Galveston County and the greater Houston region face an increasing risk of Hurricane Harvey-scale rainfall because of climate change, a new study from a leading meteorologist and hurricane expert said.
The Houston region is six times more likely to experience Harvey-like rain in any given year than it was just two decades ago because of climate change, according to a Massachusetts Institute of Technology study published this week in the “Proceedings of the National Academy of Sciences.”
Between 1981 and 2000, there was a 1 percent annual chance of experiencing rainfall of Harvey’s magnitude in Texas, according to the study by Kerry Emanuel, a meteorology professor and hurricane expert at the Massachusetts Institute of Technology.
By 2017, the odds of those storms had increased to a 6 percent annual chance, according to the study. And models suggest those chances will increase to 18 percent by 2081 if the growth of greenhouse gas emissions to the atmosphere continues unmitigated, according to the study.
“You’re rolling the dice every year,” Emanuel said. “When you take a very, very rare, extreme rainfall event like Hurricane Harvey, and you shift the distribution of rain toward heavier amounts because of climate change, you get really big changes in the probability of those rare events.”
City leaders need to take into consideration changing weather patterns as they prepare for the future, Emanuel said.
“Should you be putting in a more advanced storm-sewer system that may cost billions of dollars, or not?” Emanuel said. “The answer to that question depends upon whether you think Harvey was a one-off — very unlikely to happen anytime in the next 100 years — or whether it may be more common than you thought.”
Harvey dumped a U.S.-storm record of 5 feet of rain across southeastern Texas in late August, leading to catastrophic flooding and killing at least 70 people in the state, while likely causing more than $150 billion in damage, according to the study.
Scientists are modifying how they calculate the likelihood of storms and “biblical” rainfall because historical records provide little insight. That’s because records are spotty and the period from which rainfall has been collected is short, according to the study.
And climate change is shifting the odds of high-intensity storms, the study said. Scientists have started moving toward climate-based models to try and forecast future storms, according to the university.
To conduct the study, Emanuel used computer models to simulate past, present and future storms in Texas. The researchers used actual data from more than 3,000 storms that passed within 300 kilometers of Houston between 1980 and 2016, according to the study.
The team ran these hurricane models under likely future scenarios to predict future risk, according to the study.