text: Rising temperatures due to global warming will make it harder for many aircraft around the world to take off in coming decades, says a new study. During the hottest parts of the day, 10 to 30 percent of fully loaded planes may have to remove some fuel, cargo or passengers, or else wait for cooler hours to fly, the study concludes. The study, which is the first such global analysis, appears today in the journal Climatic Change. 
   
   "Our results suggest that weight restriction may impose a non-trivial cost on airline and impact aviation operations around the world," said lead author Ethan Coffel, a Columbia University PhD. student. 
   
   As air warms, it spreads out, and its density declines. In thinner air, wings generate less lift as a plane races along a runway. Thus, depending on aircraft model, runway length and other factors, at some point a packed plane may be unable to take off safely if the temperature gets too high. Weight must be dumped, or else the flight delayed or canceled. 
   
   Average global temperatures have gone up nearly 1 degree Centigrade (1.8 Fahrenheit) since about 1980, and this may already be having an effect. In late June, American Airlines canceled more than 40 flights out of Phoenix, Ariz., when daytime highs of nearly 120 degrees made it too hot for smaller regional jets to take off. Worldwide, average temperatures are expected to go up as much as another 3 degrees C (5.4 degrees F) by 2100. But that is only part of the story; heat waves will probably become more prevalent, with annual maximum daily temperatures at airports worldwide projected to go up 4 to 8 degrees C (7.2 to 14.4 F) by 2080, according to the study. It is these heat waves that may produce the most problems. 
   
   "This points to the unexplored risks of changing climate on aviation," said coauthor Radley Horton, a climatologist at Columbia University's Lamont-Doherty Earth Observatory. "As the world gets more connected and aviation grows, there may be substantial potential for cascading effects, economic and otherwise." Most studies so far have focused on how aviation may affect global warming (aircraft comprise about 2 percent of global greenhouse-gas emissions), not vice versa. But a handful of studies have warned that warming climate may increase dangerous turbulence along major air routes, and head winds that could lengthen travel times. Rising sea levels are already threatening to swamp some major airports. Coffel and Horton may be the only ones so far to look at takeoffs. 
   
   In 2015, they published a smaller-scale paper, predicting up to four times more future temperature-related takeoff problems for the common Boeing 737-800 at Phoenix, as well as Denver, New York's LaGuardia and Washington's Ronald Reagan. The new study projects effects on a wide range of jets at these, plus 15 of the other busiest airports in the United States, Europe, the Mideast, China and south Asia. 
   
   The authors estimate that if globe-warming emission continue unabated, fuel capacities and payload weights will have to be reduced by as much as 4 percent on the hottest days for some aircraft. If the world somehow manages to sharply reduce carbon emissions soon, such reductions may amount to as little as 0.5 percent, they say. Either figure is significant in an industry that operates on thin profit margins. For an average aircraft operating today, a 4 percent weight reduction would mean roughly 12 or 13 fewer passengers on an average 160-seat craft. This does not count the major logistical and economic effects of delays and cancellations that can instantly ripple from one air hub to another, said Horton. 
   
   Some aircraft with lower temperature tolerances will far worse than others, and certain airports--those with shorter runways, in hotter parts of the world or at higher elevations, where the air is already thinner--will suffer more. For instance, facing LaGuardia's short runways, a Boeing 737-800 may have to offload weight half the time during the hottest days. Dubai, in the United Arab Emirates, might be worse; its runways are long, but its temperatures are already very high. Airports probably less affected because they are in temperate regions and have long runways include New York's JFK, London Heathrow and Paris's Charles de Gaulle. 
   
   Horton said that some effects could be mitigated with new engine or body designs, or expanded runways. But modifications would come at a cost, as aircraft are already highly engineered for efficiency; and expanded runways in densely packed cities such as New York are not an option. "The sooner climate can be incorporated into mid- and long-range plans, the more effective adaptation efforts can be," said Coffel. 
   
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   The paper was coauthored by Terence R. Thompson of Logistics Management Institute, a Virginia-based consulting company that studies aviation and other issues. 
   
   The paper, "The impacts of rising temperatures on aircraft takeoff performance," is available from the journal Climatic Change. Elizabeth.hawkins@springer.com. Scientist contacts: 
   
   Ethan Coffel ec2959@columbia.edu 
   
   Radley Horton rh142@columbia.edu +1 646-320-9938 
   
   More information: Kevin Krajick, Senior editor, science news, The Earth Institute/Lamont-Doherty Earth Observatory kkrajick@ei.columbia.edu 212-854-9729 
   
   Lamont-Doherty Earth Observatory is Columbia University's home for Earth science research. Its scientists develop fundamental knowledge about the origin, evolution and future of the natural world, from the planet's deepest interior to the outer reaches of its atmosphere, on every continent and in every ocean. http://www. ldeo. columbia. edu | @LamontEarth ||||| Last month, Phoenix enduring a blistering heat wave, with temperatures so high that airport officials had to cancel dozens of flights. The reason was two-fold. First off, some jet engines risk catching on fire in extreme heat. And when air gets hot, it expands and becomes less dense—so an airplane’s wings can’t generate enough lift to get off the ground. Planes either need to speed up during take-off or use a longer runway. 
   
   But Phoenix’s flight delays aren’t a one-off event. As the Earth’s climate undergoes a 1 to 3 degree Celsius warming over the next half-century, extreme heat waves will hit more frequently. Some of these heat waves will hit airports with short runways. Forget about rain delays or missing flight crews. At places like Washington’s Reagan National Airport, New York’s LaGuardia Airport, and Dubai International, the real trouble will come during heat waves. 
   
