Warming Scenarios Research Articles

Summer primary production of Arctic kelp communities is more affected by duration than magnitude of simulated marine heatwaves.

Fjord systems in the Norwegian Arctic are experiencing an increasing frequency and magnitude of marine heatwaves. These episodic heat stress events can have varying degrees of acute impacts on primary production and nutrient uptake of mixed kelp communities, as well as modifying the biogeochemical cycling in nearshore systems where vast areas of kelp create structural habitat. To assess the impact of future marine heatwaves on kelp communities, we conducted a 23 day mesocosm experiment exposing mixed kelp communities to warming and heatwave scenarios projected for the year 2100. Three treatments were considered: a constant warming (+1.8°C from the control), a medium magnitude and long duration heatwave event (+2.8°C from the control for 13 days), and two short-term, more intense, heatwaves(5 day long scenarios with temperature peaks at +3.9°C from the control). The results show that both marine heatwave treatments reduced net community production, whereas the constant warm temperature treatment displayed no difference from the control. The long marine heatwave scenario resulted in reduced accumulated net community production, indicating that prolonged exposure had a greater severity than two high magnitude, short-term heatwave events. We estimated an 11°C temperature threshold at which negative effects to primary production appeared present. We highlight that marine heatwaves can induce sublethal effects on kelp communities by depressing net community production. These results are placed in the context of potential physiological resilience of kelp communities and implications of reduced net community production to future Arctic fjord environmental conditions.

Quantitative assessment of the effects of rising temperature on the grain protein of winter wheat in china and its adaptive strategies

With advancements in genetics and technology, wheat yields have continuously increased, but grain quality has remained stagnant or even decreased in recent decades. The effects of temperature on the future grain quality of winter wheat in China are unknown. This study used an improved WheatGrow model, along with two future temperature scenarios, to quantify the regional impacts of temperature increases on grain protein in China and aimed to find effective strategies to adapt to the impact of temperature increases on quality. Compared with those in the baseline period, the protein concentration of wheat grains in the main winter wheat production region of China increased by 0.27% and 0.41% under the 1.5 ℃ and 2.0 ℃ temperature increase scenarios, respectively. However, the grain protein concentrations in the Sichuan Basin of Medium and Weak Gluten Wheat Subregion (Ⅴ) decreased. The temperature rise was estimated to increase the proportion of strong gluten-type wheat but reduce the proportion of medium gluten-type wheat, with the proportion of weak gluten-type wheat changing slightly. Advanced planting date was projected to increase the grain protein concentration in the Northern Strong Gluten Wheat Subregion (Ⅰ), the Northern of Huang-Huai Strong and Medium Gluten Wheat Subregion (Ⅱ), the Southern of Huang-Huai Medium Gluten Wheat Subregion (Ⅲ) and the Yangzi River of Medium and Weak Gluten Wheat Subregion (Ⅳ), whereas a delayed planting date reduced the protein concentration in subregions Ⅰ, Ⅱ, and Ⅲ. In addition, the grain protein concentration was not significantly affected in the higher high-temperature threshold varieties in the southern winter wheat production region under the global warming scenarios. However, if more strong gluten-type wheat is required in the northern China in the future, varieties with lower high-temperature thresholds can be selected without considering wheat yields. Moreover, increasing the nitrogen fertilizer application rate could further increase the wheat protein concentration under future warming scenarios, and the protein concentration of wheat was more sensitive to the nitrogen fertilizer application rate in the northern winter wheat production region than in the southern region. These findings are crucial for improving grain quality across different wheat production regions of China in the future.

