Global Warming Levels Research Articles

Association of Ozone and Temperature with Ischemic Heart Disease Mortality Risk: Mediation and Interaction Analyses.

Global warming and elevated ozone (O3) levels are gradually gaining widespread attention, and exposure to which may cause many physiological changes associated with cardiovascular events such as hypertension, cardiomyocyte apoptosis, etc. In addition, ischemic heart disease (IHD) is the leading cause of death worldwide. However, the contributions of temperature and O3, independently or in combination, to IHD mortality are not well understood. This study employs a two-stage analytical protocol (generalized additive model followed by meta-analysis) to explore the respective associations of temperature and O3 with IHD mortality, and determine their possible mediation and interaction effects. Our results suggest that increases of 10 μg/m3 in O3 and 1 °C in temperature at lag01 day are associated with increased IHD mortality risks of 0.789% and 0.686%, respectively. O3 can mediate the relationship between temperature and IHD mortality, with a pooled estimate of 0.140%, while temperature can mediate the association between O3 and IHD mortality, with a pooled estimate of 0.162%. The additive and multiplicative interaction effects of O3 and temperature were significantly associated with IHD mortality. The study findings demonstrate that higher temperature and O3 concentrations can increase human IHD mortality risk through interaction and mediation effects, providing a scientific basis for the synergistic management of temperature and O3 or associated interventions.

Human Adaption to Climate Change: Marine Disaster Risk Reduction in the Era of Intelligence

With the intensification of global warming and sea level rise, extreme weather and climate events occur frequently, increasing the probability and destructive power of marine disasters. The purpose of this paper is to propose the specific application of artificial intelligence (AI) in marine disaster risk reduction. First, this paper uses computer vision to assess the vulnerability of the target and then uses CNN-LSTM to forecast tropical cyclones. Second, this paper proposes a social media communication mechanism based on deep learning and a psychological crisis intervention mechanism based on AIGC. In addition, the rescue response system based on an intelligent unmanned platform is also the focus of this research. Third, this paper also attempts to discuss disaster loss assessment and reconstruction based on machine learning and smart city concepts. After proposing specific application measures, this paper proposes three policy recommendations. The first one is improving legislation to break the technological trap of AI. The second one is promoting scientific and technological innovation to break through key technologies of AI. The third one is strengthening coordination and cooperation to build a disaster reduction system that integrates man and machine. The purpose of this paper is to reduce the risk of marine disasters by applying AI. Furthermore, we hope to provide scientific references for sustainability and human adaptation to climate change.

Exploring climate stabilisation at different global warming levels in ACCESS-ESM-1.5

Abstract. Under the Paris Agreement, signatory nations aim to keep global warming well below 2 °C above pre-industrial levels and preferably below 1.5 °C. This implicitly requires achieving net-zero or net-negative greenhouse gas emissions to ensure long-term global temperature stabilisation or reduction. Despite this requirement, there have been few analyses of stabilised climates, and there is a lack of model experiments to address our need for understanding the implications of the Paris Agreement. Here, we describe a new set of experiments using the Australian Community Climate and Earth System Simulator Earth system model (ACCESS-ESM-1.5) that enables the analysis of climate evolution under net-zero emissions, and we present initial results. Seven 1000-year-long simulations were run with global temperatures stabilising at levels in line with the Paris Agreement and at a range of higher global warming levels (GWLs). We provide an overview of the experimental design and use these simulations to demonstrate the consequences of delayed attainment of global net-zero carbon dioxide emissions. We show that there are substantial differences between transient and stabilising climate states and differences in stabilisation between GWLs. As the climate stabilises under net-zero emissions, we identify significant and robust changes in temperature and precipitation patterns including continued Southern Ocean warming and changes in regional precipitation trends. Changes under net-zero emissions differ greatly between regions, including contrasting trajectories of sea ice extent between the Arctic and Antarctic. We also examine the El Niño–Southern Oscillation (ENSO) and find evidence of reduced amplitude and frequency of ENSO events under climate stabilisation relative to projections under transient warming. An analysis at specific GWLs shows that significant regional changes continue for centuries after emission cessation and that these changes are stronger at higher GWLs. Our findings suggest substantial long-term climate changes are possible even under net-zero emission pathways. These simulations are available for use in the community and will hopefully motivate further experiments and analyses based on other Earth system models.

