Rising summer heat is amplifying jet noise near airports

Air gets thinner as it warms, and that matters the moment a jet leaves the runway. With less dense air under the wings, the plane generates less lift at a given speed, which slows its climb and prolongs the time engine noise hangs over nearby homes.

A team tested how this simple bit of physics plays out at real airports and found a clear pattern. In a warmer climate, early climb angles get smaller, so the footprint of engine sound on the ground stretches farther from the runway.

The research was led by Dr. Jonny Williams at the University of Reading (UR) and focuses on European airports in summer, when heat and density effects are most pronounced.

Thin air keeps jets lower longer

Air density is the amount of air mass in a given volume. When temperature rises, density falls, and lift decreases with it at takeoff speeds.

The climb angle is the angle between the flight path and the horizon immediately after liftoff. A lower climb angle means the jet spends more time near neighborhoods before it gains altitude.

Engineers also track sound pressure levels and decibel values to map how noise travels around airports. Even small geometric changes near the ground can shift a 50 dB contour outward and expose more homes to regular noise.

Lower climb angles do not require greater sound output from the engine to cause a problem. They simply keep the noise source closer to the listener for longer, which amplifies what people hear on the ground.

Hotter summers expand noise zones

A peer-reviewed study analyzed 30 European airports, linked climate model projections to takeoff performance, and simulated how those changes alter near-field noise.

The researchers found average reductions in climb angle of 1 to 3 percent by mid-century, with the hottest days reducing it by as much as 7.5 percent.

That shift pushes the 50 dB footprint outward in many places. The authors estimate up to a 4 percent increase in the number of affected residents, and in the densest areas that could mean as many as 2,500 additional people regularly exposed by the middle of the century.

The study isolates climate effects and does not account for future engine or airframe advances that may suppress some sound at the source. The underlying point still stands: warmer air alone increases ground noise because of geometric changes.

“Over the next three decades, thousands of extra people in London could be blighted by noise pollution caused by climate change,” said Dr. Williams.

Aircraft noise harms health and sleep

Across Europe, millions of people already live with aircraft noise near major airports. In 2023, about 3.4 million people were affected by regular noise at 98 major airports.

Exposure is not just a nuisance. A comprehensive review links aircraft noise to higher blood pressure, stress responses, and increased cardiovascular disease risk in exposed populations.

The frequency makeup of the sound matters as well. Growing research finds that low-frequency noise is especially irritating, more disruptive to sleep, and it attenuates more slowly over distance.

Those features align with the new modeling. As climb angles drop in heat, the low-frequency portion of the engine spectrum carries farther, and this is the band people often find most bothersome at home.

Models link heat to louder takeoffs

The analysis connects basic physics to public health metrics in a few steps. First, it applies the ideal gas law to relate warmer temperatures to lower air density near the runway.

Next, it calculates the resulting decrease in climb angle using a published relationship between density and the forces acting on the aircraft during initial climb. Then it projects how that change affects the size of the 50 dB contour on the ground with a noise propagation model that accounts for air absorption and directionality from turbofan engines.

Finally, it overlays population maps to estimate how many additional residents fall within that contour by mid-century. It also reports a separate metric called Lden, which weights evening and nighttime sound more heavily because those periods disturb rest more.

Climate pressure outpaces noise control

Quieter engines and better airframes will continue reducing noise, and operators can adjust flight paths to shift noise around the compass.

Procedural changes can trade sound closer to the airport for sound farther away, and vice versa.

The challenge is that climate pressure pushes broadly in one direction. If heat reduces climb angles on many summer days, airports will need a mix of technology, scheduling, and procedures to keep exposure from increasing.

Airlines avoid peak heat hours

Land-use planning still matters, including where new homes are permitted under busy departure paths. Insulation programs can reduce indoor exposure for the most affected neighborhoods.

Airports can continue adopting and refining takeoff procedures that lift aircraft away from people as quickly as safety allows.

Airlines can also avoid the hottest afternoon periods on the worst days, when performance margins shrink and noise travels farther.

Heat trends already affecting flights

Heat trends are already evident in daily operations. The same physics behind takeoff weight restrictions on very hot days also lowers climb angles and expands noise footprints.

Summer warming is not evenly distributed across Europe, and neither is population density. That is why a modest percentage change in area can still bring hundreds or thousands of new residents into a noise contour around a single airport.

The study is published in the journal Aerospace.

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