Greenhouse Gas Concentrations Research Articles

Isolating the effect of biomass burning aerosol emissions on 20th century hydroclimate in South America and Southeast Asia

Biomass burning is a significant source of aerosol emissions in some regions and has a considerable impact on regional climate. Earth system model simulations indicate that increased biomass burning aerosol emissions contributed to statistically significant decreases in tropical precipitation over the 20th century. In this study, we use the Community Earth System Model version 1 Large Ensemble (CESM1-LENS) experiment to evaluate the mechanisms by which biomass burning aerosol contributed to decreased tropical precipitation, with a focus on South America and Southeast Asia. We analyze the all-but-one forcing simulations in which biomass burning aerosol emissions are held constant while other forcings (e.g., greenhouse gas concentrations) vary throughout the 20th century. This allows us to isolate the influence of biomass burning aerosol on processes that contribute to decreasing precipitation, including cloud microphysics, the radiative effects of absorbing aerosol particles, and alterations in regional circulation. We also show that the 20th century reduction in precipitation identified in the CESM1-LENS historical and biomass burning experiments is consistent across Coupled Model Intercomparison Project Phase 5 models with interactive aerosol schemes and the CESM2 single-forcing experiment. Our results demonstrate that higher concentrations of biomass burning aerosol increases the quantity of cloud condensation nuclei and cloud droplets, limiting cloud droplet size and precipitation formation. Additionally, absorbing aerosols (e.g., black carbon) contribute to a warmer cloud layer, which promotes cloud evaporation, increases atmospheric stability, and alters regional circulation patterns. Corresponding convectively coupled circulation responses, particularly over the tropical Andes, contribute to further reducing the flow of moisture and moisture convergence over tropical land. These results elucidate the processes that affect the water cycle in regions prone to biomass burning and inform our understanding of how future changes in aerosol emissions may impact tropical precipitation over the 21st century.

Hybrid porous media gasification of urban solid waste pre-treated by hydrothermal carbonization.

Global population growth and rising consumption levels have significantly increased resource use and energy demand, leading to higher greenhouse gas concentrations and increased waste output. As a result, alternative waste treatment methods for sustainable municipal solid waste (MSW) management are crucial. This research evaluates the efficiency of integrating hydrothermal carbonization (HTC) and gasification for an optimized MSW biomass blend. HTC was conducted for one hour at 220°C in a 5 L reactor, followed by gasification in a hybrid porous medium gasifier. The study investigated the effects of different filtration speeds on combustion temperature and hydrogen concentrations. The results showed that a filtration speed of 35 cm/s resulted in a maximum combustion temperature of 1035.7°C. The temperature remained consistent across filter speeds, while higher velocities yielded higher hydrogen concentrations. Additionally, increasing the filtration velocity raised temperatures in the hybrid bed while increasing the volumetric fraction of biomass decreased maximum temperatures. This research contributes to the understanding of merging HTC and gasification for MSW biomass blend treatment, aiming to reduce environmental impacts and costs while promoting renewable resources for long-term energy production.

Effective climate sensitivity distributions from a 1D model of global ocean and land temperature trends, 1970–2021

Current theoretically based Earth system models (ESMs) produce Effective Climate Sensitivities (EffCS) that range over a factor of three, with 80% of those models producing stronger global warming trends for 1970–2021 than do observations. To make a more observationally based estimate of EffCS, a 1D time-dependent forcing-feedback model of temperature departures from energy equilibrium is used to match measured ranges of global-average surface and sub-surface land and ocean temperature trends during 1970–2021. In response to two different radiative forcing scenarios, a full range of three model free parameters are evaluated to produce fits to a range of observed surface temperature trends (± 2σ) from four different land datasets and three ocean datasets, as well as deep-ocean temperature trends and borehole-based trend retrievals over land. Land-derived EffCS are larger than over the ocean, and EffCS is lower using the newer Shared Socioeconomic Pathways (SSP245, 1.86 °C global EffCS, ± 34% range 1.48–2.15 °C) than the older Representative Concentration Pathway forcing (RCP6, 2.49 °C global average EffCS, ± 34% range 2.04–2.87 °C). The strongest dependence of the EffCS results is on the assumed radiative forcing dataset, underscoring the role of radiative forcing uncertainty in determining the sensitivity of the climate system to increasing greenhouse gas concentrations from observations alone. The results are consistent with previous observation-based studies that concluded EffCS during the observational period is on the low end of the range produced by current ESMs.

