UK smog: Nitrogen doesn't just cause air pollution - it is a huge threat to Britain's wildlife too, experts warn


The nitrogen pollution contributing to Britain’s smog poses the biggest threat to wildlife that the public has never heard of – with the potential to wipe out everything from clover to butterflies in eco-systems across the country – experts have warned.

The amount of nitrogen stored in the soil as a result of soaring emissions from agriculture, power stations and cars is now so great it has reached critical levels in the majority of non-agricultural land, according to Clare Whitfield, air pollution consultant at the government’s statutory conservation adviser.

Nitrogen-rich soil reduces biodiversity because it causes species which thrive on nitrates to flourish at the expense of those that don’t.

“Nitrogen represents a major threat to biodiversity in the UK and across Europe. It is an under-acknowledged and very big issue that has slowly crept up on us,” said Ms Whitfield.

The rapid accumulation of nitrogen in the soil has already damaged eco-systems across the country as thick outcrops of beneficiaries such as grass, heather, thistles and nettles “swamp out” a wide range of species such as flowers, bees, beetles, lizards, snakes and spiders by depriving them of water, space, light and the other conditions they need.

High levels of nitrogen also cause problems by leaching into groundwater which can impair the blood’s oxygen-carrying capacity in small infants causing “blue baby syndrome” and can be toxic for ruminants such as cattle and sheep.

The problem has got worse in recent years and, with the majority of eco-systems outside agriculture above the ‘critical load’ for nitrogen, that trend is set to continue, Ms Whitfield said. The critical load is the point beyond which the rate of nitrogen deposited from the air to the ground poses an increasing risk of habitat damage.

Once in the ground, nitrogen can remain for hundreds, even thousands of years while the level of accumulation is not measured and its potential impact not fully understood, experts said.

“The nitrogen level is building up all the time as we continue to add to the pot and increase the cumulative impact,” Ms Whitfield added.

Her comments will increase pressure on the government to get nitrogen levels under control two months after the European Commission launched legal proceedings against it for failing to reduce “excessive” levels of nitrogen dioxide air pollution from traffic, despite 15 years of warnings and several extensions and postponements granted to the government.

Other European countries have also failed to meet the air quality directive – that should have been adopted in 2008 – but the EU environment commissioner, Janez Potocnik, has singled out Britain for its “persistent” breaches of the air quality directive. The government has been sent a letter of the  formal notice of the intention to take Britain to court the government has until next Friday (April 18th) to respond.

Unlike so-called natural and semi-natural habitats, which are generally harmed by rising nitrogen levels, farmland is benefitting from the increase – and fuelling it - because crops benefit enormously from nitrogen-rich fertilisers. Ammonia, a pungent colourless compound of nitrogen and hydrogen released by livestock exacerbates the problem.

“This is the biggest threat to biodiversity that the public is not aware of. For wildlife it really is a pernicious and pertinent cause of decline in very many species as the burning of fossil fuels turns the volume of nitrate falling onto habitats from a drizzle to a downpour,” said Matt Shardlow, head of the Buglife insect charity.

“The longer we keep pouring this into natural habitats, the more it accumulates and unless we can reverse the situation we can expect many of these declines to continue,” he added.

Getting nitrates out of the ground is a “real challenge”, Mr Shadlow said. Methods include a sustained programme of “cropping off” – or burning – and removing vegetation, or deep ploughing, when a tractor turns over the top metre of soil to bury the nitrates further underground.

Nitrogen emissions also need to come down, Mr Shardlow said. “There is no obvious sign of that happening at the moment but that could start to come down with hybrid and electric cars,” he said – but adds that even if that does happen, the accumulation of nitrates in the soil will be so high that it will still need to be dealt with.

A spokesman for the Department for Environment, Food and Agriculture (Defra) said: “Air quality has improved significantly in recent decades. Just like for other [EU] member states, meeting the NO2 (nitrogen dioxide) limit alongside busy roads has been a challenge.”

“That is why we’re investing heavily in transport measures to improve the air quality around busy roads and we are working with the Commission to ensure this happens as soon as possible,” he added.

The species being edged out by rising nitrogen levels in the soil

Wildflowers such as Bird’s Foot Trefoil and Clover which don’t thrive on nitrogen and get shaded out by the plants, which also consume the water

Bees and other pollinators suffer because fewer flowers mean less nectar

Grasshoppers may eat grass but they still suffer when too much of it takes over their environments, because they like to lay their eggs in the bare ground so they can be exposed to the sunlight and grow.

Cirl buntings are hindered because they eat grasshoppers, which are in decline

Capercaillie and black grouse suffer because their chicks get trapped in the cold, dense, wet heather

Caterpillars suffer because the increase in plants makes the ground colder

Reptiles such as lizards and snakes are hurt by the loss of the bare ground they need to bask in

Butterflies such as the Large Blue and Silver spotted Skipper suffer because they need large, bare habitats to survive

Insects such as beetles and ants, which require warm chalky or sandy ground on which to nest, suffer from dense vegetation

