Warm Nights Research Articles

Analysis of Climate Change Indices in Musanze District, Rwanda

This study used daily rainfall, minimum temperature, and maximum temperature data from the Rwanda Meteorology Agency (Meteo Rwanda) for the years 1983 - 2016 to analyze climate change indices in the Musanze district of Rwanda. Rainfall and temperature extreme indices were determined using the methodology provided by Expert Team on Climate Change Detection Monitoring Indices (ETCCDMI). Climate Data Tool (CDT), which is R-based package developed by International Research Institute for Climate and Society (IRI) was used to compute the indices. Sen's slope estimator and the modified Mann-Kendall (m-MK) test were both applied to identify trends and determine the degree of change. The Monthly Temperature (TXx, TXn, TNx, and TNn) indices generally showed a warming in the eastern and a cooling in the western parts of the district, according to the trend results; however, the Minimum tail of temperature indices showed a slightly reduced cooling which is a sign of warm nights and hot days in highland areas of volcanic region. For the same period, the district's eastern regions have higher precipitation intensity and wetness, which gradually declines toward the middle and western regions. In addition, a considerable upward trend in the annual total precipitation for days above the 95th percentile (very wet days) and the annual count for precipitation equal or greater than 20 mm (very heavy precipitation days). Additionally, temperature indices showed a large rise in the minimum and maximum values of daily minimum temperatures, annual minimum and maximum values of daily maximum temperatures, and the percentage of days with daily maximum temperatures above the 90th percentile (warm days). In view of these evolving trends in weather and climate patterns, the study recommends local farmers and other stakeholders involved in socioeconomic activities in the district to implement the necessary climate change mitigation and adaptation measures.

Climate extremes and their impacts on agriculture across the Eastern Corn Belt Region of the U.S.

The Eastern Corn Belt Region (ECBR) is an important agricultural sector for the U.S. This study analyzes the climate extremes over the contemporary (1980–2018) and future (2036–2099) periods over the ECBR. We evaluated the performance of 32 downscaled models from the U.S. Global Change Research Program's Localized Constructed Analogs (LOCA) of the Coupled Model Intercomparison Project (CMIP5) to simulate extreme temperature and precipitation indices. The LOCA downscaled models were evaluated for the recent past against the National Aeronautics and Space Administration (NASA)-supported gridded observational dataset DAYMET. Results reveal key trends throughout the region that are consistent with previous studies, including significant increases in extreme minimum temperatures, reduction of cold nights, increase of warm nights, and decreases in diurnal temperature ranges. Much of the region demonstrates extreme warming trends in the coldest night of the year (more than 5 °C) and an increase in the heaviest precipitation events over 1980–2018. An optimal model ensemble (OME) was constructed using a Kling-Gupta Efficiency and Bhattacharyya coefficient evaluation to construct a comprehensive ranking procedure. Having outperformed a standard multi-model ensemble approach, the OME was used to evaluate the future changes of extreme climate indices under RCP4.5 and RCP8.5 scenarios. Though the OME showed consistently strong warming throughout the ECBR, variability among the optimal models and across watersheds is quite significant, especially for precipitation indices. Thus, constraining the uncertainty in future climate models, specifically as it relates to agriculture decisions that support climate-resilience, remains a challenge.

Potential future malaria transmission in Odisha due to climate change

Future projections of malaria transmission is made for Odisha, a highly endemic region of India, through numerical simulations using the VECTRI dynamical model. The model is forced with bias-corrected temperature and rainfall from a global climate model (CCSM4) for the baseline period 1975–2005 and for the projection periods 2020s, 2050s, and 2080s under RCP8.5 emission scenario. The temperature, rainfall, mosquito density and entomological inoculation rate (EIR), generated from the VECTRI model are evaluated with the observation and analyzed further to estimate the future malaria transmission over Odisha on a spatio-temporal scale owing to climate change. Our results reveal that the malaria transmission in Odisha as a whole during summer and winter monsoon seasons may decrease in future due to the climate change except in few districts with the high elevations and dense forest regions such as Kandhamal, Koraput, Raygada and Mayurbhanj districts where an increase in malaria transmission is found. Compared to the baseline period, mosquito density shows decrease in most districts of the south, southwest, central, north and northwest regions of Odisha in 2030s, 2050s and 2080s. An overall decrease in malaria transmission of 20–40% (reduction in EIR) is seen during the monsoon season (June-Sept) over Odisha with the increased surface temperature of 3.5–4 °C and with the increased rainfall of 20–35% by the end of the century with respect to the baseline period. Furthermore, malaria transmission is likely to reduce in future over most of the Odisha regions with the increase in future warm and cold nights temperatures.