Weakening of springtime Arctic ozone depletion with climate change

Abstract. In the Arctic stratosphere, the combination of chemical ozone depletion by halogenated ozone-depleting substances (hODSs) and dynamic fluctuations can lead to severe ozone minima. These Arctic ozone minima are of great societal concern due to their health and climate impacts. Owing to the success of the Montreal Protocol, hODSs in the stratosphere are gradually declining, resulting in a recovery of the ozone layer. On the other hand, continued greenhouse gas (GHG) emissions cool the stratosphere, possibly enhancing the formation of polar stratospheric clouds (PSCs) and, thus, enabling more efficient chemical ozone destruction. Other processes, such as the acceleration of the Brewer–Dobson circulation, also affect stratospheric temperatures, further complicating the picture. Therefore, it is currently unclear whether major Arctic ozone minima will still occur at the end of the 21st century despite decreasing hODSs. We have examined this question for different emission pathways using simulations conducted within the Chemistry-Climate Model Initiative (CCMI-1 and CCMI-2022) and found large differences in the models' ability to simulate the magnitude of ozone minima in the present-day climate. Models with a generally too-cold polar stratosphere (cold bias) produce pronounced ozone minima under present-day climate conditions because they simulate more PSCs and, thus, high concentrations of active chlorine species (ClOx). These models predict the largest decrease in ozone minima in the future. Conversely, models with a warm polar stratosphere (warm bias) have the smallest sensitivity of ozone minima to future changes in hODS and GHG concentrations. As a result, the scatter among models in terms of the magnitude of Arctic spring ozone minima will decrease in the future. Overall, these results suggest that Arctic ozone minima will become weaker over the next decades, largely due to the decline in hODS abundances. We note that none of the models analysed here project a notable increase of ozone minima in the future. Stratospheric cooling caused by increasing GHG concentrations is expected to play a secondary role as its effect in the Arctic stratosphere is weakened by opposing radiative and dynamical mechanisms.

The fusion of multiple scale data indicates that the carbon sink function of the Qinghai-Tibet Plateau is substantial

BackgroundThe Qinghai-Tibet Plateau is the “sensitive area” of climate change, and also the “driver” and “amplifier” of global change. The response and feedback of its carbon dynamics to climate change will significantly affect the content of greenhouse gases in the atmosphere. However, due to the unique geographical environment characteristics of the Qinghai-Tibet Plateau, there is still much controversy about its carbon source and sink estimation results. This study designed a new algorithm based on machine learning to improve the accuracy of carbon source and sink estimation by integrating multiple scale carbon input (net primary productivity, NPP) and output (soil heterotrophic respiration, Rh) information from remote sensing and ground observations. Then, we compared spatial patterns of NPP and Rh derived from the fusion of multiple scale data with other widely used products and tried to quantify the differences and uncertainties of carbon sink simulation at a regional scale.ResultsOur results indicate that although global warming has potentially increased the Rh of the Qinghai-Tibet Plateau, it will also increase its NPP, and its current performance is a net carbon sink area (carbon sink amount is 22.3 Tg C/year). Comparative analysis with other data products shows that CASA, GLOPEM, and MODIS products based on remote sensing underestimate the carbon input of the Qinghai-Tibet Plateau (30–70%), which is the main reason for the severe underestimation of the carbon sink level of the Qinghai-Tibet Plateau (even considered as a carbon source).ConclusionsThe estimation of the carbon sink in the Qinghai-Tibet Plateau is of great significance for ensuring its ecological barrier function. It can deepen the community’s understanding of the response to climate change in sensitive areas of the plateau. This study can provide an essential basis for assessing the uncertainty of carbon sources and sinks in the Qinghai-Tibet Plateau, and also provide a scientific reference for helping China achieve “carbon neutrality” by 2060.

Soil moisture precipitation feedbacks in the Eastern European Alpine region in convection-permitting climate simulations.

