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IS THE WEATHER ACTUALLY BECOMING MORE EXTREME?

20.05.22

WHAT'S IT ABOUT?

Overview from TED

From 2016 to 2019, the world saw record-breaking heat waves, rampant wildfires, and the longest run of category 5 tropical cyclones on record. The number of extreme weather events has been increasing for the last 40 years, and current predictions suggest that trend will continue. So, is the increase in extreme weather due to random chance, or changing climate? R. Saravanan investigates.

"While weather will always be a chaotic system, shifts in our climate do increase the likelihood of extreme weather events."

White Brick Wall
R. Saravanan

Educator

TED-Ed Original lessons feature the words and ideas of educators brought to life by professional animators.

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MY TAKE...

I find these short TED-Ed lessons fascinating. Much like my own iluli videos, they take complex topics and break them down using animation. I’m a visual learner, so find it far easier to absorb information through this medium than any other. Of course, books, podcasts and the like are incredibly useful tools for learning, but it’s rare I have an uninterrupted hour or two to myself to fully engage. No matter how packed my schedule, I can find a few minutes to learn something new.


For today’s five-minute session, I wanted to learn more about the weather. With amber alerts sounding out across the country warning of yet another storm, I was curious to find out why the weather is becoming more extreme. Aside from the so-called “Great Storm of 1987”, I don’t remember there being quite so many wet and windy days when I was growing up.


Of the Great Storm of 1987, the BBC commented:


“Douglas Hurd, the Home Secretary at the time, referred to it as "the worst night since the Blitz". Eighteen people died and over 15 million trees were lost when hurricane-force winds blasted through south-east England. Meteorological research revealed a completely new weather phenomenon called the sting jet. This powerful 100mph wind can literally smash anything in its path. It was the first ‘sting jet’ to be documented in Britain.”


Since that fateful night, there have been several other notable bouts of bad weather to batter the British Isles, commencing with the Burns Day storm on 25th January 1990. The BBC wrote:


“The storm proved even more deadly than the one in 1987 because it hit during the day. It caused chaos – killing some children in their schools when the roof collapsed, and throwing cars off the road. Forty-seven people lost their lives and at least half a million homes were without electricity. The total estimated damage was over £2bn. Unlike 1987, the Met Office had predicted the storm’s progress and had issued warnings.”


In late October 2000, five of the UK’s major rivers burst their banks, bringing about the wettest autumn in 200 years. According to Countryfile:


“Gusts of 93mph battered the country leaving thousands of homes without power and more than 10,000 homes and businesses were flooded at 700 locations. It was estimated that the cost of the damage was £1 billion.”


Just three years later, in 2003, came a heatwave. In August, a new UK record was set with temperatures soaring to 38.5C in Faversham, Kent. This record has since been overtaken, with temperatures of 38.7C recorded in Cambridge Botanic Garden on 25th July 2019. According to the BBC:


“By the end of the summer of 2003 the heat had claimed the lives of over 2,000 people in Britain, mostly through heat stroke or dehydration. Since then the government Heat-Health Watch system warns if the forecast for daytime temperatures is 30C or above and 15C at night.”


And who can forget the scenes of utter devastation following the flash flooding of Boscastle in 2004. When the river burst its banks, residents of the usually picturesque Cornish village climbed to their rooftops to await rescue from emergency teams. Nearly 150 cars were swept out to sea and more than 50 properties were severely damaged or destroyed. Miraculously no one died.


Since then, the UK has encountered storms Abigail, Eva, Frank, Barbara, Doris, Brian, Ciara and Francis, to name but a few.

JENNIFER, ALISON, PHILLIPA, SUE…

The naming of storms is relatively new, beginning in 2015 as a joint initiative between the Met Office and Met Eireann. According to the Met Office:


“The naming of storms using a single authoritative system should aid the communication of approaching severe weather through media partners and other government agencies. In this way the public will be better placed to keep themselves, their property and businesses safe.”


The overview continues:


“The criteria we use for naming storms is based on our National Severe Weather Warnings service. This is based on a combination of both the impact the weather may have, and the likelihood of those impacts occurring. A storm will be named when it has the potential to cause an amber or red warning.


