Frequent fliers know the routine: seat up, bags stowed, phones in airplane mode, keep your seat belts fastened at all times as we can never predict rough air. When flight attendants go over their safety speech at the beginning of a flight, they're not doing it because they have to. The information is presented to help keep you safe. Rough air — polite airline-speak for turbulence — really can be unpredictable and dangerous if you're not strapped in when it happens.

Turbulence is caused by an aircraft flying through unstable air. Planes experience turbulence when they encounter an area with winds changing direction or speed (like a jet stream or air flowing over the peaks of mountains), or when they encounter swiftly rising air like one would find in a thunderstorm or fair-weather cumulus clouds on a hot summer day. As veteran airline pilot Patrick Smith notes on his "Ask a Pilot" website, turbulence is more of an inconvenience than a threat to the structural integrity of the aircraft.

The danger to the passengers in the cabin, however, is very real.

Last Friday, Yahoo News published an article declaring that turbulence-related injuries are on the rise and consulted with climate change experts to speculate as to what's causing all of this lap-baby-flinging turbulence.

In the last month, three major incidents of turbulence-related injuries made international news. A flight attendant for United Airlines was taken to the hospital in critical condition after she cracked the ceiling with her head during extreme turbulence. Eight people were hospitalized after a transpacific Cathay Pacific flight hit major turbulence. A flight attendant on a regional flight in Australia broke her leg during another bout of turbulence.

The Yahoo News article cites numerous reasons why experts believe turbulence itself seems to be an increasing phenomenon, but aside from mentioning unrestrained lap babies becoming projectiles, the article largely ignores the big question: "why are people getting hurt?"

The answer to the question has nothing to do with climate change or flight paths or any of that fake intellectual reporting that Yahoo is trying to pull. The reason people are getting hurt during extreme turbulence is because they aren't buckled into their seats. It's that simple.

The next time you get on an airplane, listen for the "clicks" around you. For every person who buckles up, another one or two likely won't. Just as people found stealthy ways to hide iPod use from flight attendants before the electronics ban was dropped last year, people will find every way possible to fake buckling their seat belts without actually doing it.

The reason turbulence-related injuries are on the rise is because people aren't strapped into their seats to keep from flying around like popcorn when rough air occurs. Every one of the incidents Yahoo News cited referred to injuries inflicted on people who weren't wearing their seat belts — including lap babies and flight attendants walking around in the aisles.

Sometimes unpredictable rough air will cause injuries. That's a given when people are moving around the cabin. But the "growing problem" can be eliminated using the only two words that matter, and the ones they didn't mention until the very end of the article: buckle up.

[Photo via United Airlines]