Different xylogenesis responses to atmospheric water demand contribute to species coexistence in a mixed pine–oak forest

Seasonal patterns of wood formation (xylogenesis) remain understudied in mixed pine–oak forests despite their contribution to tree coexistence through temporal niche complementarity. Xylogenesis was assessed in three pine species (Pinus cembroides, Pinus leiophylla, Pinus engelmannii) and one oak (Quercus grisea) coexisting in a semi-arid Mexican forest. The main xylogenesis phases (production of cambium cells, radial enlargement, cell-wall thickening and maturation) were related to climate data considering 5–15-day temporal windows. In pines, cambium activity maximized from mid-March to April as temperature and evaporation increased, whereas cell radial enlargement peaked from April to May and was constrained by high evaporation and low precipitation. Cell-wall thickening peaked from June to July and in August–September as maximum temperature and vapour pressure deficit (VPD) increased. Maturation of earlywood and latewood tracheids occurred in May–June and June–July, enhanced by high minimum temperatures and VPD in P. engelmannii and P. leiophylla. In oak, cambial onset started in March, constrained by high minimum temperatures, and vessel radial enlargement and radial increment maximized in April as temperatures and evaporation increased, whereas earlywood vessels matured from May to June as VPD increased. Overall, 15-day wet conditions enhanced cell radial enlargement in P. leiophylla and P. engelmannii, whereas early-summer high 15-day temperature and VPD drove cell-wall thickening in P. cembroides. Warm night conditions and high evaporation rates during spring and summer enhanced growth. An earlier growth peak in oak and a higher responsiveness to spring–summer water demand in pines contributed to their coexistence.

Long-term trends in daily extreme air temperature indices in Ireland from 1885 to 2018

Long-term instrumental series are crucial to analyse extreme air temperature indices and to examine modern climate warming within a historical context. This research provides the first assessment in Ireland of the frequency, duration, intensity and geographical distribution of the daily extreme air temperature indices recommended by the ETCCDI (Expert Team on Climate Change Detection and Indices) and based on long-term rescued, quality-controlled and homogenised data. Prior analysis of air temperature indices in Ireland had focused on the period since the second half of the 20th century, where digital data were readily available. Earlier estimations of long-term air temperature trends in Ireland focused on non-homogenised data from a small network of stations. For this research, 11 long-term (1885–2018) maximum and minimum air temperature series were analysed to assess seasonal and annual trends and construct extreme air temperature indices in Ireland. The non-parametric Mann-Kendall test was employed to test the statistical significance of the maximum and minimum air temperatures and indices trends (p < 0.05). Significant increasing trends were assessed in the seasonal and annual maximum and minimum air temperature series in Ireland, with greater increases in the spring and autumn seasons. Significant increasing trends were determined in the warm days (+6.8 days), warm nights (+7.5 nights), warm spell duration index (+3.9 days), growing season length (+22 days), coldest night (+2.7 °C) and coldest day (+1.5 °C) in the period 1885–2018 in Ireland. In the same period, significant decreasing trends were identified in the cold days (−9.3 days), cold nights (−7 nights), frost days (−13.7 days), cold spell duration index (−6.9 days) and diurnal air temperature range (−0.1 °C) in Ireland. The results follow global patterns presented in the Six Assessment Report of the Intergovernmental Panel on Climate Change. The findings of this research will be crucial to assist stakeholders and policymakers in defining climate action, adaptation and mitigation plans in response to shifting trends in air temperature extremes.