A novel convection permitting modelling framework that combines a pseudo-global warming approach with continuously forced deep soil moisture from prescribed perturbation storylines is applied in the Eastern European Alpine region and parts of the Pannonian Basin to investigate soil moisture precipitation (SMP) feedbacks on summertime precipitation and the feedbacks' role under changed climate conditions. A set of 1-year convection-permitting (3 km horizontal grid spacing) soil moisture sensitivity simulations with the regional climate model of the Consortium for Small-Scale Modelling in Climate Mode are conducted. In order to account for global warming, end-of-the-century climate change effects from four global climate models, projecting the greenhouse gas concentration scenario RCP 8.5, are imprinted. The simulations reveal that (1) the locations of precipitation events are highly sensitive to soil moisture modifications while intensities and the internal structure of precipitation events are nearly unaffected and (2) high precipitation intensities are more likely in combinations with positive temporal but distinctive (either strong positive or strong negative) spatial SMP coupling. Low precipitation intensities are in favour of combinations of negative temporal and positive spatial coupling. The analyses suggest that soil moisture at a given time acts as a guiding field for the location of the next precipitation event. Interestingly, this behaviour is independent of climate change, although the coupling strength's increase is 1.5-1.7 times larger than expected from linear climate change scaling when climate becomes 50% dryer. Finally, it is found that (1) local deviations in the climate change signal of summertime precipitation in the range of up to ±40% are caused by uncertainty in deep soil moisture in the range of ±10% and (2) these local deviations in the climate change signal are dominated by soil moisture uncertainty in future climate conditions.

Assessment of the Influence of Instrument Parameters on the Detection Accuracy of Greenhouse-Gases Absorption Spectrometer-2 (GAS-2)

Satellite-based monitoring of atmospheric greenhouse gas (GHG) concentrations has emerged as a prominent and globally recognized field of research. With the imminent launch of the Greenhouse-Gases Absorption Spectrometer-2 (GAS-2) on the FengYun3-H (FY3-H) satellite in 2024, there is a promising prospect for substantial advancements in GHG detection capabilities. Crucially, the accurate acquisition of spectral information by GAS-2 is heavily reliant on its instrument parameters. However, the existing body of research predominantly emphasizes the examination of atmospheric parameters and their impact on GHG detection accuracy, thereby leaving a discernible gap in the comprehensive evaluation of instrument parameters specifically concerning the acquisition of atmospheric greenhouse gas concentration data by GAS-2. To address this knowledge gap, our study employs a radiation transfer model grounded in radiation transfer theory. This comprehensive investigation aims to quantitatively analyze the effects of various instrument parameters, encompassing crucial aspects such as spectral resolution, spectral sampling rate, signal-to-noise ratio, radiometric resolution, and spectral calibration accuracy (including instrument line shape function, central wavelength shift, and spectral resolution broadening). Based on our preliminary findings, it is evident that GAS-2 has the necessary spectral resolution, spectral sampling rate, and signal-to-noise ratio, slightly surpassing existing international instruments and enabling a significant detection accuracy level of 1 part per million (ppm). Moreover, it is essential to recognize the critical impact of instrument spectral calibration accuracy on overall detection precision. Among the five commonly used instrument line shape functions, the sinc function has the least impact on detection accuracy. Additionally, GAS-2’s radiance quantization depth is 14 bits, which is comparable to similar international payloads and maintains a root mean squared error below 0.1 ppm, thus ensuring a high level of precision. This study provides a comprehensive evaluation of the influence of GAS-2’s instrument parameters on detection accuracy, offering valuable insights for the future development of spectral calibration, the optimization of similar payload instrument parameters, and the overall improvement of instrument quantification capabilities.

