At Bank Junction in the heart of the City of London, newly planted flowers splash colour on to a heavily concreted area. But these are no ordinary flowerbeds: they are part of efforts to prepare the historic financial district for the effects of climate change.
Across the Square Mile, the City of London Corporation is rolling out environmental measures, from upgrades to riverside walls for protection against rising water levels to swapping British flowers for Mediterranean varieties better suited to the heat.
The corporation plans to invest £68mn between 2020 and 2027 on climate action. But this is only a fraction of the total bill that will need to be spent in the coming decades to prepare the capital for a future of more extreme weather.
The Thames Estuary 2100 project, the UK’s largest flood risk programme created to protect communities in London and along the river, alone is expected to cost £16.2bn when completed in 2100.
But climate experts are concerned the City’s efforts to deal with global warming will not be enough if poorer London boroughs struggle to take the action needed, while also raising questions about inefficient glass and steel towers that are poorly designed for a warming world.
Bob Ward, chair of the London Climate Ready Partnership, a coalition of government, business and community leaders focused on building resilience to extreme weather, said the Square Mile was a “leader in London” when it came to preparing for climate change.
But, he added: “If the City of London does a good job, but other areas don’t, someone else will suffer even more. It is right that the City is doing what it can, but . . . it needs to persuade [other boroughs] to be similarly active in tackling the problem.”
The flowerbeds at Bank Junction have been designed with a granular fill material to hold surface water and prevent flooding. Rain from the road drains under one bed, while the other catches water from the pavement. Surface water flooding is expected to increase as climate change makes rainfall more intense, with the City’s heavily paved surfaces leaving the area especially at risk.
Alison Gowman is one of the team of aldermen who act as elected stewards for the City local authority. As one of the world’s most important financial districts, ensuring the Square Mile was prepared for the effects of climate change was vital, she said.
“We are trying to balance the City’s history with the need to protect the City,” she added.
Many cities around the world have begun looking at the challenge of how to adapt for climate change. About $63bn globally was spent on adaptation in 2021-2022, according to a report from the Climate Policy Initiative and the Global Center on Adaptation, with experts saying this will need to increase rapidly in the years to come as temperatures rise.
New York, which lacks the tidal flood protection of London, is starting to build new coastal protection infrastructure, with an expected bill of $52bn to protect the city from coastal storms.
Singapore has focused on green spaces, while Tokyo has concentrated on developing a “robust preparedness system”, with regular disaster drills, “so people know what to do when the clouds burst or the rivers overflow”, said Mark Watts, executive director of C40, a group focused on making urban centres sustainable.
Climate change has already hit the British capital, with flash flooding in 2021 and temperatures of 40C in 2022.
Emma Howard Boyd, former chair of the Environment Agency, the public body responsible for environmental protection in the UK, agreed that the City was ahead of its peers in the capital especially when it came to its riverside strategy.
“You are only as good as your weakest link — this is where you need that collaborative working across the whole of London,” she added.
The London Climate Resilience Review, commissioned by London mayor Sadiq Khan, this month warned that the British capital was underprepared for the “disastrous consequences” of climate change, with severe flooding and extreme heat posing a “lethal risk”.
It argued that while “significant climate adaptation and resilience action” was taking place across London, it would not be enough to meet forecast rises in global temperatures.
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The report called for a review into the economics of adaptation and climate resilience, citing the National Audit Office, which said the government had been “unable to provide an estimate of how much it spends to manage the risks for droughts, high temperatures and heatwaves, surface water flooding and storms.
“Action is taken by a wide range of government departments and agencies, and no one collects this information,” it noted.
One of the Square Mile’s biggest attractions — its riverside location — is also a key vulnerability. The Thames Barrier, located east of the City, and walled defences along the Square Mile’s 2km of riverside frontage have helped protect the area from flooding.
The Environment Agency is due to make a decision on the future of the barrier by 2040, while the walled defences should protect the district for the next 25 years, said Tim Munday, lead environmental resilience officer at the corporation.
But Munday, who has been out with his measuring tape examining the walls, said these would need to be upgraded in the years to come and made up to 50cm taller in places by 2050 and 100cm higher by 2100.
Developers of new riverside buildings are being told to build these defences now or ensure they can easily be constructed in the coming years, while owners of existing buildings along the Thames are being contacted about wall upgrades.
In some instances, the City will also rise up alongside the flood defences, with the ground level increased to ensure the new higher walls do not block the view of the Thames.
Doing this work will be particularly complicated in areas such as Queenhithe, the only surviving Anglo-Saxon dock in the world and an endangered monument. This is where balancing the City’s history and the impact of climate change will converge, said Gowman.
Elsewhere, the Whittington Garden, named for former Lord Mayor of London Dick Whittington, was transformed from “a more formal garden” to one designed “on the basis of not needing a lot of water”, said Gowman. There is thyme and lamb’s ear, as well as other Mediterranean plants.
On Paul’s Walk on the riverfront, the corporation has opted for “ultra Mediterranean planting”, she added, while giving a tour of the City. “It’s not English garden pretty,” she said, but it is practical.
“Green corridors” are also being introduced, where plants and trees are used to create cooler walking routes. This planting is part of efforts to deal with the urban heat island effect, where a built-up area is significantly warmer than its surroundings. In some cases the planting has reduced air temperatures between 3-8C during heatwaves, the corporation said.
The local authority has also installed 20 sensors across the City to measure temperature, pressure and humidity to understand different “micro climates” across the Square Mile.
On one morning in June, a sensor at Walbrook Wharf was almost 1C cooler than at Holborn Circus. It is also rolling out sensors to measure soil moisture and water entering sewers.
Still there are concerns that the City’s buildings — especially newer glass and steel constructions — are exacerbating the heat effect, especially when using air conditioning to cool buildings, then pumping warm air outside.
“We need to make sure anything new we build is well adapted for extreme heat,” said Ward, with shutters, less glass and painting roofs white to reflect sunlight.
Ward added there needed to be a mindset shift around building as the City heats up and an acceptance that London is becoming a warmer place. He added that this would be vital to avoid the “shocking mistakes” seen in developments such as the Walkie Talkie building.
A decade ago, the skyscraper had to be fitted with a sunshade after the concave design reflected sunlight on to street below, causing heat damage to cars in the process.
In a recent planning document, the corporation said the city could expect 56 days of heatwaves — defined as three or more consecutive days with temperatures of at least 28C — per year by 2080 compared with 14 days in 2020.
It added that the City’s dense and urbanised environment is at risk of extreme heat, saying any new developments should “actively” contribute to reducing the heat island effect.
Ward said all the climate adaptation measures being taken by the City were vital, even if they also come with an initial cost.
“The climate is changing and it’s going to continue to get worse until the world gets to net zero emissions,” he said.
“But the economic case [for adaptation] could not be clearer,” he said. “These are investments in making sure that the City can cope in the future.”
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