Uncertainties in projections of climate extremes indices in South America via Bayesian inference

AbstractHistorical simulations and projections of climate extremes indices of precipitation and temperature were analysed over South America until the end of the 21st century through 31 general circulation models (GCMs) under four Representative Concentration Pathways. Simulations were compared with reanalysis data, and a Bayesian inference method was used to assess the uncertainties involved in the multi‐model climate projections. Regarding the precipitation extremes indices, the GCMs' simulations reasonably approached the reanalysis data, but with heterogeneous biases, both in sign and in the location of the highest values. The temperature extremes indices presented the smallest biases when compared to precipitation. Projections show a gradual growth of precipitation extremes events as the analysed radiative forcing scenario increases, both in magnitude and extent, over a large part of South America. Projections also indicate a decrease in cold days and nights and an increase in warm days and nights, more pronounced in the equatorial region. Bayesian inference method smoothed changes in precipitation extremes events, both in magnitude and extent, compared to the simple GCMs' ensemble mean. There was no considerable variation in the temperature indices when applying the Bayesian inference. Finally, the probability density functions resulted in a predominance of multimodal and wide curves for the precipitation indices, showing great uncertainties in the GCMs' results, differently from those for the temperature indices, where the GCMs presented good agreement represented through unimodal and narrow curves.

Trend and Indices Analysis of Temperature and Precipitation in Order to Find the Impact of Climate Change in Metu District, Southwestern Ethiopia

Climate change is one of the greatest challenges faced by humankind as it poses an existential threat to many aspects of the current social–ecological landscape of natural and human systems. A set of temperature data for trend and compound indices derived using daily resolution climatic time series data was examined to assess climate change from 1982 to 2019 used for trend and indices analysis. This study was undertaken to analyze temperature trend and precipitation indices in Metu, southwestern of Ethiopia. The study employed Mann-Kendall’s test to detect change in temperature trends and R-limdex for analyze the trend of temperature and precipitation indices. Results for temperature trend analysis for Metu district indicated significant increasing trends at 1%; overall, the observed trends were statistically significant at 1% and 5%. On the other hand, the distribution of the annual precipitation index trends indicated that the negative and positive significant trends mainly occurred in the study area. In terms of temperature indices, all stations have shown consistent patterns for every extreme temperature index. Increasing annual trend magnitudes in six temperature indices (i.e., warm nights, Max. Tmin, Min. Tmax and Max Tmax. The study suggests strategies to enhance the adaptive capacity of agricultural systems and to reduce the likelihood of production risks. Keywords: Climate Change: Precipitation; Temperature; Trend: Induces DOI: 10.7176/JNSR/13-9-02 Publication date: May 31 st 2022

Evaluation of CMIP6 models in the representation of observed extreme temperature indices trends in South America

The consequences of climate change are particularly noticeable through extreme events, which have already changed in intensity and frequency worldwide. This study aims to evaluate the ability of 33 CMIP6 models to simulate the observed trends of four extreme temperature indices in South America during the period 1979–2014. We use daily minimum and maximum temperatures from an observational database, ERA5 reanalysis, and CMIP6 models to estimate the international indices: cold nights, warm nights, cold days, and warm days. Trends are calculated using Sen’s slope for different seasons and spatial scales (continental, sub-regional, and at each grid point) and tested with the Mann–Kendall test. All databases agree on an increase (decrease) in the frequency of warm (cold) extremes in South America, with the most intense changes in the austral spring. In particular, the warm nights index and the northern sub-regions of South America show the most pronounced trends. In contrast, in the southern sub-regions of South America, the observations do not indicate significant trends of the minimum temperature indices, which differ from the trends estimated by the CMIP6 ensemble median and most of the individual models. In general, the ensemble median simulates significant long-term changes at almost all grid points, unlike the observations and reanalysis. Finally, the simulated trends related to minimum temperature are slightly better represented than those related to maximum temperatures. Nevertheless, neither model stands out as the best, and all of them have difficulty simulating trends, especially for cold days.

