Hot Events Research Articles

Scénáře budoucích změn nebezpečných sdružených událostí ve střední Evropě

Many recent high-impact weather and climate events developed due to several concurrent climatic drivers amplifying their negative impacts on society and environment. In this paper, we analyse scenarios of future changes in cold–windy and dry–hot compound events in Central Europe, using an ensemble of CORDEX regional climate models forced by two possible greenhouse gas concentration pathways (low-emission RCP4.5 and high-emission RCP8.5). A distinct decrease of compound cold–windy days was found. At the end of the 21st century, the frequency of these days is projected to decrease by 64% (86%) under the RCP4.5 (8.5) pathway (against the 1970–2000 period). By contrast, climate models simulate longer of dry–hot seasons over Central Europe. In mid-21st century, their median length is projected to increase by 5–20 days regardless of the concentration pathway. At the end of the 21st century, dry–hot seasons are projected to become longer by as much as a whole month under RCP8.5. Although model simulations are to some extent uncertain, scenarios of possible future changes in compound events can be useful in adaptation to ongoing climate change.

How persistent and hazardous will extreme temperature events become in a warming Portugal?

The impact of rising greenhouse gases (GHGs) in the atmosphere on the temperature distributions is felt not only in the mean values but primarily in the extremes. The temperature distributions are becoming slightly flattened and more broadened towards higher values, leading to a decrease in extreme cold events and more importantly to a considerable increase in the frequency and intensity of extreme hot events. These changes are no longer simple projections but are already occurring. It is thus imperative an assessment of the projected changes even under reduced emissions scenarios for the entire 21st century. In this study, a multi-variable ensemble based on 13 EURO-CORDEX high-resolution simulations at 0.11° resolution, was used to analyse the extreme heat events as well as the Universal Thermal Climate Index (UTCI) for such extremes between March and November over Portugal. The 13 simulations have in common three Representative Concentration Pathways (RCP), RCP2.6, RCP4.5 and RCP8.5 as well as data covering a historical period (1971–2000) and three future consecutive periods, 2011–2040, 2041–2070 and 2071–2 100. The results show that severe future heatwaves will develop beyond the extended summer months in all scenarios. Even under a high mitigation scenario (RCP2.6), the number of heatwaves will more than double in number, relative to the historical record. In the high emission scenario (RCP8.5), a sharp increase in the number, severity and areal extension of heatwaves is projected for the end of the 21st century. The analysis of the heat stress indicates that most of the projected future heatwaves will induce heat stress and the projected increase in areal extension and the number of occurrences will have an impact on morbidity and mortality rates simply due to the shear rise in the number of the affected population and the increased frequency of occurrence.

Differential responses of CO2 and latent heat fluxes to climatic anomalies on two alpine grasslands on the northeastern Qinghai–Tibetan Plateau

Discrete extreme heat events, deluges, and droughts will become more frequent and disproportionately affect the processes and functions of grassland ecosystems. Here, we compared the responses of CO2 and heat fluxes to natural extreme events in 2016 in a lower alpine meadow and neighboring upper shrubland on the northeastern Qinghai–Tibetan Plateau. Unlike insensitive sensible heat flux, latent heat flux (LE) increased by 21.8 % in the meadow and by 56.4 % in the shrubland during a dry period and subsequent compound hot-dry period in August. Changes (Δ, data for 2016 minus the corresponding means from other years) in the heat flux at both sites were determined by changes in solar radiation (ΔSwin), as sufficient soil moisture was available. ΔLE was more sensitive to ΔSwin in the open-canopy shrubland, reflecting its greater capacity for evaporative cooling to buffer climate anomalies. CO2 fluxes responded weakly to extreme wet or dry events but strongly when those events were accompanied by exceptional heat. During single or compound hot events, the mean changes in total ecosystem respiration (ΔTER) increased by about 30 % in both grasslands, although ΔTER was more sensitive to changes in the topsoil temperature in the more productive meadow than in the shrubland. The mean changes in gross primary productivity (ΔGPP) fluctuated by <10 % in the warmer meadow but increased by 29.3 % in the cooler shrubland relative to the respective baseline, probably because of the differences in canopy structure and root depth and the consequent high-temperature stress on vegetation photosynthesis. The changes in net ecosystem CO2 exchange (ΔNEE) were significantly related to ΔTER in the meadow and increased by 55.8 %, whereas ΔNEE was controlled mainly by ΔGPP in the shrubland and decreased by 22.4 %. Overall, both alpine grasslands were resistant to rainfall anomalies but susceptible to exceptional warmth, with the differential responses being ascribed to canopy structure and root depth. Our results provide helpful insights based on which the carbon sequestration and water-holding functions of alpine grasslands during future climate change can be predicted.

