Increase In Mean Temperature Research Articles

Modeling Climate Change Impact on the Streamflow in the Upper Wabe Bridge Watershed in Wabe Shebele River Basin, Ethiopia

Climate change affects the availability of water resources by altering the pattern and magnitude of precipitation, temperature, and streamflow. The projection of climate change impact on the streamflow is used to identify the level of changes and desirable intervention measures. In this research, Soil and Water Assessment Tool (SWAT) model and the regional circulation model (RCM) outputs of CORDEX Africa climate model associated with mid and high-level Representative Concentration Pathways (RCP4.5 and RCP8.5) climate scenarios were used to evaluate the change in streamflow in two future projection scenarios (2041-2070 and 2071-2099). The study is directed to the Upper Wabe Bridge watershed found in the Wabe Shebele basin, Ethiopia. The result shows an increase in mean temperature by 3.46 and 5.15°C for RCP4.5; and 4.78 and 5.88°C for RCP8.5 in mid and long-term periods, respectively. The study also confirmed an increasing trend in annual precipitation by +26.3 and +31.85% for RCP4.5 and RCP8.5 climate scenarios, respectively, at the end of 21st century. In Kiremt (rainy) season precipitation shows an increasing trend by +44.28% and +59.34% for RCP4.5 and RCP8.5 climate scenarios, respectively, but Bega (dry) season show decreasing trend. The future projected annual streamflow shows increase trends under both climate scenarios in both projection periods. The mean seasonally streamflow decreases in the Belg (short rainy) season by -10.91% and increases in the Kiremt (rainy) season by 17.4%. Hence, the increment trend in streamflow during the Kiremt season will have the utmost significance for the requirement of storage and rainwater harvesting structures for irrigation development during dry season. Therefore, incorporating the possible effect of climate change is vital during water resources planning and development.

50 Years of Pollen Monitoring in Basel (Switzerland) Demonstrate the Influence of Climate Change on Airborne Pollen.

Climate change and human impact on vegetation modify the timing and the intensity of the pollen season. The 50 years of pollen monitoring in Basel, Switzerland provide a unique opportunity to study long-term changes in pollen data. Since 1969, pollen monitoring has been carried out in Basel with a Hirst-type pollen trap. Pollen season parameters for start dates, end dates and duration were calculated with different pollen season definitions, which are commonly used in aerobiology. Intensity was analyzed by the annual pollen integral (APIn), peak value and the number of days above specific thresholds. Linear trends were calculated with the non-parametric Mann Kendall method with a Theil-Sen linear trend slope. During the last 50 years, linear increase of the monthly mean temperatures in Basel was 0.95–1.95°C in the 3 winter months, 2–3.7°C in spring months and 2.75–3.85°C in summer months. Due to this temperature increase, the start dates of the pollen season for most of the spring pollen species have advanced, from 7 days for Poaceae to 29 days for Taxus/Cupressaceae. End dates of the pollen season depend on the chosen pollen season definition. Negative trends predominate, i.e., the pollen season mostly ends earlier. Trends in the length of the pollen season depend even more on the season definitions and results are contradictory and often not significant. The intensity of the pollen season of almost all tree pollen taxa increased significantly, while the Poaceae pollen season did not change and the pollen season of herbs decreased, except for Urticaceae pollen. Climate change has a particular impact on the pollen season, but the definitions used for the pollen season parameters are crucial for the calculation of the trends. The most stable results were achieved with threshold definitions that indicate regular occurrence above certain concentrations. Percentage definitions are not recommended for trend studies when the annual pollen integral changed significantly.

The effect of meteorological variables on salmonellosis incidence in Kermanshah, West of Iran: a generalized linear model with negative binomial approach.