Analysis of Climate Variability and Its Impact on Crop Yield Over Waghemra Zone, Ethiopia

Climate variability manifested by seasonal rainfall and temperature variability greatly affects agricultural crop production under rain-fed conditions (main source of income for rural communities). Therefore, this study has focused on analyzing the impacts of climate variability on rain-fed wheat and sorghum production in Waghemra Zone, Ethiopia. Daily rainfall and temperature data were collected from National Meteorological Agency of Ethiopia and crop yield data was collected from Central Statics Agency of Ethiopia. Temporal variability of rainfall, temperature and crop yield was analyzed using coefficient of variation (CV) and standardized anomaly method. The rainfall and temperature trends were assessed via Mann-Kendall test and Sen’s slope estimator. The impacts of climate variability on crop yields were evaluated using correlation and regression analysis. The rainfall analysis exhibited large inter-annual and seasonal variation both in amount and distribution. The rainfall has showed decreasing trends in Belg and increasing in both annual and Kiremt season. Moreover, the detected trends are not significant. In contrast, minimum and maximum temperature showed significantly increasing trends at annual and seasonal time scales. The number of warm days and nights has increased and the number of cold days and nights has decreased. The regression analysis revealed that climate variability over the study area has differential effects on the yield of Wheat and Sorghum with coefficient of determination 86% and 84%, respectively. The observed rainfall and temperature variability has posed major risks to rain-fed agriculture and specific adaptation strategies are needed to cope with the risks, sustain farming and improve food security.

Warmer Nights Are Adding Fuel to Nighttime Fires

Cool, moist nights are rarer than they were a few decades ago, and that’s giving wildfires an edge over crews trying to hold fire lines.

Evaluation of nonlinear dynamic patterns of extreme precipitation and temperatures in central England during 1931–2019

Abstract Since climate change has altered extreme precipitation and temperature patterns, further study of these patterns is essential. The examination of precipitation and temperature patterns is of great significance to water engineers, water resources management, and hydrological studies. Accordingly, this study explored the nonlinear dynamic patterns and their sources governing extreme precipitation and temperatures using multifractal, shuffling, surrogating techniques, and extreme climate indices. The temperature and precipitation data regarding central England (1931–2019) were collected and used for analysis. The results of extreme climate indices demonstrated climate change in the study area. Besides, the multifractal analysis indicated that all indices’ time series were characterized by multifractality. Despite the fact that multifractality of the maximum 1-day precipitation, minimum of maximum temperature, and maximum of maximum temperature was predominantly produced by correlation properties (long-range correlations between small and large local fluctuations), the multifractal characteristics of the warm nights were due to a probability density function (PDF) predominance. Moreover, multifractal properties of the diurnal temperature range, maximum 5-day precipitation, maximum of minimum temperature, minimum of minimum temperature, cool nights, and cool and warm days were produced by the identical extent of correlation properties and the PDF.

Warm nights increase Fusarium Head Blight negative impact on barley and wheat grains

The disease known as Fusarium Head Blight (FHB) is one of the most devastating cereal diseases, among which Fusarium graminearum and Fusarium poae have been isolated to be the main etiological agents in cereal crops such as barley and wheat. Currently, global climate change is one of the major concerns worldwide, and temperature is likely to be one of the most affected variables in the future. However, it is unknown how these changes will affect fungal diseases such as FHB. The present research aimed to study the F. graminearum/F. poae-barley/wheat pathosystem under future climatic conditions. The effects of the increase in night temperatures (3 °C) on disease variables, grain quality, and mycotoxin contamination were evaluated under field conditions over three years (2016, 2017, and 2018). For both crops, the results showed that warm nights favoured F. graminearum development over F. poae, reducing grain quality parameters and increasing the mycotoxin concentration significantly. The results obtained along the present work provide a better understanding of the F. graminearum/F. poae-barley/wheat pathosystem and the basis for potential future research related to climate change studies under field conditions directly impacting food quality and safety.