Soil moisture dominates the variation of gross primary productivity during hot drought in drylands

The frequency and severity of hot drought will increase in the future due to impact of climate change and human activities, threatening the sustainability of terrestrial ecosystems and human societies. Hot drought is a typical type of drought event, high vapor pressure deficit (VPD) and low soil moisture (SM) are its main characteristics of hot drought, with increasing water stress on vegetation and exacerbating hydrological drought and ecosystem risks. However, our understanding of the effects of high VPD and low SM on vegetation productivity is limited, because these two variables are strongly coupled and influenced by other climatic drivers. The southwestern United States experienced one of the most severe hot drought events on record in 2020. In this study, we used SM and gross primary productivity (GPP) datasets from Soil Moisture Active and Passive (SMAP), as well as VPD and other meteorological datasets from gridMET. We decoupled the effects of different meteorological factors on GPP at monthly and daily scales using partial correlation analysis, partial least squares regression, and binning methods. We found that SM anomalies contribute more to GPP anomalies than VPD anomalies at monthly and daily scales. Especially at the daily scale, as the decoupled SM anomalies increased, the GPP anomalies increased. However, there is no significant change in GPP anomalies as VPD increases. For all the vegetation types and arid zones, SM dominated the variation in GPP, followed by VPD or maximum temperature. At the flux tower scale, decoupled soil water content (SWC) also dominated changes in GPP, compared to VPD. In the next century, hot drought will occur frequently in dryland regions, where GPP is one of the highest uncertainties in terrestrial ecosystems. Our study has important implications for identifying the strong coupling of meteorological factors and their impact on vegetation under climate change.

Responses and Post-Recovery of Physiological Traits after Drought–Heatwave Combined Event in 12 Urban Woody Species

The frequency and intensity of droughts combined with heatwave events have increased under climate change, increasing destruction in urban areas and leading to severe impacts on urban plants. These impacts remain poorly understood at the species level. Here, we investigate the effects of a drought–heatwave event on 12 urban woody species using in situ records of the dynamic changes in physiological traits in the field before, during and after the drought–heatwave event to assess resistance and resilience to hot drought. We found the following: (1) Hydraulic and photosynthesis traits showed an instantaneous decline during the hot drought event in the 12 species, with severe drought-induced xylem embolism in hydraulic systems and a high percentage loss of hydraulic conductivity (PLC). (2) The two conifer species were less resistant to hot droughts than broadleaves but capable of post-stress recovery, suggesting that conifers showed better resilience and that broadleaves showed better resistance under hot drought stress. (3) The evergreen species showed strong resistance, while three deciduous species showed strong resilience to hot drought stress. (4) The three shrubs may be more vulnerable to hot droughts than trees, as they showed lower resistance and were not able to recover the current year’s growth.

