20 August 2021 – by Atoosa Gitiforoz
A new study published by Nature reveals a stark increase in the number of people exposed to flooding. For example, between 2000 and 2015, the number of people exposed to flood-affected areas in Bangladesh increased by 14.3 million.Â
The study, using Moderate Resolution Imaging Spectroradiometer (MODIS)Â from 2000-2018 produced 913 flood maps, demonstrating a 20-24% increase in flood exposure in the first 15 years of the 21st century – almost 10 times higher than previous estimates from 1970-2010. Whilst previous studies focused on Sub-Saharan Africa and Asia, this study identifies 57 countries where flood exposure is expected to grow.Â
It is worth noting that one of the reasons this study has in fact produced such high estimates is due to the inclusion of dam breaks, pluvial events and snowmelts – factors often not included in other global models. However, the study does likely underestimate flood exposure trends in rapidly urbanizing areas, says the author; this is due to uncertainties in satellites and population growth modelling.Â
The study concludes by pointing to ways flood-exposed population estimates could be improved in the future i.e. including more events over longer periods of time or at higher resolution, increasing the number of modelled events such as flash flooding where satellite temporal coverage is inadequate, comparing observation and modelling trends and refining future global population spatial estimates.Â
Enhancing both estimation and vulnerability analyses can ultimately boost flood adaptation efforts and drive investment into mitigation efforts.