Global warming level indicators of climate change and hotspots of exposure

Abstract In the 21st century, a growing population will be exposed to various hazards caused by a warming climate. Here we present a new database of 12 climate change indicators with a total of 42 variants at different global warming levels (GWLs) (1.2 °C–3.5 °C), which is based on global climate and hydrological model data from the Coupled Model Intercomparison Project round 6 and the Inter-Sectoral Impact Model Intercomparison Project round 3b at 0.5° spatial resolution. It comprises of indicators relating to temperature and precipitation extremes, heatwave events, and hydrological variability. To facilitate the comparison of hazards from different indicators, including for an audience without a scientific background, we have developed a bivariate hazard score which is applied on the grid cell level and incorporates statistics on both the absolute hazard (e.g. low or high precipitation) and the relative change under global warming compared to the reference period (e.g. a large change from low to high precipitation). Additionally, we calculate exposed land area and population through the 21st century for a large set of countries and regions by combining this score with gridded projections of population from the Shared Socioeconomic Pathways (SSPs). The datasets are intended for use by the wider research community and analysts seeking digestible climate hazard and exposure data summarized by GWLs. To illustrate potential uses of the data, in a preliminary analysis we find that even at 1.5 °C large parts of the land area and population face substantial unavoidable risks from multiple indicators, with 86% of the world’s population exposed to at least three indicators with at least medium hazard using the population projections for SSP2 in the year 2050. This picture only worsens with increasing warming, as the land areas facing the highest number of impacts coincide with some of the most densely populated parts of the world.

The Process of Soil Carbon Sequestration in Different Ecological Zones of Qingtu Lake in the Arid–Semi-Arid Region of Western China

As a vital component of the global carbon pool, soils in arid and semi-arid regions play a significant role in carbon sequestration. In the context of global warming, increasing temperatures and moisture levels promote the transformation of barren land into wetlands, enhancing carbon sinks. However, the overdevelopment of oases and excessive extraction of groundwater lead to the opposite effect, reducing carbon sequestration. This study examines two soil types—meadow soil (MS) and swamp soil (SS)—from Qingtu Lake, an arid lake in western China. It analyzes the sources of soil inorganic carbon, the composition and origin of dissolved organic matter (DOM), and the relationships between microbes, soil organic carbon (SOC), soil inorganic carbon (SIC), mineral composition, and soil texture. The results indicate that inorganic carbon in the study area consists of both primary carbonate minerals and secondary pedogenic carbonates. The DOM primarily consists of two components, both identified as terrestrial humic substances. In meadow soils, bacterial activity drives the weathering of plagioclase, which releases Ca2+ necessary for the formation of pedogenic carbonates. Plagioclase also provides colonization sites for microbes and, along with microbial activity, participates in the soil carbon cycle. Within the soil community, bacteria appear to play a more critical role than fungi. In contrast, microbial contributions to the carbon cycle in swamp soils are weaker, with minerals predominantly interacting with organic carbon to form mineral-associated organic matter, thus promoting the soil carbon cycle. These findings have important implications for understanding soil carbon sinks under different micro-ecological conditions in arid and semi-arid regions. Through targeted human intervention, it is possible to enhance carbon sequestration in these areas, contributing to the mitigation of global climate change.