Field-Measured Hydraulic Traits and Remotely Sensed NDVI of Four Subtropical Tree Species Showed Transient Declines during the Drought–Heatwave Event

Unpredictable drought–heatwave events occur frequently worldwide, causing low water availability (drought) and high temperatures (hot), with consequences for forest decline and mortality. Our knowledge of the potential instantaneous reactions and subsequent recovery of water-related physiological processes and vegetation indices in hot drought events remains unclear. Here, we investigated how the 2022 summer drought–heatwave event in the subtropical regions of China affected hydraulic traits and NDVI values in the forests of four common subtropical tree species. During the hot drought, the NDVI values of all four forests decreased (−31%~−23%), accompanied by leaf scorch and tree crown dieback. Among the four species, a hot drought event caused an instantaneous descent in hydraulic conductivity (Ks, −72%~−31%), stomatal conductance (gs, −94%~−50%), and midday water potential (−40%~−169%), with severe drought-induced stem xylem embolism. A trade-off was found between resistance and resilience in hot-drought-induced hydraulic dysfunction, as species with lower declines in Ks and gs during the hot drought had a shorter recovery in the post-stress phase. This study highlights that the 2022 hot drought event had severe negative instantaneous impacts on the forests of four subtropical tree species, which were reflected both in water-related physiological processes in the field and in remote sensing data from satellites.

Dramatic increase in the probability of 2006-like compound dry and hot events over Southwest China under future global warming

Compound dry and hot events, the combination of high temperature and scarce rainfall, are receiving attention in recent times due to their devastating stress on ecosystems, agricultural production, and public health worldwide. Knowing the risk of compound dry and hot events, particularly for the severe ones on record, is essential for developing effective measures to mitigate the negative impacts. However, most of the existing investigations only focus on the long-term trend of compound dry and hot events during the past decades, and future changes in those record-breaking events remain sparsely reported, especially in China. With a focus on the typical severe compound dry and hot event over Southwest China in summer 2006, this study quantifies the future probability of such compound extreme under various emission and societal development scenarios. Results show that the compound dry and hot event in 2006 is the most severe during 1901–2020, with widespread spatial extent in Southwest China. The observed change in temperature plays a dominant role in the variation of compound severity. Based on Coupled Model Intercomparison Project phase 6 (CMIP6) multi-model simulations, we further show that the maximum ratio of the increase in the area affected by compound dry and hot events to that of 2006 is projected to probably be about twofold under the Shared Socioeconomic Pathway (SSP) 1–2.6 scenario in about 2040, while it would likely climb to nearly triple for the other two scenarios SSP2-4.5 and SSP5-8.5 in about 2060 and 2050, respectively. These findings could provide a support for urgent adaptation and mitigation efforts against compound dry and hot events to mitigate the impact.

The timescale of thermal quench during disruptions in EAST

Since 2015, the timescale of thermal quench (TQ) during disruptions on the EAST tokamak has been examined using electron cyclotron emission and soft x-ray diagnostic systems. The database includes both major disruptions (MDs) and hot vertical displacement events (VDEs), where the TQ duration of the former is within 56–788 μs, and the latter is approximately within 100–3000 μs. In particular, for MDs, the lower bound of TQ duration, indicating the minimum durations at different current plateaus, decreases as the plasma current increases. This decrease is due to the connection length shortening and the plasma temperature increasing. For MDs, two typical TQ processes, single-stage TQ and double-stage TQ, are characterized by different magnetic perturbations. In single-stage TQ, a fast-loss stage is triggered by magnetic perturbation exceeding 4.3 × 10−3 T with a fast growth rate of 1.5 × 10−2 μs−1. In contrast, fast quench is triggered by a slightly smaller magnetic perturbation of 3.6 × 10−3 T in double-stage TQ, and the growth rate 5.3 × 10−3 μs−1 is an order of magnitude smaller than single-stage TQ. For hot VDEs, the plasma temperature collapses step by step from the edge to the core, and every progressive collapse corresponds to a magnetic perturbation, whose growth rate is approximately equal to or less than double-stage TQ. The whole process of TQ energy release can be divided into the transport in a stochastic field within the separatrix and in the scrape-off layer and, according to the typical parameters of EAST, TQ duration in MDs is roughly estimated to be 245 μs by an approximate formula, which is consistent with the experimental results.

