Hundreds of commercial flights will be told to change their paths over the northeastern Atlantic Ocean during the next two winters to show how minor altitude adjustments can reduce aviation's climate impact.
The British government is backing the landmark airspace-scale trial, launched Tuesday, to avoid creating condensation trails, or contrails. Google UK is contributing its artificial intelligence-powered forecasts to identify the contrail regions.
When airplanes fly through cold and humid areas, ice crystals can form around the soot particles emitted from the engine, creating clouds that trap heat and warm the planet. The Shanwick Oceanic Control Area in the eastern half of the North Atlantic corridor, the location of the trial, is a busy gateway for air traffic between Europe and North America. It's also a hot spot for where contrails form.
The 30-month research program known as Operation Blue Skies includes test periods this winter and next, when air traffic controllers will tell some flights to deviate up to 2,000 feet (610 meters) to avoid areas where contrails are likely to form. These will be minor altitude adjustments within standard flight operations, coordinated through established air traffic control communication channels, according to the British government.
There will be about 20 to 40 test days per winter, when there is less air traffic. Around 10,000 flights are expected to pass through the Shanwick airspace during the testing. Hundreds of those flights would deviate their routes. That 1 % to 5% would be enough to demonstrate a statistically significant reduction in contrail formation on an airspace-scale, said Paul Hodgson, Google's technical lead for Operation Blue Skies.
Individual airlines have tested shifting altitudes to avoid contrail regions. Earlier this year, Google and American Airlines announced that the airline significantly reduced the climate impact of some flights using Google’s AI-based forecasting tool to help prevent contrails.
This new effort expands on individual airline trials to try mitigating contrails across an entire flight corridor.
The thin, white lines that form behind airplanes are responsible for a surprising amount of Earth’s warming — 1% to 2%, according to Contrails.org, a nonprofit research organization dedicated to reducing aviation’s climate impact through contrail management, as part of the Breakthrough Energy group founded by Bill Gates. Modeling shows that the Shanwick airspace accounts for about 5% of the total contributed by contrails, with a significant amount occurring during winter.
Keir Mather, the UK minister responsible for aviation, said the government is partnering with Google to back British experts and innovators to find practical ways to make flying cleaner. The government is paying for more than half of the 5 million pound ($6.76 million) study.
Google called contrails one of the most urgent yet solvable climate challenges facing aviation today.
Hodgson said testing over an airspace, versus individual airline trials, can show how it's possible to move multiple planes away simultaneously from an area where contrails will form, and can show if contrails can be reduced overall for a region. This could provide a blueprint for similar airspaces, he added.
Along with Google and the UK Department for Transport, the consortium includes the Met Office, the UK’s leading air navigation service provider NATS, Contrails.org, Imperial College London and the University of Cambridge.
An Imperial College London study in 2020 found that small changes to flight paths could reduce the climate impact of contrails. Professor Marc Stettler said Operation Blue Skies is a chance to test that idea in the real world, on a scale never seen before.
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FILE - An airplane flies high in the sky with the moon in the background in Garmisch-Partenkirchen, Germany, Jan. 1, 2023. (AP Photo/Matthias Schrader, File)
TAMPA, Fla. (AP) — A gunman plowed a car into a courtyard on Citibank's sprawling business campus near Tampa on Wednesday and opened fire with a rifle, killing a woman before a security guard fatally shot him, authorities said.
The Hillsborough County Sheriff's Office did not give a motive for the shooting or say whether the gunman and his lone victim knew each other.
The attack sent workers scrambling as the suspect crashed his car among outdoor tables where people were eating lunch, then started shooting, said Chief Deputy Frank Losat of the sheriff’s office. He said 3,200 people were on the campus at work during the attack.
The gunman fatally shot the woman before a security guard confronted him in a cafeteria, Losat said. The guard and the gunman exchanged fire, and the guard killed him, Losat said.
“Was there a potential for further violence? Absolutely," Losat told a news conference. "So kudos to that security guard.”
The names of the gunman and the woman killed were not immediately released.
Losat said four other people were taken to a hospital with non-life-threatening injuries. He didn't know whether any of them had been shot or struck by the gunman's vehicle.
The Citibank campus in suburban Tampa includes four three-story office buildings that house thousands of the banking giant’s employees.
David Dzien, a Citibank vice president, told The Associated Press he was returning to work after lunch when he saw the shooter's sedan crash through a fence about 150 yards (137 meters) away from him, followed by an “incredible clatter” that he later realized was gunfire.
People near the crashed car suddenly dispersed and others began to scream, Dzien said, as he sprinted back into the building and evacuated through a fire escape.
“I can still hear the particular type of scream," he said, “and I’m still trying to process it, frankly.”
The attack occurred on a day when “VIPs” who don’t normally work at the complex were present for a “quarterly review,” Dzien said.
Sheriff's deputies began arriving at the campus within a minute of the first 911 call, Losat said. The response was huge, with more than 360 deputies — many in tactical gear — rushing to the scene.
Those deputies spent 2 1/2 hours searching and clearing the building where the shootings occurred plus adjacent office buildings, Losat said.
Radio traffic on Broadcastify.com from responding officers described an exhaustive floor-by-floor search as people were found sheltering in locked rooms and closets, then carefully escorted from the buildings and parking garage.
Citigroup said in a statement that it was “aware of an incident” at the complex and was cooperating with authorities.
Employees at the Sheraton Tampa Brandon Hotel, a few hundred feet from the Citibank complex, were having a monthly employee luncheon in the hotel’s ballroom when they saw a massive flood of police vehicles headed toward the campus.
General Manager Matt Chauvin said Citibank employees ran over and told the front desk there was an active shooter.
“We at first locked the doors and, you know, went into lockdown, but the employees kept coming over," Chauvin said.
Chauvin estimated the hotel sheltered about 300 Citibank workers. Hotel staff gave them water and lunch, and let some go into hotel rooms “to sort of decompress or make phone calls.”
“Luckily we were far enough away that they were all safe,” he said.
Bynum reported from Savannah, Georgia. AP journalists Cybele Mayes-Osterman in Chicago, R.J. Rico in Atlanta and Claudia Lauer in Philadelphia contributed to this story.
Hillsborough County Chief Deputy Frank Losat holds a news conference after a shooting at an office complex for on Wednesday, Nov. 4, 2026, in Brandon, Fla. (AP Photo/Chris O'Meara)
Hillsborough County Chief Deputy Frank Losat holds a news conference after a shooting at an office complex for on Wednesday, Nov. 4, 2026, in Brandon, Fla. (AP Photo/Chris O'Meara)
Law enforcement arrive at the scene of a shooting on Wednesday, Nov. 4, 2026, in Brandon, Fla. (AP Photo/Chris O'Meara)
A person is wheeled out to an ambulance at the scene of a shooting on Wednesday, Nov. 4, 2026, in Brandon, Fla. (AP Photo/Chris O'Meara)
A person is wheeled out to an ambulance at the scene of a shooting on Wednesday, Nov. 4, 2026, in Brandon, Fla. (AP Photo/Chris O'Meara)
