SCIENCE

Flights from the UK to the US could take longer due to changes in the jet stream, according to a new study. (BBC)

What is a jet stream? Use our short encyclopedic entry to find out.

Teachers, scroll down for a quick list of key resources in our Teachers’ Toolkit, including this gorgeous map of worldwide winds.

Discussion Ideas

• The BBC article says that changes in the jet stream could make transatlantic flights slower. That isn’t entirely true. Why? Take a look at the gorgeous animation above or this equally gorgeous animation for some help.
  • Changes in the jet stream will only make one leg of the journey longer. Jet streams are westerlies, which means they flow from west to east. Changes in the jet stream might make west-bound flights longer (to U.S. ← from Europe), but eastbound flights faster (from the U.S. → to Europe).

• Take a look at the images above. Why is the great circle route highlighted?
  • According to our encyclopedic entry, the shortest distance between two airports is a segment of a great circle, which is the spherical equivalent of a straight line. However, the new research reminds us, it is more economical to reduce the journey time than the distance traveled. For this reason, aircraft routinely deviate from the great circle route (travel a longer distance) to account for headwinds and tailwinds (shorten the journey time).

• Take another look at the images above. Why do you think eastbound flights follow different flight paths than westbound flights?
  • The eastbound flights are piggybacking on the powerful polar jet stream, which streaks across the atmosphere below the great circle route.
  • The westbound flights avoid the jet stream by following a flight path above the great circle route.

• According to the BBC, “there is no firm observational evidence of changes in the jet stream.” So why are climate scientists predicting such changes? Take a look at the image above for some help.
  • Meteorologists know how the jet stream works, and can use climate models to predict its behavior. “We know what drives the jet stream, it’s the temperature difference between the warm tropical regions and the cold polar regions at flight levels. We understand what that temperature difference is going to do in response to global warming, it’s increasing, we are very confident that the jet stream is increasing as a consequence,” says the study’s lead researcher.

• According to our encyclopedic entry, there are two polar jet streams, one in the Northern Hemisphere and one in the Southern. Use this stunning interactive map to zoom in on both jet streams over the Atlantic. Why do you think the University of Reading and the BBC focused on the Northern Hemisphere jet stream as it crosses the North Atlantic?
  • They’re British; this is their atmospheric backyard.
  • Those are some billion-dollar flight paths. According to the research, “the North Atlantic flight corridor between Europe and North America is one of the world’s busiest, with approximately 600 crossings each day.” Check out a great visualization of those air traffic patterns here.

• According to the BBC, longer flight times “will increase carbon emissions and fuel consumption, and potentially raise ticket prices.” How?
  • “So there is a robust increase in the round-trip journey time, which means planes spending longer in the air, when you add that up for all transatlantic aircraft you get an extra 2,000 hours of planes in the air every year, with $22 million extra in fuel costs and 70 million kilograms (154 million pounds) of CO2.” Airlines are likely to increase ticket prices to cover the additional fuel costs. (There will also be more turbulence.)

TEACHERS’ TOOLKIT

BBC: Climate change ‘to make transatlantic flights longer’

Nat Geo: What is a jet stream?

NASA Visualization Explorer: Aerial Superhighway

Earth: A Global Map of Wind, Weather, and Ocean Conditions

(extra credit!) Environmental Research Letters: Transatlantic flight times and climate change