Nighttime Warming Research Articles

Suitable temperature indicator for adverse health impacts in sub-tropical cities: a case study in Hong Kong from 2010-2019.

Heat-health warning systems and services are important preventive actions for extreme heat, however, global evidence differs on which temperature indicator is more informative for heat-health outcomes. We comprehensively assessed temperature predictors on their summer associations with adverse health impacts in a high-density subtropical city. Maximum, mean, and minimum temperatures were examined on their associations with non-cancer mortality and hospital admissions in Hong Kong during summer seasons 2010-2019 using Generalized Additive Models and Distributed Lag Non-linear Models. In summary, mean and minimum temperatures were identified as strong indicators for mortality, with a relative risk(RR) and 95% confidence interval(CI) of 1.037 (1.006-1.069) and 1.055 (1.019-1.092), respectively, at 95th percentile vs. optimal temperature. Additionally, minimum temperatures captured the effects of hospital admissions, RR1.009 (95%CI: 1.000- 1.018). In stratified analyses, significant associations were found for older adults, female sex, and respiratory-related outcomes. For comparison, there was no association between maximum temperature and health outcomes. With climate change and projected increase of night-time warming, the findings from this comprehensive assessment method are useful to strengthen heat prevention strategies and enhance heat-health warning systems. Other locations could refer to this comprehensive method to evaluate their heat risk, especially in highly urbanized environments and subtropical cities.

Warming suppresses grassland recovery in biomass but not in community composition after grazing exclusion in a Mongolian grassland

We conducted a 4-year temperature manipulation experiment in a Mongolian grassland to examine the effect of daytime and nighttime warming on grassland recovery after grazing exclusion. After constructing a livestock exclusion fence in the grassland, we established daytime and daytime-and-nighttime warming treatments within the fenced area by a combination of open-top chambers (OTC) and electric heaters. We measured the numbers of plants and aboveground biomass by species after recording percentage vegetation cover every summer for three warming treatments inside the fence—non-warming, daytime warming, and daytime-and-nighttime warming—and for the grassland outside of the fence. OTCs increased daytime temperature by about 2.0 °C, and heaters increased nighttime temperature by 0.9 °C during the growing period. Grazing exclusion had little effect on grassland biomass but reduced the abundance of poorly palatable species and modified plant community composition. Daytime warming decreased soil moisture and lowered aboveground biomass within the fenced grassland but had little effect on plant community composition. Nighttime warming lowered soil moisture further but its effects on grassland biomass and community composition were undetectable. We concluded that recovery of plant biomass in grasslands degraded by grazing would be lowered by future climate warming through soil drying. Because warming had little effect on the recovery of community composition, adverse effects of warming on grassland recovery might be offset by improving plant productivity through mitigation of soil drying by watering. Soil drying due to nighttime warming might have detectable effects on vegetation when warming persists for a long time.

Silicate Application Alleviated the Depressive Impacts of Nighttime Warming on the Rice Growth, Yield and Quality in Southern China

ABSTRACTNighttime warming decreased single rice production in southern China, while silicate supply increased the yield and stress resistance. It is still unclear regarding the impacts of silicate application on the growth, yield and quality in rice under nighttime warming. A field experiment was conducted to investigate the impacts of silicate application on the growth, yield and quality during rice growing period under nighttime warming. The warming was set at two levels, that is, ambient temperature (CK) and nighttime warming (NW). The open passive nighttime warming was used in this study, that is, rice canopy was covered with aluminium foil reflective film at night (19:00–6:00). Silicate fertiliser (steel slag) was applied at two levels, that is, Si0 (0 kg SiO2·hm−2) and Si1 (200 kg SiO2·hm−2). The results indicated that, compared with the control, the average nighttime temperature on rice canopy and at 5 cm soil layer increased by 0.51°C–0.59°C and 0.28°C–0.41°C during the rice growing period, respectively. Under nighttime warming, silicate supply increased the dry weight of shoot, total dry weight of the whole plant and yield by 64.1%, 55.3% and 7.1% at the filling‐maturity stage, respectively. Silicate application significantly reduced dry matter translocation rate with 15%–18%, but significantly increased the root‐shoot ratio with 0.39–0.41 in rice. Under nighttime warming, silicate supply significantly increased milled rice rate, head rice rate and total starch content by 2.3%, 2.5% and 41.8%, respectively. Nighttime warming reduced the yield by decreasing the number of effective panicle, seed setting rate and 1000‐grain weight, but increasing empty chaff grain. Silicate supply increased the yield by increasing the number of effective panicle, filled grains per panicle, seed setting rate and 1000‐grain weight, but reducing empty chaff grain. This study suggests that silicate supply can effectively alleviate the suppressive effects of nighttime warming on single rice growth, yield and quality in Southern China.