Susan Sarandon described David Bowie as
peopleSusan Sarandon reveals more on her David Bowie romance
Arsenal supporters gather for a recent ‘fan party’ in New Jersey
sportDidier Drogba returns to Chelsea on one-year deal
Arts and Entertainment
The Secret Cinema performance of Back to the Future has been cancelled again
Have you tried new the Independent Digital Edition apps?
ebookA unique anthology of reporting and analysis of a crucial period of history
Life and Style
Balmain's autumn/winter 2014 campaign, shot by Mario Sorrenti and featuring Binx Walton, Cara Delevingne, Jourdan Dunn, Ysaunny Brito, Issa Lish and Kayla Scott
fashionHow Olivier Rousteing is revitalising the house of Balmain
Arts and Entertainment
Christian Grey cradles Ana in the Fifty Shades of Grey film
filmFifty Shades of Grey trailer provokes moral outrage in US
BBC broadcaster and presenter Evan Davis, who will be taking over from Jeremy Paxman on Newsnight
peopleForget Paxman - what will Evan Davis be like on Newsnight?
Life and Style
fashionCustomer complained about the visibly protruding ribs
The new dawn heralded by George Osborne has yet to rise
voicesJames Moore: As the Tories rub their hands together, the average voter will be asking why they're not getting a piece of the action
Dejan Lovren celebrates scoring for Southampton although the goal was later credited to Adam Lallana
newsComedy club forced to apologise as maggots eating a dead pigeon fall out of air-conditioning
Arts and Entertainment
Jo Brand says she's mellowed a lot
tvJo Brand says shows encourage people to laugh at the vulnerable
Life and Style
People may feel that they're procrastinating by watching TV in the evening
Travel Shop
the manor
Up to 70% off luxury travel
on city breaks Find out more
Up to 70% off luxury travel
on chic beach resorts Find out more
sardina foodie
Up to 70% off luxury travel
on country retreats Find out more
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Senior Risk Manager - Banking - London - £650

£600 - £650 per day: Orgtel: Conduct Risk Liaison Manager - Banking - London -...

Commercial Litigation Associate

Highly Attractive Package: Austen Lloyd: CITY - COMMERCIAL LITIGATION - GLOBAL...

Systems Manager - Dynamics AX

£65000 - £75000 per annum + Benefits: Progressive Recruitment: The client is a...

Service Delivery Manager (Software Development, Testing)

£40000 - £45000 per annum: Ashdown Group: A well-established software house ba...

Day In a Page

Evan Davis: The BBC’s wolf in sheep’s clothing to take over at Newsnight

The BBC’s wolf in sheep’s clothing

What will Evan Davis be like on Newsnight?
Finding the names for America’s shame: What happens to the immigrants crossing the US-Mexico border without documents who never make it past the Arizona desert?

Finding the names for America’s shame

The immigrants crossing the US-Mexico border without documents who never make it past the Arizona desert
Inside a church for Born Again Christians: Speaking to God in a Manchester multiplex

Inside a church for Born Again Christians

As Britain's Anglican church struggles to establish its modern identity, one branch of Christianity is booming
Rihanna, Kim Kardashian and me: How Olivier Rousteing is revitalising the house of Balmain

Olivier Rousteing is revitalising the house of Balmain

Parisian couturier Pierre Balmain made his name dressing the mid-century jet set. Today, Olivier Rousteing – heir to the house Pierre built – is celebrating their 21st-century equivalents. The result? Nothing short of Balmania
Cancer, cardiac arrest, HIV and homelessness - and he's only 39

Incredible survival story of David Tovey

Tovey went from cooking for the Queen to rifling through bins for his supper. His is a startling story of endurance against the odds – and of a social safety net failing at every turn
Backhanders, bribery and abuses of power have soared in China as economy surges

Bribery and abuses of power soar in China

The bribery is fuelled by the surge in China's economy but the rules of corruption are subtle and unspoken, finds Evan Osnos, as he learns the dark arts from a master
Commonwealth Games 2014: Highland terriers stole the show at the opening ceremony

Highland terriers steal the show at opening ceremony

Gillian Orr explores why a dog loved by film stars and presidents is finally having its day
German art world rocked as artists use renowned fat sculpture to distil schnapps

Brewing the fat from artwork angers widow of sculptor

Part of Joseph Beuys' 1982 sculpture 'Fettecke' used to distil schnapps
BBC's The Secret History of Our Streets reveals a fascinating window into Britain's past

BBC takes viewers back down memory lane

The Secret History of Our Streets, which returns with three films looking at Scottish streets, is the inverse of Benefits Street - delivering warmth instead of cynicism
Joe, film review: Nicolas Cage delivers an astonishing performance in low budget drama

Nicolas Cage shines in low-budget drama Joe

Cage plays an ex-con in David Gordon Green's independent drama, which has been adapted from a novel by Larry Brown
How to make your own gourmet ice lollies, granitas, slushy cocktails and frozen yoghurt

Make your own ice lollies and frozen yoghurt

Think outside the cool box for this summer's tempting frozen treats
Ford Fiesta is UK's most popular car of all-time, with sales topping 4.1 million since 1976

Fiesta is UK's most popular car of all-time

Sales have topped 4.1 million since 1976. To celebrate this milestone, four Independent writers recall their Fiestas with pride
10 best reed diffusers

Heaven scent: 10 best reed diffusers

Keep your rooms smelling summery and fresh with one of these subtle but distinctive home fragrances that’ll last you months
Commonwealth Games 2014: Female boxers set to compete for first time

Female boxers set to compete at Commonwealth Games for first time

There’s no favourites and with no headguards anything could happen
Five things we’ve learned so far about Manchester United under Louis van Gaal

Five things we’ve learned so far about United under Van Gaal

It’s impossible to avoid the impression that the Dutch manager is playing to the gallery a little