Climate Change Likely Supercharged Hurricane Harvey

Two separate studies find that climate change boosted the storm’s rainfall by at least 15 percent.

close
Boat rescue traffic on the flooded Jimmy Johnson Road in Port Arthur, Texas, on August 30.
close
Evacuees wait at Woodrow Wilson Middle School for word about what shelter they will be sent to after they were evacuated from the flooding of Hurricane Harvey on August 30, 2017 in Port Arthur, Texas. Harvey, which made landfall north of Corpus Christi late Friday evening, is expected to dump upwards to 40 inches of rain in Texas over the next couple of days.
close
A highway stands immersed in floodwaters from Hurricane Harvey in this aerial photograph taken above West Columbia, Texas on August 30.
close
Evacuees sit on a boat after being rescued from flooding from Hurricane Harvey on August 30 in Port Arthur, Texas.
close
Recreational vehicles sit on their sides in flood water in the wake of Hurricane Harvey on August 29 in Houston, Texas.
close
Residential neighborhoods near the Interstate 10 sit in floodwater in the wake of Hurricane Harvey on August 29 in Houston, Texas.
close
Texas Army National Guard members Sergio Esquivel, left, and Ernest Barmore carry 81-year-old Ramona Bennett after she and other residents were rescued from their Pine Forest Village neighborhood due to high water from Hurricane Harvey on August 29.
close
People take shelter at the George R. Brown Convention Center after flood waters from Hurricane Harvey inundated the city of Houston on August 29.
close
Mark Ocosta and his baby Aubrey Ocosta take shelter at the George R. Brown Convention Center.
close
People walk to a Harris County Sheriff air boat while escaping a flooded neighborhood during the aftermath of Hurricane Harvey in Houston, Texas on August 29.
close
Rescuers in boats help trapped residents escape rising floodwaters due to Hurricane Harvey in Spring, Texas on August 28.
close
Shardea Harrison looks on at her 3 week old baby Sarai Harrison who is being held by Dean Mize. Mize and Jason Legnon used his airboat to rescue Shardea and her daughter from their home after the area was inundated with flooding from Hurricane Harvey on August 28.
close
People walk down a flooded street as they evacuate their homes after the area was inundated with flooding from Hurricane Harvey in Houston, Texas on August 28.
close
People use a inflatated mattress to evacuate their homes after the area was inundated with flooding from Hurricane Harvey on August 28.
close
Firefighters put out a fire during the aftermath of Hurricane Harvey on August 28.
close
Flood victims are seen at a shelter in the George R. Brown Convention Center during the aftermath of Hurricane Harvey in Houston on August 28.
close
Stranded vehicles sit where they got stuck in high water from Hurricane Harvey in Houston, Texas on August 28.
close
Abandoned cars sit on Interstate highway 45 near downtown Houston, Texas after it was flooded due to rain from Hurricane Harvey.
close
A stranded motorist escapes floodwaters on Interstate 225 after Hurricane Harvey inundated the Texas Gulf coast with rain causing mass flooding in Houston, Texas on August 27.
close
Andrew White, left, helps a neighbor down a street after rescuing her from her home in his boat in the River Oaks neighborhood after it was inundated with flooding from Hurricane Harvey on August 27 in Houston, Texas.
close
A resident walks down a flooded street in the River Oaks neighborhood after it was inundated with water from Hurricane Harvey on August 27 in Houston, Texas.
close
Volunteers and officers from the neighborhood security patrol help to rescue residents in the River Oaks neighborhood after it was inundated with flooding from Hurricane Harvey on August 27 in Houston, Texas.
close
People are rescued from flood waters from Hurricane Harvey in an armored police mine-resistant ambush protected (MRAP) vehicle in Dickinson, Texas.
close
Stewart Adams, of San Marcos, Texas, plays in the winds from Hurricane Harvey in Corpus Christi, Texas on August 25.
close
Hurricane Harvey is pictured off the coast of Texas from aboard the International Space Station on August 25.
close
Houses surrounded by flood waters caused by Hurricane Harvey are seen from a U.S. Coast Guard helicopter during a flight from Port Aransas to Port O'Connor, Texas, on August 26.
close
People gather supplies out of destroyed homes to take back to a shelter near City-By-The Sea, Texas, as Hurricane Harvey hits the Gulf Coast on August 26.
close
Steve Culver cries with his dog Otis as he describes the "most terrifying event in his life," when Hurricane Harvey blew in and destroyed most of his home while he and his wife took shelter there on August 26 in Rockport, Texas.
close
A man walks through flood waters and onto the main road after surveying his property, which was hit by Hurricane Harvey in Rockport, Texas.
close
A woman makes her way out of the wreckage of her home as neighbors try to help her out the window after Hurricane Harvey destroyed the apartment on August 26 in Rockport, Texas. Donna was hiding in the shower after the roof blew off and the walls of her home caved in from the wind.
close
This RV was destroyed during Hurricane Harvey on State Highway 188, outside of Rockport, Texas.
close
Dead cows killed in Hurricane Harvey lie on highway 35 near Fulton, Texas.
close
Jeff Page watches a helicopter fly overhead as he stands near a hotel damaged during Hurricane Harvey in Rockport, Texas.
close
A firefighter wipes his face as he searchs for survivors at an apartment complex in Rockport, Texas.
close
A destroyed laundromat is seen in Rockport, Texas.
close
Children play in a flooded road following the passage of Hurricane Harvey on August 26 in Galveston, Texas.
close
Business owner and resident Carlos Lopez clears debris from outside his shop, which was hit by Hurricane Harvey in Rockport, Texas, on August 26.
close
A multi-level storage facility housing boats was damaged by Hurricane Harvey in Rockport, Texas.
close
Women are illuminated by the light of a smart phone as they seek refuge in the Good Samaritan Rescue Mission during Hurricane Harvey in Corpus Christi, Texas, on August 25.
Tap images for captions

