By Dino Grandoni, The Washington Post

The back-to-back landfalls of two harrowing storms in Texas and in Florida have reignited both the scientific debate over the link between hurricanes and global warming and the political debate over what, if anything, to do to address climate change.

So far, the only Republicans willing to engage in either have been moderates or those representing low-lying coastal districts vulnerable to sea-level rise and storm surges. Members of President Trump’s Cabinet, such as Environmental Protection Agency chief Scott Pruitt, have said that “it’s insensitive” to discuss the “cause and effect of these storms” in the midst of the dual disasters of Hurricanes Harvey and Irma.

On Thursday, President Trump, too, was dismissive of any link between climate change and hurricanes. When asked on Air Force One whether the two recent storms have changed his view on climate change, Trump told reporters: “We’ve had bigger storms than this.” He went on talk about bigger storms that he said occurred in the 1930s and 1940s.

Hurricane patterns in the Atlantic basin, which includes the Caribbean and Gulf of Mexico, have long been a puzzle to scientists. Even so, hurricane researchers were perplexed by Trump’s comment.

Spencer Platt, Getty Images A woman leaves her flooded home the morning after Hurricane Irma swept through the area on Sept. 11, 2017 in Fort Myers, Florida. Hurricane Irma made another landfall near Naples yesterday after inundating the Florida Keys. Electricity was out in much of the region with localized flooding.

Spencer Platt, Getty Images A family leaves their flooded home in a rural area the morning after Hurricane Irma swept through the area on Sept. 11, 2017 in Naples, Florida. Hurricane Irma made another landfall near Naples yesterday after inundating the Florida Keys. Electricity was out in much of the region with extensive flooding.

Nicholas Kamm, AFP/Getty Images A man paddles through a flooded neighborhood in Bonita Springs, Florida, northeast of Naples, on Sept. 11, 2017 after Hurricane Irma hit Florida.



Spencer Platt, Getty Images Jizreel Plancher calls out from the back of a truck to see if people need help the morning after Hurricane Irma swept through the area on Sept. 11, 2017 in Naples, Florida. Hurricane Irma made another landfall near Naples yesterday after inundating the Florida Keys. Electricity was out in much of the region with localized flooding.

Spencer Platt, Getty Images A couple walk through the flooded streets the morning after Hurricane Irma swept through the area on Sept. 11, 2017 in Naples, Florida. Hurricane Irma made another landfall near Naples yesterday after inundating the Florida Keys. Electricity was out in much of the region with localized flooding.

Will Dickey/The Florida Times-Union via AP An Urban Flood Water Rescue Team with the Jacksonville Fire and Rescue Department makes its way along a flooded street on the Southbank of downtown as Hurricane Irma passes by Monday, Sept. 11, 2017 in Jacksonville, Fla.



Spencer Platt, Getty Images An electrical worker repairs stop lights the morning after Hurricane Irma swept through the area on Sept. 11, 2017 in Naples, Florida. Hurricane Irma made another landfall near Naples yesterday after inundating the Florida Keys. Electricity was out in much of the region with localized flooding.

Mark Wilson, Getty Images The roof of a gas station is shown damaged by Hurricane Irma winds on Sept. 11, 2017 in Bonita Springs, Florida. Yesterday Hurricane Irma hit Florida's west coast leaving widespread damage and flooding.

Spencer Platt, Getty Images People wait in line for a store to open for food and water the morning after Hurricane Irma swept through the area on Sept. 11, 2017 in Naples, Florida. Hurricane Irma made another landfall near Naples yesterday after inundating the Florida Keys. Electricity was out in much of the region with localized flooding.



Chip Somodevilla, Getty Images Hotel guests are served breakfast by lamplight as the power remains off at the Courtyard by Marriott one day after Hurricane Irma struck the state Sept. 11, 2017 in Fort Lauderdale, Florida. Irma made landfall as a Category 4 storm twice in the United States on Sunday after tearing a path across islands in the Caribbean Sea.

