Abstract. As China becomes increasingly urbanised, flooding has become a regular
occurrence in its major cities. Assessing the effects of future climate
change on urban flood volumes is crucial to informing better management of
such disasters given the severity of the devastating impacts of flooding
(e.g. the 2016 flooding events across China). Although recent studies have
investigated the impacts of future climate change on urban flooding, the
effects of both climate change mitigation and adaptation have rarely been
accounted for together in a consistent framework. In this study, we assess
the benefits of mitigating climate change by reducing greenhouse gas (GHG)
emissions and locally adapting to climate change by modifying drainage
systems to reduce urban flooding under various climate change scenarios
through a case study conducted in northern China. The urban drainage
model – Storm Water Management Model – was used to simulate urban flood
volumes using current and two adapted drainage systems (i.e. pipe
enlargement and low-impact development, LID), driven by bias-corrected
meteorological forcing from five general circulation models in the Coupled
Model Intercomparison Project Phase 5 archive. Results indicate that urban
flood volume is projected to increase by 52 % over 2020–2040 compared to the
volume in 1971–2000 under the business-as-usual scenario (i.e.
Representative Concentration Pathway (RCP) 8.5). The magnitudes of urban
flood volumes are found to increase nonlinearly with changes in precipitation
intensity. On average, the projected flood volume under RCP 2.6 is 13 %
less than that under RCP 8.5, demonstrating the benefits of global-scale
climate change mitigation efforts in reducing local urban flood volumes.
Comparison of reduced flood volumes between climate change mitigation and
local adaptation (by improving drainage systems) scenarios suggests that
local adaptation is more effective than climate change mitigation in reducing
future flood volumes. This has broad implications for the research community
relative to drainage system design and modelling in a changing environment.
This study highlights the importance of accounting for local adaptation when
coping with future urban floods.
Impacts of future climate change on urban flood volumes in Hohhot in northern China: benefits of climate change mitigation and adaptations