Salmonella is one of the main causes of gastroenteritis, and its incidence may be affected by meteorological variables. This is the first study about the effect of climatic factors on salmonella incidence in Kermanshah, Iran. Data about salmonellosis cases in Kermanshah were inquired from Center for Communicable Disease Control, at the Ministry of Health and Medical Education of Iran, for the 2008 to 2018 time-frame. Meteorological variables including maximum, minimum and mean of temperature and humidity, sunshine hours and rainfall were inquired for the same time frame. Negative binomial generalized linear models (GLM) were used to assess the effect of meteorological variables on the weekly incidence of salmonellosis. During the years under study, 569 confirmed cases were registered in Kermanshah province. Study results showed a 3 % increase in salmonellosis incidence, after 1 % increase in minimum humidity in the week before (incidence rate ratio (IRR): 1.03; 95 % confidence interval (CI):1.02-1.05) and also a 4 % increase in incidence for 1°C increase in mean temperature in the same week (IRR: 1.04; 95 % CI:1.02-1.06). Increase in minimum humidity and mean temperature may have a role in increasing the incidence of salmonellosis in Iran.

Retrofitting Southern African cities: A call for appropriate rooftop greenhouse designs as climate adaptation strategy

In response to the burgeoning building integrated agriculture (BIA) discourse and industry, and assumptions of this land use form as a climate change adaptation strategy, this study considers the impact of rooftop greenhouses (RTGs) on the thermal performance of the built environment in current and future climate conditions. Based on empirical evidence, the study simulates the thermal impact of completely retrofitting an existing building in a Southern African urban context with passively controlled, non-integrated RTGs under current and future climate change affected climatic conditions. The study concludes that the current greenhouse technologies used in South African rooftop farms provide limited thermal modulation capacity for farmers, as well as generally negatively affecting the thermal performance of the associated buildings. Simulating both highly and poorly insulated buildings reveal contrasting impacts on the indoor thermal environment, with a 0.73 °C decrease and 0.55 °C increase in mean temperatures, respectively. Conversely, the highly insulated simulation reveals an annual energy consumption increase of 3.5%, which progressively worsens under higher climate change induced temperatures. These findings, based on current practices in the BIA industry, hope to inform both the choice of technology, as well as the development of appropriate greenhouse technologies to maximise their performance and enable co-benefits as often assumed in the industry.

Projected changes in temperature, precipitation and potential evapotranspiration across Indus River Basin at 1.5–3.0 °C warming levels using CMIP6-GCMs

The projections of mean temperature, precipitation (P), and potential evapotranspiration (PET) reflect the probabilities of long-term changes of hydrologic processes and induced extreme events. In this paper, we investigated the future changes in some pivotal climatic variables (mean temperature, precipitation, and potential evapotranspiration) under 1.5 °C, 2.0 °C, and 3.0 °C specific warming levels (SWLs) across the Indus River Basin of South Asia. The seven global climate models output under seven different emission scenarios (SSP1–1.9, SSP1–2.6, SSP2–4.5, SSP3–7.0, SSP4–3.4, SSP4–6.0, and SSP5–8.5) from the latest Sixth phase of Coupled Model Intercomparison Project (CMIP6) are used for this purpose. The Penman-Monteith approach is applied to estimate PET, and the water balance equation is for reflecting water surplus/deficit. Results indicate that except for precipitation, the greater increases in temperature and PET are inclined to happen with continued global warming. The highest increase in temperature is accounted for 14.6% (2.4 °C), and the enhanced PET is estimated at 5.2% higher than the reference period (1995–2014) under 3.0 °C SWL. While the precipitation is projected to increase by the highest 4.8% for 2.0 °C warming level. The differences in regional climate for an additional 0.5 °C (2.0–1.5 °C) and 1.0 °C (3.0–2.0 °C) of warming, the temperature is projected to increase by 0.4 °C and 0.9 °C in the entire IRB respectively. The highest increase in mean temperature (5.1%) and PET (2.4%) in the IRB are predicted to intensify for an additional 1.0 °C than that of 0.5 °C of warming, but precipitation is intended to decrease by 0.4%. Spatially, the increase in temperature, precipitation, and PET are dominated towards high elevation in the upper basin (north) under all the SWLs. The increased variability in climatological parameters across IRB depicts an evident occurrence of both wet events (upper basin) as well as dry events (lower basin) with the increase in global average temperature rise. However, these findings provide an insightful basis for water resource management as well as initiating mitigation and adaptation measures in the IRB related to water surplus (floods) and water deficit (droughts).

