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The energy crisis caused by climate change is the most significant challenge of the 21st century. Single-objective and multi-objective optimization studies for buildings often only consider the building itself, without considering the impacts of climate change. However, in the future, energy-efficient design and appropriate operating parameters will be crucial considerations in the face of global climate change. This paper aims to discuss the impact of climate change in the humid-hot region over the past 60 years on the energy consumption of office buildings and propose countermeasures. Firstly, the meteorological data of Guangzhou from 1960 to 2020 is statistically analyzed, and four typical meteorological years and corresponding air conditioning design days are established. Secondly, Energyplus is used to simulate the building's energy consumption, and the energy consumption factors are analyzed for sensitivity using jEplus. Finally, a multi-objective optimization is performed using jEPlus + EA with the Non-dominated Sorting Genetic Algorithm (NSGA-II). The results found that climate change led to a significant increase in the duration of high outdoor temperatures during summer. Specifically, the daily dry-bulb temperature for air conditioning design increased by 0.4–0.7 °C, and due to climate change, the energy consumption of the office building increased by about 4.6 %. The main factor affecting the cooling energy consumption in summer was the indoor cooling set point (8.29%–30%), infiltration air volume (1.0%–8.6%), fresh air volume (3.2%–16.06%), the glazing solar transmission rate (1.25%–9.0%), building orientation (0%–1.43%), and relatively small influence of envelope insulation performance. The operation scheme determined by multi-objective optimization can reduce the cooling energy consumption of the building by 10.6%–16.8%, which can mitigate the rise in energy consumption resulting from climate change to a greater extent. [Display omitted] • Discuss the impact of climate change over the past 60 years on the energy consumption of office buildings. • There was a significant increase in the duration of high outdoor temperatures during the summer. • Multi-objective optimization is performed using jEPlus + EA. • Climate change caused energy consumption to increase by about 4.6 %. • Optimal solutions can reduce the cooling energy consumption of the building by 10.6%–16.8%. [ABSTRACT FROM AUTHOR]

Changes in winter low flow (WLF) in cold-region rivers affect engineering design, water quality, and river ecosystem health. This paper aims to quantify to what extent WLF will change under climate warming and to propose a practical forecasting model for WLF predictions. The new concept of cumulative watershed temperature (CWT) is used as a convenient lumped surrogate for complicated hydrological processes that influence WLF. Statistical analyses of century-long flow data from the Fraser River in British Columbia, Canada show a strong dependence of WLF on CWT. In winter season, time series of CWT and WLF are shown to each divide into a falling and a rising limb at the data point of their lowest values, being −358 °C and 827 m3/s (historical averages), respectively. The falling and rising limbs describe the cumulative freezing and thawing effects of air temperatures fluctuating around the freezing point on WLF changes. The correlation between CWT and WLF (time series) data points on the rising limbs forms the forecasting model, expressing WLF as a function of CWT in terms of their z-scores. The model takes input of Global Circulation Model (GCM) projections of temperature increases by the end of 21st century under different Representative Concentration Pathways (RCPs), and predicts changes of Fraser River WLF from the historical average. RCP4.5 causes a 22.6% increase (ensemble average from six GCMs). RCP8.5 increases WLF by 20% (for some future years) to 44% (for others). The methods reported in this paper can be adapted to other cold regions. • Climate warming causes future winter low flow of the Fraser River in B.C. to increase. • Cumulative watershed air temperature controls the magnitude of winter low flow. • Design low flows from traditional methods need corrections due to climate warming. [ABSTRACT FROM AUTHOR]