Future changes of hot extremes in Spain: towards warmer conditions

One of the most relevant effects of climate change is its influence on the frequency and intensity of extreme events. The analysis and understanding of these events are of great importance due to the probability of causing environmental and social damage. In this study, we investigate changes in extreme hot temperature events over Spain for the near future (2021–2050) in relation to a control period (1971–2000) by using regional climate model simulations from the EURO-CORDEX project. The projection results show a significant increase in the number of extremely warm temperatures throughout the area. A significant strong increase in warm days and warm nights is projected over the domain. Simulations also project more frequent summer days and tropical nights over most parts of the region. The most significant increase in relation to the present climatology corresponds to warm nights, while simulations corresponding to tropical nights project the smallest changes.

A study on the effects of climate change on viticulture on Santorini Island

The Mediterranean basin is regarded as one of the regions the most affected by climate change in the world. Traditionally, viticulture in this region copes with high temperatures, heat waves and drought. Such particularly extreme conditions, which induce severe abiotic stress on plants, are expected to intensify due to the predicted climate changes in the future. Our study focuses on the viticulture of Santorini Island, located in South Aegean (Greece). Vines have been cultivated on Santorini Island for thousands of years on their own roots owing to the phylloxera-free volcanic soil of the island. The vineyards of Mediterranean regions are already encountering difficulties because of ongoing climate change. The aim of this study was to analyse chronological climate data, evaluate the trends in the change of climate parameters and bioclimatic indices and correlate them with viticultural indices. In brief, the average annual temperature has increased in the last 45 years by almost 4 °C and a significant increase in the frequency of days with high temperatures has been recorded. Bioclimatic indicators correspond to warmer climates with warmer nights and longer periods of drought. Finally, it appears that the high temperatures occurring during the critical stages of the development and differentiation of the vine seem to affect production in the following growing season, while earlier harvest dates and higher sugar content than 45 years ago are observed.

Spatio-temporal analysis of precipitation, temperature and drought from 1985 to 2020 in Penang, Malaysia

AbstractThis study aims to analyze the spatial and temporal variability of precipitation, temperature and drought in Penang from 1985 to 2020. The trend and magnitude changes in climate series were tested using the Mann–Kendall test and Sens’ slope methods. A significant increasing trend of annual precipitation was detected in the middle and northern parts of Penang mainland by 21.38 and 35.01 mm/decade. Annual mean maximum temperature increased significantly on Penang Island and the middle of Penang mainland at the rates of 0.25 and 0.34 °C/decade, while annual mean minimum temperature increased significantly for all stations from 0.36 to 0.52 °C/decade, showing increases of warm nights in the past few years. Extreme drought events (SPI-3 &amp;gt; −2) over Penang were mostly occurred during the strong El Niño years, e.g. 1988–1989, 1997–1998, 2010–2011 and 2014–2016. The number of drought events is higher during the 2001–2010 (4–11 events) period as compared to the 1991–2000 (6–9 events) and 2011–2020 (7–8 events). Interestingly, the 2011–2020 period tends to have a shorter drought duration, but more intense droughts have been observed, particularly on Penang Island and the northern and southern parts of Penang mainland.

