Name: The giant metal walls keeping London above water
Uploaded: 2025-06-19T17:00:38.000Z
Duration: 5 min 34 s
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London is prone to severe flooding, like the disastrous 1928 Thames flood that displaced thousands and the notorious 1953 North Sea storm that killed over 2,000 people throughout Europe.

By far the biggest event was 1953 and it's the biggest natural hazard to affect the UK in the last 200 years.

Since then, this region hasn't experienced such catastrophic floods, mainly due to this The Thames Barrier, a storm surge defence system that opened in 1984.

The barrier, which stretches for a third of a mile across the Thames at Woolwich, is the largest structure of its kind in the world.

So how has the Thames Barrier protected London for this long?

And in a world where flooding is more and more common, how will the Thames Barrier adapt to keep up?

It's the first movable barrier ever built in the River Thames and protects the most populous part of London.

As the second largest movable barrier in the world, it's made up of 10 steel gates that span 520 metres across this river.

The outer four gates always have their barriers up and closed.

And these central, larger six gates are left open most of the time, to let ships pass through and for the river to flow naturally.

So what triggers the closing of the rest of the barrier?

The UK's Environmental Agency, which monitors the North Sea's tide levels, river flow, and weather, gathers data on a daily basis to determine whether to open or close the barrier.

When the decision is announced, the gates can begin closing.

It takes about 90 minutes to close all the gates, which can go as high up as 20 metres.

And they're designed to withstand over 9,000 tonnes of gushing water, which is the equivalent of almost 118 large swimming pools.

The gates remain closed for high tide for about four to five hours.

Once the flood recedes, the gates are lowered to their resting position.

The general idea is that the gates block the gushing water to protect the city.

The Thames barrier alone protects 1.42 million people, 320 billion pounds of residential properties.

We had a very, very big storm in 2013, in Storm Xavier, no one died.

One of the reasons why that was, was because of forecasting, but also as a direct result of these storm surge barriers being built.

In the year of Storm Xavier, the barrier was closed 50 times.

For perspective, in the entire decade of the 80s, it was closed a total of four times.

The more the barriers open and close, the faster they deteriorate.

And experts fear that climate change will disrupt tide predictability in the UK.

Sea level rise is the most certain and probably the most costly consequences of climate change.

And we've already seen a 25 centimetre increase in sea level over the last 100, 120 years.

To prepare for that getting worse, the UK put together the Thames Estuary 2100 plan, a plan to upgrade London's flood defence systems that recognises that we don't actually know how bad climate change is going to get.

And it was a very novel, very unique plan in that rather than just a static adjustment to account for sea level rise, they actually took an adaptive approach and they said, look, we don't know exactly what the future holds, we're going to put a series of plans in place that can adapt.

So we know we need a new Thames barrier, but we don't know exactly when.

We think we need a new barrier in 2070, but if sea level rise faster than normal, we can bring that plan forward.

The Thames Estuary 2100 plan ultimately comes in three phases.

From now until 2035, the main priority is to maintain what exists already, like the Thames barrier, by ensuring it can still withstand the pressure of high tides.

The plan acknowledges that we don't yet know how much higher they'll need to be raised, and leaves room for variability.

After 2070, the third phase will again examine the effects of climate change on London.

If water levels are increasing at alarming rates, more interventions like additional barriers may be added.

The success of the Thames barrier has inspired the creation of more than 50 additional flood barriers around the world, protecting millions of people from disaster.

But according to experts, the most impressive part isn't the Thames barrier itself, but the UK government's willingness to adapt for the future.

And now countries all around the world are sort of copying that approach from small towns to big cities like New York are taking this more sort of adaptive approach, and that was very much pioneered in London.