Assessing urban flood and drought content in the Nationally Determined Contributions (NDCs): a multi-hazard perspective

Abstract

The intensifying impact of climate change on the global hydrological cycle has manifested in heightened intensity, frequency, and duration of extreme hydrological events worldwide, posing significant challenges for urban resilience and sustainability. The latest Intergovernmental Panel on Climate Change Report (IPCC, 2023) highlights the rising frequency and intensity of compound events, such as floods and droughts, occurring simultaneously or in close succession, further exacerbating these risks.

Floods and droughts, prominent climate hazards affecting the global population, are more destructive when occurring together, with devastating impacts on communities and ecosystems (IPCC, 2023; Tabari et al., 2021). These events have disproportionately affected urban areas, where urbanization, together with climate change, intensifies temperature and precipitation patterns, leading to concentrated, intense precipitation and extended drought periods (United Nations Office for Disaster Risk Reduction, 2023).

Despite the recognized interconnectedness of floods and droughts within the hydrological cycle, current research, policymaking, and practice, particularly in urban areas, often fail to adequately integrate these hazards. While floods and droughts exacerbate each other's impacts, worsening extremes and affecting the average values of their records, they are typically treated separately in water management planning. Moreover, partly due to the immediacy of flood impacts, which attract more research attention, droughts' delayed and widespread consequences, often overlooked, are equally critical to address in comprehensive water management strategies.

This disparity in attention is partly attributed to the immediacy and visibility of flood impacts, which tend to garner more research attention than the slower onset and broader effects of droughts. However, droughts' delayed and widespread consequences extend across a larger spatial scale, making them equally critical to address in comprehensive water management strategies.

To address these gaps, this study aims to analyse how floods and droughts are addressed, both as standalone occurrences and interconnected phenomena, within the Nationally Determined Contributions (NDCs). The primary objective is to identify shortcomings in multi-hazard analysis and foster the development of policies informed by a holistic, multi-hazard perspective.

This research draws upon the comprehensive NDCs Urban Content Analysis framework developed by the UNESCO Chair on Urban Resilience, UN-Habitat, and UNDP between 2016 and 2023. The most recent report, released in 2022, analyses 194 NDCs submitted to the UNFCCC Secretariat by June 27, 2023 (Tollin et al., 2022). The report reveals that water and infrastructure are consistently identified as the most critical sectors for addressing urban adaptation challenges and responses, while flooding emerges as the most frequently mentioned climate hazard in urban contexts. This follow-up study specifically highlights the interplay between floods and droughts in urban settings.

The results highlight a limited focus on urban floods and droughts in NDCs, both as standalone and interconnected phenomena. However, consistent themes related to both hazards emerge, encompassing shared impacts, the need for common monitoring and evaluation systems, integrated water management, shared loss and damages, and the persistent lack of data.

In conclusion, strengthening the incorporation of floods and droughts in the policy-making process is crucial to bridging the gaps between national policies and urban strategies and practices, ensuring the resilience of cities in the face of climate change-induced extreme hydrological events.