Effects of Warming and No-Tillage on Soil Carbon, Nitrogen, Phosphorus and Potassium Contents and pH of an Alpine Farmland in Tibet

There are still great uncertainties about effects of climate warming and no-tillage on soil carbon, nitrogen, phosphorus and potassium contents and pH in alpine farmlands. A warming (control; daytime warming, DW; nighttime warming, NW; all-day warming, DW + NW) and no-tillage (no-tillage vs. tillage) experiment was conducted in an alpine farmland of the Lhasa, Xizang since 2015. Soil organic carbon, total nitrogen, total phosphorus, total potassium (TK), available nitrogen, available phosphorus, available potassium, dissolved organic carbon (DOC), active organic carbon, particulate organic carbon (POC), light fraction organic carbon, and heavy fraction organic carbon contents and pH at four depths (0–5, 5–15, 15–25, and 25–35 cm) were measured. Warming effects on concerned soil variables differed with warming time, soil depth, and no-tillage. No-tillage effects on concerned soil variables differed with warming-time (daytime, nighttime, and all-day warming) and soil depths. Therefore, daytime warming and nighttime warming have different effects on soil variables, although the effects of nighttime warming on soil variables are not always greater than those of daytime warming. Effects of daytime warming and nighttime warming on soil variables are not simple addition or subtraction effects. There are interactions between diurnal asymmetrical warming and no-tillage on soil variables.

Nighttime Warming Reduced Copper Concentration and Accumulation in Wheat Grown in Copper-Contaminated Soil by Affecting Physiological Traits

The changes in biomass (including yield), copper (Cu) concentration, and the accumulation of wheat (Triticum aestivum. L) in response to soil Cu pollution under nighttime warming had still not been explored. Hence, this study was carried out, and these variations were analyzed from a physiological perspective. Pot trials were performed at two levels of ambient temperatures (no-warming (NT) and average nighttime warming of 0.28 °C (WT)) and two levels of soil Cu concentrations (control check without Cu application (CK) and 100 mg/kg Cu application (Cu)). Soil was collected from the carbonate cinnamon soil region of central China. The warming effects of the passive nighttime warming system were prominent, and the average increment was 0.28 °C. Antioxidant enzyme activities were promoted by warming (p < 0.05) and Cu. The highest yield was achieved in NT-Cu, mainly attributed to relatively strong root activity and photosynthesis caused by supplemental Cu, but the Cu concentration in its grains was close to the threshold (10 mg/kg) for Cu concentration in foodstuff and could present a potential food safety risk. Though nighttime warming did not increase the total biomass and yield of wheat, it decreased the Cu accumulation of wheat grown in Cu-contaminated soil, especially in grains. Moreover, WT-CK and WT-Cu increased the Cu concentration in the roots and glumes and reduced the Cu concentration in grains by 13.09% and 55.84%, respectively, probably because of a lower transpiration rate. Among them, the Cu concentration of grains in WT-Cu was the lowest and significantly lower than other applications. Our findings reveal that nighttime warming has the potential to reduce the Cu risk of grains in wheat grown in the Cu-contaminated carbonate cinnamon soil region of central China and could then provide a theoretical reference for risk assessment of food quality for wheat subjected to dual stress from nighttime warming and Cu pollution.

