Advancing human displacement modelling: A case study of the 2022 summer
floods in Pakistan
Abstract
The devastating 2022 summer flood in Pakistan displaced about 7 million
people in the Sindh province alone. Up to one third of the country’s
area, mostly the country’s south, was flooded. Effective response to
intensifying and compounding climate change hazards requires impact
assessments to include socio-economic components, as well as
uncertainties arising from the dynamic interactions between impacts.
Such quantitative evidence largely remains limited and fragmented, due
to methodological challenges and data limitations. Using the open-source
impact assessment platform CLIMADA, we study to what extent
flood-related hazards can be used to quantify displacement outcomes in a
data-limited region. Using flood depths, exposed population, and impact
functions, we link flood vulnerability to displaced people. This allows
us to estimate internal displacement resulting from the flood event, and
to further assess how displacement varies across different areas. We
find that a flood depth threshold of 0.67m (CI 0.35 - 1.10) provides a
best fit to all data from Sindh province. We find a negative correlation
between displacement and the degree of urbanisation. By testing the
performance of our model in explaining differing displacement estimates
reported across Pakistan, we show the limitations of existing impact
assessment frameworks. We emphasise the importance of estimating
potential displacement alongside other impacts to better characterise,
communicate, and ultimately respond to the impacts of floods.