Groundbreaking research predicts that global flooding is expected to worsen in the coming decades if nations do not fulfill their commitments to reduce carbon emissions.
The study, released today and conducted by researchers at the University of Bristol in collaboration with the global water risk intelligence company Fathom, showcases detailed projections of various flooding types across different climate change scenarios with remarkable accuracy.
Using an extensive mapping framework, the results suggest that global flooding could surge by approximately 50% from 2020 to the end of the century if high climate sensitivity occurs and countries do not adhere to their emissions reduction promises.
Dr. Oliver Wing, the lead author and an Honorary Research Fellow at the University of Bristol’s Cabot Institute for the Environment, as well as the Chief Research Officer at Fathom, stated: “This research reflects years of effort to help communities worldwide mitigate the changing threat of flooding. The results emphasize the critical need for all nations to keep their commitment to reducing carbon emissions.”
In a favorable scenario where all global carbon targets are met, average flood risk is projected to increase by just 9% from 2020 to 2100. Conversely, in a less optimistic scenario with higher emissions, flooding risk could escalate by as much as 49% by the end of the century.
In the coming decades, projected increases in flood risk are somewhat moderate. Between 2020 and 2050, risk is expected to rise by 7% in a low carbon emissions scenario, but this could double to over 15% under a high emissions scenario.
Dr. Wing added: “It’s crucial to recognize that these global averages come with significant geographical disparities. While some areas may experience reduced flood risk, others might see increases that far exceed the global average, even in a lower emissions context.”
The report points out that coastal flooding remains a significant concern, independent of global emission reduction outcomes. Even in a low emissions scenario, coastal flooding is predicted to nearly double, with a 99% increase by 2100, primarily due to the delayed effects of sea level rise linked to ongoing warming.
Rainfall-induced flooding appears particularly susceptible to human-driven climate change. Under a low emissions scenario, this type of flooding is projected to grow by 6% by 2100, while a high emissions scenario indicates a staggering 44% increase.
The greatest projected increases in flooding are expected around global coastlines, tropical Africa, and Asia, along with significant changes in arid regions of North Africa. The highest likelihood for flood increases is predicted for the North Atlantic and Indian Ocean shores, as well as for Southeast Asia and Pacific islands.
Recently developed global flood models assess population exposure to flooding, the potential value of at-risk assets, the costs and benefits of flood defenses, and the effects of climate and socio-economic changes on future losses. While most models focus solely on river flooding, this study incorporates the notable effects of coastal flooding and has undergone the most thorough validation of any global flood model to date.
Countries that pledged significant emissions reductions at COP27 are clearly warned by this study that failing to meet these goals on time will considerably influence flooding levels.
Co-author Professor Paul Bates CBE, who is a Professor of Hydrology at the University of Bristol’s Cabot Institute for the Environment and the Co-founder of Fathom, remarked: “This research project involved comprehensive benchmarking of our global flood modeling results.”
“With the highest resolution results achieved so far, we aim for our model to be useful across various sectors, such as safeguarding critical infrastructure from future flooding, assisting insurers in establishing premium rates, and meeting climate regulatory requirements.”
Additional contributors from the University of Bristol include Prof. Jeff Neal, a Professor of Hydrology at the Cabot Institute for the Environment and Chief Scientific Advisor at Fathom, along with two scientists from Fathom who are set to commence their PhDs at the University.