Nonuniform response of vegetation phenology to daytime and nighttime warming in urban areas

The phenological response of vegetation to changing climates requires exploration across environments, including urban areas with elevated daytime and nighttime temperatures (TD and TN) and artificial lights. Here, we analyzed multiple remotely-sensed datasets (2012–2021) from and around a highly-urbanized area, Seoul, in South Korea. While the urban fraction and artificial lights largely contributed to advancing the start-of-season (SOS) and delaying the end-of-season (EOS) (30.7–42.1%), SOS changes were more driven by TD (15.7%), whereas EOS changes were more attributed to TN (21.8%). A higher response of the SOS to TD was found in more urbanized areas with higher artificial lights, while the sensitivity of the EOS to TN increased in brighter areas during nighttime. These findings indicate that vegetation’s response to rising temperatures will become dynamic, given the potential constraints by light and other attributes, calling for further assessments of its implication for terrestrial ecosystems and carbon cycle.

Trend Analysis of MODIS Land Surface Temperature and Land Cover in Central Italy

Land Surface Temperature (LST) is an important climate factor for understanding the relationship between the land surface and atmosphere. Furthermore, LST is linked to soil moisture and evapotranspiration, which can potentially alter the severity and regime of wildfires, landslide-triggering precipitation thresholds, and others. In this paper, the monthly daytime and nighttime LST products of Moderate Resolution Imaging Spectroradiometer (MODIS) are employed for the period 2000–2023 in order to find areas that have been cooling or warming in a region of great interest in Central Italy, due to its complex geological and geomorphological settings and its recent seismic sequences and landslide events. The annual MODIS land cover images for 2001–2022 are also utilized to investigate the interconnection between LST and land cover change. The results of the non-parametric Mann–Kendall trend test and its associated Sen’s slope reveal a significant nighttime warming trend in the region, particularly in July, linked to forest and woodland expansion. Grasslands toward the coastline with low elevation (less than 500 m a.s.l.) have experienced significant heat waves during the summer, with an LST of more than 35 °C. A significant negative correlation between the elevation and LST is observed for each calendar month. In particular, the daytime and nighttime LST have more than 80% correlation with elevation during winter and summer, respectively. In addition, nighttime warming and gradual drainage are noticed in Lake Campotosto. The results of this study could be useful for wildfire and landslide susceptibility analyses and hazard management.

Moderating AC Usage Can Reduce Thermal Disparity between Indoor and Outdoor Environments.

In the context of escalating urban heat events due to climate change, air conditioning (AC) has become a critical factor in maintaining indoor thermal comfort. Yet the usage of AC can also exacerbate outdoor heat stress and burden the electricity system, and there is little scientific knowledge regarding how to balance these conflicting goals. To address this issue, we established a coupled modeling approach, integrating the Weather Research and Forecasting model with the building energy model (WRF_BEP + BEM), and designed multiple AC usage scenarios. We selected Chongqing, China's fourth-largest megacity, as our study area due to its significant socioeconomic importance, the severity of extreme heat events, and the uniqueness of its energy infrastructure. Our analysis reveals that AC systems can substantially reduce indoor temperatures by up to 18 °C; however, it also identifies substantial nighttime warming (2-2.5 °C) and a decline in thermal comfort. Particularly for high-density neighborhoods, when we increase 2 °C indoors, the outdoor temperature can be alleviated by up to 1 °C. Besides, despite the limited capacity to regulate peak electricity demand, we identified that reducing the spatial cooled fraction, increasing targeted indoor temperature by 2 °C, and implementing temporal AC schedules can effectively lower energy consumption in high-density neighborhoods, especially the reduction of spatial cooled fraction (up to 50%). Considering the substantial demand for cooling energy, it is imperative to carefully assess the adequacy and continuity of backup energy sources. The study underscores the urgency of reassessing energy resilience and advocates for addressing the thermal equity between indoor and outdoor environments, contributing to the development of a sustainable and just urban climate strategy in an era of intensifying heat events.

