Disaster Effects of Climate Change and Associated Scientific Challenges
Introduction: Capturing Attention with Climate Change Impacts
Climate change is a global phenomenon that has left indelible marks on the Earth’s various spheres, including the atmosphere, lithosphere, hydrosphere, biosphere, and cryosphere. The interactions among these spheres play a pivotal role in shaping the climate system. Natural disasters, as the most intense manifestations of these interactions, have far-reaching implications for human society. For instance, the 2021 Zhengzhou “7·20” extreme rainfall event, triggered by the combined effects of climate change, typhoons, and topographical factors, led to severe urban flooding and secondary disasters, affecting millions of people. This example underscores the critical need to understand how climate change influences natural disasters and the scientific challenges ahead.
Characteristics of Climate Change-Induced Hazards
Increasing Temperature and Extreme Weather Events
Global warming has led to significant temperature rises, with the average surface temperature increasing by 0.99°C from 2001–2020 compared to 1850–1900. This warming has intensified extreme weather events, such as heatwaves, heavy rainfall, and tropical cyclones. For example, the 2022 Sichuan Luding earthquake combined with post-earthquake flash floods resulted in nearly 100 fatalities, highlighting the amplified risks due to climate change. Such events are indicative of the new characteristics and trends that natural disasters exhibit under a changing climate.
Altered Hydrological Cycles and Disaster Patterns
The accelerated water cycle due to climate change has led to more extreme dry and wet periods. Areas that were previously arid, like the Sahara Desert, have experienced unusual heavy snowfall events, as seen in 2018 and 2021. Additionally, the frequency and intensity of extreme precipitation events have increased, with a projected 1.3-fold rise in the frequency of ten-year extreme precipitation events and a 6.7% increase in intensity under a 1.1°C global warming scenario. These changes affect the source, material, and energy conditions for disasters, altering their occurrence patterns.
Response Mechanisms of Natural Disasters to Climate Change
Interactions in Different Geomorphic Units
Natural disasters respond differently across various geomorphic units. In marine environments, the strengthened interaction between the ocean and atmosphere has increased the compound risk and destructive power of marine disasters. Tropical cyclones, for example, are influenced by sea surface temperature, atmospheric circulation, and other factors. Changes in the El Niño-Southern Oscillation (ENSO) can shift the formation and intensity of tropical cyclones, affecting regions like the western North Pacific.
In terrestrial environments, the hydrological cycle intensification has led to more pronounced spatial differences in drought and flood disasters. For instance, the Yangtze River Basin in 2022 experienced both severe drought in the middle and lower reaches and floods in the upstream, reflecting the complex responses of natural disasters to climate change. High mountainous areas, sensitive to climate change, have seen accelerated glacier melting, permafrost degradation, and increased mountain hazards such as landslides and debris flows.
Future Trends of Disaster Risks
Pregnant Environment Evolution
Without significant greenhouse gas emission reductions, the climate is projected to warm rapidly, exacerbating thermal, hydrological, and gravitational hazards. By 2100, the frequency of summer compound heatwaves in the Northern Hemisphere could increase eightfold, and the intensity could triple. Sea-level rise due to glacier melting could threaten coastal cities, while droughts are expected to expand to 50–56% of the global land area by the end of the century.
Increased Exposure and Vulnerability
Population growth, urbanization, and land use changes are increasing the exposure and vulnerability of regions to natural disasters. For example, densely populated urban areas and coastal cities are at higher risk due to rising sea levels and extreme weather events. The Himalayan region, with its sensitive cryosphere, faces amplified risks from glacier retreat and increased tourism activities.
Scientific Challenges in Addressing Climate Change-Related Disaster Risks
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Coupling Mechanisms of Spheres and Forces: Understanding how internal and external forces interact under climate change to trigger disasters is crucial. The coupling of tectonic activities, topographical changes, and climate factors needs further exploration to predict major disasters.
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Spatio-Temporal Disaster Development: The changing spatiotemporal scales of natural disasters require a better understanding of their development patterns. Bridging the gap between large-scale climate predictions and local disaster events is essential for accurate risk assessment.
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Extreme Event Information and Risk Identification: The lack of comprehensive information on extreme events, such as “black swan” and “gray rhino” events, poses challenges in risk prediction. Developing data-driven systems to identify and predict risks is necessary.
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Disaster Dynamics and Risk Evolution: The nonlinear nature of climate systems makes disaster dynamics and risk evolution difficult to predict. Unraveling the complex interactions among multiple media and fields is key to addressing this challenge.
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Disaster Risk Management and Resilient Society: Building a resilient society that can withstand and recover from disasters is vital. Addressing the uncertainties in risk assessment and promoting inclusive disaster management strategies are critical for reducing climate change-related risks.
Conclusion
Climate change has significantly altered the characteristics and risks of natural disasters, presenting numerous scientific challenges. By addressing these challenges through integrated approaches, we can enhance our understanding of the Earth’s system, adapt to global changes, and mitigate disaster risks. Future research should focus on developing innovative methods to predict and manage natural disasters, ensuring the safety and resilience of human societies in a changing climate.
doi: 10.1360/TB-2023-0325
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