Tenderness

Tenderness Mary Milstead (bio) I return to the image of her bare feet—they are small and white, and I am drawn to her softness, which is familiar to me. Telling my mother's story requires this sort of time travel. I know her well, from her silver-white hair down to her painted toenails, but I didn't know her when it happened. It would be another four years before I was born. On a recent summer visit to my home in Portland, my very Texan mother and I sat on my back porch in the afternoon sun. I offered her a foot rub and she accepted, sliding off her flip-flops. She loves the heat, and is always cold when she visits, but we were lucky enough that August visit to be bathed in sunshine—finally, it was warm enough. It was our last afternoon before she flew back home, so we were savoring our time together. She reached down and showed me with her fingers where the pressure point was for her lungs, just below the bone at the ball of her foot. ________ That night, before anything happened, she had been sitting on a low wall looking out at the city lights. Legs crossed, flip-flops dangling from her toes. Her hair was long and black, wavy and parted in the middle. It was mid-January, but a warm night. 1972. She was a nineteen-year-old out on a date with her boyfriend, and she doesn't remember what they were talking about. They hadn't been there long, and it was nice out. [End Page 59] Earlier they'd been at a potluck with a group of friends, and when they'd left, Michael suggested they stop for a while at Mt. Bonnell, a popular overlook with a view of Lake Austin and the city lights in the distance. They'd never been there together before. My mother told me that when he first suggested it, she felt nervous. She was clear that it wasn't any kind of premonition—she never sensed the impending tragedy until it was upon them—just a general sense that it was getting dark. And of course good girls avoided places that might be dangerous at night. But she was with Michael, and he was a great guy: she was safe. She thought, really, that just being with a man meant being safe. It usually did. She and Michael were newly dating, but they'd known each other for a while. He worked as a manager at a natural health food store and was part of her tight circle of friends—mostly young, mostly college students, people interested in spiritual growth and love and peace. She and Michael had talked about marriage, and she thought she might spend the rest of her life with him. So she had a momentary twinge of fear, but it didn't last, and by the time she was walking up the stone steps toward the top of Mt. Bonnell, she was mostly calm and happy, enjoying the night. They sat and talked on a low stone wall with a perfect view. It was just the two of them up there that night, at least as far as they could tell. There was a parked VW Bug in the clearing, but no other people. And so, when one of her flip-flops fell into the dirt just below, she didn't reach down to get it. She heard it land with a soft thud and figured she'd just grab it when they left. Instead, they were soon interrupted by a voice in the dark behind them. "Turn around, and don't make any trouble." Two men, a gun. My mother was not the type of girl to make trouble. And she knew instantly that this was not a joke, not some kind of prank or mistake, no matter how surreal it felt. She would do everything they told her to do. Within a few minutes, one of the men was holding her off to the side of the clearing by her long black hair. The other man was standing by the parked...

Recent Climatology (1991-2020) and Trends in Local Warm and Cold Season Extreme Temperature Days and Nights in Arabia.

The Arabian Peninsula (Arabia) is among the places to have experienced the greatest amount of warming during recent decades, and this trend is projected to continue. Specifics related to the characteristics (frequency, duration, and intensity) of extreme temperature events (ETEs) over Arabia as a whole are either largely outdated or limited only to specific areas. The seasonal ETE definitions commonly used in local studies are neither climatological- nor phenomenon-based. Using a novel and straightforward framework, the seasons of four extreme temperature types (extreme warm days/nights (EWDs/EWNs) and extreme cold days/nights (ECDs/ECNs)) were identified on the simultaneous basis of event occurrence and impact times. Assessments of ETE frequency, duration, and intensity and their recent changes were then provided based on the most recent climate data (1991–2020). Results showed that the use of traditional seasonal definitions (e.g., meteorological seasons) tends to assume a spatiotemporal homogeneity in the seasonality of ETEs and their potential risk levels throughout the year. The developed framework distinguished months with events that have larger potential impacts together with their local seasons. ETE seasons were found to vary at the regional and local scales and are better defined at both the local and phenomenon levels. Early extreme warm events were hotter, and those at locations with longer local warm seasons demonstrated higher intensities. ECDs tended to be more frequent at coastal locations, whereas ECNs were more frequent over southwestern Arabia. Early and late extreme cold events were much colder than those occurring mid-season. Trend analyses revealed generally increasing regional trends in the frequency of extreme warm events, whereas extreme cold events have declined. The duration (i.e., consecutive occurrences) and intensity of EWNs have been increasing at more locations, suggesting that urgent attention is needed within such an arid and hot climate type in which nighttime stress relief is already very limited.