Pattern of cooling benefits from ecospaces during urbanization: A case study of the Yangtze River Economic Belt

Urban ecological spaces are effective thermoregulators under global warming. However, the cooling efficiency of urban ecological spaces during the urbanization has not been studied comprehensively. Here, we investigate the spatio-temporal dynamics of Urban Cold Island (UCI) intensity in 11 typical cities of the Yangtze River Economic Belt (YREB). We determined the impact of ecological landscape trends on these dynamics by using GlobalLand and MODIS 8 d mean land surface temperature (LST) data for three periods (2000, 2010, and 2020), and the landscape pattern index and diversity index. We found that in the past 20 years, the built-up area has increased by sixfold; 62.53 % and 37.47 % of YREB were warming or cooling, with 71.22 % of the daytime cooling and 93 % of the nighttime warming. The average UCI intensity of YREB has increased from 0.518 to 0.847 and is negatively correlated with LST with a decreasing slope. As the UCI intensity of green spaces increased, that of blue spaces decreased. Surface area and landscape pattern are the key determinants of UCI intensity in blue and green spaces, respectively, especially the landscape shape index (LSI). Therefore, maintaining ecological spaces, enriching the structural integrity of green spaces, and improving blue space connectivity can help cities at different development levels cope with heat stress during regional urbanization.

Asymmetrical Impact of Daytime and Nighttime Warming on the Interannual Variation of Urban Spring Vegetation Phenology

AbstractUrban warming significantly advances spring vegetation phenology. However, the potential effect of daytime and nighttime warming on the start of the urban vegetation growing season (SOS) remains to be determined. Here, we characterized the interannual response of SOS to daytime and nighttime warming from 2003 to 2020 using remotely sensed phenological observations across cities in the Northern Hemisphere (>30°N). We implemented the partial correlation analysis and the process‐based phenology model to quantify the effects of daytime and nighttime warming on vegetation. We found that either daytime or nighttime warming can promote an earlier urban spring SOS for Northern Hemisphere cities, while the phenological response varies across cities. Additionally, the response of SOS to daytime and nighttime urban warming (ST, expressed in advance days of SOS per °C warming) offset each other at an average rate of 0.08 days/°C per decade. Our results suggest that daytime warming predominates the temporal variation of SOS for high‐latitude cities, whereas nighttime warming is the primary driver of SOS change in low‐latitude cities. By revealing the effect and contributions of daytime and nighttime warming on the urban SOS, our results highlight the importance of considering daytime and nighttime temperatures separately in the response of vegetation phenology to urban thermal warming and climate variability.

Nighttime warming and nitrogen addition effects on the microclimate of a freshwater wetland dominated by Phragmites australis

The critical impacts of microclimate on carbon (C) cycling have been widely reported. However, the potential effects of global change on wetland microclimate remain unclear, primarily because of the absence of field manipulative experiment in inundated wetland. This study was designed to examine the effects of nighttime warming and nitrogen (N) addition on air, water, and sediment temperature and also reveal the controlling factors in a Phragmites australis dominated freshwater wetland on the North China Plain. Nighttime warming increased daily air, water, and sediment temperature by 0.24 °C, 0.27 °C, and 0.36 °C, respectively. The diurnal temperature range of water was decreased by 0.44 °C under nighttime warming, whereas warming had no effect on diurnal temperature range of air and sediment. In addition, N addition caused a reduction of 0.20 °C and 0.14 °C in daily water and sediment temperature by increasing vegetation coverage. There was a significant interaction between nighttime warming and N addition on water temperature. Furthermore, the vapor pressure deficit is the main factor affecting the extent of the warming-induced increases in air temperature. The changes of height and leaf area index of Phragmites australis are responsible for the cooling effects in the N addition plots. This study provides empirical evidence for the positive climate warming – microclimate feedback in freshwater wetland. However, N deposition leads to decreased water and sediment temperature. Our findings highlight the importance of incorporating the differential impacts of nighttime warming and N addition on air, water, and sediment temperature into the predictions of wetland C cycling responses to climate change.

