At a Glance

Extreme heat caused by climate change may take a toll on air travel.Hot air changes the density of air, which makes it more difficult for planes to take off.Flights may become more turbulent, more expensive and less predictable as a result.

Climate change isn't just taking its toll at ground level – it's having big impactsin the skies.

Researchers have started to analyzeglobal warming's impacts on aviation and a plane’s ability to fly. Extreme heat makes it difficult for aircraft to take off because hot air is less dense than cold, and the hotter the temperature, the more speed is needed to lift off.

In Phoenix, American Airlines. The flights were being operated by its regional partner, American Eagle, which use Bombardier CRJ aircraft that have a maximum operating temperature of 118 degrees. Temperatures in the area reached a high of 119 degrees on Tuesday.

(PHOTOS:)

Scientists say , which could make flying more expensive, less predictable and have a greater risk of injury to travelers due to turbulence, according to the New York Times.

“We tend to ignore the atmosphere and just think that the plane is flying through empty space, but of course, it’s not,” University of Reading meteorology professor Paul D. Williams told the Times. “Airplanes do not fly through a vacuum. The atmosphere is being modified by climate change.”

A 2015 study on the effect of extreme heat and aviation determinedhotter temperatures an airplane can have for takeoff by changing the surface air density.

“The number of summer days necessitating weight restriction has increased since 1980 along with the observed increase in surface temperature,” states the study. “Climate change is projected to increase mean temperatures at all airports and to significantly increase the frequency and severity of extreme heat events at some.”

For planes like a Boeing 737, the scientists foundthe number of weight-restriction days from May to September will increase by 50 to 200 percent by 2050 to 2070 at La Guardia Airport in New York; Ronald Reagan Washington National Airport; Phoenix Sky Harbor International Airport and Denver International Airport.

“We can say with confidence that there will be more weight-restricted days, and larger weight restrictions,” study author Radley Horton told the Times.

(MORE:)

Heat can still affect flights even if the planesmanage to make it off the ground. Air can become turbulent due to an invisible phenomenon known as “thermals.”

According to NOAA, , so once an air parcel becomes warmer than its surroundings and starts to rise, it has the possibility to rise thousands of feet into the air. The rising air creates the thermal.

That warm air eventually reaches a height where it’s unable to climb any further andcooler surroundings will cause it to sink because the pressure is lower and the parcel is denser. Riding through air that is rising and falling at different speeds creates a bumpy trip.

Though modern planes respond better to turbulence than the older models, passengers may still experience bumpier rides. Williams told the Times“the number of serious injuries being caused by turbulence has a clear upward trend.”

Manufacturers are in the process of trying to make aircraftadapt better to bumpy rides and to develop technology that’s better at predicting and detecting clear-air turbulence.

MORE ON WEATHER.COM: Winds Toss Planes in Texas