Periodic Reporting for period 1 - TrueHeat (Best-Estimate Projections of Future Compound Extreme Heat, its Impacts and Driving Mechanisms)
Okres sprawozdawczy: 2022-11-01 do 2024-10-31
In a warming world, extreme heat will become more frequent, and more extreme, leading to potentially devastating socioeconomic and ecological damages. Beyond maximum peak temperatures, the complex interplay of additional factors such as humidity, lack of nighttime cooling, and prolonged drought can lead to compounding risks and increased impacts. When unprecedented record-shattering compound heat stress extremes occur, it raises the question of whether the current tools of the climate community such as climate models are sufficient to capture the risk and intensity of rare but plausible devastating extremes under present, and especially future climate conditions. Are climate model projections downplaying the risk and intensity of current and future extreme compound heat stress due to missing or incorrect process representation? Can we sufficiently sample the most unlikely and extreme albeit still plausible events? And how does low-probability, high-impact extreme compound heat stress develop, which intensity, persistence, compounding or level of impact could it reach?
As we strive to adapt to a warming planet, it is imperative to comprehend the full extent of these compound heat stress events and their potential societal, economical and ecological impact. The primary goal of TrueHeat is to unravel the intricate dynamics of the most rare but physically plausible extreme compound heat stress and its drivers and impacts in present and future climates. The project is structured in a three-tier approach to address these critical questions.
Project Pathway to Impact:
1. Curating Best-Estimate Heat Projections: We will exploit the growing number of large ensembles from single climate models to develop refined future heat projections. These projections will incorporate state-of-the-art evaluation techniques, enabling us to enhance our understanding of how extreme heat events might unfold under different climate scenarios according the models that best represent real-world climate conditions. By combining these projections with up-to-date epidemiological data and models, we aim to assess the potential impact of heat stress on human health, providing valuable insights into the near-term mortality risks associated with extreme heat.
2. Investigating Current Climate Variability: We will use climate prediction data to identify where in the world to assess where the chaos in the climate system could produce the largest heat stress intensification already under our current climate, while determining what leads to forecasted instances of extreme unprecedented heat to not occur, or occur in a less extreme form in reality.
3. Sampling Clustering Heat Stress: Employing an innovative ensemble boosting technique, we will generate sets of simulations that deliberately explore the most extreme but physically plausible worst-case heat clustering events, where extreme heat occurs repeatedly in a season or concurrently over several remote regions. This unique approach will enable us to quantify the variability in the characteristics of these clustering extreme heat stress events, assessing their potential short- and long-term driving factors.
Expected Impact and Significance:
This project will yield the best-informed knowledge of the unlikely but physically plausible heat that we may come to experience in the near-term future, determining how instances of extreme compound heat can turn into their most impactful and unprecedented version. This newfound knowledge will offer crucial insights for policymakers, urban planners, public health officials, and disaster management teams, enabling them to formulate more effective strategies to mitigate the adverse effects of extreme heat events. This project's outcomes are poised to provide a comprehensive view of the risks posed by extreme compound heat stress, shedding light on both their driving mechanisms in a changing climate and their potential implications for human well-being, ecosystem health, and socioeconomic stability. With these insights, we can make informed decisions to better prepare for the challenges presented by a rapidly changing climate, ultimately safeguarding our planet and its inhabitants for generations to come.
As we strive to adapt to a warming planet, it is imperative to comprehend the full extent of these compound heat stress events and their potential societal, economical and ecological impact. The primary goal of TrueHeat is to unravel the intricate dynamics of the most rare but physically plausible extreme compound heat stress and its drivers and impacts in present and future climates. The project is structured in a three-tier approach to address these critical questions.
Project Pathway to Impact:
1. Curating Best-Estimate Heat Projections: We will exploit the growing number of large ensembles from single climate models to develop refined future heat projections. These projections will incorporate state-of-the-art evaluation techniques, enabling us to enhance our understanding of how extreme heat events might unfold under different climate scenarios according the models that best represent real-world climate conditions. By combining these projections with up-to-date epidemiological data and models, we aim to assess the potential impact of heat stress on human health, providing valuable insights into the near-term mortality risks associated with extreme heat.