This paper focuses on the relationship between atmospheric circulation and solid precipitation (SP) happening in the weather station of Isola 2000. Located in the French department of the Alpes-Maritimes at an altitude of 1912 m, it has the oldest series of daily SP and snow depth (SD) observations from the department. Study has two objectives, analyzed past orientations concerning air temperature, SP and SD, then, characterizes and explains the atmospheric circulation condition producing SP. Results show a warming of air temperature since the early 2000s, counterintuitive accompanied by an increase in the frequency of SP and a larger thickness of SD. In addition, by crossing SP observations with ERA-INTERIM reanalysis (EI-R), seven covariations have been measured: vertical velocity 700 hPa; specific humidity 850 hPa; sea level pressure; air temperature 850 hPa; geopotential height 700 hPa; U-component of wind 700 hPa, V-component of wind 700 hPa. The mapping of these variables shows two types of atmospheric circulation implicated in SP: westerly cyclonic circulation, producing SP in the range of 1–5 cm and 6–20 cm; southern circulation with a depression focused on Iceland and a trough on Western Europe, causing SP in the range of 21–40 cm and 41–93 cm. [ABSTRACT FROM AUTHOR]

Permafrost is very sensitive to climate factors, with warm permafrost particularly vulnerable to climate change. This paper aims to provide a detailed case study of climate trends of a high-latitude Alaskan site underlain by warm permafrost based on historical data and predictions from the Coupled Model Intercomparison Project Phase 5 (CMIP5). The climate data, including air temperature, precipitation, wind speed, and their annual and seasonal trends from 1950 to 2099, are presented for Bethel, Alaska. The downscaled data are compared with the historical data in the overlap period. Both air and design freezing and thawing indices are calculated using various methods. In comparison, the downscaled model predictions align well with air temperature and wind speed records but not for precipitation, indicating the need for further downscaling at a finer resolution. The historical annual temperature records show a warming rate of 0.40 °C per decade, which is predicted to almost double to 0.78 °C per decade in the 21st century, leading to shorter winters and longer summers. The historical annual precipitation increased by a rate of 14.8 mm per decade from 1950 to 2020, and this trend is predicted to continue but at a slightly lower rate. The wind speed decreased consistently from 1984 to 2020 by 0.9 km/h per decade. However, the CMIP5 predicts that such a trend will diminish, with the mean annual wind speed remaining almost unchanged in this century. The air freezing index exhibits a consistent downtrend from 1950 to 2020, whereas the air thawing index remained flat until 1980 and rose afterward; the CMIP5 predicts that both trends will continue in the 21st century. The design air freezing and thawing indices are sensitive to the assessment periods for both methods. An assessment period shorter than 30 years, e.g., ten years, is recommended to find design indices. It is conservative to use the monthly mean air temperature method for evaluating the design air freezing index and apply the extreme event method for the design thawing index. • Compare downscaled model data at a finer resolution with other models in CMIP5. • Assess the design freezing and thawing indices by two methods with varying periods. • Recommend methods and periods for evaluating design freezing/thawing indices. • Discuss climate change effects on infrastructure, design strategies, future studies. [ABSTRACT FROM AUTHOR]

The effect of climate change on heating, ventilation and airconditioning (HVAC) system performances has become prominent, and HVAC fault impacts may also vary with climate change. This paper evaluates the impacts of HVAC operational faults on system energy and occupant thermal comfort under the current, 2030s and 2050s climates using a validated model. The energy and thermal comfort impact indicators were proposed to rank single and multiple faults under each climate period. Supply fan stuck at maximum speed, and the combinations associated with this fault were ranked first in energy and thermal comfort rankings, respectively. Based on the investigations of multiple faults interactions, it is found that the synergetic/antagonistic effect of multiple faults combinations can lead to a significantly higher/lower combined impact than any single fault impact among the combination when the single faults present opposite impacts. Moreover, heating coil supply air temperature sensor negative bias, and the combination of thermostat positive offset and outdoor air damper stuck fully open led to the most increase system total electricity by 34.3 GJ and 35.3 GJ from current to 2050s period. The results are useful for researchers to prioritise the faults with significant impacts for developing fault detection and diagnosis framework. [Display omitted] [ABSTRACT FROM AUTHOR]