“Other weather types will also be considered, specifically rain if its impact could lead to flooding as advised by the Environment Agency, SEPA and Natural Resources Wales flood warnings. Therefore 'storms systems' could be named on the basis of impacts from the wind but also include the impacts of rain and snow.”


The Met Office website also features the question “Are we having more storms?”:


“Stormy weather is not unusual in the winter and we only need to go back to the winter of 2013-14 to see a similarly stormy winter. Overall, the period from mid-December 2013 to mid-February 2014 saw at least 12 major winter storms, and, when considered overall, this was the stormiest period of weather the UK has experienced for at least 20 years.


“We have seen comparable or more severe storms in recent years, including 3 January 2012 and 8 December 2011, each of which caused widespread impacts.”


Not only, then, are storms increasing in frequency and / or intensity, but our collective memory of them is improving. By naming each storm, we have a point of reference. Perhaps your garden fence blew down during Storm Doris, or Storm Brian knocked out your power for a few days?


That said, us Brits are the lucky ones. When you consider the full-blown hurricanes, cyclones, tsunamis and wildfires other countries have had to contend with, we’ve got away quite lightly.

But just how unexpected are these freak weather events? That’s where Saravanan comes in…

CHAOS RAINS

To answer the question, Saravanan says, it is necessary to understand the differences between weather and climate – “what they are, how we predict them, and what those predictions can tell us.”


He explains:


“Meteorologists define weather as the conditions of the atmosphere at a particular time and place. Currently, researchers can predict a region’s weather for the next week with roughly 80% accuracy. Climate describes a region’s average atmospheric conditions over periods of a month or more. Climate predictions can forecast average temperatures for decades to come, but they can’t tell us what specific weather events to expect.


“These two types of predictions give us such different information because they’re based on different data.”


To forecast weather, meteorologists measure what’s called the atmosphere’s ‘initial conditions’ - the current levels of precipitation, air pressure, humidity, wind speed and wind direction:


“Twice every day, meteorologists from over 800 stations around the globe release balloons into the atmosphere. These balloons carry instruments called radiosondes, which measure initial conditions and transmit their findings to international weather centres. Meteorologists then run the data through predictive physics models that generate the final weather forecast.”


And the end result is just that – a forecast, the probability of a particular weather event occurring. Weather is fundamentally a chaotic system, rendering it impossible to produce perfect predictions. The video features a butterfly flapping its wings to illustrate how even the smallest of disturbances can have a major impact on atmospheric conditions – undoubtedly a nod to the so-called ‘father of chaos theory’, Ed Lorenz.


Saravanan continues:


“Climate prediction, on the other hand, is far less turbulent. This is partly because a region’s climate is, by definition, the average of all its weather data. But also because climate forecasts ignore what’s currently happening in the atmosphere, and focus on the range of what could happen. These parameters are known as boundary conditions, and as their name suggests, they act as constraints on climate and weather..


“Most boundary conditions have well-defined values that change slowly, if at all. This allows researchers to reliably predict climate years into the future. But here’s where it gets tricky. Even the slightest change in these boundary conditions represents a much larger shift for the chaotic weather system.


“For example, Earth’s surface temperature has warmed by almost 1 degree Celsius over the last 150 years. This might seem like a minor shift, but this 1-degree change has added the energy equivalent of roughly one million nuclear warheads into the atmosphere. This massive surge of energy has already led to a dramatic increase in the number of heatwaves, droughts, and storm surges.”


So, what does this all mean? Saravanan sums it up succinctly stating that while weather will always be a chaotic system, shifts in our climate do increase the likelihood of extreme weather events.


The lesson concludes:


“Scientists are in near universal agreement that our climate is changing and that human activity is accelerating those changes. But fortunately, we can identify what human behaviours are impacting the climate most by tracking which boundary conditions are shifting. So even though next month’s weather might always be a mystery, we can work together to protect the climate for centuries to come.”


And if you still need convincing of our collective responsibility to fix what humanity has broken, I’d highly recommend David Attenborough’s A Life on Our Planet - essential viewing for when we next batten down the hatches!

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