scholarly journals The effect of forced change and unforced variability in heat waves, temperature extremes, and associated population risk in a CO<sub>2</sub>-warmed world

2021 ◽  
Vol 21 (15) ◽  
pp. 11889-11904
Author(s):  
Jangho Lee ◽  
Jeffrey C. Mast ◽  
Andrew E. Dessler

Abstract. This study investigates the impact of global warming on heat and humidity extremes by analyzing 6 h output from 28 members of the Max Planck Institute Grand Ensemble driven by forcing from a 1 % yr−1 CO2 increase. We find that unforced variability drives large changes in regional exposure to extremes in different ensemble members, and these variations are mostly associated with El Niño–Southern Oscillation (ENSO) variability. However, while the unforced variability in the climate can alter the occurrence of extremes regionally, variability within the ensemble decreases significantly as one looks at larger regions or at a global population perspective. This means that, for metrics of extreme heat and humidity analyzed here, forced variability in the climate is more important than the unforced variability at global scales. Lastly, we found that most heat wave metrics will increase significantly between 1.5 and 2.0 ∘C, and that low gross domestic product (GDP) regions show significantly higher risks of facing extreme heat events compared to high GDP regions. Considering the limited economic adaptability of the population to heat extremes, this reinforces the idea that the most severe impacts of climate change may fall mostly on those least capable of adapting.

2021 ◽  
Author(s):  
Jangho Lee ◽  
Jeffery C. Mast ◽  
Andrew E. Dessler

Abstract. This study investigates the impact of global warming on heat and humidity extremes by analyzing 6-hourly output from 28 members of the Max Planck Institute Grand Ensemble driven by forcing from a 1 %/year CO2 increase. We find that unforced variability drives large changes in regional exposure to extremes in different ensemble members, and these variations are mostly associated with ENSO variability. However, while the unforced variability of the climate can alter the occurrence of extremes regionally, variability within the ensemble decreases significantly as one looks at larger regions or at a global population perspective. This means that, for metrics of extreme heat and humidity analyzed here, forced variability of the climate is more important than the unforced variability at global scales. Lastly, we found that most heat wave metrics will increase significantly between 1.5 °C and 2.0 °C, and that low GDP regions shows significant higher risks of facing extreme heat events compared to high GDP regions. Considering the limited economic adaptability of population to heat extremes, this reinforces the idea that the most severe impacts of climate change may fall mostly on those least capable to adapt.


CJEM ◽  
2020 ◽  
Vol 22 (S1) ◽  
pp. S87-S87
Author(s):  
F. Kegel ◽  
O. Luo ◽  
S. Richer

Introduction: The average temperature in Canada has risen 1.7°C between 1948-2016, increasing the frequency, severity and duration of extreme heat events. These events can exacerbate underlying health conditions, bringing patients to emergency departments (EDs). There is limited data associating sustained heat events to Canadian ED volumes and performance. This retrospective analysis assessed the impact of humidex and temperature on ED volume and length of stay (LOS). Methods: LOS is an indicator of ED overcrowding and system performance. The authors compared median and maximum LOS (hours) and patient volumes in both ambulatory and stretcher ED sections of two community hospitals (NDH, VH) in Montreal, QC to humidex and temperature during the summers of 2016-2018. Data were analyzed with one-way ANOVA and post hoc means analysis with Fisher LSD tests of a priori determined thresholds of mean three-day maximum humidex and temperature preceding ED presentation. Results: The mean maximum humidex and temperature values for the 2016-2018 summers in Montreal, QC were 30.4 and 26.1°C, respectively (n = 276 days). Elevated mean three-day maximum humidex was associated with increased ED volumes (F[3,88] = 4.2,p = 0.008) and median LOS (F[3,88] = 7.7,p = 0.0001) in the NDH. Mean three-day maximum humidex was associated with ED volumes (F[3,272) = 2.9,p = 0.03) but not with median and maximum LOS (p > 0.05) in the VH. Parallel comparisons with mean three-day maximum temperature similarly showed an association with increased ED volumes (F[3,88] = 5.0,p = 0.003) and increased duration of median LOS (F[3,88] = 3.5,p = 0.02) in the NDH. Mean three-day maximum temperature was associated with increased ED volumes (F[3,272] = 3.3,p = 0.02) but not with median and maximum LOS (p > 0.05) in the VH. Conclusion: Warming climates are associated with an increased number of ED presentations and longer median ED LOS. As heat events disproportionately impacted NDH, future investigations need to determine why these two hospitals were affected differently. This study provides local evidence that climate change can disrupt emergency services by increasing the demand for and delaying timely care. This is the first study that the authors are aware of that demonstrates these findings. Hospitals need to be climate ready. Heat waves often happen during times when summer bed closures and vacations already impact system capacity. EDs should dynamically adapt to meet community needs during periods of extreme heat.