On the statistical distribution of temperature and the classification of extreme events considering season and climate change—an application in Switzerland

With the increased occurrence of hot spells in recent years, there is growing interest in quantifying the recurrence of extreme temperature events. However, pronounced temperature anomalies occur all year round, and a reliable classification in terms of the time of occurrence in the year is needed. In this study, we present a novel approach to classifying daily air temperatures that take into account the seasonal cycle and climate change. We model the distribution of the daily Swiss temperatures using the skewed generalized error distribution with four time-varying parameters, thereby accounting for non-Gaussianity in daily air temperature, while the climatic trend is modeled linearly with smoothed northern hemisphere temperature as an explanatory variable. The daily observations are then transformed into a standard normal distribution. The resultant standardized temperature anomalies are comparable within a year and between years and are used for quantile-based empirical classification. The approach is suitable to classify historical and current extreme temperatures with respect to the temperature range expected at the time of the event. For example, a heat wave occurring at the end of June is classified as less likely to occur than a heat wave of similar intensity occurring in mid-July, as is shown for the two 7-day heat waves that struck Switzerland in the summer of 2019. Furthermore, climate change has increased the probability of hot events and decreased the probability of cold events in recent years. The presented approach thus allows a fair classification of extreme temperatures within a year and between years and offers new possibilities to analyze daily air temperature.

Summertime climatic effects of urbanization and their impacts on human thermal comfort in Xiangjiang watershed, South-Central China

Urbanization has been a substantial force to change the natural environment, and several urbanization-related climatic issues, such as urban heat island (UHI) effect, would pose a great threat to public health. However, the climatic effects of urbanization and their possible links with human thermal comfort remain poorly understood. In this study, we examined the impact of urbanization on summertime air temperature, extreme hot events and human-perceived heat stress in Xiangjiang watershed, a typical inland highly urbanized area of China. Results showed that in the context of global warming Xiangjiang watershed experienced extensive summertime warming, especially nighttime warming in the past nearly half-century, and urbanization aggravated the warming effect in urban areas by increasing nighttime air temperature as well, creating the UHI effect. Meanwhile, all three types of extreme hot events, i.e. independent hot days (IHD), independent hot nights (IHN), and compound hot events (CHE) showed increasing trends. Urbanization significantly increased the occurrence, duration and intensity of CHE, which involved both the daytime and nighttime extreme hot temperatures. Urban expansion contributed 51.39%, 30.91% and 25.69% of the increases in occurrence, duration and intensity of CHE, respectively. Besides, increasing air temperature and extreme hot events would inevitably enhance the heat stress on people, especially in the nighttime, and urbanization exacerbated the nighttime discomfort on people with contribution to 26.92% of increases in nighttime heat stress index (HI). Nearly one quarter of summer nights in urban areas have reached very warm level of severe heat situation for human beings in the late stage (1996–2019). Urbanization-induced increases in CHE and nighttime HI caused an aggravation of human heat discomfort since people failed to relief the excess heat stress of daytime at night. This study provided new insights to understand urban climatic effect and its relation to human heat-related comfort.

An innovative application of 5GDHC: A techno-economic assessment of shallow geothermal systems potential in different European climates

Energy consumption for thermal purposes represents the most impacting energy issue in the European building sector. In addition to space heating, space cooling is constantly growing, due also to climate change, which provokes extreme hot events in summer even in moderate climates. To approach this challenge, it is essential to invest in lowering the overall energy demand, to increase the energy conversion efficiencies and to replace fossil fuels with renewable energy sources.The research here presented deals with the European decarbonization goals and focuses on shallow geothermal technology in district thermal systems (DTS), i.e. Geo-5GDHC.The research investigates whether Geo-5GDHC can be cost-effective in different scenarios based on climatic contexts, insulation levels and the possible integration of photovoltaic and thermal technology (PVT).Through the elaboration of proper KPIs and the implementation and use of a tool specifically developed to couple a Geo-5GDHC energy assessment model with an economic analysis (PILEDHC), the research highlights results and guidelines for providing solutions for new and innovative DTS, considering both energy and economic aspects in different contexts.

