(CN) – Coastlines and populations around the world are three times more vulnerable to coastal flooding and rising sea levels due to climate change than previously believed, according to a study published Tuesday in Nature Communications.
Study authors Scott Kulp and Benjamin Strauss made this startling discovery by using a new digital elevation model, known as CoastalDEM, that helps calculate global population exposure levels to rising coastal tides. Using this model, which removes certain statistical biases through an advanced neural network, the authors found Earth’s population is at a far greater risk from rising coastal waters than previous models have ever suggested.
The study reports that approximately 110 million people around the world currently live below the high tide line, and another 250 million people live on land that is below current annual flood levels. Previous models suggested only 28 million lived below the high tide line and 65 million lived below flood levels.
Kulp and Strauss found greenhouse gas levels will play a significant role in determining how drastically these models will change by the end of the 21st century. If greenhouse gases are reduced beyond 2020, the model predicts only 190 million people will live on land below anticipated sea levels by the end of the century. Should greenhouse gases rise in the next 80 years, however, the model shows 630 million people will live below the flood levels.
This suggests that even in a more optimistic greenhouse gas future, the problem of rising sea levels will be stark and severe.
“Even with low carbon emissions and stable Antarctic ice sheets, leading to optimistically low future sea levels, we ﬁnd that the global impacts of sea-level rise and coastal ﬂooding this century will likely be far greater than indicated by the most pessimistic past analyses relying on SRTM,” the study says, referring to the previous model.
The authors say that given the dangers posed by these scenarios, it is imperative to prepare for coastal challenges in the coming years. This includes gaining a newfound perspective on what kinds of coastal defenses we use as protection for coastal populations and adopting a more long-term attitude when it comes to how we manage and maintain them.
Kulp and Strauss also note preparing for the future includes increasing our understanding of the rising sea level problem and how populations will respond to it.
“Further research on global-scale modeling of the timing, locations, and intensity of migratory responses to increased coastal ﬂooding is urgently needed to minimize the potential human harm caused by such threats,” they write in the study.
The authors did not respond to a request for comment by press time.