The urban island: climatic suitability of Linepithema humile (Hymenoptera: Formicidae) and the role of cities in the invasion of the Western Palearctic

AbstractUrban environments often present environmental conditions that facilitate the introduction and establishment of nonnative and invasive species. These can expand their range into areas with unfavorable climates by taking advantage of the ecological and climatic homogenization of cities, bypassing the ecological barriers presented by the surrounding environment. One way to monitor the expansion of these species is using potential distribution models. We used as a model species the Argentine ant, Linepithema humile (Hymenoptera: Formicidae) whose invasion has caused serious consequences for biodiversity and economic losses worldwide. We used the average result of six different algorithms and used climatic variables and population density as a proxy for the urbanization level in the Western Palearctic to build the predictive model. The model indicates this ant prefers to inhabit areas with Mediterranean and Temperate Oceanic climates and that its suitability depends on two main factors: the continentality (temperature annual range) and the degree of urbanization. The species is predicted to be absent in areas with large temperature contrasts throughout the year, particularly in rural and peri‐urban areas (i.e. adjacent to urban areas) of inland regions. Conversely, the species has a predilection for coastal and urban areas where environmental conditions are attenuated by the influence of the sea or the “urban heat island” effect in the case of inland cities. In this sense, cities act as “bioclimatic islands” facilitating the establishment of the Argentine ant as a reservoir, enlarging its distribution into climatically nonoptimal areas, and promoting its future expansion in a scenario of global warming and socioeconomic change.

Transcriptional Changes Underlying the Degradation of Plant Community in Alpine Meadow Under Seasonal Warming Impact.

Global warming is exhibiting a seasonal trend, while different seasons have different warming variations. However, the impact of seasonal warming on plants remains unclear. This study employed Open Top Chambers (OTCs) to simulate future seasonal warming scenarios in alpine meadow. The study examined plant community dynamics following long-term seasonal warming. The transcriptional and physiological responses of two dominant species (Kobresia pygmaea and Stipa purpurea) were examined. Results suggest that seasonal warming effects are correlated with both the duration of warming and the season which warming occurs. A long annual warming duration, especially growing season warming, made plants confront various stresses. K. pygmaea adopted a stress-avoidance strategy, showing a negative response, and leading to population decline or disappearance. This kind of dieback had also been observed in other Cyperaceae species. Meanwhile, due to positive responses, S. purpurea adopted a stress-tolerance strategy and overcame the impact of warming, partially gained the dominance over Cyperaceae species. Overall vegetation coverage and plant community diversity decreased over the years. These results reveal the impact of seasonal warming to plants, explaining the reasons for changes in plant communities under seasonal warming and providing new insights for future plant conservation under seasonal warming.

Vital rate responses to temperature lead to butterfly population declines under future warming scenarios

Vital rate responses to temperature lead to butterfly population declines under future warming scenarios

Interplay of UV-filter pollution and temperature rise scenarios on Mytilus galloprovincialis health: Unveiling sperm quality and adult physiology, biochemistry, and histology insights

Addressing the impacts of emerging contaminants within the context of climate change is crucial for understanding ecosystem health decline. Among these, the organic UV-filters 4-methylbenzylidenecamphor (4-MBC) and benzophenone-3 (BP-3) are widely used in cosmetics and personal care products. Their unique physico-chemical properties, along with their growing commercialization and consumption, have made them ubiquitous in aquatic environments through both direct and indirect releases, raising significant concerns about their potential threats to inhabiting biota. Additionally, increasing surface water temperatures exacerbate ecological risks, making it imperative to understand the implications for non-target species at different biological levels. This study investigated the short- and long-term effects of UV-filters 4-MBC or BP-3, at ecologically relevant concentrations, combined with current and predicted warming scenarios, on the performance and male reproductive health of Mytilus galloprovincialis mussel populations. Using biomarkers across sub-cellular, cellular, tissue, and individual levels, the study revealed significant physiological and biochemical impairments in both sperm cells and adults exposed to UV-filters. Temperature emerged as the primary driver influencing mussel responses and modulating the impacts of 4-MBC/BP-3, emphasizing their sensitivity to temperatures outside the optimal range and interactive effects between stressors. Specifically, sperm motility declined with increasing UV-filter concentrations, while temperature alone influenced ROS production, leading to compromised mitochondrial activity and DNA damage in the presence of combined stressors, indicative of potential reproductive impairments. Adults exhibited high UV-filter bioconcentration potential in whole tissues, compromised physiological status, morphophysiological changes in digestive glands, oxidative stress, and alterations in metabolic capacity, antioxidant defences, and biotransformation mechanisms, correlating with UV-filter exposure and temperature increase. Among the UV-filters tested, 4-MBC was the most detrimental, especially when combined with warming. Overall, this study underscores the vulnerability of M. galloprovincialis to cumulative stressors and highlights the importance of employing a multi-biomarker approach to assess and mitigate the impacts of stressors on coastal ecosystems.

