Scientists Predict Increase in Flooding for Coastal Cities Due to Climate Change

New research conducted by scientists at MIT reveals that coastal cities and communities are likely to experience more frequent major hurricanes in the coming years as a result of climate change. To aid in preparation for these future storms, the scientists have developed a method to predict the amount of flooding that coastal communities are expected to face as hurricanes evolve over the next few decades.

Compound Flooding: A Complex Hazard

When hurricanes make landfall, they generate storm surge in coastal regions by whipping up salty ocean waters with their strong winds. Additionally, torrential rainfall during these storms can further induce flooding inland. The interaction between multiple flood sources, such as storm surge and rainfall, can compound a hurricane’s hazards, leading to significantly more flooding. This new study introduces a physics-based method for predicting how the risk of compound flooding may evolve under a warming climate in coastal cities.

Lessons from Hurricane Sandy

The impact of compound flooding can be seen in the aftermath of Hurricane Sandy in 2012. The storm caused historic and devastating floods across New York and New Jersey as a result of a combination of storm surge and rainfall-driven flooding. This serves as an example of the potential risks coastal cities face.

Predicting Future Risks

The MIT team applied their compound flood-modeling method to New York City to assess how climate change may influence the risk of compound flooding from hurricanes similar to Sandy over the next few decades. Their projections show that, in the present climate, a Sandy-level compound flooding event is likely to occur in New York City every 150 years. However, by midcentury, a warmer climate will increase the frequency of such flooding to once every 60 years. By the end of the century, the city can expect destructive floods of this magnitude every 30 years, a fivefold increase compared to the current climate.

Implications for Preparation and Protection

The researchers hope that their flood forecasts will assist city planners in preparing for and protecting against future disasters. By providing essential tools for conducting compound flooding risk assessments at a granular level, down to each street or building, this methodology equips coastal city authorities and policymakers with the information needed to implement adaptive measures. Reinforcing coastal defenses and enhancing community resilience can help mitigate damages caused by compound flooding from hurricanes under a warming climate.

Amplifying Factors

Interestingly, the increase in risk for compound flooding in New York City is predominantly due to rising sea levels rather than changes in the hurricanes themselves as a result of climate change. The researchers incorporated the effects of sea level rise into their models and found that it played a significant role in amplifying the risk of compound flooding. This highlights the urgency of proactive strategies to mitigate damages, considering the projected increase in coastal populations and the trillions of dollars in assets situated in flood-prone areas.