Enhancing Renewable Energy Systems, Contributing to Sustainable Development Goals of United Nation and Building Resilience Against Climate Change Impacts

Climate change impacts due to unprecedented rising concentrations of greenhouse gas (GHG) are intensifying and widespread, making extreme climate events more widespread, frequent, and severe. To mitigate the worst consequences of climate warming, herein it is investigated how the global community can collectively achieve a large‐scale, sustained reduction in GHG emissions, and how to effectively move away from a predominantly fossil fuel‐based economy to one dominated by renewable energy? This transition is necessary to achieve the sustainable development goals (SDGs) of United Nations (UN) to ensure resilient and healthy environment for present and future generations, especially the SDG 7 of UN, “Affordable and Clean Energy”, set up to achieve global development of modern renewable energy systems. Investment policies and patterns of developed and developing countries in transitioning to energy productions primarily from renewable sources and obstacles such as scale‐up challenges, innovations in new energy systems, policies, financing mechanisms, and implementation strategies are examined. Furthermore, a comprehensive overview of the present global status of hydropower, wind, and solar, the three most significant renewable electricity technologies, as well as their basic operating principles, costs, and potential is conducted. Hydroelectric, wind, and solar power had grown from 3429, 346, and 34 TWh yr−1 in 2010 to 4274, 1598, and 846 TWh yr−1 in 2020, a growth of about 1.25, 4.60, and 24.9 times in a decade, respectively. Strategies to achieve energy systems that are of or near net zero GHG emissions by 2050s through the deployment of renewable energy systems are also investigated.

Environmental and Health Impacts of Crude Oil Exploration in the Niger Delta

Purpose: This research aims to assess the environmental and health consequences of crude oil exploration in the Niger Delta, focusing on the emission of greenhouse gases and air pollutants and their impacts on public health. Methodology: Literature search was done independently by the authors. After searching for articles on the identified databases, other sources of available and useful data on the subject such as the print press, student’s thesis and dissertation among others were sourced by hand search to augmented resources from the electronic databases.The Literature search was based on the careful evaluation of key words in the title and abstract of identified studies. Findings: The synthesis of available literature revealed significant insights into the environmental and health repercussions of crude oil exploration in the Niger Delta. The impact of gas flaring emerged as a major concern, leading to the release of pollutants like carbon dioxide, methane, and volatile organic compounds. These emissions contribute to elevated atmospheric temperatures, greenhouse gas concentrations, and the formation of acid rain, exacerbating global warming and disease transmission. The exposed population experiences a range of health problems including chronic respiratory diseases, cardiovascular abnormalities, altered blood parameters, and an increased risk of non-communicable diseases such as hypertension and diabetes. Prolonged exposure to pollutants from oil exploration is linked to disrupted sleep patterns, elevated stress levels, and neurophysiological disturbances, further contributing to adverse health outcomes. Unique contribution to theory, practice, and policy: This study advances existing knowledge by providing a comprehensive analysis of the multifaceted interplay between crude oil exploration, environmental degradation, and human health in the Niger Delta region. The research offers a substantial contribution to theoretical understanding by illuminating the intricate relationship between anthropogenic activities, environmental factors, and health outcomes. Moreover, the study provides practical implications by proposing a series of recommendations aimed at mitigating the negative impacts of oil exploration. These recommendations advocate for stricter regulations on emissions, increased monitoring and enforcement, adoption of cleaner technologies, community engagement, and investment in healthcare and environmental remediation. The findings inform policy formulation by supplying evidence-based insights to develop robust regulations and interventions that promote sustainable development, protect public health, and safeguard the environment for future generations.

Observational Constraint on the Contributions of Greenhouse Gas Emission and Anthropogenic Aerosol Removal to Tibetan Plateau Future Warming

AbstractA decline of anthropogenic aerosol (AA) emission is expected worldwide over the coming decades. But the climate effects of aerosol removal and greenhouse gases (GHG) emission at regional scale are poorly distinguished and constrained. Taking the Tibetan Plateau (TP) as an instance, analyses of the state‐of‐the‐art climate models participating in the Detection and Attribution Model Intercomparison Project imply that while the observed warming from 1961 to 2020 is predominantly attributed to GHG emission, the future temperature rise will be influenced by the combined effects of persistent increase in GHG concentration and reduction of AA emission. Here, we develop a new constraint method considering the changed contribution of AA forcing. Constrained by detected individual external forcings, the joint contributions of GHG (1.74°C) and AA forcings (0.10°C) will lead to a warming around 1.85°C over the TP during mid‐century (2041–2060) relative to 1995–2014 under SSP2‐4.5 scenario, which is 0.44°C cooler than the raw projection.