Asymmetric Warming of Day and Night Benefits the Early Growth of Acer mono Seedlings More Than Symmetric Warming.

Asymmetric warming refers to the difference between the increase in daytime maximum temperature and the increase in nighttime minimum temperature and has been documented in temperate regions. However, its impacts on seedling growth have been largely ignored. In this study, seedlings of a widely distributed tree species, Acer mono Maxim., were exposed to both symmetric warming (SW) and asymmetric warming scenarios (day warming [DW], night warming [NW] and diurnal asymmetric warming [DAW]). Compared to control, all warming scenarios were found to enhance belowground biomass. DW promoted the seedling growth, while NW reduced the stem biomass. DAW did not impact the total biomass relative to the control. Compared to SW, DAW advanced phenology, increased indole-3-acetic acid content and chlorophyll content, which enhanced total biomass and stored more NSC in the root. Future DAW would be not beneficial to the growth of A. mono seedlings by comparing with the control. This research encourages further exploration of tree growth experiments under asymmetric warming conditions, as most studies tend to underestimate the warming effects on plant growth by focusing on SW. Incorporating the responses of seedling physiology and growth to non-uniform diurnal warming into earth system models is crucial for more accurately predicting carbon and energy balances in a warmer world.

The Influence of Large‐Scale Spatial Warming on Jet Stream Extreme Waviness on an Aquaplanet

AbstractThe effect of modified equator‐to‐pole temperature gradients on the jet stream by low‐level polar warming and upper‐level tropical warming is not fully understood. We perform aquaplanet simulations to quantify the impact of different sea surface temperature distributions on jet stream strength, large wave amplitudes and extreme waviness. The responses to warming in the waviness metrics Sinuosity Index and Local Wave Activity are sensitive to the latitude range over which they are calculated. Therefore, we use a latitude range that accurately represents the position of the jet. The uniform warming scenario strengthens the jet and reduces large wave amplitudes. Reductions in meridional temperature gradients lead to weakened mid‐latitudinal jet strength and show significant decreases in large wave amplitudes and jet stream waviness. These findings contradict the mechanism that weakened jet streams increase wave amplitudes and extreme jet stream waviness. We conclude that weakened jet streams do not necessarily become wavier.

Quantifying and Rating the Energy Resilience Performance of Buildings Integrated with Renewables in the Nordics under Typical and Extreme Climatic Conditions

The future buildings and society need to be resilient. This article aims to propose a novel concept of the energy resilience framework and implement a color-based rating system to quantify and rate the energy resilience performance of buildings in Nordic climates. The objective is to conduct a comparative analysis between old (1970s) and new (2020s) single-family buildings integrated with renewable energy sources and storage, assessing their energy resilience performance for heating during power outages, under extreme and typical climatic conditions. The study utilizes dynamic simulation of the buildings and renewable energy systems, conducting parametric studies to calculate proposed resilience indicators and rate their resilience performance, employing both passive and active methods. The total costs of the design variables are also calculated for economic evaluation. Given the complexities arising from climate change, the article uses a simplified method to synthesize regional climate to consider extreme climate change impacts on energy resilience performance. For the old building lacking PV, the robustness duration increased from 1 h to 3 h, and the degree of disruption (DoD) varied from 0.545 to 0.3 in extreme cold to warm climate scenarios, with the higher DoD number indicating worse performance. The impact of the season within the same climate scenario is also evident, as the habitability and robustness durations increased during spring compared to winter. The resilience improved with PV and battery. The new building showed that the robustness duration increased from 3 to 15 h, habitability durations increased, and the DoD varied from 0.496 to 0.22 from extreme cold to warm climates without renewables and storage. With the integration of PV and battery, the new building was able to achieve a lower DoD and better performance with lower PV and battery capacity, compared to the old building. Furthermore, utilizing the color grading method (red to green), optimal technical solutions and corresponding design variables were identified for each building type and climate scenario that could support decision-making. The total cost of the optimal solutions varied, as new buildings required lower costs to reach optimal performance. However, for optimal resilience performance during extreme cold climate scenarios, higher costs are required for each building type. The proposed resilience framework, indicators, color grading system, and costing could potentially support improvements in building regulations, ensuring the development of optimally resilient buildings, particularly in the face of extreme climatic conditions.