City-level vulnerability to temperature-related mortality in the USA and future projections: a geographically clustered meta-regression

SummaryBackgroundExtreme heat exposure can lead to premature death. Climate change is expected to increase the frequency, intensity, and duration of extreme heat events, resulting in many additional heat-related deaths globally, as well as changing the nature of extreme cold events. At the same time, vulnerability to extreme heat has decreased over time, probably due to a combination of physiological, behavioural, infrastructural, and technological adaptations. We aimed to account for these changes in vulnerability and avoid overstated projections for temperature-related mortality. We used the historical observed decrease in vulnerability to improve future mortality estimates.MethodsWe used historical mortality and temperature data from 208 US cities to quantify how observed changes in vulnerability from 1973 to 2013 affected projections of temperature-related mortality under various climate scenarios. We used geographically structured meta-regression to characterise the relationship between temperature and mortality for these urban populations over the specified time period. We then used the fitted relationships to project mortality under future climate conditions.FindingsBetween Oct 26, 2018, and March 9, 2020, we established that differences in vulnerability to temperature were geographically structured. Vulnerability decreased over time in most areas. US mortalities projected from a 2°C increase in mean temperature decreased by more than 97% when using 2003–13 data compared with 1973–82 data. However, these benefits declined with increasing temperatures, with a 6°C increase showing only an 84% decline in projected mortality based on 2003–13 data.InterpretationEven after accounting for adaptation, the projected effects of climate change on premature mortality constitute a substantial public health risk. Our work suggests large increases in temperature will require additional mitigation to avoid excess mortality from heat events, even in areas with high air conditioning coverage in place.

Long-term natural dynamics of an alpine lichen heath in the Teberda State Biosphere Reserve, northwestern Caucasus

The alpine vegetation of Europe and the Caucasus has experienced substantial changes due to climate warming and reduced grazing. Exposed ridge communities, such as alpine heaths, are presumed to be less vulnerable to such processes. Herein, we analyze long-term dynamics (over 37 years) of an alpine lichen heath in the Teberda State Biosphere Reserve, Karachaevo-Cherkessian Republic, Russia. We counted the shoots of all vascular plants present on permanent plots. Autocorrelated linear regressions, a non-metric multidimensional scaling ordination, and a fourth-corner analysis were applied to characterize the relationships between shoot numbers, climate variables (temperatures and precipitation), functional traits, and species strategies. Nine species, including dominant Festuca ovina L. and Antennaria dioica (L.) Gaertn., increased their abundances, whereas Carex spp. were observed to decrease. The overall dynamics were mainly driven by increasing mean temperatures during the growing season (July and August). None of the changes observed in the selected traits were correlated with increasing or decreasing numbers of species; however, some traits (plant height, specific root length, specific leaf area, and leaf carbon content) were potentially associated with climate variables. The observed dynamics suggested an overall increase in the abundance of herbaceous plants. Generally, our results support “greening” effects in tundra and alpine biomes.

Thermal evolution ameliorates the long‐term plastic effects of warming, temperature fluctuations and heat waves on predator–prey interaction strength

Abstract How thermal evolution may affect trophic interactions and its implications for trophic system stability remains unstudied. To advance insights in how global warming shapes trophic interactions, we need to consider besides increases in mean temperatures, also daily thermal fluctuations (DTF) and heat waves (HW), and how their effects are modulated by thermal evolution. Using a common‐garden approach, we tested how each thermal factor affected predator metabolic rate and functional response parameters, and used these responses to predict long‐term predator–prey interaction strength between larvae of the damselfly Ischnura elegans and the water flea Daphnia magna. Using high‐ and low‐latitude predator populations with the latter being exposed to higher mean temperatures, higher DTF and more frequent HW, we assessed the potential impact of thermal evolution at the high latitude using a space‐for‐time substitution. In line with thermal adaptation, growth rates were faster and handling times shorter in low‐latitude compared to high‐latitude larvae at 24°C while the opposite was true at 20°C. Warming weakened the long‐term interaction strength, except for the high‐latitude trophic system at DTF and HW where plastic responses therefore may not stabilize the high‐latitude system. This extends the emerging insight that temperature variation may make ectotherms more vulnerable to warming. The contributions of metabolic rate, search rate and handling time in shaping thermal effects on interaction strength differed between latitudes. A key finding was that thermal evolution may further weaken the long‐term interaction strength of the high‐latitude trophic system under increases in mean temperatures, even at DTF and potentially also at HW. Our results underscore the importance of daily thermal fluctuations and heat waves in shaping predator–prey interactions, and may suggest an overall stabilizing contribution of predator thermal evolution ameliorating thermal plastic effects on food web stability. A free Plain Language Summary can be found within the Supporting Information of this article.