In August 2017, Hurricane Harvey dumped more than four feet of rain on Houston, Texas, in a matter of days, sending unprecedented floods through one of the largest cities in the U.S.

In the deluge’s aftermath, climate scientists noted that storms like Harvey are rare—but cautioned that unusually warm waters, made likelier by human activity, may have supercharged the hurricane’s extreme rainfall. Now, two separate teams of scientists have found humans’ fingerprints all over the storm.

One research team’s results, accepted for publication in Geophysical Research Letters (GRL), found that in comparison to a typical 1950s hurricane, climate change likely increased Harvey’s seven-day rainfall by at least 19 percent. A separate study, published today in Environmental Research Letters (ERL), found similar results, showing that climate change boosted Harvey’s three-day rainfall by about 15 percent.

Both studies also found that climate change roughly tripled the odds of a Harvey-type storm.

“It is not news that climate change affects extreme precipitation, but our results indicate that the amount is larger than expected,” said Michael Wehner, a climate scientist at the Lawrence Berkeley National Laboratory who coauthored the GRL study, in a press release.

Both studies were announced at the American Geophysical Union’s fall meeting in New Orleans, Louisiana.

Loading the Dice

Just as a gambler can’t predict how a single roll of the dice will go, scientists can’t determine whether climate change definitely caused any one weather event. However, in the same way that casinos might catch a gambler using loaded dice, scientists can quantify weather events’ natural odds and see how today’s weather unnaturally differs.

In Wehner’s case, he and his colleague Mark Risser examined data from Houston-area weather stations between 1950 and 2016, to determine the area’s heavy rainfall events. They then coupled these data to climate records, accounting for CO2 levels and El Niño, and compared Harvey against these trends.

When stacked against a 1950s-style hurricane, climate change boosted Harvey’s rainfall by as much as 38 percent, and it may have made Harvey roughly three times likelier.

Climate 101: Air Pollution

The ERL study takes a different approach but comes to similar conclusions. Using U.S. Gulf Coast rainfall records going back to 1880, researchers found that rare, extreme rainfall events have gotten more intense. The effect is no mere fluke: The team’s climate models show that warming from human activity likely drove the uptick.

When the researchers, members of the World Weather Attribution group, turned their gaze to Harvey, it found that climate change made a Harvey-like storm in the Gulf Coast anywhere from 1.5 to five times likelier. What’s more, the rainfall in such a storm increased as much as 19 percent.

Both teams were surprised by this strong signal. In the industrial era, the Gulf of Mexico has seen one degree Celsius (1.8 degrees Fahrenheit) of warming, in line with global averages. Generally, this warming makes the air above a body of water about six to seven percent wetter—far less than the boost Harvey likely received.

Human Impact on Our Changing Planet

The announcements are the latest results pouring out of the American Geophysical Union’s ongoing meeting that underpin scientific consensus: that humans are profoundly reshaping Earth’s climate.

At a press conference on Tuesday, the U.S. National Oceanic and Atmospheric Administration released its latest Arctic Report Card and announced that today’s extent and rate of melting has no precedent in the last 1,500 years.

On Wednesday, scientists also announced that Arctic warming threatens the 1,300-mile Alaskan Highway—a quarter of which is built over permafrost—and that in the last four decades, New Zealand’s glaciers have shrunk by more than 30 percent.

World leaders aim to hold Earth’s warming by 2100 to two degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial temperatures, despite the U.S. federal government’s recent climate reversalsunder President Donald Trump.

However, even if humankind hits the two-degree target, future generations will see Harveys of their own. The ERL study estimates that by the end of the century, storms with extreme rainfall like Harvey’s will become three times likelier than they are today.

However, if we stay on a “business-as-usual” path, relying on fossil fuels as we do today, Harvey-like hurricanes in 2100 could have rainfall boosted by as much as 50 percent.

“If we miss those targets, the increase in frequency and intensity could be much higher,” said ERL study coauthor Karin van der Wiel, a postdoctoral researcher at the Royal Netherlands Meteorological Institute, in a press release. 

PUBLISHED

Follow Us

twitter