Fire weakens land carbon sinks before 1.5 °C

To avoid the worst impacts of climate change, the Paris Agreement committed countries to pursue efforts to limit global warming to 1.5 °C by urgently reducing greenhouse gas emissions. However, the Paris temperature ambitions and remaining carbon budgets mostly use models that lack feedback among fire, vegetation and carbon, which are essential for understanding the future resilience of ecosystems. Here we use a coupled fire–vegetation model to explore regional impacts and feedbacks across global warming levels. We address whether the 1.5 °C goal is consistent with avoiding significant ecosystem changes when considering shifts in fire regimes. We find that the global warming level at which fire began to impact global carbon storage significantly was 1.07 °C (0.8–1.34 °C) above pre-industrial levels and conclude that fire is already playing a major role in decreasing the effectiveness of land carbon sinks. We estimate that considering fire reduces the remaining carbon budget by 25 Gt CO2 (~5%) for limiting temperature rise to 1.5 °C and 64 GtCO2 (~5%) for 2.0 °C compared to previous estimates. Whereas limiting warming to 1.5 °C is still essential for avoiding the worst impacts of climate change, in many cases, we are already reaching the point of significant change in ecosystems rich in carbon and biodiversity.

Persistently Elevated High‐Latitude Ocean Temperatures and Global Sea Level Following Temporary Temperature Overshoots

AbstractAs exceeding the 1.5°C level of global warming is likely to happen in the near future, understanding the response of the ocean‐climate system to temporarily overshooting this warming level is of critical importance. Here, we apply the Adaptive Emissions Reduction Approach to the Earth System Model GFDL‐ESM2M to conduct novel overshoot scenarios that reach 2.0, 2.5 and 3.0°C of global warming before returning to 1.5°C over the time period of 1861–2500. We also perform a complementary scenario that stabilizes global temperature at 1.5°C, allowing to isolate impacts caused by the temperature overshoots alone, both during their peaks and after their reversals. The simulations indicate that substantial residual ocean surface warming persists in the high latitudes after the overshoots, with most notable regional anomalies occurring in the North Atlantic (up to +3.1°C in the 3°C overshoot scenario compared to the 1.5°C stabilization scenario) and the Southern Ocean (+1.2°C). The residual warming is primarily driven by the recoveries of the Atlantic and Southern Ocean meridional overturning circulation and associated increases in ocean heat transport. Excess subsurface heat storage in low and mid‐latitudes prevents steric sea level rise (SLR) from reverting to 1.5°C stabilization levels in any overshoot scenario, with steric sea level remaining up to 32% higher in the 3°C overshoot scenario on centennial time scales. Both peak impacts and persistent changes after overshoot reversal bear significant implications for future assessments of coastlines, regional climates, marine ecosystems, and ice sheets.

Effects of diluted seawater in drinking water on physiological responses, feeding, drinking patterns, and water balance in crossbred dairy goats

Background and Aim: In tropical regions, the intrusion of saline from seawater (SW) due to global warming and sea level rise in recent years is an important natural factor influencing goat well-being. This study aimed to determine the effects of diluted SW in drinking water on the physiological responses and eating and drinking patterns of crossbred dairy goats under tropical conditions. Materials and Methods: Twenty dairy goats were divided into four groups (five animals each) based on body weight and milk yield. Animals received either fresh drinking water (SW0.0, control) or diluted SW at concentrations of 0.5% (SW0.5, low salinity), 1% (SW1.0, moderate salinity), and 1.5% (SW1.5, high salinity). The experiment was performed for 49 days (1st–7th week). Throughout this period, daily food and water intake were measured every day. In addition, blood collection was performed on day 25. Total urine and feces were collected from days 25 to 29. Meal and drinking patterns were determined on days 31 and 32. Results: Salinity did not influence dry matter intake throughout the experiment (p > 0.05). However, SW had a significant effect on eating patterns. The effect of SW on water intake (WI) was pronounced from the 2nd to 7th weeks of this experiment (p < 0.05). The water balance decreased and plasma antidiuretic hormone levels increased from SW1.5 to SW2.5 compared to the other treatments. Rectal temperature and respiration rate increased from 15:00 to 17:00 in SW1.5 patients. The concentrations of plasma electrolyte, creatinine, and heat shock protein 70 did not differ between treatments (p > 0.05). The urinary excretion of Na+ from SW1.5 and K+ and Cl- from SW1.0 was higher than that from SW0.0 and SW0.5 (p < 0.01). Conclusion: Lactating crossbred goats adapted to low and moderate SW by increasing urine volume and urinary electrolyte excretion (Uex), whereas animals responded to high SW by either increasing Uex or altering drinking patterns to minimize salt stress. Keywords: antidiuretic hormone, dairy goat, kidney, saline water, water balance.