2. Investigating Current Climate Variability: We will use climate prediction data to identify where in the world to assess where the chaos in the climate system could produce the largest heat stress intensification already under our current climate, while determining what leads to forecasted instances of extreme unprecedented heat to not occur, or occur in a less extreme form in reality.
3. Sampling Clustering Heat Stress: Employing an innovative ensemble boosting technique, we will generate sets of simulations that deliberately explore the most extreme but physically plausible worst-case heat clustering events, where extreme heat occurs repeatedly in a season or concurrently over several remote regions. This unique approach will enable us to quantify the variability in the characteristics of these clustering extreme heat stress events, assessing their potential short- and long-term driving factors.
Expected Impact and Significance:
This project will yield the best-informed knowledge of the unlikely but physically plausible heat that we may come to experience in the near-term future, determining how instances of extreme compound heat can turn into their most impactful and unprecedented version. This newfound knowledge will offer crucial insights for policymakers, urban planners, public health officials, and disaster management teams, enabling them to formulate more effective strategies to mitigate the adverse effects of extreme heat events. This project's outcomes are poised to provide a comprehensive view of the risks posed by extreme compound heat stress, shedding light on both their driving mechanisms in a changing climate and their potential implications for human well-being, ecosystem health, and socioeconomic stability. With these insights, we can make informed decisions to better prepare for the challenges presented by a rapidly changing climate, ultimately safeguarding our planet and its inhabitants for generations to come.
1. Generating Worst-Case Heat and Drought Storylines over Europe Using Ensmeble Boosting
One of the key achievements of the project was the use of an innovative ensemble boosting technique to generate storylines of the most extreme but physically plausible heat and drought conditions that could occur over Europe under current climate conditions. The analysis provides a framework to explore the upper limits of heat and drought intensity and persistence and their associated impacts as well as mechanisms that cause them. This research is currently being compiled into a manuscript for publication.
2. Generating Potentially Deadly Humid Heatwaves over Europe using Ensemble Boosting
The ensemble boosting method was also applied to investigate scenarios of deadly humid heat conditions. These conditions arise when high temperatures and humidity levels combine to impair the body’s ability to dissipate heat through sweating and evaporation, leading to a rapid rise in core body temperature. Such mechanisms can result in heat stroke and significantly increase risks of heat-related mortality and morbidity, especially among vulnerable populations.
This study focused on identifying where in Europe, if at all, these extreme temperature and humidity conditions could occur under current climate conditions, and for how long they might persist. The findings are critical for assessing regional vulnerability to extreme heat and for developing targeted adaptation strategies. This work forms the basis of a separate manuscript in preparation.
3. Evaluation of Climate Model Variability and Constrained Projections
A performance-based evaluation of several climate models large ensembles was conducted to assess their ability to simulate observed variability in surface temperatures across all regions of the world. The results from this evaluation are then used to determine which climate models most accurately represent real-world climate variability in the historical period, and, using this climate models, to produce constrained projections of changes in temperature variability for different regions worldwide. These projections offer refined insights into how variability might evolve under different climate scenarios, improving our ability and confidence to anticipate and prepare for future changes. This research is also being prepared for publication.
4. Access and Use of MCC Epidemiological Data for Heat Mortality Assessment
A proposal to secure access to the Multi-Country Multi-City (MCC) Collaborative Research Network has also been submitted and accepted. This network provides high-resolution epidemiological data, which will be utilized to assess heat-related mortality risks and evaluate the potential near-term impacts of extreme heat on human health. These efforts aim to inform public health strategies and are foundational for future work and publications focused on heat-related mortality.
One of the key achievements of the project was the use of an innovative ensemble boosting technique to generate storylines of the most extreme but physically plausible heat and drought conditions that could occur over Europe under current climate conditions. The analysis provides a framework to explore the upper limits of heat and drought intensity and persistence and their associated impacts as well as mechanisms that cause them. This research is currently being compiled into a manuscript for publication.
2. Generating Potentially Deadly Humid Heatwaves over Europe using Ensemble Boosting
The ensemble boosting method was also applied to investigate scenarios of deadly humid heat conditions. These conditions arise when high temperatures and humidity levels combine to impair the body’s ability to dissipate heat through sweating and evaporation, leading to a rapid rise in core body temperature. Such mechanisms can result in heat stroke and significantly increase risks of heat-related mortality and morbidity, especially among vulnerable populations.