   During the hottest part of the day, 10 to 30 percent of planes will have to offload cargo or people, according to a new study by graduate student Ethan Coffell and climate scientist Radley Horton at Columbia University. “This study shined a light on a potential vulnerability,” Horton says. “A lot of airplanes at full capacity are ill-equipped to take off on some of the world’s runways when temperatures get really high.” 
   
   The scientists looked at five common commercial airplane models—the Boeing 737-800, Airbus A320, Boeing 787-8, Boeing 777-300, and Airbus A380—and calculated how their takeoffs would be affected at 19 airports around the world, based on projected temperatures from 27 different global climate models. The runways represented the most common climates, elevations, and runway conditions at busy airports around the world—including US airports in Denver, Phoenix, Chicago, Atlanta, New York, Washington, DC, Los Angeles, Houston and Miami. 
   
   The good news for air travelers is that London, Paris, and JFK in New York will be able to shrug off the worst of future heat waves. But a Boeing 777-300 departing from Dubai at the time of the daily highest temperature may be weight-restricted about 55 percent of the time according to the study, which appears today in the journal Climactic Science. Because of the short runways, airplanes at Washington’s Reagan-National (7,170 feet) and New York’s LaGuardia (7,000 feet) will also have to lighten their load to get off the ground. Expanding the runways probably won’t work, given that they are either sandwiched along the Potomac River or Jamaica Bay. 
   
   Heat waves aren’t the only problem facing the aviation industry as the Earth’s climate changes rapidly. Other scientists have calculated that severe turbulence—the kind that sends drink carts flying and sometimes even unbuckled passengers—will increase over certain transatlantic routes that follow the meandering jet streams. 
   
   Paul D. Williams, an atmospheric scientist at the University of Reading who published on the connection between climate change and turbulence this past year, thinks the industry needs to start dealing with climate change more aggressively. They could develop engines that produce fewer greenhouse gases, for one, as well as adapt its planes to the future world. “I’ve yet to see a benefit of climate change to aviation,” Williams says. “All the published studies have been about thing getting worse.” 
   
   There are plenty of solutions out there, some more complicated than others. Flights may have to leave earlier in the day when its cooler, Horton suggests, or aircraft manufacturers may have to make planes lighter. Or engineers could step in, building some kind of special new wings that generate additional lift. There’s one other option that probably won’t happen: leaving three or four paying customers back at the terminal in order to make the takeoff weight. ||||| NEW YORK (Thomson Reuters Foundation) - More frequent heat waves and rising temperatures due to global warming may ground up to a third of airplanes worldwide during hot days in decades to come with some airports in New York and Dubai likely to be hard hit, a study showed on Thursday. 
   
   Airlines may increasingly be forced to cut their loads of passengers, cargo or fuel in order to take off safely because warming air lessens the ability of airplane wings to generate lift, according to U.S. researchers. 
   
   Worldwide, average temperatures are expected to climb some 5.5 degrees Fahrenheit (3 Celsius) by 2100, researchers said. 
   
   But it is more prevalent heat waves that pose a larger threat to the airline industry, they said in a study published in the journal Climate Change. 
   
   Annual maximum daily temperatures at airports could rise by 7 to 14 degrees Fahrenheit (4 to 8 Celsius) by 2080, they found, leading to more costly delays in take-offs or cancellations. 
   
   During the hottest parts of the day, between 10 and 30 percent of fully loaded planes may have to dump weight in order to begin their journey. 
   
   The phenomenon could force the aviation industry to brace for thinner profit margins, the authors said. 
   
   A full 160-seat aircraft trying to safely take off in searing heat may, for instance, need to remove 13 passenger, said the study. 
   
   But the costs of delays or cancellations could also disrupt other sectors of the economy as they trickle down, they said. 
   
   "Our results suggest that weight restriction may impose a non-trivial cost," said Ethan Coffel, the study's lead author and a researcher at Columbia University in New York City, in a statement. 
   
   Airports likely to be most affected according to the researchers' appraisal of 19 major airports include New York's LaGuardia, due to short runways, and Dubai International Airport in the United Arab Emirates, because of scorching heat. 
   
   Projections found the least affected airports included New York's John F. Kennedy International Airport, London's Heathrow and Paris' Charles de Gaulle. 
   
   Last month, major airlines were forced to delay or cancel dozens of flights out of Las Vegas and Phoenix airports, citing difficulty in operating aircraft amid a heat wave. 
   
   Previous research has found that changes in climate may increase turbulence on flights, the researchers said. 
   
   They said their study was the first such global analysis.
target: – Remember in June when it got too hot for planes to take off in Phoenix? A new study suggests stories like that will become quite common in the not-too-distant future. Via Reuters, the study published in Climatic Change estimates that rising temperatures could leave up to one-third of planes grounded during heat waves in the coming decades. The problem centers around the wings’ capacity for lift, which is lessened in warmer conditions. By 2100, worldwide average temperatures are expected to rise by 5.4 degrees Fahrenheit. To safely take off, airlines would need to make adjustments during the hottest part of the day, with 10% to 30% of planes affected. Full flights will either stay grounded until conditions cool down or lighten their loads by removing fuel, cargo, or passengers, per a release at EurekAlert. Think 12 to 13 people asked to leave a 160-person passenger plane. "Our results suggest that weight restriction may impose a non-trivial cost," one of the study’s lead authors says. Wired reports that among the airports studied, New York’s LaGuardia and Washington’s Reagan-National fared poorly because of short runways, as did Dubai International Airport, where extreme heat could force reduced loads up to 55% of the time during peak temperatures. Better news: New York's JFK wouldn't be much affected. Delayed departures won't be the only hassle. Scientists say severe turbulence would become more common. “I’ve yet to see a benefit of climate change to aviation,” says atmospheric scientist Paul Williams, who believes it’s high time for the airline industry to prepare and adapt. (An essay at New York provided a decidedly bleak outlook on climate change.)