Opposing Changes in Indian Summer Monsoon Rainfall Variability Produced by Orbital and Anthropogenic Forcing

AbstractFuture projections indicate that Indian Summer Monsoon Rainfall (ISMR) faces a “wetter and more variable” climate. However, the reasons remain uncertain. The Last Interglacial (LIG) climate provides a potential analog for future warming. Investigating ISMR responses to these two warming scenarios could help understand the causes of ISMR changes. Using PMIP4 simulations, we find that ISMR became “wetter and more stable” during the LIG, contrasting the future climate. The opposing changes in ISMR variability are related to divergent changes in the El Niño‐Southern Oscillation (ENSO) amplitudes, ENSO‐ISMR relationships, and ENSO‐induced large‐scale atmospheric circulation anomalies. During the LIG, orbital forcing weakened ENSO variability and its impacts on ISMR. A westward positioning of ENSO shifted the atmospheric circulation anomalies westward, suppressing extreme ISMR anomalies. These processes are supported by atmospheric model simulations. Our results suggest that different warming patterns (dynamic effects) are more critical than moisture‐increasing effects in controlling regional climate variability.

Turning up the heat: Effects of temperature on agonistic acoustic communication in the two-spotted goby (Pomatoschistus flavescens)

Acoustic communication is linked to fitness traits in many animals, but under the current scenario of global warming, sound signals can be affected by rising temperatures, particularly in ectothermic organisms such as fishes. This study examines the effect of water temperature in acoustic communication in the two-spotted goby, Pomatoschistus flavescens. To address this, we looked at the effect of different temperatures on the acoustic features of drums produced by males during territorial defence and related it with their auditory sensitivity. We also analysed the differences in acoustic features between male agonistic drums and previously reported male courtship sounds, to better understand how acoustic communication may be affected by different temperature conditions. We recorded two-spotted goby males during territorial intrusions for 10 min at 16 °C, 19 °C, and 21 °C in the laboratory. We found that agonistic drums were shorter, had fewer pulses and shorter pulse periods at higher temperature, in contrast with the peak frequency that remained unaffected. Male agonistic and mating drums (recorded in a previous study) at 16 °C only differed in pulse period, which was higher in mating drums. Hearing thresholds obtained with Auditory Evoked Potentials at 16 °C, revealed higher sensitivity below 400 Hz, matching the main energy of agonistic and mating sounds. Our findings suggest that increasing temperature could potentially affect acoustic communication in this species by reducing the duration of agonistic drums, which might hinder effective communication. Nevertheless, the impact may not be significant as there was a good match between the best hearing sensitivity and the peak frequency range of their calls, which was not influenced by temperature. As fish and other organisms are increasingly threatened by multiple anthropogenic stressors, including warming, future research should address how changes in water temperature impact acoustic communication within a more realistic multi-stressor scenario.

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.

Impacts of climate change on diarrhoeal disease hospitalisations: How does the global warming targets of 1.5-2°C affect Dhaka, Bangladesh?

Dhaka is one of the world's densely populated cities and faces significant public health challenges including high burden of diarrhoeal diseases. Climate change is intensifying existing environmental problems including urban heat island effect and poor water quality. While numerous epidemiological studies have linked meteorological factors to diarrhoeal diseases in Bangladesh, assessment of the impacts of future climate change on diarrhoeal diseases is scarce. We provide the assessment of climate change impacts on diarrhoeal disease in Dhaka and project future health risks under climate change scenarios. About 3 million acute diarrhoea cases presenting to the Dhaka Hospital of the International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b) during 1981-2010 were linked to daily temperature, rainfall and humidity and association investigated using time series adapted negative binomial regression models employing constrained distributed lag linear models. The findings were applied to climate projections to estimate future risks of diarrhoea under various global warming scenarios. There was a significantly raised risk of diarrhoea hospitalisation in all ages with daily mean temperature (RR: 3.4, 95% CI: 3.0-3.7) after controlling for the confounding effects of heavy rainfall, humidity, autocorrelations, day of the week effect, long-term time, and seasonal trends. Using the incidence rate ratio (IRR) of 1.034, temperature increases based on the global warming targets of 1.5-2°C could result in an increase of diarrhoea hospitalisations by 4.5-7.4% in all age groups by the 2100s. These effects were more pronounced among <5 children where the predicted temperature increases could raise diarrhoea hospitalisation by 5.7% - 9.4%. Diarrhoea hospitalisation will increase significantly in Dhaka even if the global warming targets adopted by the Paris Agreement is reached. This underscores the importance of preparing the city for management and prevention of diarrhoeal diseases.