Effects of temperature and photoperiod on the seasonal timing of Western honey bee colonies and an early spring flowering plant.

Temperature and photoperiod are important Zeitgebers for plants and pollinators to synchronize growth and reproduction with suitable environmental conditions and their mutualistic interaction partners. Global warming can disturb this temporal synchronization since interacting species may respond differently to new combinations of photoperiod and temperature under future climates, but experimental studies on the potential phenological responses of plants and pollinators are lacking. We simulated current and future combinations of temperature and photoperiod to assess effects on the overwintering and spring phenology of an early flowering plant species (Crocus sieberi) and the Western honey bee (Apis mellifera). We could show that increased mean temperatures in winter and early spring advanced the flowering phenology of C. sieberi and intensified brood rearing activity of A. mellifera but did not advance their brood rearing activity. Flowering phenology of C. sieberi also relied on photoperiod, while brood rearing activity of A. mellifera did not. The results confirm that increases in temperature can induce changes in phenological responses and suggest that photoperiod can also play a critical role in these responses, with currently unknown consequences for real‐world ecosystems in a warming climate.

Ocean carbon uptake under aggressive emission mitigation

Abstract. Nearly every nation has signed the UNFCC Paris Agreement, committing to mitigate anthropogenic carbon emissions so as to limit the global mean temperature increase above pre-industrial levels to well below 2 ∘C, and ideally to no more than 1.5 ∘C. A consequence of emission mitigation that has received limited attention is a reduced efficiency of the ocean carbon sink. Historically, the roughly exponential increase in atmospheric CO2 has resulted in a proportional increase in anthropogenic carbon uptake by the ocean. We define growth of the ocean carbon sink exactly proportional to the atmospheric growth rate to be 100 % efficient. Using a model hierarchy consisting of a common reduced-form ocean carbon cycle model and the Community Earth System Model (CESM), we assess the mechanisms of future change in the efficiency of the ocean carbon sink under three emission scenarios: aggressive mitigation (1.5 ∘C), intermediate mitigation (RCP4.5), and high emissions (RCP8.5). The reduced-form ocean carbon cycle model is tuned to emulate the global-mean behavior of the CESM and then allows for mechanistic decomposition. With intermediate or no mitigation (RCP4.5, RCP8.5), changes in efficiency through 2080 are almost entirely the result of future reductions in the carbonate buffer capacity of the ocean. Under the 1.5 ∘C scenario, the dominant driver of efficiency decline is the ocean's reduced ability to transport anthropogenic carbon from surface to depth. As the global-mean upper-ocean gradient of anthropogenic carbon reverses sign, carbon can be re-entrained in surface waters where it slows further removal from the atmosphere. Reducing uncertainty in ocean circulation is critical to better understanding the transport of anthropogenic carbon from surface to depth and to improving quantification of its role in the future ocean carbon sink.

Regeneration of tropical montane cloud forests increases water yield in the Brazilian Atlantic Forest

AbstractTropical montane cloud forests (TMCF) have paramount importance with regards to hydrological and ecological functions. Despite such importance in terms of water provision, they are one of the most endangered ecosystems on the planet. One important topic that is still unclear is related to TMCF regeneration: can it recover the hydrological function of such critical ecosystems? In the present paper, the hydrological effects of the natural regeneration of TMCF were examined. We selected three catchments with different degrees of TMCF, and we examined the relationship between the amount of TMCF over time and hydrological variables such as water yields and baseflow using a time series (1984–2011). Our results suggest that the increase in TMCF cover can contribute to increases in water yield. This pattern was found in a catchment with an increase of approximately 20% of forest cover. In catchments with TMCF increase lower than this threshold, water yield and flow path were influenced by hydroclimatic variables such as air temperature and rainfall. The effect of the reduction in water yield, in accordance with the increase in mean temperature, sheds light on possible consequences of climate change on ecosystem services produced in foggy environments. In light of these findings, aiming to increase the water yield, we recommend that regions frequently affected by fog are prioritized for forest restoration or conservation. To ensure significant effects, regeneration and/or successional development of TMCF has to reach at least 20% of a catchment area.