A visual analysis of NSF thesis research in biosafety from 2001 to 2022

This paper aims to conduct a literature visualization analysis of Chinese papers published by National Natural Science Foundation (NSFC)-funded projects in the field of biosafety in China from the year 2001 to the year 2022. Methods: From the China Knowledge Network database, we set the time period from 1 January 2001 to 31 October 2022 and the Chinese journal literature funded by NSFC projects. The association between the authors of the papers was analyzed using VOSviewer1.6.18. Moreover, CiteSpace6.1.R3 was used to visualize the paper's institutional collaboration, the keywords and the timeline of the papers. Results: It revealed that a few teams, including Tong Yigang, Zhou Yusen, Yang Ruifu and Cao Wuchun as the core, were involved in the NSFC-funded biosafety field. The State Key Laboratory of Biosafety of Pathogenic Microorganisms was the main institutional undertaking unit, and inter-institutional collaboration was more dispersed. Research frontiers are focused on the prevention and management of major emerging and emergent infectious diseases, biotechnology development, application, identification, evaluation and management of unknown risks, etc. Conclusion: From year 2000 to year 2022, the biosafety field focused on funding infectious diseases and epidemiology, and the research direction concentrated on the hot events of society, the development trend of science and technology and national strategic needs. However, there was a trend toward financing being excessively focused in a small number of units and teams and away from the field of microbial drug resistance. It is suggested that the NSFC guidelines and directions should include special projects related to microbial drug resistance, and the selection of projects should be appropriately enriched in terms of research teams, research institutions and research directions.

Increasing compound drought and hot event over the Tibetan Plateau and its effects on soil water

Climate extremes, such as droughts and hot events, are expected to become more frequent and intense as the Earth’s climate continues to change. Indeed, they will likely pose increasingly serious threats to both humanity and the sustainability of natural ecosystems. Compound climate extremes may significantly impact regions sensitive to climate change, such as the Tibetan Plateau (TP), although there is currently a notable lack of research on compound extreme drought and hot events (CEDHs) that affect this region. We employed the copula model using the standardized precipitation index (SPI), standardized temperature index (STI), and standardized soil moisture index (SSMI) to explore patterns of changes in CEDHs and assess the risk of soil water scarcity under CEDHs. Our results showed that the probability of CEDHs increased significantly across the TP over time, mainly due to hot events becoming more common. The conditional probability of soil water scarcity (SSMI < -0.8) under moderate CEDHs (defined as SPI < − 0.8 and STI > 0.8) increased by 81.8% and 21.4% over time compared with those under individual hot and dry conditions, respectively. Our findings have important implications for mitigating the impacts of CEDHs under future global warming scenarios.

Potential for surprising heat and drought events in wheat-producing regions of USA and China

Previous analyses of the possibility of global breadbasket failures have extrapolated risks based on historical relationships between climate and yields. However, climate change is causing unprecedented events globally, which could exceed critical thresholds and reduce yields, even if there is no historical precedent. This means that we are likely underestimating climate risks to our food system. In the case of wheat, parts of the USA and China show little historical relationship between yields and temperature, but extreme temperatures are now possible that exceed critical physiological thresholds in wheat plants. UNprecedented Simulated Extreme ENsemble (UNSEEN) approaches use large ensembles to generate plausible unprecedented events, which can inform our assessment of the risk to crops. We use the UNSEEN approach with a large ensemble of archived seasonal forecasts to generate thousands of plausible events over the last 40 years and compare the results with historically observed extreme temperature and precipitation. In the US midwest, extreme temperatures that would have happened approximately 1-in-100-years in 1981 now have a return period of 1-in-6 years, while in China, the current return period is on the order of 1-in-16 years. This means that in the US midwest, extreme temperatures that used to have a 1% chance to occur in 1981 now have a 17% chance to occur in any given year, while in China, the chance increased from 1% to 6%. Record-breaking years exceeding critical thresholds for enzymes in the wheat plant are now more likely than in the past, and these record-breaking hot years are associated with extremely dry conditions in both locations. Using geopotential height and wind anomalies from the UNSEEN ensemble, we demonstrate that strong winds over land pull dry air towards the regions these during extremely hot and dry unseen events. We characterize plausible extremes from the UNSEEN ensemble that can be used to help imagine otherwise unforeseen events, including a compound event in which high impacts co-occur in both regions, informing adaptation planning in these regions. Recent temperature extremes, especially in the US midwest, are unlikely to be a good proxy for what to expect in the next few years of today’s climate, and local stakeholders might perceive their risk to be lower than it really is. We find that there is a high potential for surprise in these regions if people base risk analyses solely on historical datasets.

