As the country sweltered through one of the many heatwaves of a baking summer in late June, towering thunderclouds were gathering over the south of England and across much of northern Europe.
asserted
thunderclouds → swelter → Europe
It was a Saturday, and with the holiday season getting under way, thousands of passengers were heading to London's Heathrow and Gatwick airports to catch flights abroad.
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thousands → get → flights
It was always going to be a very busy day.
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It → go → ?
What followed, however, was chaos for travellers.
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followed → follow → travellers
As air traffic controllers struggled to route aircraft around the storms, airspace became heavily congested and many planes due to fly were simply forced to wait on the ground.
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planes → struggle → ground
In the end, some 900 flights to and from both airports were delayed, some by up to 11 hours.
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flights → delay → hours
Dozens more were cancelled.
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Dozens → cancel → ?
At airports across Europe, passengers expecting to fly into London also faced long waits and uncertainty.
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passengers → expect → waits
The weather in the UK may now have cooled, and passengers may soon forget their experiences.
uncertain
passengers → cool → experiences
But some within the industry believe what happened in June should be seen as a warning.
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happened → believe → warning
But there are concerns that such incidents are only going to become more common as the effects of climate change mount up around the world and weather systems are likely to become increasingly unstable, making disruption more likely and adding to costs for airlines, airports and travellers.
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disruption → be → airlines
Tim Atkinson, an airline risk consultant and former pilot, says the very crowded skies over the UK and northern Europe mean the region is particularly exposed.
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region → say → UK
He thinks there is a real risk, for example, that all of London's airports could be affected by storms at the same time, potentially with major consequences in the air and on the ground.
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all → think → ground
"What we're seeing now is very rapid climate change," he says.
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he → see → What
"We're going from the kind of weather activity which takes out an airport, and which the system kind of copes with… to a situation where, with very little predictability, it would be possible to lose all of the London airports from real-time operation quite swiftly and with little notice".
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it → go → notice
Such a scenario, he thinks, would make the disruption for passengers caused by the incident in June seem relatively minor – and could even put lives at risk.
uncertain
disruption → think → risk
When I visit, it is a hot and humid day, there are ominous dark clouds in the sky, and heavy, thundery downpours are hitting the surrounding region.
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downpours → visit → region
In Terminal Control, the part of the building responsible for flights heading to or from airports in London and southern England, those same storm cells are being monitored continuously.
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cells → head → London
Their progress is tracked on large radar screens, while at the same time weather forecasts are carefully scrutinised.
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forecasts → track → time
Air traffic tends to come in waves during the day.
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traffic → tend → day
Right now, at lunchtime, it is relatively quiet and the storms have yet to affect major routes.
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storms → have → routes
But with activity expected to intensify in the afternoon, staff are already preparing for what could be a tricky few hours.
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what → expect → afternoon
Stormy weather can shrink the available airspace, meaning traffic has to be restricted and rerouted.
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traffic → shrink → airspace
If planes are unable to land at one airport, for example due to high winds, they may need diverting to another.
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they → land → another
But that can create its own problems; if too many unscheduled aircraft land at an already busy airport, it might not have sufficient infrastructure to accommodate them all.
uncertain
it → create → them
Planes need fuel and somewhere to park.
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Planes → need → fuel
Passengers need food and facilities.
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Passengers → need → food
Ultimately, if there isn't space, it can simply refuse to accept all but emergency traffic.
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it → be → traffic
This is where the scenario set out by Atkinson comes in.
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scenario → set → Atkinson
He warns of a situation where traffic is diverted from Heathrow, Gatwick, Luton and Stansted at the same time, leaving aircraft coming in across the Atlantic and a large number of European flights all looking for somewhere to land at the same time, and some with dwindling fuel reserves.
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traffic → warn → reserves
This would at the very least create serious disruption for passengers, who might end up hundreds of miles from their destinations.
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who → create → destinations
But it could also, he thinks, create "a very serious risk event, such as an aircraft running out of fuel in the sky".
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aircraft → think → sky
Aircraft are legally required to carry enough fuel to take them to an alternative airport if necessary, and to allow them to fly for an extra 30 minutes on top of that.
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them → require → that
Not everyone shares Atkinson's concern.
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everyone → share → concern
Former airline executive Andrew Charlton, who manages the Swiss-based consultancy Aviation Advocacy, thinks the risk is low.
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risk → manage → consultancy
"You've always got to imagine the worst-case scenario", he says.
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he → get → scenario
"But I also think we need to keep that worst case in context.
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we → think → context
"Yes, it's possible to imagine it.
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it → imagine → it
But I'm also fairly comfortable with the ability of this industry to react well and make good decisions…
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I → react → decisions
of all the things that wake me up at 3am…this is not the top of that list."
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this → wake → list
…and 59 more, not listed.