Change in Wind Renewable Energy Potential Under Stratospheric Aerosol Injections

AbstractWind renewable energy (WRE) is an essential component of the global sustainable energy portfolio. Recently, there has been increasing discussion on the potential supplementation of this conventional mitigation portfolio with Solar Radiation Modification (SRM). However, the impact of SRM on conventional mitigation measures has received limited attention to date. In this study, we explore one part of this impact, the potential effect of one type of SRM, Stratospheric Aerosol Injections (SAI), on WRE. Using hourly output from the Earth System Model CNRM‐ESM2‐1, we compare WRE potential under a medium emission scenario (SSP245) and a high emission scenario (SSP585) with an SRM scenario that has SSP585 baseline conditions and uses SAI to offset warming to approximately SSP245 global warming levels. Our results suggest that SAI may affect surface wind resources by modifying large‐scale circulation patterns, such as a significant poleward jet‐shift in the Southern Hemisphere. The modeled total global WRE potential is negligibly reduced under SAI compared to the SSP‐scenarios. However, regional trends are highly variable, with large increases and decreases in WRE potential frequently reaching 12% across the globe with SAI. This study highlights potential downstream effects of SRM on climatic elements, such as wind patterns, and offers perspectives on its implications for our mitigation efforts.

Climate Change Projections for Stroke Incidence in Taiwan: Impact of 2°C and 4°C Global Warming Level.

This study aimed to establish the exposure-lag-response effect between daily maximum temperature and stroke-related emergency department visits and to project heat-induced stroke impacts under global warming levels (GWL) of 2°C and 4°C. Stroke-related emergency department visits in Taiwan from 2001 to 2020 were identified using the National Health Insurance Research Database (NHIRD). The study population consisted of 1,100,074 initial stroke cases matched with 2,200,148 non-stroke controls. We employed Distributed Lag Nonlinear Models (DLNM) in a case-crossover study to investigate the association between temperature and stroke. Generalized Estimating Equations (GEE) models with a Poisson function were used to correlate high-temperature exposure with annual stroke incidence rates. Projections were made under two global warming scenarios, GWL 2.0°C and 4.0°C, using Coupled General Circulation Model (GCMs). Baseline data from 1995 to 2014 were transformed for spatial distribution at the township level. Geographic Information System (GIS) spatial analysis was performed using Quantum GIS 3.2.0 software. DLNM exposure-lag-response effect revealed that daily maximum temperature exceeding 34°C significantly increased the risk of stroke-related emergency department visits, particularly for ischemic stroke. Under the 2°C GWL scenario, the frequency of days with temperatures surpassing 34°C is projected to rise substantially by the median year of 2042, with a further increase to 92.6 ± 18.0 days/year by 2065 under the 4°C GWL scenario. Ischemic stroke showed the highest increase in temperature-related incidence rates, notably rising from 7.80% under the GWL 2°C to 36.06% under the GWL 4°C. Specifically, the annual temperature-related incidence rate for ischemic stroke is expected to increase significantly by 2065. Regions such as Taichung, Hsinchu, Yilan, and Taitung demonstrated pronounced changes in heat-related ischemic stroke incidence under the GWL 4°C. The findings emphasize the importance of addressing temperature-related stroke risks, particularly in regions projected to experience significant temperature increases. Effective mitigation strategies are crucial to reduce the impact of rising temperatures on stroke incidence and safeguard public health.

Groundwater sustainability in India through nonrice-dominated cropping pattern.