Detectable Anthropogenic Intensification of the Summer Compound Hot and Dry Events Over Global Land Areas

AbstractCompound hot and dry events (CHDEs) pose an increasing threat to global warming and have received growing attention in recent decades. We conducted a detection and attribution analysis (D&amp;A) using the optimal fingerprint technique to analyze the changes in observed CHDEs at continental and sub‐continental scales from 1961 to 2014. The responses of CHDEs changes to anthropogenic (ANT), greenhouse gases (GHG), aerosols (AER), and natural (NAT) forcings were obtained from the Coupled Model Intercomparison Project phase 6 forcing experiment. In a two‐signal D&amp;A analysis that considered ANT and NAT simultaneously, ANT signals were robustly detected and separated from NAT in all continental domains and more than 65% of subcontinental domains (29 out of 44 domains). The trend attributed to the ANT forcing is comparable to the observed trend over domains where the ANT signal is detectable. We also conducted a three‐signal D&amp;A analysis that regressed observation onto GHG, AER, and NAT simultaneously. The GHG signals were detectable in all continents except Oceania, and it contributed dominantly to the observed trend over 22 out of 29 regions where ANT signals had emerged. Multivariate biases correction can largely reduce the models' biases in simulating the marginal distribution and the dependence structure, which can provide a more accurate future risk of CDHEs. We found that limiting global warming to 1.5℃ rather than 2.0℃ can significantly mitigate the impact of compound events in most areas of global land, particularly in South America, Africa, and Oceania.

A novel multi-objective scheduling model for grid-connected hydro-wind-PV-battery complementary system under extreme weather: A case study of Sichuan, China

Affected by extreme hot and dry weather events, the power supplied by hydropower is seriously insufficient in Sichuan province during the summer of 2022, causing severe power shortage and incalculable economic losses for the society. Therefore, a novel multi-objective scheduling model based on grid-connected hydro-wind-solar-battery energy resources combining flexible reserves is proposed to collaboratively guarantee the power supply reliability of both the contracted long-distance power transmission and the local electricity demand under extreme hot and dry weather. The intermittent nature of water inflow, wind speed, solar irradiance, and load is considered, and the multi-scenarios are produced using Latin Hypercube Sampling method. In this work, thermal plants are regarded as flexible reserves for easing the load shedding level of local load. The McCormick's Envelope method is implemented to linearize the power production model of the hydropower station. A multi-objective model, including minimum penalty cost of load shedding and carbon dioxide emission, is proposed to achieve the economic-environmental equilibrium of the power system. The proposed multi-objective optimal hybrid energy complementary strategy is transformed into a single objective model via ε-constraint method, and the fuzzy satisfying method is introduced to select the best compromise solution in the Pareto Front. The meteorological information of the summer of 2022 is collected to verify the effectiveness of this proposed mixed-integer-linear-programming energy complementary model based on a hydropower station on the Jinsha River in Sichuan province, China. Numerical experiments demonstrate that the proposed model is efficient and can enhance the reliability of real-world power systems under extreme hot and dry weather. A set of policy suggestions have been provided for Sichuan province to develop the power grid to face the extreme weather effect.

Research on Public Opinion Guidance Mechanism of Tik Tok Hot Event Explanation Short Video

With the continuous development of technology, in recent years, short video shows a rapid development trend, both its user scale and the number of applications has been rapidly improved. Tik Tok, as one of the larger short video platforms in China, has become an entertainment tool for people by virtue of its comprehensive audio-visual presentation. Tik Tok short video, because of its diversified communication elements, can quickly capture hot events and arouse widespread concern, stimulate the social synergy of public opinion and promote the construction of a good social order; At the same time, it will help to improve the style of departments and institutions, make up for the lack of legal system, enhance communication and understanding from all walks of life, and finally realize the positive value of public opinion mobilization. Based on the development status and characteristics of Tik Tok short video, this paper focuses on the core issues of positive energy transmission and public opinion guidance of Tik Tok APP, explores the public opinion guidance mechanism of Tik Tok short video explaining hot events, and discusses the possible problems in the process of public opinion generation. In order to contribute to the related research.