Impact of Climate Change on water security and Endorsing importance of Rainwater Harvesting Technology in Nepal

The day-by-day increment in the concentration of greenhouse gases (GHGs) in the atmosphere is widely believed to be a main contributing factor for climate change. It affects widely on diverse sectors such as water resources, agriculture, forestry, human health, biodiversity, and snow cover and aquatic life. Nepal is experiencing the adverse impact of climate change; this includes such as a variability in temperature and precipitation, overbank flooding from snow-fed rivers, and variability in available river and stream water quantity. Climate in the Nepal Himalayas is changing faster than the global average. Moreover, the changes in the high-altitudes have been found more pronounced than in the low-altitudes. Since, there is no definite trend that could be found in the annual precipitation records, clear decreasing trends could be seen in annual number of rainy days during the study period of 1971-2000. The glaciers in the Nepal Himalayas are shrinking rapidly and there will be no glaciers left by 2180. An accelerated glacier melt will cause an increase in water availability at the beginning but ultimately a decrease in water availability after the glaciers disappear. This will widen the gap between water supply and demand. Changing climate may further exacerbate the water stress which already happening in Nepal due to the monsoon dominated climate. Climate change (CC) will also further increase the seasonal imbalance- too much of water during rainy season and too less of it during dry seasons. Rainwater harvesting technology has the potential to provide numerous benefits to communities and individuals, particularly in areas where water resources are scarce or unreliable. From the analysis and through our research work it is found that if we can simply install and construct rainwater harvesting technology in our individual household only. It nearly fulfills about 15-25% of our domestic water demand. As in urban and rural area of Nepal still nearly about 50% of water demand is fulfilled by groundwater source which increase to 60-70% in dry season. The projected physical impacts of climate change on water resources would have substantial socioeconomic impacts and consequences for Nepal. The hydropower potential and agricultural production would be seriously affected by global warming. A reduction in agricultural production would be experienced due to water security and have significant impact on the food security and livelihoods of the subsistence farmers, who make the majority of the Nepal’s population. As the urgent need for climate change mitigation remains crucial, putting all the necessary resources and institutions in place for future adaptation is indispensable. The Inter-governmental Panel on Climate Change (IPCC) has listed rainwater-harvesting as a key strategy for a planned adaptation in the water sector. The policy statements about rainwater harvesting-based climate change adaptation are currently not being effectively coordinated.

Climate models underestimate the sensitivity of Arctic sea ice to carbon emissions

Arctic sea ice has steadily diminished as atmospheric greenhouse gas concentrations have increased. Using observed data from 1979 to 2019, we estimate a close contemporaneous linear relationship between Arctic sea ice area and cumulative carbon dioxide emissions. For comparison, we provide analogous regression estimates using simulated data from global climate models (drawn from the CMIP5 and CMIP6 model comparison exercises). The carbon sensitivity of Arctic sea ice area is considerably stronger in the observed data than in the climate models. Thus, for a given future emissions path, an ice-free Arctic is likely to occur much earlier than the climate models project. Furthermore, little progress has been made in recent global climate modeling (from CMIP5 to CMIP6) to more accurately match the observed carbon-climate response of Arctic sea ice.

Comparing the impacts of ozone-depleting substances and carbon dioxide on Arctic sea ice loss

The rapid decline of Arctic sea ice is widely believed to be a consequence of increasing atmospheric concentrations of greenhouse gases (GHGs). While carbon dioxide (CO2) is the dominant GHG contributor, recent work has highlighted a substantial role for ozone-depleting substances (ODS) in Arctic sea ice loss. However, a careful analysis of the mechanisms and relative impacts of CO2 versus ODS on Arctic sea ice loss has yet to be performed. This study performs this comparison over the period 1955–2005 when concentrations of ODS increased rapidly, by analyzing a suite of all-but-one-forcing ensembles of climate model integrations, designed to isolate the forced response to individual forcing agents in the context of internal climate variability. We show that ODS have played a significant role in year-round Arctic sea ice extent and volume trends over that period, accounting for 64% and 32% of extent and volume trends, respectively. These impacts represent 50% and 38% of the impact from CO2 forcing, respectively. We find that ODS act via similar physical processes to CO2, causing sea ice loss via increased summer melt, and not sea ice dynamics changes. These findings imply that the future trajectory of ODS emissions will play an important role in future Arctic sea ice evolution.