Thermal balance in Andean lizards: A perspective from the high mountains

AbstractHigh Andean lizards in the Andes face numerous challenges in high‐altitude environments characterized by significant temperature, spatial and temporal variations. These factors greatly influence their thermal characteristics and adaptive strategies for coping with temperature fluctuations. This study aims were to investigate the thermal biology of high mountain lizards (&gt;2000 m) inhabiting the Andes Mountain range, using information from existing literature, and to identify the potential impacts of the original climate change scenarios developed in this study. Within the Andes, high‐altitude species are primarily found in families like Liolaemidae, Gymnophthalmidae, Tropiduridae, Anolidae and Leiourisauridae. Notably, we found in the literature that the higher body temperatures and maximum critical temperatures in southern species compared to those closer to the tropics. Typically, diurnal and seasonal temperature variations have a significant impact on the body temperature of these high‐altitude lizards, but their adaptive behaviours and physiological mechanisms enhance their resistance to extreme temperatures. Populations situated below the equator often exhibit higher body temperatures and maximum critical temperatures, largely due to their exposure to higher ambient temperatures during summer. With all global warming scenarios indicating temperature increases in latitudinal regions, tropical high‐altitude lizards, historically less thermally adaptable, may be particularly susceptible to these temperature rises. It is crucial to consider that additional factors, such as species activity patterns, thermal resource availability and diminishing suitable thermal habitats, will also play a pivotal role in shaping the future of these lizard species, making the situation even more complex and challenging.

City-Scale, City-Relevant Climate Hazard Indicators Under 1.5°C, 2.0°C, and 3.0°C of Global Warming

This paper describes a data set of 14 temperature- and precipitation-related climate hazard indicators, calculated for 996 cities at the 1.5°C, 2.0°C, and 3.0°C global warming scenarios.

Stronger aggregation reduces temperature sensitivity of soil organic carbon decomposition in croplands

AbstractThe temperature sensitivity (Q10) of soil organic C (SOC) decomposition is an important parameter to predict C dynamics under climate change. Given that SOC is mainly protected by aggregates and minerals, differentiating the Q10 of the two C fractions helps to explain bulk soil C dynamics. In the present study, we collected agricultural soils from adjacent paddy and upland areas in mid‐temperate (Mollisols) and subtropic (Ultisols) regions of China. We employed density fractionation to separate aggregate‐protected and free mineral‐associated C fractions of soil samples and determined the Q10 of SOC and the two C fractions at 15 and 25°C incubated conditions. Results showed that the Q10 of SOC for Mollisols were lower than that for Ultisols, with an exception of aggregates in upland soils. Aggregate‐protected C had lower Q10 than free mineral‐associated C, except in the upland Mollisols. The Q10 of SOC was negatively correlated with the proportion of C protected in aggregates, whereas it was positively correlated with the proportions of mass or C of free minerals. Given that the mass and C proportion of aggregates in bulk soils of Mollisols were 271% and 80% higher than of Ultisols, respectively, the SOC of Mollisols exhibited lower Q10 than Ultisols. Therefore, stronger soil aggregation and higher proportion of aggregate‐protected C contributed to the lower temperature sensitivity of SOC in Mollisols. Consequently, agricultural practices aimed at promoting soil aggregation will alleviate SOC loss under future global warming scenarios.