Over-exploitation of groundwater for irrigation caused rapid groundwater depletion in north India, leading to food and water security challenges. However, the crucial role of changing cropping patterns on groundwater savings under the observed and projected warming climate remains unexplored. Here, we show that altering the existing rice-dominated cropping systems in India can be a potential solution for groundwater sustainability under the current and future climate. Satellite and model-based estimates show that north India lost ∼336 and 297 km3 of groundwater, respectively during 2002-2022. We developed optimized crop switching scenarios for groundwater savings considering nutritional requirements, farmers' profit, and crop production. Crop switching considering all the three targets (crop switch one: CSI) and allowing rice replacement with alternate crops (crop switch two: CSII) could save 45 and 91 km3 groundwater, respectively in north India during the observed climate (2002-2022) compared with the current cropping pattern. Altering the current cropping pattern can lead to substantial groundwater savings under the projected future climate without comprising nutritional targets and farmers' profit at the state level. Replacing 37% area of rice with other crops (CSII) can recover 61 to 108 km3 groundwater compared with -13 to 43 km3 with current cropping pattern under the 1.5-3 °C global warming levels. Similarly, under the CSI scenario, 36 to 86 km3 groundwater can be recovered in the future warming world. Moreover, the benefits of crop switching in groundwater saving are higher during the prolonged dry periods compared with the baseline under the warming climate. Therefore, crop switching offers substantial benefits for groundwater sustainability under the current and projected future climate in India.

Projected Changes in Rainfall Extremes over West African Cities Under Specific Global Warming Levels Using CORDEX and NEX-GDDP Datasets

We analyze long-term extreme events in daily precipitation for the period of 1950–2005 and future projections from 2006 to 2100 based on representative concentration pathways (RCP8.5) over West Africa, including twelve major cities of the subregion. The study uses two datasets from the Coordinated Regional Downscaling Experiments (CORDEX) and NASA Earth eXchange Global Daily Downscaled Projections (NEX–GDDP), for their potential to simulate extreme rainfall characteristics over West Africa. CORDEX datasets are dynamically downscaled from 9 General Circulation Model (GCM) and the NEX-GDDP is statistically downscaled from 21 GCM simulations from CMIP5. The ensemble members of each dataset were used for the analysis and evaluated with eight observations. The projected changes in the rainfall indices were analyzed at four Global Warming Levels (GWLs) under the RCP8.5 climate-forcing scenario. The projections from the CORDEX and NEX-GDDP ensembles were compared. Self-Organizing Map (SOM) analysis was used to classify the projected changes from the simulations into twelve groups, based on their characteristics. Both CORDEX and NEX-GDDP models perform well in simulating the frequency and intensities of daily rainfall characteristics for important parts of the domain. However, substantial differences exist between the models and their relative performance varies with the indices. In all cases, NEX-GDDP outperforms CORDEX in stimulating the extreme indices. On the projections, CORDEX showed a wider spread than the NEX–GDDP for RTOT and vice versa for R97.5pTOT for all the GWLs.

Temperature-related mortality burden and projected change in 1368 European regions: a modelling study