Climate change-induced impacts on PM2.5 in Taiwan under 2 and 4 °C global warming

Climate change can perturb meteorological parameters and affect air quality, human health, and the economy. This study examined the climate change-induced meteorological impacts on PM2.5 in Taiwan, an island with a dense population and complex topography. We conducted high-resolution simulations of the current and future climate using the National Center for Atmospheric Research's Weather Research and Forecasting model and the Community Multiscale Air Quality Modeling System. As verified by observations, the model could reproduce the spatial and seasonal characteristics of PM2.5 in Taiwan, including higher concentrations in cold seasons and lower concentrations in warm seasons. The number of polluted days in the current climate was more than 30 days per season in central Taiwan and more than 70 days in southern Taiwan in autumn and winter. Under the 2 °C and 4 °C global warming scenarios, climate change-induced impacts worsened the PM2.5 air quality in Taiwan in cold seasons. In winter, the number of polluted days increased by 3–6 days in the whole of Taiwan, while it decreased by 3–5 days in southern Taiwan in autumn. Analysis of climate change-induced impacts on northeasterly days, air stagnation, and ventilation indices revealed that the weaker low-level wind in cold seasons was the dominant factor of the worsened PM2.5 air quality under global warming in Taiwan. In addition, the climate change-induced worsening of PM2.5 air quality could be locally mitigated by northeasterly days and nighttime warming in urban areas in northern Taiwan and by precipitation in southern Taiwan. Overall, these findings indicated that climate change-induced impacts on air quality cover both urban and global scales. To better adapt to climate change, discussing interactions between the responses to global warming in urban areas using hierarchical models and high-resolution simulations is necessary.

Nighttime warming promotes copper translocation from root to shoot of wheat (Triticum aestivum L.) through enlarging root systems

Nighttime warming promotes copper translocation from root to shoot of wheat (Triticum aestivum L.) through enlarging root systems

Analyzing the Land Surface Temperature Response to Urban Morphological Changes: A Case Study of the Chengdu–Chongqing Urban Agglomeration

AbstractUrban morphological change impacts the land surface temperature (LST) through modifying the net radiation, convective heat transfer, evapotranspiration, and heat storage on the ground. It is essential to quantify the contributions of these physical changes on LST changes. In this work, we conduct simulations using a weather research and forecasting model for the Chengdu–Chongqing urban agglomeration to identify causes of LST changes due to urban morphological changes through different morphological parameters: the aspect ratio, building plan area fraction, and average building height. A new method is proposed and used to quantify the contribution of these physical changes on LST changes. The results show as the aspect ratio increases, an increase of the average LST is induced by variations in radiation, and daytime cooling and nighttime warming are induced by variations in heat storage. There is warming associated with an increase in the building plan area fraction, which is mostly caused by a decrease in the efficiency of the long‐wave radiant heat emitted from the surface to the atmosphere. We also find that an increase in the average building height enhance the efficiency of convective heat transfer, which results in cooling. These results are important for the management of urban thermal environments.

Interannual Variations in Terrestrial Net Ecosystem Productivity and Climate Attribution in the Southern Hilly Region of China.