This study focused on identifying where in Europe, if at all, these extreme temperature and humidity conditions could occur under current climate conditions, and for how long they might persist. The findings are critical for assessing regional vulnerability to extreme heat and for developing targeted adaptation strategies. This work forms the basis of a separate manuscript in preparation.
3. Evaluation of Climate Model Variability and Constrained Projections
A performance-based evaluation of several climate models large ensembles was conducted to assess their ability to simulate observed variability in surface temperatures across all regions of the world. The results from this evaluation are then used to determine which climate models most accurately represent real-world climate variability in the historical period, and, using this climate models, to produce constrained projections of changes in temperature variability for different regions worldwide. These projections offer refined insights into how variability might evolve under different climate scenarios, improving our ability and confidence to anticipate and prepare for future changes. This research is also being prepared for publication.
4. Access and Use of MCC Epidemiological Data for Heat Mortality Assessment
A proposal to secure access to the Multi-Country Multi-City (MCC) Collaborative Research Network has also been submitted and accepted. This network provides high-resolution epidemiological data, which will be utilized to assess heat-related mortality risks and evaluate the potential near-term impacts of extreme heat on human health. These efforts aim to inform public health strategies and are foundational for future work and publications focused on heat-related mortality.
The project has made significant strides in understanding and projecting extreme compound heat stress. The main results include:
Worst-Case Storylines for Near-Term Projections: Utilizing ensemble boosting, the project has identified the most extreme but physically plausible scenarios of 1. Extreme heat and drought and 2. Extreme humid heat conditions that could occur in Europe in today’s climate. This includes assessing the potential duration and intensity of these events under current conditions and comparing them to events in the observed record.
Constrained Long-Term Projections: Comprehensive evaluation of climate model ensembles has led to constrained projections of changes in surface temperature variability. This work enhances confidence in identifying regions at risk of future extreme heat events worldwide.
Key Needs for Further Uptake and Success
To build on the progress made and ensure the success of the project outcomes, the following needs have been identified:
Mechanistic Exploration of Extreme Events: Further investigation into the specific mechanisms leading to the most extreme but physically plausible heat and drought events under today’s climate conditions is essential. This includes analyzing the atmospheric, oceanic, and land surface processes driving these extremes and disentangle their contributions using state-of-the-art methods such as atmospheric flow analogues.
Impact Assessment Using MCC Mortality Data: Utilizing the MCC network’s epidemiological data, the project should assess the estimated mortality during simulated worst-case heat and drought summers. These estimates should be compared to observed mortality during recent extreme events to contextualize the potential human impacts of such scenarios.
Enhanced Validation Techniques: Further validation of the ensemble boosting methodology against observed data will help refine and verify the plausibility of simulated extreme scenarios, ensuring robustness in future applications.
Worst-Case Storylines for Near-Term Projections: Utilizing ensemble boosting, the project has identified the most extreme but physically plausible scenarios of 1. Extreme heat and drought and 2. Extreme humid heat conditions that could occur in Europe in today’s climate. This includes assessing the potential duration and intensity of these events under current conditions and comparing them to events in the observed record.
Constrained Long-Term Projections: Comprehensive evaluation of climate model ensembles has led to constrained projections of changes in surface temperature variability. This work enhances confidence in identifying regions at risk of future extreme heat events worldwide.
Key Needs for Further Uptake and Success
To build on the progress made and ensure the success of the project outcomes, the following needs have been identified:
Mechanistic Exploration of Extreme Events: Further investigation into the specific mechanisms leading to the most extreme but physically plausible heat and drought events under today’s climate conditions is essential. This includes analyzing the atmospheric, oceanic, and land surface processes driving these extremes and disentangle their contributions using state-of-the-art methods such as atmospheric flow analogues.
Impact Assessment Using MCC Mortality Data: Utilizing the MCC network’s epidemiological data, the project should assess the estimated mortality during simulated worst-case heat and drought summers. These estimates should be compared to observed mortality during recent extreme events to contextualize the potential human impacts of such scenarios.
Enhanced Validation Techniques: Further validation of the ensemble boosting methodology against observed data will help refine and verify the plausibility of simulated extreme scenarios, ensuring robustness in future applications.