Over the last two decades, hurricanes Floyd, Matthew and Florence have caused significant flooding throughout North Carolina. Photo by Ken Cedeno/UPI | License Photo
July 23 (UPI) -- Storms are getting bigger and floods are getting worse as a result of climate change, according to a historic 120-year-old data set.
Researchers have been tracking tropical cyclone landfalls and precipitation associated with Coastal North Carolina storms since 1898. When scientists analyzed the 120-year record, they found six of the seven highest precipitation events have happened during the last 20 years.
"North Carolina has one of the highest impact zones of tropical cyclones in the world, and we have these carefully kept records that shows us that the last 20 years of precipitation events have been off the charts," Hans Paerl, professor of marine and Environmental Sciences at the University of North Carolina's Hill Institute of Marine Sciences, said in a news release.
Over the last two decades, hurricanes Floyd, Matthew and Florence have caused significant flooding. Scientists determined that the probability of so many large storms and damaging floods occurring in 20-year period period of time was 2 percent.
Global warming offers a better explanation for the heavy rains and floods than bad luck, scientists concluded. As the planet warms, the moisture carrying capacity of ocean storms is increasing.
Over the last 120 years, North Carolina has experienced increasing levels of heavy rainfall. Heavy precipitation events have increased dramatically since the 1990s.
"The price we're paying is that we're having to cope with increasing levels of catastrophic flooding," Paerl said. "Coastal watersheds are having to absorb more rain. Let's go back to Hurricane Floyd in 1999, which flooded half of the coastal plain of North Carolina. Then, we had Hurricane Matthew in 2016. Just recently we had Hurricane Florence in 2018. These events are causing a huge amount of human suffering, economic and ecological damage."
Because storms and flooding hit the coast so frequently, the kinds of natural barriers and human-built infrastructure that can mitigate flooding damages don't have time to regenerate or be rebuilt.
Authors of the new study -- published this week in the journal Scientific Reports -- warn that as temperatures increase, storms and flooding will continue to get worse, further damaging the swamps and wetlands that help protect the coast from storm surges.
An increase in flooding, scientists warn, will also likely increase levels of storm runoff, carrying pollution and fertilizers into major waterways. Increasing levels of storm runoff triggers nutrient loading, which can spawn harmful algal blooms. In Florida, increased coastal precipitation has been linked with declining coral health.
"We can help minimize the harmful effects of a 'new normal' of wetter storm events," Paerl said. "Curbing losses of organic matter and nutrients by vegetative buffers around farmlands and developed areas prone to storm water runoff, minimizing development in floodplains and avoiding fertilizer applications during hurricane season, and reducing greenhouse gas emissions are positive steps which we can all contribute to."