Mt. Everest (Qomolangma or Sagarmatha), the highest mount on Earth and located in the central Himalayas between China and Nepal, is characterized by highly concentrated glaciers and diverse landscapes, and is considered to be one of the most sensitive area to climate change. In this paper, we comprehensively synthesized the climate and environmental changes in the Mt. Everest region, including changes in air temperature, precipitation, glaciers and glacial lakes, atmospheric environment, river and lake water quality, and vegetation phenology. Historical temperature reconstruction from ice cores and tree rings revealed the distinct features of 20th century warming in the Mt. Everest region. Meteorological observations further proved that the Mt. Everest region has been experiencing significant warming (approximately 0.33 °C/decade) but relatively stable precipitation during 1961−2018 AD. Projected results (during 2006−2099 AD) under different representative concentration pathway scenarios showed a general warming trend in the region, with larger warming occurring in winter than in summer. Meanwhile, the precipitation projections varied spatially with no significant trends over the region. Intensive glacier shrinkage was characterized by decreasing glacier areas, while glacier-fed river runoff increased. Glacial lakes expanded with increasing glacial lake areas and numbers. These findings indicated a clear regional hydrological response to climate warming. Owing to the remote location of Mt. Everest, the present atmospheric environment remained relatively clean; however, long-range transport of atmospheric pollutants from South Asia and West Asia may have substantially influenced the Mt. Everest region, resulting in increasing concentrations of pollutants since the Industrial Revolution. Anthropogenic activities have been shown to influence river and lake water quality in this remote region, especially in the downstream. The end of the vegetation growing season advanced in the northern slope and did not change in southern slope region of the Mt. Everest, and there was no significant change in start date of the growing season in the region. This review will enhance our understanding of climate and environmental changes in the Mt. Everest region under global warming. • Climate and environmental changes were synthesized in the Mt. Everest region. • Glaciers have retreated significantly, posing impacts to river runoff and glacial lakes. • Transboundary transport of atmospheric pollutants influenced the region. • TThere was no significant change in start date of the growing season. [ABSTRACT FROM AUTHOR]

• Depending on stream temperature model, different warming of streamwater is projected. • Projection from particular model occasionally differ from the majority of models. • A number of stream temperature models should be used together for future climates. • Stream temperature in analyzed streams is to be warmed by 2–3.5 °C by 2100 (RCP 8.5). • In specific streams marginal cooling in projected in some months until 2050. In the majority of studies aiming at stream temperature warming due to climate change just a single water temperature model is used. Choosing a single model may highly impact the conclusions from the study. In this paper four relatively different empirical or semi-empirical models: perceptron neural networks, product unit networks, extended logistic regression and air2stream were applied to project the impact of climate change on water temperature in rivers located in temperate climatic zones of the USA and Poland. The models were driven by daily air temperature and streamflow projected by the rainfall-runoff model. In the first step, the models were calibrated and validated. Then the projections of water temperature were derived for the historical periods and two future periods taking into account: (a) climate simulations from the CORDEX initiative (NA-CORDEX and EURO-CORDEX), (b) the GR4J rainfall-runoff model and (c) different water temperature models. The obtained results indicate that due to global warming, the stream temperatures are expected to increase by about 1–2 °C for 2021–2050 and by 2–3 °C for 2071–2100 periods. These changes are not uniformly distributed throughout the year. The largest warming in the USA is found in the summertime, in Poland – in spring and autumn. For some months the discrepancies in the projected stream temperature between various stream temperature models are large. Product unit neural network, logistic regression-based model or air2stream occasionally led to projections that differ from those obtained by the majority of models even by 2 °C. We strongly recommend using at least a few stream temperature models for analysing the impact of climate change on water temperatures or the fate of the aquatic ecosystem. [ABSTRACT FROM AUTHOR]