Excessively high and low temperatures substantially affect human health. Climate change is expected to exacerbate heat-related morbidity and mortality, presenting unprecedented challenges to public health systems. Since localised assessments of temperature-related mortality risk are essential to formulate effective public health responses and adaptation strategies, we aimed to estimate the current and future temperature-related mortality risk under four climate change scenarios across all European regions. We modelled current and future mortality due to non-optimal temperatures across 1368 European regions, considering age-specific characteristics and local socioeconomic vulnerabilities. Overseas territories were excluded from the analysis. We applied a three-stage method to estimate temperature-related risk continuously across age and spatial dimensions. Age and city-specific exposure-response functions were obtained for a comprehensive list of 854 European cities from the Urban Audit dataset of Eurostat. Regional aggregates were calculated using an aggregation and extrapolation method that incorporates the risk incidence in neighbouring cities. Mortality was projected for present conditions observed in 1991-2020 and for four different levels of global warming (1·5°C, 2°C, 3°C, and 4°C increase) by regions, and subregions using an ensemble of 11 climate models produced by the Coordinated Regional Climate Downscaling Experiment-CMIP5 over Europe, and population projection data from EUROPOP2019. Our results highlight regional disparities in temperature-related mortality across Europe. Between 1991 and 2020, the number of cold-related deaths was 2·5 times higher in eastern Europe than western Europe, and heat-related deaths were 6 times higher in southern Europe than in northern Europe. During the same time period, there were a median of 363 809 cold-related deaths (empirical 95% CI 362 493-365 310) and 43 729 heat-related deaths (39 880-45 921), with a cold-to-heat-related death ratio of 8·3:1. Under current climate policies, aligned with 3°C increase in global warming, it is estimated that temperature-related deaths could increase by 54 974 additional deaths (24 112-80 676) by 2100, driven by rising heat-related deaths and an ageing population, resulting in a cold-to-heat-related death ratio of 2·6:1. Climate change is also expected to widen disparities in regional mortality, particularly impacting southern regions of Europe as a result of a marked increase in heat-related deaths. This study shows that regional disparities in temperature-related mortality risk in Europe are substantial and will continue to increase due to the effects of climate change and an ageing population. The data presented can assist policy makers and health authorities in mitigating increasing health inequalities by prioritising the protection of more susceptible areas and older population groups. We identify the projected areas of heightened risk (southern Europe), where policy intervention aimed at building adaptation and enhancing resilience should be prioritised. European Commission.

Hysteresis of Northern Hemisphere permafrost to carbon dioxide emissions

Abstract Carbon dioxide removal (CDR) is proposed to limit the level of global warming and minimize the impacts of climate crises. However, how permafrost may respond to negative carbon emissions remains unknown. Here, the response of near-surface permafrost in the Northern Hemisphere is investigated based on idealized carbon dioxide (CO2) ramp-up (284.7–1138.8 ppm) and symmetric ramp-down model experiments. The results demonstrate that the timing of the minimum permafrost area lags the maximum CO2 concentration for decades, which is also observed in soil temperatures at different depths and active layer thicknesses. When the CO2 concentration is reversed to the preindustrial level, the permafrost area decreases by ~12% relative to the initial conditions, together with additional warming in the ground temperature at the top of the permafrost, indicating the hysteresis of permafrost to CO2 removal. The most profound hysteretic responses occur at high latitudes for soil temperatures owing to Arctic amplification, while at the southern margins of the permafrost zones for permafrost and active layer thickness that largely linked to the climate state. Moreover, the sensitivity of permafrost and the associated thermodynamic factors to CO2 change is generally lower during the CO2 ramp-down phase than during the ramp-up phase, likely due to the release of stored heat on land. The results reveal the behaviour of permafrost in response to negative carbon emissions, which is informative for the projections of permafrost towards carbon neutral targets. In addition, the results may provide a reference for permafrost-related tipping points (e.g., releasing long-term stored greenhouse gases and destabilising recalcitrant soil carbon) and risk management in the future.

Concurrent extremes in mid-latitude Asia triggered by resonance of multi-scale zonal wind

Abstract Climatic changes worsen concurrent extreme climate events. In July and August of 2022 and 2020, respectively, unexpected concurrent extreme events occurred in mid-latitude Asia. The sudden and severe consequences highlight the importance of a thorough understanding of the drivers of such extreme events, which is crucial for improving predictions and implementing preventive measures to mitigate future risks. By applying multi-scale window transform methodology, a unique mechanism of multi-scale zonal wind resonance is identified, which manifests as a quasi-stationary co-coupling with low-frequency zonal winds. This resonance leads to barotropic instability, triggering abnormal low-frequency Rossby wave behavior in the entrance and exit regions of the quasi-stationary jet stream. Simultaneously, the intensified meridional wind, coupled with adiabatic atmospheric warming, amplifies baroclinic instability, resulting in an enhanced wave pattern and the high concurrence events of 2022. Under long term future global warming levels of 4 °C, the concurrence, strengthened by multi-scale zonal wind resonance, is expected to persist. The mechanism evident in 2022 plays a broader and more significant role in concurrent events compared to the mechanism in 2020. Under the process of warming, resonance phenomena, as observed in 2022, are projected to become more frequent.