The vegetation ecosystem in the southern hilly region of China (SHRC) plays a crucial role in the country's carbon reservoir. Clarifying the dynamics of net primary productivity (NPP) in this area and its response to climate factors in the context of climate change is important for national forest ecology, management, and carbon neutrality efforts. This study, based on remote sensing and meteorological data spanning the period 2001 to 2021, aims to unveil the spatiotemporal patterns of vegetation productivity and climate factors in the southern hilly region, explore interannual variation characteristics of vegetation productivity with altitude, and investigate the response characteristics of NPP to various climate factors. The results indicate that from 2001 to 2021, the annual average NPP in the southern hilly region had a significant increasing trend of 2.13 ± 0.78 g m-2 a-1. The trend of NPP varies significantly with altitude. Despite a general substantial upward trend in vegetation NPP, regions at lower elevations exhibit a faster rate of increase, suggesting a diminishing difference in the NPP of different elevation ranges. The overall rise in average temperature has positive implications for the southern hilly region, while the impact of precipitation on vegetation NPP demonstrates noticeable spatial heterogeneity. Regions in which vegetation NPP is significantly negatively correlated with precipitation are mainly concentrated in the southern areas of Guangdong, Fujian, and Jiangxi provinces. In contrast, other regions further away from the southeastern coast tend to exhibit a positive correlation. Over the past two decades, there has been an asymmetry in the diurnal temperature variation in the SHRC, with the nighttime warming rate being 1.8 times that of the daytime warming rate. The positive impact of daytime warming on NPP of vegetation is more pronounced than the impact of nighttime temperature changes. Understanding the spatiotemporal patterns of NPP in the SHRC and the characteristics of its response to climate factors contributes to enhancing our ability to protect and manage vegetation resources amidst the challenges of global climate change.

Impacts of Extreme Precipitation and Diurnal Temperature Events on Grassland Productivity at Different Elevations on the Plateau

The impact of extreme climate events on vegetation growth and ecosystem function has garnered widespread attention, particularly in plateau regions, which are facing increasingly severe environmental pressures. This study employs the Events Coincidence Analysis (ECA) method to examine the impacts of extreme climate events on the Net Primary Productivity (NPP) of vegetation in plateau regions. Specifically, we focus on the unique phenomenon of asymmetric daytime and nighttime warming and evaluate the compounding effect of extreme precipitation with extreme temperature events. The results indicate that grassland NPP has higher overall sensitivity and Coincidence Rates (CR) to extreme precipitation events compared to extreme temperature events. Specifically, extreme drought events significantly negatively impact grassland NPP, and the sensitivity of NPP increases with the severity of extreme drought events. In lower elevations (<3200 m), grassland NPP shows a strong response to extreme precipitation events, with sensitivity decreasing with increasing elevation, especially for alpine meadows. Extreme high-temperature events contributed significantly to NPP in mid to high elevations (3000–5000 m). Compound extreme climate events amplify the average coincidence degree with NPP anomalies, with extreme precipitation events playing a major role in compound effects. The CR of compound climate events can reach above 0.6, reflected in the anomaly increase of NPP in temperate grasslands at higher elevations caused by compound events of extremely wet and extremely high temperatures.

Impacts of climate change on fractional vegetation coverage of temperate grasslands in China from 1982 to 2015

The vegetation coverage of temperate grasslands in China has changed substantially due to climate change during the past decades, which significantly affects the function of grassland ecosystems. To appropriately carry out adaptive management and protect temperate grassland vegetation, it is important to understand the variations in fractional vegetation coverage (FVC) of China's temperate grasslands and how they are responding to climate change. Using the GIMMS NDVI and climatic datasets, this study explored the dynamics of FVC and their climatic drivers across the temperate grassland region of China during 1982∼2015. The results showed that the growing season mean FVC increased by 0.12% per year during 1982∼2015. The increases in precipitation and minimum temperature in the growing-season (especially in spring) could enhance the FVC of various vegetation types. In summer, the FVC of temperate steppe and desert steppe could drastically increase with increasing precipitation. In addition, this study found that the impacts of daytime and night-time warming on the FVC of temperate grasslands were asymmetric. Daytime warming can moderately increase FVC of temperate grasslands, while night-time warming could significantly increase it. Furthermore, the increase in summer daytime and night-time temperatures leads to a weak decrease and a moderate increase in FVC, respectively. This asymmetric effect was more evident for the temperate steppe and desert steppe in the central area. In autumn, the temperatures increase had significant positive impacts on the FVC of temperate meadows and steppes. This study highlights the differences in the impacts of climate change at different time scales on the FVC of grasslands with various vegetation types, and indicates that the asymmetric influences of daytime and night-time temperatures in different seasons on FVC must be included in calculating the vegetation coverage of China's temperate grasslands. The results could provide information for maintaining grassland ecosystem functions and managing environmental systems.