This paper aims to analyse the distribution and temporal evolution of convective precipitation in the Mediterranean region of Spain. To accomplish this goal, we used 148 sets of 5-min rainfall rate data from the 1989–2015 period. The selected regions were the Júcar Hydrographic Confederation (CHJ) and the Internal Basins of Catalonia (CIC), which cover most of the autonomous communities of Catalonia and the Valencian Community (east Spain). The average 5-min intensity threshold of 35 mm/h and the β parameter, defined as the ratio between convective precipitation versus total precipitation in any period, were used to characterise convective precipitation. Convective episodes were categorised as "very convective", "moderately convective", and "slightly convective" based on the β value. After quality control, the series of 129 stations were clustered into homogeneous precipitation zones that also include β as one of the variables of characterisation. The results show that convective precipitation can contribute to total annual precipitation by up to 16% on average, but it is generated by a very small percentage of convective events (between 3% and 6% across all the stations) in comparison with the total number of rainfall episodes. In this sense, moderately convective events are the most common, with a predominantly unimodal monthly distribution of β, with summer the most convective season. Trends show a significant increase in precipitation, convective precipitation, and convective episodes in the CHJ. On the other hand, a positive trend of convective events is predominant in the CIC region, despite an overall precipitation decrease in the analysed period. These results are relevant given that extreme daily rainfall does not show a positive or significant trend, and they are in line with the impact of climate change on increased atmospheric instability and water vapour in the atmosphere. They highlight the need to work with sub-daily precipitation series in the case of the Mediterranean, which is mainly affected by flash floods. • The contribution of convective precipitation in the East of Spain exceeds 10% annually and can reach 100% in late summer. • Convective precipitation is caused by less than 5% of annual rain episodes that are associated to heavy rains. • Orography (height, orientation, and distance to the sea) plays the major role in triggering convective precipitation. • There is a predominant increase of convective precipitation resulting from a strengthening of thermodynamic conditions. • SST has increased 0,3ºC more than air temperature in the Mediterranean region that results in increasing potential instability. [ABSTRACT FROM AUTHOR]

• Evaporation trends of tropical reservoirs in Brazil were investigated. • Both positive and negative trends in evaporation were observed. • In the industrial region, the negative trend was potentially caused by the impact of pollutant released to the atmosphere. • In the coastal region, the positive trend was related to increasing air temperature. This paper aims to analyze the trends (Mann-Kendall test) of evaporation and climatological variables, including air temperature, relative humidity and wind speed in four reservoirs located in the Brazilian Northeast. The evaporation was estimated through remote sensing using the Surface Energy Balance System for Water (AquaSEBS) model from 1985 to 2018. In addition, it was verified which meteorological parameter has the highest correlation (R2) with the evaporation in order to assess why this process is changing throughout the years in each reservoir. The model performed well, with root mean square error (RMSE) ≤ 1.25 mm/day, percent bias (PBIAS) ≤ 13.70% and coefficient of determination (R2) ≥ 0.51. One reservoir located closer to a coastal zone presented a positive trend (+0.24 mm/34 years), corroborating the measurements of a reference class A pan, and Penman-Monteith equation, while the others, located closer to industrial areas, displayed negative trends (−0.26 to −0.080 mm/34 years). This reduced evaporation was attributed to the impact of industrial pollutant release to the atmosphere, while the increasing effect in the other reservoir was due to its proximity to the coast, which implies an air renewal as the sea breeze contributes for an improvement in the air quality. The meteorological data also presented positive and negative correlations: Temperature exhibited a positive trend (+0.57 °C/34 years), whereas humidity (−4.83%) and wind speed (−0.29 m/s), a negative trend. Evaporation displayed moderate coefficient of determination (R2 > 0.31) with wind speed and humidity. Yet, the reduction of evaporation may be associated with a possible counterbalancing effect of wind speed over humidity. Overall, the results contribute to a better understanding of evaporation trends in a water-scarce region and can be used in a water resources management context as the increasing/reduction of evaporation might significantly impact water availability in this area. [ABSTRACT FROM AUTHOR]