Core Viewpoint - The northwest regions of China, traditionally known for drought, are increasingly facing severe rainfall events, leading to a heightened flood risk and a need for improved disaster preparedness [1][2]. Group 1: Changes in Precipitation Patterns - The northwest region is becoming "wetter," but rainfall is increasingly "extreme," with significant increases in precipitation and runoff since the 1980s [2][3]. - Extreme precipitation events have become more frequent, particularly in northern Xinjiang, the Hexi Corridor, and the Longzhong area, with cities like Lanzhou experiencing a notable increase in sudden heavy rainfall events [2][3]. - Global warming is closely linked to these changes, enhancing atmospheric moisture capacity and altering moisture transport pathways, leading to more extreme rainfall in the northwest [2][3]. Group 2: Vulnerability and Risk Factors - The climate vulnerability of northwest cities is characterized by natural conditions that are inherently inadequate, such as concentrated rainfall and weak soil moisture retention, which increase the risk of flooding and geological disasters [4][5]. - Urbanization has exacerbated disaster risk by increasing exposure to hazards and reducing the effectiveness of natural water retention systems [4][5]. - Existing infrastructure often fails to meet the demands of extreme weather events, as many designs are based on historical climate data that do not account for current climate variability [4][5]. Group 3: Forecasting and Monitoring Challenges - Despite improvements in forecasting capabilities, predicting localized extreme rainfall remains a significant challenge due to the complex terrain and sparse observation stations in the northwest [5][6]. - Current forecasting accuracy for short-term precipitation has improved, with over 80% accuracy for short-term forecasts and 90% for heavy rainfall warnings, but localized events still present difficulties [5][6]. Group 4: Recommendations for Disaster Preparedness - A systematic approach is needed to translate climate prediction data into actionable disaster preparedness strategies, including risk assessment, adaptive measures, and dynamic updates to plans [6][7]. - Collaboration between climate scientists and urban planners is essential to enhance urban resilience, though challenges such as data barriers and policy implementation difficulties persist [7][8]. - Future urban planning should prioritize high-risk areas identified through scientific assessments to optimize resource allocation and improve disaster response [11][12].

Core Viewpoint - The northwest region of China, previously characterized by drought, is now facing frequent heavy rainfall events, indicating a shift in climate patterns that necessitates urgent updates to flood prevention standards and infrastructure modifications [1] Group 1: Current Climate Changes - The northwest region is experiencing increased precipitation and runoff since the 1980s, with a notable rise in extreme rainfall events, particularly in cities like Lanzhou [2][3] - Global warming is linked to these changes, enhancing atmospheric moisture capacity and altering moisture transport pathways, leading to more intense rainfall in the region [2][4] Group 2: Disaster Chain Events - The occurrence of "short-term heavy rainfall—mountain floods—urban waterlogging" is becoming a frequent pattern in the northwest, driven by global warming, regional topography, and urbanization [3][5][6] Group 3: Urban Vulnerability - Urban areas in the northwest, such as Lanzhou, exhibit significant climate vulnerability due to natural conditions, weak socio-economic resilience, and inadequate infrastructure to handle extreme weather events [7] Group 4: Forecasting and Monitoring - Advances in numerical forecasting and data integration have improved the prediction accuracy of heavy rainfall events, yet challenges remain due to the region's complex terrain and sparse observation points [8] Group 5: Recommendations for Disaster Preparedness - A systematic approach is needed to convert climate prediction data into actionable disaster prevention strategies, including risk assessment, adaptive measures, and dynamic updates to strategies based on evolving climate data [9][10][11] Group 6: Collaboration and Data Sharing - Effective collaboration between climate scientists and urban planning departments is essential for enhancing urban climate resilience, though challenges such as data barriers and policy implementation difficulties persist [12] Group 7: Future Projections and Standards - Simulations indicate that Lanzhou may face more intense rainfall in the future, necessitating a revision of flood prevention standards based on non-stationary climate conditions [13][14][15] - Traditional engineering designs based on historical climate data may underestimate future risks, highlighting the need for updated design values and climate change adjustment factors [15] Group 8: Risk Assessment and Resource Allocation - Identifying high-risk areas through scientific models is crucial for prioritizing climate adaptation investments and optimizing resource allocation [17][18] - Current assessments have identified specific high-risk zones in Lanzhou, which can inform urban planning and disaster management strategies [19][20]