Mark Wilson, Getty Images Road crews clear debris after Hurricane Irma passed through on Sept. 11, 2017 in Naples, Florida. Hurricane Irma made landfall in the Florida Keys as a Category 4 storm on Sunday, lashing the state with 130 mph winds as it moved up the coast.

Brian Blanco, Getty Images A large tree is seen laying in the front yard of a home after high winds from Hurricane Irma came through the area on Sept. 11, 2017 in Fort Meade, Florida. The Category 4 hurricane made landfall in the United States in the Florida Keys at 9:10 a.m. yesterday, after raking across the north coast of Cuba.



Will Dickey/The Florida Times-Union via AP, The Associated Press Urban Flood Water Rescue Team 2, with the Jacksonville Fire and Rescue Department, makes its way along San Marco Boulevard on the Southbank of downtown as Hurricane Irma passes by Monday, Sept. 11, 2017 in Jacksonville, Fla.

Joe Raedle, Getty Images A boat is seen washed ashore at the Dinner Key marina after Hurricane Irma passed through the area on Sept. 11, 2017 in Miami, Florida. Hurricane Irma made landfall in the Florida Keys as a Category 4 storm on Sunday, lashing the state with 130 mph winds as it moved up the coast.

Mark Wilson, Getty Images A home is shown damaged after Hurricane Irma hit the area on Sept. 11, 2017 in East Naples, Florida. Hurricane Irma made landfall in the Florida Keys as a Category 4 storm on Sunday, lashing the state with 130 mph winds as it moved up the coast.



Mark Wilson, Getty Images The Sunrise Motel remains flooded after Hurricane Irma hit the area on Sept. 11, 2017 in East Naples, Florida. Yesterday Hurricane Irma hit Florida's west coast leaving widespread damage and flooding.

Spencer Platt, Getty Images A teen walks through flooded streets the morning after Hurricane Irma swept through the area on Sept. 11, 2017 in Naples, Florida. Hurricane Irma made another landfall near Naples yesterday after inundating the Florida Keys. Electricity was out in much of the region with localized flooding.

Joe Raedle, Getty Images Philippa Regueira returns home through a street littered with downed trees and branches after seeking shelter in a friend's home after Hurricane Irma passed through the area on Sept. 11, 2017 in Miami, Florida. Florida took a direct hit from the Hurricane.



David Santiago/Miami Herald via AP The Interstate remains empty as the outer bands of Hurricane Irma reached South Florida early Saturday, Sept. 9, 2017 in Miami.

Mike Stocker/South Florida Sun-Sentinel via AP The winds and sea are whipped up off of the Rickenbacker Causeway as two people cross the street in Miami as Hurricane Irma approaches on Saturday, Sept. 9, 2017.

Chip Somodevilla, Getty Images A car sits abandoned in storm surge along North Fort Lauderdale Beach Boulevard as Hurricane Irma hits the southern part of the state Sept. 10, 2017 in Fort Lauderdale, Florida. The powerful hurricane made landfall in the United States in the Florida Keys at 9:10 a.m. after raking across the north coast of Cuba.



Joe Raedle, Getty Images A person walks through a flooded street in the Brickell area of downtown as Hurricane Irma passes through on Sept. 10, 2017 in Miami, Florida. Hurricane Irma made landfall in the Florida Keys as a Category 4 storm on Sunday, lashing the state with 130 mph winds as it moves up the coast.

Saul Loeb, AFP/Getty Images Heavy winds and rain from Hurricane Irma are seen in Miami, Florida on Sept. 10, 2017. Hurricane Irma's eyewall slammed into the lower Florida Keys, lashing the island chain with fearsome wind gusts, the US National Hurricane Center said.

Chip Somodevilla, Getty Images Large waves produced by Hurricane Irma crash into the end of Anglins Fishing Pier Sept. 10, 2017 in Fort Lauderdale, Florida. The Category 4 hurricane made landfall in the United States in the Florida Keys at 9:10 a.m. after raking across the north coast of Cuba.