Heat Wave Trends in Southeast Asia: Comparison of Results From Observation and Reanalysis Data

AbstractSoutheast Asia (SEA), a region climatologically important but limited by data availability, is suffering from serious scarceness of heat wave (HW) research. Using the observational and reanalysis data, we find that in most parts of SEA, HWs are becoming more frequent, longer‐lasting, and stronger, and affect more land areas. The increasing trends of HW characteristics defined by minimum temperatures are larger than those by maximum temperatures, alarming a situation of anomalously warm night. Magnitude of yearly hottest HW event increases faster, and duration of yearly longest HW shows significant trends in more areas than their average counterparts. ERA5 reproduces well the HW trends defined by daily minimum temperatures, but underestimate those by maximum temperature. The data set CHIRTS improves on daily maximum temperature and associated HW trends, but deteriorates on daily minimum temperature. This study highlights the importance of high‐quality data, either observational or reanalysis, on the HW study in SEA.

Observed trends in extreme temperature events over northern part of the Korean Peninsula during 1960–2019 and a comparative overview

The aim of the study is to estimate the trend in extreme temperature events in the northern part of Korean Peninsula during 1960–2019, as well as to conduct a comparison experiment with the other representative results, all trends are examined based on quality-controlled daily maximum and minimum temperature data from 37 weather stations. Results are as follows. First, frost days (FD0) and ice days (ID0) showed a clear downward trend, whereas warm days (SU25) and warm nights (TR20) experienced an obvious uptrend, with SU25 exceeding TR20, while very hot days (TX35), extreme hot days (TX37) and very extreme hot days (TX39) showed abrupt increasing trends, especially twice in TX37 and six times in TX39, respectively. Both of cold nights (TN10) and cold days (TX10) decreased by about −0.7d/decade, hot nights (TN90) and hot days (TX90) increased by 0.6d and 1.0d/decade, respectively. Second, as compared with to representative results in global by the relevant reference and study period, all uptrends in TR20, SU25 and annual maximum of daily maximum temperature (TXx) were significantly higher than those in most regions in China, SU25 and TR20 were mostly greater than those in most regions, except for some regions in Europe. In particular, TR20 upward trend exceeded any other region's results. Meanwhile, TX10 and TNn experienced stronger downward and upward tendencies than those in whole China respectively. Especially, TNn experienced the strongest upward trend in comparing with the others. Overall, results revealed hot weather frequency and nighttime warm events over the study area have experienced a larger increasing trend than those in global land.

Reduced Risks of Temperature Extremes From 0.5°C less Global Warming in the Earth's Three Poles

AbstractFuture projection of temperature extremes in the “Earth's three poles” (the Arctic, Antarctica, and Third Pole‐Tibetan Plateau [TP]) is of importance to risk assessment and policymaking owing to the high sensitivity to climate change in these regions. In this study, future projections of four extreme temperature indices were constructed after the application of a bias correction method in models of Phase 6 of the Coupled Model Intercomparison Project (CMIP6). The reduced intensification of temperature extremes in the Earth's three poles if warming can be limited to 1.5°C instead of 2°C above the pre‐industrial level was examined. Results showed that all the extreme temperature indices show significant increasing trends under both the SSP2–4.5 and SSP5–8.5 scenarios over the Earth's three poles (SSP: Shared Socioeconomic Pathway). For the coldest night (TNn), warmest night (TNx), and warmest day (TXx), the greatest increase by the end of the 21st century under SSP5–8.5 occurs in the Arctic, followed by the TP and finally Antarctica. For the coldest day (TXn), the greatest increase occurs in the Arctic, followed by Antarctica and finally the TP. If global warming can be limited to 1.5°C rather than 2°C, the intensification of TNn, TNx, TXn, and TXx in the Arctic (Antarctica/TP) under SSP5–8.5 is projected to reduce by 66% (21.7%/44.26%), 50.31% (54.79%/60.52%), 71.58% (12.91%/65.81%), and 41.73% (81.3%/57.34%), respectively, and the results are similar for SSP2–4.5. Therefore, keeping a lower warming target is essential for reducing the risk of extreme events in the Earth's three poles.