Crisis resilience in medical practices and clinics

Climate change because of anthropogenic greenhouse gas emissions increasingly triggers extreme weather events. Of all the continents, Europe is warming the fastest. Heat and drought, forest fires and floods will worsen in Europe even in optimistic global warming scenarios, affecting living conditions across the continent. Extreme weather events threaten energy and food security, ecosystems, infrastructure, water resources, financial stability, and people's healthcare. Many of these risks have already reached critical levels and could take on catastrophic proportions without immediate, decisive action. This paper outlines current challenges for medical practices and clinics in the context of climate change and provides examples and guidance for strengthening crisis resilience. Selective literature review on the different requirements for crisis resilience in practices and clinics was performed. Medical practices and clinics achieve crisis resilience by high degrees of adaptability and flexibility. They prepare for climate change-related challenges and are, therefore, able to protect themselves and maintain their function in the healthcare system. Recent weather events in Germany revealed insufficient resilience among the healthcare sector; hence, improvements are necessary. Changing environmental conditions urgently require the healthcare sector to adapt and effectively strengthen crisis resilience in order to ensure that critical infrastructure remains functional and the population has access to healthcare.

Carbon pricing: Necessary but not sufficient

Global carbon pricing has been recognized as one of the most efficient mechanisms that can be used to reduce CO2 emissions, but questions remain about the magnitude of the price and the speed of implementation. We examine this important issue by extending the Dynamic Integrated Climate and Economy (DICE) model to estimate global carbon prices that will be required to reach various warming scenarios. Our analysis suggests that while carbon pricing can play a critical role in reducing greenhouse gas emissions and limiting global warming, it must be supported by other policy measures and innovations in order to reach the Paris Agreement targets. In particular, we found there was no feasible carbon pricing scenario that was high enough to limit emissions sufficiently to achieve anything below 2.4°C warming on its own. We project significant differences in global physical costs due to climate change across various warming scenarios, which range from a total (to 2100) of $152tr under a 1.5° scenario to $765tr under 4.2° warming.

Impacts of current and climate induced changes in atmospheric stagnation on Indian surface PM2.5 pollution

Severe PM2.5 pollution threatens public health in India. Atmospheric stagnation traps emitted pollutants, worsening their health impacts. Global warming is anticipated to alter future stagnation patterns, impacting the effectiveness of air quality policies. Here, we develop a region-specific index that characterizes meteorological conditions driving stagnation and associated PM2.5 increases. Applying this index to an ensemble of climate models and global warming scenarios, we find that future stagnation changes result from both global CO2-driven circulation changes and local aerosol-driven meteorological responses. By 2100, we project an increase in winter stagnation in the Indo-Gangetic Plain (IGP) of 7 ± 3 days that leads to an increase in PM2.5 of ~7 ug/m3 in a high-warming and high-aerosol scenario. However, annual stagnation occurrences decrease across most of India. Thus, stringent air quality regulations in the IGP during winters will be critical to reduce surface PM2.5 concentrations as climate warms. Such regulations will directly improve air quality while reducing future stagnation occurrences, providing additional air quality benefits.

Historical and Future Asymmetry of ENSO Teleconnections with Extremes

Abstract El Niño-Southern Oscillation (ENSO) is the dominant source of climate variability globally. Many of the most devastating impacts of ENSO are felt through extremes. Here we present and describe a spatially complete global synthesis of extreme temperature and precipitation relationships with ENSO. We also investigate how these relationships evolve under a future warming scenario under high greenhouse gas emissions using fourteen models from the Coupled Model Intercomparison Project Phase 6 (CMIP6) ensemble. Firstly, we demonstrate that models broadly capture observed ENSO teleconnections to means and extremes using the Twentieth Century Reanalysis version 3 (20CRv3). The models project that more regions will experience an amplification of the historical ENSO teleconnection with mean temperature and precipitation than a dampening under a high-emissions climate projection. The response of the ENSO teleconnection with extremes is very similar to the mean response, with even larger changes in some regions. Hence, regions that are predicted to experience an amplification of the ENSO teleconnection under future warming can also expect a comparable amplification in the intensity of extremes. Furthermore, models that suggest greater amplification of ENSO amplitude also tend to exhibit greater intensification of teleconnections. Future changes in regional climate variability may be better constrained if changes in ENSO itself are better understood.