Human-caused climate change made Hurricane Harvey rainfall that hit the United States in August more intense, international researchers said Wednesday.
The research found that human-caused climate change made the record rainfall that fell over the southern U.S. city of Houston during Hurricane Harvey roughly three times more likely and 15 percent more intense, a news release of Houston-based Rice University said.
"The takeaway from this paper is that Harvey was more intense because of today's climate, and storms like Harvey are more likely in today's climate," said Antonia Sebastian, co-author of the study and a postdoctoral research associate with the Severe Storm Prediction, Education and Evacuation from Disasters Center of Rice University.
"It highlights the need to consider that our hazards are changing over time, and that we should be considering those changes in the design of our infrastructure," she said.
The study was conducted by a team of scientists from the World Weather Attribution, an international project to study the influence of climate change on extreme weather events, such as extreme rainfall, heat waves and droughts.
The team was made up of researchers from renowned institutions in the United States and Europe, including Rice, the University of Oxford, Princeton University and others.
Harvey made landfall on Aug. 25 at a Mexico Gulf coastal town in southeastern Texas as a Category 4 hurricane and stalled. As the most powerful tropical storm to have hit Texas in more than 50 years, it dropped heavy rain and caused record catastrophic flooding in Houston and the surrounding region.
In Harris County, Houston, a 51.89 inches (131.8 cm) of rain -- the highest storm total in U.S. history -- was recorded over the six-day period through Aug. 30.
For a specific location like Houston, the study found that the maximum observed rainfall is still extremely rare in today's climate -- less than a one-in-9,000-year event.
The researchers said that even if the Earth meets the global targets set by the Paris Agreement, an event like Harvey will see a further increase of about a factor of three in probability.
The Paris Agreement, agreed on by almost every country in the world in 2015, aims to tackle climate change by cutting greenhouse gas emissions and sets a global target of keeping the average temperature rise no higher than 2 degrees Celsius above pre-industrial levels.
U.S. President Donald Trump announced on June 1 that the country would cease all participation in the agreement, stating that "The Paris accord will undermine (the U.S.) economy," and "puts (the United States) at a permanent disadvantage."
On Nov. 13, the United States reasserted that it would quit the agreement as soon as it is "eligible to do so."
In accordance with Article 28 of the Paris Agreement, the earliest possible effective withdrawal date by the United States cannot be earlier than Nov. 4, 2020.