Can litigation assist in implementing the outcome of the global stocktake?

Rising global temperatures and concentrations of greenhouse gases (GHGs) are reaching record highs. The consequences being reported globally are becoming increasingly severe. At the 26th Conference of the Parties (COP26) in 2021, the parties to the Paris Agreement agreed on the terms of a global stocktake mechanism to periodically assess the implementation of the Paris Agreement and the achievement of the agreement’s long-term goals. The outcome of the global stocktake will be a finding of whether insufficient progress has been made in achieving the long-terms goals of the Paris Agreement and mitigating climate change. This article explores the ways in which the outcome of the global stocktake can inform parties’ actions under the Paris Agreement and be used in climate litigation. The outcome of the global stocktake may be able to be used in litigation in four ways: first, to enforce a party’s obligations under the Paris Agreement; second, to enforce relevant resolutions of the COP; third, to implement the principle of solidarity; and fourth, to use a factual assessment of the parties’ progress in achieving the Paris Agreement to establish insufficiency. This article examines these four ways that litigation might assist in implementing the outcome of the global stocktake.

Methane gas emissions (CH4) in paddy fields in Minasatene District, Pangkep Regency: Microbial abundance against increased methane gas

Global warming caused by various human activities results in increased concentrations of Greenhouse Gas (GHG) emissions. This causes the problem of climate change. One of the sources of Indonesia’s greenhouse gas (GHG) emissions comes from the agricultural sector. Methane (CH4) is the second most important greenhouse gas and has a global warming potential 25 times greater than CO2. Paddy fields contribute to GHG emissions due to the condition of the rice fields which are always flooded which produce gases such as CO2, N2O and Methane (CH4). This study aims to determine the effect of microbial abundance on increasing emissions of methane gas (CH4) in paddy fields. This research was conducted by collecting samples in the field with variations at 30th, 60th, and 90th day after planting (DAP). The results of laboratory analysis showed that the results of C-Organic analysis were 1.45-2.56%, the results of soil microbial abundance analysis for the total bacterial population ranged from 1.2 x 104 - 6.3 x 105 (CFU/g) and the results of analysis flux of CH4 at 30thDAP sampling from the three sample points ranged from 2.13 - 11.29 (mg/m2/hour). For the 60thDAP sample from the three sample points it ranges from 10.01 - 22.77 (mg/m2/hour). For the 90thDAP sample from the three sample points it ranges from 21.98 - 25.54 (mg/m2/hour). The results of the analysis of methane (CH4) emissions in one growing season show different values of methane emissions at different locations and sampling times.

Climate of Syria Based on Cordex Simulations: Present and Future

AbstractRegional climate models are widely used to assess current and future impacts of climate change. In this study, we evaluate the performance of regional climate models from the Coordinated Regional Climate Downscaling Experiment programme integrated over the following three CORDEX domains: AFR, MNA and WAS. Four meteorological variables (temperature, precipitation, solar radiation and cloud cover) were evaluated over Syria at a grid spacing of 0.44°. The performance of five models in simulating the present climate characteristics (1989–2008) is evaluated with respect to the observations: CRU, ERA5 reanalysis and SARA and CLARA satellite data. We find that the mini-ensemble captures well the general spatial patterns and annual cycles of the selected variables. Anotheraim of this study was to assess the expected change of the mentioned four climate variables over Syria under the moderate emission scenario (RCP4.5) and the high emission scenario (RCP8.5) in the near future (2031–2050) and in the far future (2080–2099) with respect to the present climate (1989–2008). The simulations show a decreasing trend in cloud cover (between 6% and 10%) and precipitation (up to 9%) by mid and late century, regardless of the forcing scenarios. The simulations show a pronounced warming over Syria, which is expected to reach 6 °C by the end of the twenty-first century following the high greenhouse gas concentration scenario (RCP8.5). Furthermore, such an increase, combined with a decrease in precipitation, will shift Syria’s climate towards a more arid one.