Joe Raedle, Getty Images A boat is washed on shore at the Watson Island marina as Hurricane Irma passed through the area on Sept. 10, 2017 in Miami, Florida. Hurricane Irma, which first made landfall in the Florida Keys as a Category 4 storm on Sunday, has weakened to a Category 2 as it moves up the coast.

Chip Somodevilla, Getty Images A car sits abandoned in storm surge along North Fort Lauderdale Beach Boulevard as Hurricane Irma hits the southern part of the state September 10, 2017 in Fort Lauderdale, Florida. The powerful hurricane made landfall in the United States in the Florida Keys at 9:10 a.m. after raking across the north coast of Cuba.

Brian Blanco, Getty Images Residents inspect the extreme receding water in Tampa Bay ahead of Hurricane Irma on Sept. 10, 2017 in Tampa, Florida. Hurricane Irma made landfall in the Florida Keys as a Category 4 storm on Sunday, lashing the state with 130 mph winds as it moves up the coast.



Chip Somodevilla, Getty Images Broken tree branches block roads in the Coral Beach neighborhood as Hurricane Irma hits the southern part of the state September 10, 2017 in Fort Lauderdale, Florida. The powerful hurricane made landfall in the United States in the Florida Keys at 9:10 a.m. after raking across the north coast of Cuba.

Michele Eve, AFP/Getty Images A fallen tree crashes atop a row of cars on Sept. 10, 2017 Miami, Florida in the wake of Hurricane Irma. Hurricane Irma's eyewall slammed into the lower Florida Keys, lashing the island chain with fearsome wind gusts, the US National Hurricane Center said.

Gerald Herbert, The Associated Press Evacuees stand in line to enter the Germain Arena, which is being used as a shelter, in advance of Hurricane Irma, in Estero, Fla., Saturday, Sept. 9, 2017.



Jim Rassol /South Florida Sun-Sentinel via AP A young girl and her family seek shelter from Hurricane Irma at the West Boynton Park and Recreation Center in Boynton, Beach, Fla., on Saturday, Sept. 9, 2017.

David Goldman, The Associated Press Hector Padron carries his mattress as evacuees are moved to another building with more bathrooms while sheltering at Florida International University ahead of Hurricane Irma in Miami, Saturday, Sept. 9, 2017.

David Goldman, The Associated Press Evacuees are moved to another building with more bathrooms while sheltering at Florida International University ahead of Hurricane Irma in Miami, Saturday, Sept. 9, 2017.



David Goldman, The Associated Press Evacuees are moved to another building with more bathrooms while sheltering at Florida International University ahead of Hurricane Irma in Miami, Saturday, Sept. 9, 2017.

Jim Rassol, South Florida Sun-Sentinel via AP People seek shelter from Irma with their pets at the West Boynton Park and Recreation Center in preparation for Hurricane Irma in Boynton, Beach, Fla., on Saturday, Sept. 9, 2017.

Saul Loeb, AFP/Getty Images Hundreds of people gather in an emergency shelter at the Miami-Dade County Fair Expo Center in Miami, Florida, Sept. 8, 2017, ahead of Hurricane Irma. Florida Governor Rick Scott warned that all of the state's 20 million inhabitants should be prepared to evacuate as Hurricane Irma bears down for a direct hit on the southern US state.



Chris O'Meara, The Associated Press Ramsey Abdelkader, right, helps Sherri Skala, left, and Jennifer Morales fill sand bags to help protect their restaurant Saturday, Sept. 9, 2017, in Clearwater Beach, Fla. Business and residents were under a mandatory evacuation order as Hurricane Irma continued to churn towards Florida.

Lara Cerri, Tampa Bay Times via AP Joseph, Jr., right, 15, of St. Petersburg, bends down to carry sandbags to his family's vehicle at Lealman Community Park, in St. Petersburg, Fla., Tuesday, Sept. 5, 2017, as residents prepare for Hurricane Irma.

Joe Raedle, Getty Images People line up to get their propane tanks filled as they prepare for Hurricane Irma on Sept. 5, 2017 in Miami, Florida. It's still too early to know where the direct impact of the hurricane will take place but the state of Florida is in the area of possible landfall.



