi‐arid regions. Plain Language Summary: The interactions between the surface of the Earth and the atmosphere above it controls the weather and climate of a region to a large extent. Accurately capturing such interactions in weather and climate models is arduous due to (a) the limited measurements on the partitioning of solar energy that reaches the surface and (b) the surface heterogeneities. Such measurements over different terrains and its comparison with various global data sets are essential to improve the climate predictions. Making use of 2‐year observations, we report the anomalous partitioning of surface energy at a semi‐arid region in India and how the rainfall and soil moisture play crucial roles in regulating it. Large differences between the observations and a modeled data set in the duration and intensity of rainfall and the energy partitioning at the surface are delineated along with the significant influence of the vegetation and soil heat storage. These results will be helpful in improving the weather and climate model simulations over the semi‐arid regions in the tropics. Key Points: Contrary to previous reports over the Indian region, partitioning of surface fluxes is more to sensible heat flux than latent heat fluxMeasurements reveal large differences in the rainfall duration and intensity and land‐atmosphere interactions compared to reanalysis dataEnergy balance closure is inversely proportional to the height of the roughness elements and their scatter around the measurement site [ABSTRACT FROM AUTHOR]

An editorial is presented on the outcomes of the 28th United Nations Climate Change Conference of the Parties (COP-28) held in Dubai, emphasizing the importance of international collaboration to address climate change. Topics include the conference's goals to limit global temperature increases, India's climate goals, and developments in climate finance, including the loss and damage fund.

Author(s): S. K. Satheesh; V. Ramanathan (corresponding author) The effect of radiative forcing by anthropogenic aerosols is one of the largest sources of uncertainty in climate predictions [1, 2, 3, [...]

The article offers information on the global acknowledgment of climate change as a reality caused by human intervention, with topics including the consequences of climate change, regional and global environmental concerns, and unique challenges faced by India, particularly the receding Sundarbans mangrove forest.

The article discusses the need for rural electrification using hybrid solar-wind energy systems to address the challenges of climate change and increasing energy demand in India. Topics include the rise in greenhouse gas concentrations; the importance of renewable energy sources like solar and wind; and the role of hybrid energy systems in providing a balanced solution for rural electrification while reducing the impact on climate.

The Himalayas, also known as third pole of the Earth feed some of the major rivers of the world viz. Ganga, Indus, Brahmaputra etc. The accurate assessment of water resources in eastern Himalayas is very important for respective policy makers. The detailed assessment of water resources and hydrological cycle component are very critical for attaining United Nations sustainable development goals (SDGs) such as affordable and clean energy, clean water and sanitation and building resilient infrastructure This study focuses on Kameng river basin, estimating the melt water & its contribution to the total discharge of the river. A 3-layer VIC model coupled with energy balance algorithm is used to estimate the patterns of melt and discharge profile in the region. Net contribution of melt water to the river were estimated to be about 18% during peak melt season in upper catchments. With advancement in technology, acquiring meteorological data via remote sensing has become more accurate & of high resolution. This data is one of the major inputs of the model. With accurate forecasting of these parameters, multipurpose hydropower projects in these regions can plan well in advance thus playing a major role in Integrated Water Resource Management. In current study the coefficient of determination & Nash-Sutcliffe efficiency were calculated to be 0.82 & 0.71 respectively. With increasing population in the region, any substantial change in the streamflow will have consequences unknown as of now, thus making this study a necessity & need of hour. [ABSTRACT FROM AUTHOR]

The article focuses on the environmental impact and heritage preservation of Lonar Lake, a unique geological formation in India. It addresses the effects of climate change on heritage sites, particularly those vulnerable to rising sea levels and emphasizes the urgent need for mitigation measures. It also discusses the ecological damage and degradation faced by Lonar Lake due to shifting perimeters and other factors, highlighting the importance of immediate conservation efforts.

We examine long‐term trends in the near‐surface black carbon mass concentration, using multiyear primary data obtained from a dense network (ARFINET) of observatories over the Indian region. We report for the first time the statistically significant decreasing trend in black carbon mass concentration, based on primary data from this region, at an average rate of ~242 ± 53 ng · m−3 · year−1 during the period 2007–2016. This finding contrasts with the generally increasing trend in the columnar aerosol optical depth, reported earlier, and the steadily increasing trend in anthropogenic activities over this region. The roles of different possible mechanisms, including possible changes in the vertical redistribution of aerosols, are discussed. Over the period 2007–2015, a significant though weak, increasing trend is seen in the contribution from aerosols above 1 km to the columnar aerosol optical depth. These observations imply possible long‐term climate consequences. Key Points: We report the first time regional synthesis of black carbon aerosols over the Indian region using primary dataThe study revealed surprising observation of decreasing trend in the near surface black carbon aerosol concentrationWe found an increasing trend in contribution from free tropospheric aerosols to the columnar aerosol optical depth [ABSTRACT FROM AUTHOR]

