(CN) — More than 200 million people worldwide live on land that's less than 6 and a half feet above sea level, putting them at grave risk of losing their homes and communities to flooding events caused by rising sea levels and severe storms, according to a new study.
Previous research has indicated that flooding events in the near future caused by climate change and rising sea levels will impact hundreds of millions of people and cause trillions of dollars in damages.
But in order to accurately predict flood risks, scientists need the most updated and precise measurements of global land elevation available. This data is sorely lacking in critical parts of the world, including the highly at-risk tropical areas of the world..
To fill this gap, Aljosja Hooijer, a specialist in wetland hydrology and flood risk management with independent applied research group Deltares, and his colleagues used satellite LiDar measurements to model elevations of coastal regions around the world. LiDar, otherwise known as light detection and ranging, is a popular method for obtaining geospatial measurements via remote mapping using pulsed laser lights.
According to a study published Tuesday in the journal Nature Communications, Hooijer and his colleagues found that, as of last year, approximately 267 million people lived less than 6 1/2 feet above sea level. The findings showed that 62% of high-risk areas were located in the tropics, especially in Indonesia, which has the most land sitting at such a low elevation.
For decades, scientists have been sounding the alarm about the danger of climate change and the irreversible effects that will accompany it. The Intergovernmental Panel for Climate Change has reported that extreme weather events linked to sea level have become much more frequent over the past few decades.
Flooding in more urban coastal cities poses a threat not only to the people and their homes, but also to roads and bridges, food and water supplies, utility providers, and more. In rural areas, ecosystems are severely disrupted, which can wreak havoc on communities that rely on natural resources.
The clock is counting down on how much time is left to protect these lowlands before sea level rise takes too great a toll. According to the National Oceanic and Atmospheric Administration, sea levels have risen approximately 9 inches since 1880, with a third of the growth taking place solely in the last two and a half years. A rise in thermal expansion, due to global warming and ocean acidification, as well as melting ice caps in Antarctica and Greenland, are the causes of this acceleration, which leads to an increase in more tropical storms and hurricanes reaching land, bringing destructive flooding to coastal regions.
Based on their calculations, the authors of the new study predict that with a 3-foot increase in sea level and zero population growth, about 410 million people will be at risk and living less than 6 and a half feet above sea level by the year 2100. The authors note that this figure will likely be larger should the populations in the developing tropics grow.
They also found that those living in the tropics will experience this trend unequally, especially those in developing countries that are less equipped to quickly adapt. The data shows that 72% of all at-risk populations live in the tropics, with 59% of those in tropical Asia.
The authors said that although theirs are inherently uncertain projections, they demonstrate the urgency of sea level rise and bring attention to the danger facing tropical communities. While many of the affected locations experience regular flooding, most lack the infrastructure to allow for proper drainage of water.
The study authors hope their research will push policymakers to distribute assistance accordingly to regions that lack adequate adaptation measures and call for the swift implementation of long-term flood plans.
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