Linking local climate scenarios to global warming levels: applicability, prospects and uncertainties

Abstract Global warming levels (GWLs) are increasingly becoming a central concept in climate change studies. In recent years, their integrative quality for climate change impact analysis has been demonstrated, and methodological advancements have helped to compensate for some inherent shortfalls of the concept. However, their applicability at the regional level is debatable, and no study to date has examined the possibility of linking local climate scenarios to GWLs. For the case of Austria, we have evaluated the relation between global and local warming patterns, and whether version changes of global climate models could be incorporated into local climate scenarios by means of the GWL concept, without updating the actual data. We applied the time sampling approach, where GWLs are determined as periods when global mean temperature anomalies cross a certain threshold. GWL periods were sampled both from the global models in the background of the local climate scenarios (CMIP5), and from an equivalent ensemble of newer-generation climate models (CMIP6). Uncertainties resulting from sampling GWLs from different global climate model ensembles were examined, and prospects for local climate change impact assessments were discussed. Accounting for updated global climate model versions might be useful when the changes at certain GWLs are related to fixed reference periods, but temperature increments between GWLs remained relatively constant across model versions, even on the local level. The study bridges a significant gap to link regional and local climate projections to GWLs. Climate change impacts assessments that build on those datasets can benefit from the integrative character of GWLs, making studies comparable across multiple disciplines and model versions, and thus fostering a way to communicate local climate change impacts more comprehensible.

2021 Heatwave Over Western North America: Structural Uncertainty and Internal Variability in GCM Projections of Humidex and Temperature Extremes

AbstractThe 2021 heatwave over Western North America (WNA) led to record‐breaking air temperatures and human‐perceived heat stress (humidex) values. The event was accompanied by drier conditions driven by prolonged atmospheric blocking. During the heatwave, the maximum 6‐day means of humidex and temperature (HX‐6 and TX‐6) exhibited larger anomalies (6.70 and 5.57°C) compared to the 95th percentiles (HX95 and TX95) (4.12 and 3.73°C), relative to 1981–2021 extended summer (June‐September) averages. Extreme indices of humidex show faster and larger increases than those of temperature, reflecting the nonlinear positive relationship between humidex and temperature. Future projections from a multi‐model ensemble of 19 Coupled Model Intercomparison Project Phase six (CMIP6) Global Climate Models (GCMs) clearly show an increase in humidex and temperature extremes, especially under intermediate and high emissions scenarios. Humidex indices (HX‐6 and HX95) show faster and larger increases than temperature indices (TX‐6 and TX95) for the same future years and global warming levels. Controlling for differences in GCM climate sensitivity to greenhouse gas forcing yields robust projections at various global warming levels, reducing the ranges of projected changes from the multi‐model ensemble. At 3.0°C global warming from pre‐industrial, the multi‐model ensemble projects occurrences of HX‐6, TX‐6, HX95, and TX95 over WNA that exceed 2021 levels to occur every 3.9, 1.7, 1.4, and 2.2 years, respectively, increasing to almost annually at 4.0°C.

European hot and dry summers are projected to become more frequent and expand northwards

Heatwaves and dry spells are major climate hazards with far-reaching implications for health, economy, agriculture, and ecosystems. The frequency of compound hot and dry summers in Europe has risen in recent years. Here we present an examination of past extreme summers and compare them to future climate conditions. We use reanalysis data (2001–2022) and model data at three global warming levels: +1.2 °C, +2 °C, and +3 °C for nine selected sub-regions. Key findings indicate a significant increase in the frequency of most extreme past occurrences under 2 °C and 3 °C warming scenarios. For specific summers, the occurrence probability rises by up to 5–6 times from 2 °C to 3 °C. Moreover, our analysis reveals a notable northward shift in the climatology of hot and dry summers under 3 °C warming. The hot and dry climate observed in Eastern Europe under current conditions is anticipated to extend into substantial parts of the Baltic coast, Finland, and Scandinavia.