Night-time radiative warming using the atmosphere

Night-time warming is vital for human production and daily life. Conventional methods like active heaters are energy-intensive, while passive insulating films possess restrictions regarding space consumption and the lack of heat gain. In this work, a nanophotonic-based night-time warming strategy that passively inhibits thermal radiation of objects while actively harnessing that of atmosphere is proposed. By using a photonic-engineered thin film that exhibits high reflectivity (~0.91) in the atmospheric transparent band (8–14 μm) and high absorptivity (~0.7) in the atmospheric radiative band (5–8 and 14–16 μm), temperature rise of 2.1 °C/4.4 °C compared to typical low-e film and broadband absorber is achieved. Moreover, net heat loss as low as 9 W m−2 is experimentally observed, compared to 16 and 39 W m−2 for low-e film and broadband absorber, respectively. This strategy suggests an innovative way for sustainable warming, thus contributes to addressing the challenges of climate change and promoting global carbon neutrality.

Photosynthesis in newly developed leaves of heat-tolerant wheat acclimates to long-term nocturnal warming.

We examined photosynthetic traits of pre-existing and newly developed flag leaves of four wheat genotypes grown in controlled-environment experiments. In newly developed leaves, acclimation of the maximum rate of net CO2 assimilation (An) to warm nights (i.e. increased An) was associated with increased capacity of Rubisco carboxylation and photosynthetic electron transport, with Rubisco activation state probably contributing to increased Rubisco activity. Metabolite profiling linked acclimation of An to greater accumulation of monosaccharides and saturated fatty acids in leaves; these changes suggest roles for osmotic adjustment of leaf turgor pressure and maintenance of cell membrane integrity. By contrast, where An decreased under warm nights, the decline was related to lower stomatal conductance and rates of photosynthetic electron transport. Decreases in An occurred despite higher basal PSII thermal stability in all genotypes exposed to warm nights: Tcrit of 45-46.5 °C in non-acclimated versus 43.8-45 °C in acclimated leaves. Pre-existing leaves showed no change in An-temperature response curves, except for an elite heat-tolerant genotype. These findings illustrate the impact of night-time warming on the ability of wheat plants to photosynthesize during the day, thereby contributing to explain the impact of global warming on crop productivity.

Fading regulation of diurnal temperature ranges on drought-induced growth loss for drought-tolerant tree species

Warming-induced droughts caused tree growth loss across the globe, leading to substantial carbon loss to the atmosphere. Drought-induced growth loss, however, can be regulated by changes in diurnal temperature ranges. Here, we investigated long term radial growth responses of 23 widespread distributed tree species from 2327 sites over the world and found that species’ drought tolerances were significantly and positively correlated with diurnal temperature range-growth loss relationships for the period 1901-1940. Since 1940, this relationship has continued to fade, likely due to asymmetric day and night warming trends and the species’ ability to deal with them. The alleviation of reduced diurnal temperature ranges on drought-induced growth loss was mainly found for drought resistant tree species. Overall, our results highlight the need to carefully consider diurnal temperature ranges and species-specific responses to daytime and nighttime warming to explore tree growth responses to current and future warmer and drier climates.