This study presents and evaluates the most comprehensive set to date of chemical, physical and optical properties of aerosols in the outflow from South Asia covering a full winter (Nov. 2014 - March 2015), here intercepted at the Indian Ocean receptor site of the Maldives Climate Observatory in Hanimaadhoo (MCOH). Cluster analysis of air-mass back trajectories for MCOH, combined with AOD and meteorological data, demonstrate that the wintertime northern Indian Ocean is strongly influenced by aerosols transported from source regions with three major wind regimes, originating from the Indo-Gangetic Plain (IGP), the Bay of Bengal (BoB) and the Arabian Sea (AS). As much as 97 ± 3% of elemental carbon (EC) in the PM10 was also found in the fine mode (PM2.5). Other mainly anthropogenic constituents such as organic carbon (OC), non-sea-salt (nss) -K+, nss-SO42− and NH4+ were also predominantly in the fine mode (70-95%), particularly in the air masses from IGP. The combination at this large-footprint receptor observatory of consistently low OC/EC ratio (2.0 ± 0.5), strong linear relationships between EC and OC as well as between nss-K+ and both OC and EC, suggest a predominance of primary sources, with a large biomass burning contribution. The particle number-size distributions for the air masses from IGP and BoB exhibited clear bimodal shapes within the fine fraction with distinct accumulation (0.1 μm < d < 1 μm) and Aitken (0.025 μm < d < 0.10 μm) modes. This study also supports that IGP is a key source region for the wider South Asia and nearby oceans, as defined by the criteria that anthropogenic AODs exceed 0.3 and absorption AOD > 0.03. Taken together, the aerosol pollution over the northern Indian Ocean in the dry season is dominated by a well-mixed long-range transported regime of the fine-mode aerosols largely from primary combustion origin. [ABSTRACT FROM AUTHOR]

An editorial is presented on challenges faced by Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) to develop healthy ecosystems and biodiversity that are fundamental to life on Earth. Topics include threat to fishing cats is habitat destruction due to anthropogenic activities and climate change; and India's wetlands are at risk of destruction due to human settlement, drainage for agriculture, pollution and logging.

An introduction is presented in which the editor discusses several articles published within issue on topics related to climate change and health.

Recent studies, over regions influenced by biomass burning aerosol, have shown that it is possible to define a 'critical cloud fraction' ( CCF) at which the aerosol direct radiative forcing switch from a cooling to a warming effect. Using 4 years of multi-satellite data analysis, we show that CCF varies with aerosol composition and changed from 0.28 to 0.13 from postmonsoon to winter as a result of shift from less absorbing to moderately absorbing aerosol. Our results indicate that we can estimate aerosol absorption from space using independently measured top of the atmosphere ( TOA) fluxes [Cloud Aerosol Lidar with Orthogonal Polarization-Moderate resolution Imaging Spectroradiometer-Clouds and the Earth's Radiant Energy System ( CALIPSO-MODIS- CERES)] combined algorithms for example. [ABSTRACT FROM AUTHOR]

This study examines differences in the surface black carbon (BC) aerosol loading between the Bay of Bengal (BoB) and the Arabian Sea (AS) and identifies dominant sources of BC in South Asia and surrounding regions during March-May 2006 (Integrated Campaign for Aerosols, Gases and Radiation Budget, ICARB) period. A total of 13 BC tracers are introduced in the Weather Research and Forecasting Model coupled with Chemistry to address these objectives. The model reproduced the temporal and spatial variability of BC distribution observed over the AS and the BoB during the ICARB ship cruise and captured spatial variability at the inland sites. In general, the model underestimates the observed BC mass concentrations. However, the model-observation discrepancy in this study is smaller compared to previous studies. Model results show that ICARB measurements were fairly well representative of the AS and the BoB during the pre-monsoon season. Elevated BC mass concentrations in the BoB are due to 5 times stronger influence of anthropogenic emissions on the BoB compared to the AS. Biomass burning in Burma also affects the BoB much more strongly than the AS. Results show that anthropogenic and biomass burning emissions, respectively, accounted for 60 and 37% of the average -standard deviation (representing spatial and temporal variability) BC mass concentration (1341±2353 ngm-3) in South Asia. BC emissions from residential (61%) and industrial (23%) sectors are the major anthropogenic sources, except in the Himalayas where vehicular emissions dominate. We find that regional-scale transport of anthropogenic emissions contributes up to 25% of BC mass concentrations in western and eastern India, suggesting that surface BC mass concentrations cannot be linked directly to the local emissions in different regions of South Asia. [ABSTRACT FROM AUTHOR]