Joe Burbank, Orlando Sentinel via The Associated Press Drivers wait in line for gasoline in Altamonte Springs, Fla., ahead of the anticipated arrival of Hurricane Irma, Wednesday, Sept. 6, 2017. Irma roared into the Caribbean with record force early Wednesday, its 185-mph winds shaking homes and flooding buildings on a chain of small islands along a path toward Puerto Rico, Cuba and Hispaniola and a possible direct hit on densely populated South Florida.

NASA/NOAA GOES Project via Getty Images In this NASA/NOAA handout image taken at 11:45 a.m. Friday, NOAA's GOES satellite shows Hurricane Irma in the Caribbean Sea, Tropical Storm Jose in the Atlantic Ocean and Tropical Storm Katia in the Gulf of Mexico.

“That’s just not correct,” Kerry Emanuel, a hurricane expert at the Massachusetts Institute of Technology told me.

Parsing Trump’s comment begins with trying to understand what Trump means by “bigger.”

Because he brought up the 1930s, Trump perhaps had in mind the infamous 1935 Labor Day hurricane that, like Irma, devastated the Florida Keys. That storm was recorded as having the lowest air pressure of any hurricane on record in the United States.

But there are other statistics by which hurricanes can set records. Indeed, Hurricane Harvey went down in storm annals for having more rainfall than any other hurricane in the continental United States.

And Hurricane Irma maintained Category 5 wind speeds for longer than any other hurricane for which scientists have satellite data. Jim Kossin, a hurricane scientist at the National Oceanic and Atmospheric Administration and the University of Wisconsin at Madison, called the duration of Irma’s high wind speeds “truly remarkable and unprecedented in the historical data.”

Other recent destructive storms were record-breakers. Hurricane Katrina in 2005 produced the largest storm surge ever observed in the United States after making landfall near New Orleans. Hurricane Sandy in 2012 had the largest diameter of any Atlantic hurricane before slamming into the Northeast.

Indeed, Trump’s declaration about the size of past storms relative to Irma, at least, contradict what he tweeted while that hurricane bore down last week on Florida when he called Irma a storm “of epic proportions, perhaps bigger than we have ever seen:”

But the occurrence alone of those superlative storms – either in 1935 or 2017 – does not answer the question of what effect the rising atmospheric and ocean temperatures have on hurricanes.

Over the past century, the Atlantic has oscillated between busy and quiet stretches. After a series of destructive storms in the 1930s, 1940s and 1950s, Atlantic hurricane activity simmered down during the 1970s and 1980s before picking back up again after 1995, after which the Atlantic has been mostly busy.

“The President may have been referring to the fact that the 1930s-1950s were an unusually active phase for hurricane activity in the Atlantic, perhaps comparable to the one we are in now,” Gabriel Vecchi, a hurricane researcher at Princeton, wrote in an email. “That is true, though we can’t say with confidence, based on my read of the evidence, that the present phase is more or less active than the one in the 1930-1950s.”

It’s that lull in the 1970s and 1980s that has puzzled scientists, who point to as possible explanations natural shifts in large-scale ocean currents or the cooling effect of pollution in the air before the United States passed stringent environmental laws in the 1970s.

“The real anomaly is that the ’70s and ’80s were unusually quiet,” Emanuel said. “It’s not that the ’30s and ’40s were unusually active.”

When it comes to the connection between these storms and the warming effect of the buildup of greenhouse gases in the air, scientists say the right question is not whether climate change causes a specific storm. The better question is whether climate-related factors can make hurricanes such as Harvey or Irma worse.

On that front, climates scientists generally agree that a warmer climate makes storms wetter, pouring more rain, and that sea-level rises make hurricane-related storm surges worse.

“I don’t see hurricanes as necessarily the best piece of evidence to see that global warming is real,” Vecchi said in his email. “The fact that the planet has been warming: surface, ocean, land, deep ocean; that ice and snow have been melting; and that sea level has been rising are much more compelling and unambiguous.”