Research on two-stage public opinion evolution configuration path based on fuzzy-set qualitative comparative analysis

PurposeUnder the background of coexistence of information overload and information fragmentation, it is of great significance to identify influencing factors and reveal the evolution logic of public opinion for public opinion governance.Design/methodology/approachTaking 24 hot social events as research cases, firstly, the evolution process of public opinion was divided into initial stage and response stage. Secondly, eight antecedent variables were extracted for qualitative comparative analysis of fuzzy sets. Finally, the configuration path of public opinion evolution results was summarized.FindingsThe research showed that compared with the initial stage, the influencing factors in the reaction stage played a key role in the continuous evolution of public opinion. The influencing factors in the initial stage and response stage played an indispensable role in promoting the evolution of public opinion to calm down.Practical implicationsThis research can provide reference for regulators to timely grasp the initiative, discourse power and leadership of public opinion development.Originality/valueResearch on the two-stage configuration path of public opinion evolution is helpful to clarify the key factors affecting the evolution trend of online public opinion of hot events.

Probability of continued local-scale warming and extreme events during and after decarbonization

Although achieving net-zero emissions is very likely to stabilize the long-term global temperature, the possibility of continued warming and extreme events could cause those efforts to be perceived as a failure if there is an expectation that stabilizing global temperature will also stabilize local and regional climate. Leveraging decarbonization scenarios from multiple global climate models, we find that much of the world faces >30% probability of decadal warming after net-zero CO2 emissions are achieved, with most areas exhibiting sustained probability of extreme hot and wet events. Further, substantial fractions of the global population and gross domestic product could experience post-net-zero warming, including hundreds of millions of people and trillions of dollars in the United States, China and India during the decade following net-zero. This likelihood suggests that some of the most populous, wealthy, and powerful regions may experience climatic conditions that could be perceived—at least in the near-term—to indicate that climate stabilization policies have failed, highlighting the importance of adaptation for ensuring that communities are prepared for the climate variations that will inevitably occur during and after decarbonization.

Trends and Return Frequencies of Hot and Cold Extreme Events in Northern Vietnam from 1961–2018

This study used observed data of maximum daily temperature (Tx) and average daily temperature (T2m) from 48 meteorological stations to investigate hot (SU35, Tx≥35 ºC), severe hot (SU37, Tx≥37 ºC), cold (FD15, T2m≤15 ºC), and severe cold (FD13, T2m≤13 ºC) events in Northern Vietnam from 1961 to 2018. Trends and frequency characteristics of SU35, SU37, FD15, and FD13 were calculated and discussed. Results showed a significant increase in the number of hot and severe hot days, while there was a notable decrease in the number of cold and severe cold days in the northern region of Vietnam. The North Central region experienced the highest increase in the number of severe hot days, ranging from 2 to 5 days per decade. In contrast, the Northwest and Northeast regions had the highest decline in the number of cold days, with a rate of 3.5 to 4.5 days per decade for cold and 1 to 3 days per decade for severe cold days. The return values of Tx for the SU35 and SU37 thresholds for 10-year and 50-year return periods exceeded 41 ºC in the Northern Delta and North Central regions, which was higher than other regions (37–40 ºC). Meanwhile, the return values of T2m for the FD15 and FD13 thresholds were the lowest in the Northeast, typically ranging from 3 to 7 ºC for a 50-year return period. These results highlight the necessity of planning adaptation measures to address changes in hot and cold extreme events, particularly in the key industrial areas of Northern Vietnam, in the context of climate change.&#x0D; Keywords: Climate change, extreme hot and cold events, generalized Pareto distribution, trend analysis.&#x0D; &#x0D;