Europe's Farm to Fork Strategy and Its Commitment to Biotechnology and Organic Farming: Conflicting or Complementary Goals?

The European Commission's Farm to Fork (F2F) strategy, under the European Green Deal, acknowledges that innovative techniques, including biotechnology, may play a role in increasing sustainability. At the same time, organic farming will be promoted, and at least 25% of the EU's agricultural land shall be under organic farming by 2030. How can both biotechnology and organic farming be developed and promoted simultaneously to contribute to achieving the Sustainable Development Goals (SDGs)? We illustrate that achieving the SDGs benefits from the inclusion of recent innovations in biotechnology in organic farming. This requires a change in the law. Otherwise, the planned increase of organic production in the F2F strategy may result in less sustainable, not more sustainable, food systems.

Dendroclimatic analysis of central Appalachian red spruce in West Virginia

We conducted dendroclimatic analyses and constructed future growth projections for red spruce (Picea rubens Sarg.) throughout the central Appalachians in the state of West Virginia. This study involved field sampling of 18 sites across red spruce’s range in six regions throughout the Monongahela National Forest that were selected based on pairwise combinations of three latitudinal groups (north, central, and south) with two aspects (north and south). Each combination of latitudinal group and aspect was referred to as a landscape cluster. Growth was negatively impacted by high summer temperature stress but responded favorably to high fall temperatures. The results also suggested that red spruce was likely impacted by the degree of winter harshness in all landscape clusters. In the northern latitudinal landscape clusters, red spruce responded favorably to warm spring temperatures by allowing an early start to the growing season. Growth projections under a future climate change scenario show that future expected increases in mean and maximum monthly temperatures will have negative effects on future spruce growth. The forecasting results suggested that red spruce in northern latitudes on south aspects or central latitudes on north aspects are the landscape clusters that will likely be the most resilient to future climate change. Dendroclimatic results and future growth projections can assist with identifying locations that are most suitable for future red spruce restoration activities.

Marginal ice zone fraction benchmarks sea ice and climate model skill

Global climate models (GCMs) consistently underestimate the response of September Arctic sea-ice area (SIA) to warming. Modeled SIA losses are highly correlated to global mean temperature increases, making it challenging to gauge if improvements in modeled sea ice derive from improved sea-ice models or from improvements in forcing driven by other GCM components. I use a set of five large GCM ensembles, and CMIP6 simulations, to quantify GCM internal variability and variability between GCMs from 1979–2014, showing modern GCMs do not plausibly estimate the response of SIA to warming in all months. I identify the marginal ice zone fraction (MIZF) as a metric that is less correlated to warming, has a response plausibly simulated from January–September (but not October–December), and has highly variable future projections across GCMs. These qualities make MIZF useful for evaluating the impact of sea-ice model changes on past, present, and projected sea-ice state.

Vegetation and Glacier Trends in the Area of the Maritime Alps Natural Park (Italy): MaxEnt Application to Predict Habitat Development

Climate change is significantly affecting ecosystem services and leading to strong impacts on the extent and distribution of glaciers and vegetation. In this context, species distribution models represent a suitable instrument for studying ecosystem development and response to climate warming. This study applies the maximum entropy model, MaxEnt, to evaluate trends and effects of climate change for three environmental indicators in the area of the Alpi Marittime Natural Park under the Municipality of Entracque (Italy). Specifically, this study focuses on the magnitude of the retreat of six glaciers and on the distribution of two different plant communities, Alnus viridis scrub and Fagus sylvatica forest associated with Acer pseudoplatanus and tall herbs (megaforbie), in relation to predicted increases in mean temperatures. MaxEnt software was used to model and observe changes over a thirty-year period, developing three scenarios: a present (2019), a past (1980) and a future (2050) using 24 “environmental layers”. This study showed the delicate climate balances of these six small glaciers that, in the next 30 years, are likely to undergo an important retreat (≈−33%) despite the high altitude and important snowfall that still characterize the area. At the same time, it is predicted that the two plant communities will invade those higher altitude territories that, not so long ago, were inhospitable, expanding their habitat by 50%. The MaxEnt application to glaciers has shown to be an effective tool that offers a new perspective in the climate change field as well as in biodiversity conservation planning.