Author(s):  
Wayne R. Lawrence ◽  
Aida Soim ◽  
Wangjian Zhang ◽  
Ziqiang Lin ◽  
Yi Lu ◽  
...  

Abstract Although prenatal exposure to high ambient temperatures were reported to be associated with preterm birth, limited research assessed the impact of weather-related extreme heat events (EHE) on birthweight, particularly by trimester. We, therefore, investigated the impact of prenatal EHE on birthweight among term babies (tLBW) by trimester and birthweight percentile. We conducted a population-based case–control study on singleton live births at 38–42 gestational weeks in New York State (NYS) by linking weather data with NYS birth certificates. A total of 22,615 cases were identified as birthweight <2500 gram, and a random sample of 139,168 normal birthweight controls was included. EHE was defined as three consecutive days with the maximum temperatures of ≥32.2 °C/90 °F (EHE90) and two consecutive days of temperatures ≥97th percentile (EHE97) based on the distribution of the maximum temperature for the season and region. We estimated odds ratios (ORs) and 95% confidence intervals (95% CI) with multivariable unconditional logistic regression, controlling for confounders. Overall exposure to EHE97 for 2 d was associated with tLBW (OR 1.05; 95% CI 1.02, 1.09); however, the strongest associations were only observed in the first trimester for both heat indicators, especially when exposure was ≥3 d (ORs ranged: 1.06–1.13). EHE in the first trimester was associated with significant reduction in mean birthweight from 26.78 gram (EHE90) to 36.25 gram (EHE97), which mainly affected the 40th and 60th birthweight percentiles. Findings revealed associations between multiple heat indicators and tLBW, where the impact was consistently strongest in the first trimester.


2021 ◽  
Author(s):  
Sang-Wook Yeh ◽  
Eun-Hye Lee ◽  
Seung-Ki Min

Abstract The frequency and duration of extreme heat events, including heat waves (HWs, daytime hot extremes) and tropical night (TNs), are increasing significantly as the climate warms, adversely affecting human health, agriculture, and energy consumption. Although many detection and attribution studies have examined extreme heat events, the underlying mechanisms associated with the recent increase in HWs and TNs remain unclear. In this study, we analyze the controlling factors behind the distinct increases in HW and TN events over the Northern Hemisphere during boreal summer (June to August). We found that the occurrence of HW events has been increasing gradually since 1980, mostly due to anthropogenic forcing. However, the occurrence of TN events increased abruptly during the late 1990s and has changed little since then. We demonstrate that this sudden increase in TN events is closely associated with low frequency variability in sea surface temperature, including the Pacific Decadal Oscillation, indicating its natural origin. We further found that CMIP5 climate models fail to capture the observed non-linear increases in TN events, implying potentially large uncertainty in future projections of nighttime heat events and its impacts on human society and ecosystem.


2014 ◽  
Vol 38 (9) ◽  
pp. 1699-1712 ◽  
Author(s):  
ROBERT TESKEY ◽  
TIMOTHY WERTIN ◽  
INGVAR BAUWERAERTS ◽  
MAARTEN AMEYE ◽  
MARY ANNE MCGUIRE ◽  
...  

2015 ◽  
Vol 7 (1) ◽  
pp. 94-102 ◽  
Author(s):  
E. Coffel ◽  
R. Horton

Abstract Temperature and airport elevation significantly influence the maximum allowable takeoff weight of an aircraft by changing the surface air density and thus the lift produced at a given speed. For a given runway length, airport elevation, and aircraft type, there is a temperature threshold above which the airplane cannot take off at its maximum weight and thus must be weight restricted. The number of summer days necessitating weight restriction has increased since 1980 along with the observed increase in surface temperature. Climate change is projected to increase mean temperatures at all airports and to significantly increase the frequency and severity of extreme heat events at some. These changes will negatively affect aircraft performance, leading to increased weight restrictions, especially at airports with short runways and little room to expand. For a Boeing 737-800 aircraft, it was found that the number of weight-restriction days between May and September will increase by 50%–200% at four major airports in the United States by 2050–70 under the RCP8.5 emissions scenario. These performance reductions may have a negative economic effect on the airline industry. Increased weight restrictions have previously been identified as potential impacts of climate change, but this study is the first to quantify the effect of higher temperatures on commercial aviation. Planning for changes in extreme heat events will help the aviation industry to reduce its vulnerability to this aspect of climate change.


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