Prolongation of Compound Dry–Hot Seasons Over Europe Under Climate Change Scenarios

AbstractCompound effects of drought and heat are regarded as one of the greatest hazards in relation to climate change. We study characteristics of dry–hot seasons in Europe in an ensemble of CORDEX regional climate models (RCMs). Evaluation against the E‐OBS gridded data set for 1976–2005 showed that the RCMs were able to reproduce the spatial pattern of the dry–hot season length but the simulated seasons tended to start later and interannual variability of their length was underestimated. Bias was larger (smaller) in the case of maximum (minimum) length over the 30‐year period compared to the median length. Changes in the dry–hot seasons were then analyzed for three time slices (2006–2035, 2036–2065, and 2066–2095) and low and high greenhouse gas concentration pathways. Distinct prolongation (compared to the 1976–2005 simulated climate) was projected for 2036–2065 in the Mediterranean and Western Europe (10–30 days), regardless of the concentration pathway. The dry–hot seasons length was similar in the 2036–2065 and 2066–2095 time slices under the low concentration pathway but major extensions were found under the high concentration scenario over large parts of Europe (20–50 days). The projected spatial patterns of changes in the dry–hot seasons length depend primarily on the driving global climate model. Although the extensions are predominantly driven by increasing temperature, simulated precipitation changes modulate the resulting pattern by amplifying (reducing) the dry–hot seasons length in Southern (Northern) Europe.

Improved spectral photometer for undergraduate observations of atmospheric infrared heat flux and greenhouse gas absorption bands

We present an experiment investigating the physics of the atmospheric greenhouse effect that can be performed by undergraduate physics students. The students construct a three-channel spectral photometer to observe the infrared heat flux in the atmosphere. With this spectral photometer, the students observe the difference in heat flux between the portion of the IR spectrum that is absorbed by water vapor and carbon dioxide and the portion that is not absorbed by atmospheric constituents. The students discover that Earth's surface is warmed by radiation from the greenhouse gas absorption bands, and the radiation of heat to space is retarded by the absorption bands. One component of the experiment is performed on the ground and the other component is performed in the atmosphere using a high-altitude balloon. The students then compare their results to a simulation of infrared radiation transport in the atmosphere.

Are thunderstorms linked to the rapid Sea ice loss in the Arctic?

Sea ice in the Arctic grows during the winter and retreats in the summer. The highly reflective white surface of sea ice reflects solar energy, cooling the planet. However, when it melts, the darker ocean absorbs more solar radiation, reinforcing the cycle of melting sea ice. Since sea ice plays a critical role in regulating Earth's climate, changes in sea ice may influence global weather patterns and ocean circulations. In addition to the rise in greenhouse gases in the Arctic, upper tropospheric water vapor (UTWV) or the specific humidity (SH) is also increasing, while acting as an additional greenhouse gas trapping in heat released from the Earth's surface. While annual greenhouse gas concentrations in the Arctic are increasing rather smoothly over time, the interannual variability in sea ice is shown here to be linked to the variability of UTWV at 400 hPa in the Arctic. We propose that increasing thunderstorm activity in the Arctic in the last decade is increasing the water vapor in the upper troposphere, partially explaining the interannual variability, and long term decrease, in the Arctic summer sea ice extent. Both the temporal and spatial analysis between UTWV and Sea Ice changes show that the decline of the summer sea ice cover in the Arctic may be linked to the increasing thunderstorm activity in the Arctic in the last decades.

Development of global monthly dataset of CMIP6 climate variables for estimating evapotranspiration

Reliable projection of evapotranspiration (ET) is important for planning sustainable water management for the agriculture field in the context of climate change. A global dataset of monthly climate variables was generated to estimate potential ET (PET) using 14 General Circulation Models (GCMs) for four main shared socioeconomic pathways (SSPs). The generated dataset has a spatial resolution of 0.5° × 0.5° and a period ranging from 1950 to 2100 and can estimate historical and future PET using the Penman-Monteith method. Furthermore, this dataset can be applied to various PET estimation methods based on climate variables. This paper presents that the dataset generated to estimate future PET could reflect the greenhouse gas concentration level of the SSP scenarios in latitude bands. Therefore, this dataset can provide vital information for users to select appropriate GCMs for estimating reasonable PETs and help determine bias correction methods to reduce between observation and model based on the scale of climate variables in each GCM.