Atmosphere Driven Mass-Balance Sensitivity of Halji Glacier, Himalayas

The COupled Snowpack and Ice surface energy and mass balance model in PYthon (COSIPY) was employed to investigate the relationship between the variability and sensitivity of the mass balance record of the Halji glacier, in the Himalayas, north-western Nepal, over a 40 year period since October 1981 to atmospheric drivers. COSIPY was forced with the atmospheric reanalysis dataset ERA5-Land that has been statistically downscaled to the location of an automatic weather station at the Halji glacier. Glacier mass balance simulations with air temperature and precipitation perturbations were executed and teleconnections investigated. For the mass-balance years 1982 to 2019, a mean annual glacier-wide climatic mass balance of −0.48 meters water equivalent per year (m w.e. a−1) with large interannual variability (standard deviation 0.71 m w.e. a−1) was simulated. This variability is dominated by temperature and precipitation patterns. The Halji glacier is mostly sensitive to summer temperature and monsoon-related precipitation perturbations, which is reflected in a strong correlation with albedo. According to the simulations, the climate sensitivity with respect to either positive or negative air temperature and precipitation changes is nonlinear: A mean temperature increase (decrease) of 1 K would result in a change of the glacier-wide climatic mass balance of −1.43 m w.e. a−1 (0.99m w.e. a−1) while a precipitation increase (decrease) of 10% would cause a change of 0.45m w.e. a−1 (−0.59m w.e. a−1). Out of 22 circulation and monsoon indexes, only the Webster and Yang Monsoon index and Polar/Eurasia index provide significant correlations with the glacier-wide climatic mass balance. Based on the strong dependency of the climatic mass balance from summer season conditions, we conclude that the snow–albedo feedback in summer is crucial for the Halji glacier. This finding is also reflected in the correlation of albedo with the Webster and Yang Monsoon index.

Heat Waves Alter Macrophyte-Derived Detrital Nutrients Release under Future Climate Warming Scenarios.

In addition to a rise in global air and water mean temperatures, extreme climate events such as heat waves are increasing in frequency, intensity, and duration in many regions of the globe. Developing a mechanistic understanding of the impacts of heat waves on key ecosystem processes and how they differ from just an increase in mean temperatures is therefore of utmost importance for adaptive management against effects of global change. However, little is known about the impact of extreme events on freshwater ecosystem processes, particularly the decomposition of macrophyte detritus. We performed a mesocosm experiment to evaluate the impact of warming and heat waves on macrophyte detrital decomposition, applied as a fixed increment (+4 °C) above ambient and a fluctuating treatment with similar energy input, ranging from 0 to 6 °C above ambient (i.e., simulating heat waves). We showed that both warming and heat waves significantly accelerate dry mass loss of the detritus and carbon (C) release but found no significant differences between the two heated treatments on the effects on detritus dry mass loss and C release amount. This suggests that moderate warming indirectly enhanced macrophyte detritus dry mass loss and C release mainly by the amount of energy input rather than by the way in which warming was provided (i.e., by a fixed increment or in heat waves). However, we found significantly different amounts of nitrogen (N) and phosphorus (P) released between the two warming treatments, and there was an asymmetric response of N and P release patterns to the two warming treatments, possibly due to species-specific responses of decomposers to short-term temperature fluctuations and litter quality. Our results conclude that future climate scenarios can significantly accelerate organic matter decomposition and C, N, and P release from decaying macrophytes, and more importantly, there are asymmetric alterations in macrophyte-derived detrital N and P release dynamic. Therefore, future climate change scenarios could lead to alterations in N/P ratios in the water column via macrophyte decomposition processes and ultimately affect the structure and function of aquatic ecosystems, especially in the plankton community.