Contribution of anthropogenic influence to the 2022-like Yangtze River valley compound heatwave and drought event

In August 2022, an unprecedented compound heatwave and drought event (CHDE) lasting 24 days occurred in the Yangtze River valley (YRV), leading to a severe reduction of the crop, fresh water, and power supply. We constructed a joint cumulative probability distribution of heatwave and drought intensity, and found that the lowest probability-based index (PI) of 0.06 in 2022 was estimated as a 1-in-662-year event over the 1961–2022 climate. We then detected the fingerprint of greenhouse gas forcing to the observed PI in a generalized extreme value framework, but not the aerosol forcing, suggesting the leading contribution of greenhouse gas forcing on such extreme CHDE. Furthermore, anthropogenic influence had increased the probability of such CHDE by more than 10 times compared to the counterfactual climate. Also, the PI decreased from about 0.30 at the present climate to about 0.14 at the 3 °C global warming level, indicating that CHDE will become more extreme over YRV.

Hundreds Dying Every day in Karachi as Pakistan Battles Brutal Summer

Global health and livelihoods have been severely impacted by climate change, which is expected to worsen in the future and bring more frequent and intense extreme events (Weiskopf et al,2020). Extreme heatwaves are increasingly common during summertime globally, contributing to an excess of mortality. As climate change continues, it is anticipated that heat-related illness and mortality will rise even more, with higher levels of global warming being associated with greater risk (Ebi et al,2021). Pakistan ranks sixth among nations most susceptible to the effects of climate change (Soomro & Shahid,2024).According to the IPCC, surface temperatures have risen by roughly 1.0°C since the middle of the 19th century and could climb by 1.10°C to 6.40°C in the 21st (IPCC,2018). Pakistan is extremely sensitive to the consequences of climate change as a developing nation, including rising temperatures, variable monsoons, melting Himalayan glaciers, and more frequent and severe extreme weather events. Future disturbances to Karachi's local weather are anticipated because of climate change (Babar et al, 2021). According to a recent BBC report, Pakistan's heatwave has claimed the lives of nearly 500 people. There has been a notable rise in mortality in southern Pakistan due to temperatures above 40°C (104°F) and heavy humidity, which makes it feel like 49°C (120°F). With 141 deaths on 25th May alone, the Edhi ambulance service reported transporting 568 bodies, as opposed to the typical 30 to 40 each day to the Karachi municipal mortuary over the course of six days. The number of persons requesting assistance in hospitals is rising. Each case's precise cause of death is still being investigated (BBC, 2024). According to Soomro and Shahid (2024), Karachi recorded the hottest temperature in the region last month, with the province of Sindh clocking close to 52.2°C. The extreme heat is making life difficult for people in other parts of Pakistan as well. Low winds, high temperatures, and high humidity are the factors that cause heatwaves. When combined with malfunctioning water supply networks, frequent power plant outages, and blackouts, the consequences for those in lower socioeconomic categories in Karachi can be catastrophic. Conversely, in wealthy Karachian areas where petrol generators are typically used to break out blackouts, very few casualties were reported (Hanif, 2017). Pakistan is classified as a mediocre performer with a climate performance ranking of 30th overall. It receives high marks for GHG emissions and energy use, but poor marks for climate policy and very low marks for renewable energy. The absence of strong government organizations devoted to climate concerns impedes efforts despite the urgent need for climate action (SDG 13). As a result, not enough progress has been made in combating climate change (CCPI, 2024). Public health in Karachi would be much improved by addressing issues with cheap, clean energy, sustainable cities and communities, clean water and sanitation, responsible consumption and production, and climate action. Focusing on important problems like dirty water, air pollution, brittle infrastructure, and energy scarcity. Controlling infectious disease outbreaks and lowering respiratory and cardiovascular illnesses associated with air pollution would be made possible by proper sewage and water cleanliness. Heat stroke casualties could be saved by using inexpensive, sustainable energy technologies. These upgrades are the need to solve the environmental and climate-related issues in Karachi. Effective measures must be taken by the government of Pakistan.