Changes in spring vegetation greenness over Siberia associated with weather disturbances during 1982–2015

AbstractAs the global climate warms rapidly, terrestrial vegetation experiences significant changes. The impact of high‐frequency variability, especially for variations related to weather disturbances (i.e., day‐to‐day weather fluctuations), however, is less studied and remains poorly understood. In the present study, we quantitatively investigated the linkages between the normalized difference vegetation index (NDVI) and weather disturbances in spring (April and May) over Siberia for the period 1982–2015. Identified by empirical orthogonal function analysis, the inherent large‐scale spatial structure of weather disturbances shows synchronous variations over Siberia. It was found that weather disturbances are significantly related to the synchronous NDVI at a large spatial scale. The regional mean (48–67°N and 50–105°E) time series of the NDVI and weather variance, a measure of weather disturbance, is correlated at −0.32 (significant at the 0.05 level), suggesting that in springs with larger weather fluctuations, the concurrent NDVI tends to clearly decrease. Changes of frost events in association with weather disturbances are investigated to help understand the vegetation greenness response. We identified springs with the largest and smallest weather variances. Then, their differences were utilized to estimate the possible maximum changes for extremely cold temperatures. The results show that corresponding to the largest variance increase, for Siberia as a whole, the number of frost days has increased by 0.9 days (5%) and the accumulated adverse temperature has undergone a substantial increase of 18.9°C·day (15%). These results suggest that when there are active weather disturbances, the simultaneous increase in extremely cold temperatures plays a dominant role in adversely impacting vegetation activity. Our study demonstrates that, in addition to the increased mean temperature, the long‐term decrease in weather disturbances over Siberia, as observed in recent decades, should also contribute significantly to vegetation greening. This finding promotes a further understanding of the impacts of climate change on regional vegetation activity.

Regulation of DNA (de)Methylation Positively Impacts Seed Germination during Seed Development under Heat Stress.

Seed development needs the coordination of multiple molecular mechanisms to promote correct tissue development, seed filling, and the acquisition of germination capacity, desiccation tolerance, longevity, and dormancy. Heat stress can negatively impact these processes and upon the increase of global mean temperatures, global food security is threatened. Here, we explored the impact of heat stress on seed physiology, morphology, gene expression, and methylation on three stages of seed development. Notably, Arabidopsis Col-0 plants under heat stress presented a decrease in germination capacity as well as a decrease in longevity. We observed that upon mild stress, gene expression and DNA methylation were moderately affected. Nevertheless, upon severe heat stress during seed development, gene expression was intensively modified, promoting heat stress response mechanisms including the activation of the ABA pathway. By analyzing candidate epigenetic markers using the mutants’ physiological assays, we observed that the lack of DNA demethylation by the ROS1 gene impaired seed germination by affecting germination-related gene expression. On the other hand, we also observed that upon severe stress, a large proportion of differentially methylated regions (DMRs) were located in the promoters and gene sequences of germination-related genes. To conclude, our results indicate that DNA (de)methylation could be a key regulatory process to ensure proper seed germination of seeds produced under heat stress.

Potential impacts of 1.5 °C, 2 °C global warming levels on temperature and rainfall over Madagascar

Outputs from 25 regional climate models within the coordinated regional downscaling experiments—Africa are used to assess the impacts of the 1.5°C and 2°C global warming levels (GWLs) over Madagascar. A robust increase in the annual mean temperature ranging from 0.9°C to 1.2°C (1.3°C–1.8°C) is projected in the 1.5°C (2°C) GWL. The west and southwestern parts of the island display the highest rise in temperature. On the other hand, the changes in rainfall signals depend on the location, the months within the rain season and the warming level with the models showing a large uncertainty in the signal of changes. During early summer, the west and southwest regions exhibit an increase in total rainfall accompanied with more wet spell days and excessive amounts of extreme rainfall. In contrast, the east and the north are characterized by a deficit in total rainfall and wet spell days while the maximum number of dry spells increase. The change signals are more pronounced in the 2°C GWL. From January to April, an overall increase in total and extreme rainfall is projected over the island. The two warming levels agree on the delay in the rainfall onset and shortening of the rainfall season with the 2°C GWL depicting more modest changes in the west and southern parts of the country compared to that of 1.5 °C GWL. These results have important implications not only for the development of the country but also for the endemic biodiversity which is already suffering from the impacts of climate change.