Asteroid ocean strike 'could strip away ozone layer'

A medium-sized asteroid plunging into the ocean would destroy much of the ozone layer, leaving the Earth exposed to dangerous levels of ultraviolet radiation, it was claimed today.





The impact from a space rock 500 metres to one kilometre in diameter would send vast amounts of water into the atmosphere, according to US expert Dr Elisabetta Pierazzo.



Seawater chemicals such as chloride and bromide would strip away significant amounts of ozone, which provides a shield against harmful sun rays.



The result would be a huge spike in ultraviolet (UV) radiation levels at the Earth's surface.



People with fair skins would find their skin burning after just a few minutes of sun exposure.



Farmers would have difficulty growing crops, and rates of skin cancer and cataracts would be likely to rise.



Previous research looking at the effects of an oceanic asteroid impact has focused on the danger of tsunamis.



Dr Pierazzo's new work, published in the journal Earth and Planetary Science Letters, used computer simulations to model the effects on atmospheric ozone.



She tested two impact scenarios, involving a 500 metre and kilometre diameter asteroid.



"The results suggest that mid-latitude oceanic impact of one kilometre asteroids can produce significant global perturbation of upper atmospheric chemistry, including multi-year global ozone depletion comparable to record ozone holes recorded in the mid 1990s," said Dr Pierazzo, from the Planetary Science Institute in Tucson, Arizona.



"The removal of a significant amount of ozone in the upper atmosphere for an extended period of time can have important biological repercussions at the Earth's surface as a consequence of increase in surface UV-B irradiance. These include increased incidence of erythema (skin reddening), cortical cataracts, changes in plant growth and changes in molecular DNA."



People may be forced to avoid direct sunlight to protect themselves against the harmful UV rays, she added.



UV intensity is measured by the ultraviolet index (UVI), with levels of 10 or above assumed to be dangerous.



The highest UVI recorded on Earth so far has been 20, said Dr Pierazzo. But a 500-metre asteroid crashing into an ocean could see UVI jump to values above 20 for several months in the northern subtropics.



A one kilometre impact would see UVI soar to 56, rising above 20 for around two years in both the northern and southern hemispheres.



"A level of 56 has never been recorded before, so we are not sure what it is going to do," said Dr Pierazzo. "It would be producing major sunburn. We could stay inside to protect ourselves, but if you go outside during daylight hours you would burn. You would have to go outside at night, after sunset, to avoid major damage."



Assuming there is enough warning, farmers could reduce the effects of the impact by planting crops with a higher UV tolerance, she said.



Food could also be stored to ensure supplies during a few years of poor productivity.

Start your day with The Independent, sign up for daily news emails
News
Courtney Love has admitted using heroin while pregnant with Frances Bean Cobain, her daughter with Kurt Cobain
people
Sport
Murray celebrates reaching the final
tennis
Arts and Entertainment
'The Archers' has an audience of about five million
radioA growing number of listeners are voicing their discontent; so loudly that even the BBC's director-general seems worried
News
i100
PROMOTED VIDEO
ebooks
ebooksA year of political gossip, levity and intrigue from the sharpest pen in Westminster
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

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

iJobs Job Widget
iJobs General

Austen Lloyd: Construction Solicitor - City

Excellent Salary: Austen Lloyd: NON-CONTENTIOUS (0-2 PQE) - A rare opportunity...

Recruitment Genius: Senior Financial Analyst

Negotiable: Recruitment Genius: A Senior Financial Analyst is required to join...

Recruitment Genius: Business Support Administrator - Part Time

Negotiable: Recruitment Genius: This is an opportunity to join the South West'...

Recruitment Genius: Secretary

£15000 per annum: Recruitment Genius: This major European Intellectual Propert...

Day In a Page

Isis hostage crisis: Militant group stands strong as its numerous enemies fail to find a common plan to defeat it

Isis stands strong as its numerous enemies fail to find a common plan to defeat it

The jihadis are being squeezed militarily and economically, but there is no sign of an implosion, says Patrick Cockburn
Virtual reality thrusts viewers into the frontline of global events - and puts film-goers at the heart of the action

Virtual reality: Seeing is believing

Virtual reality thrusts viewers into the frontline of global events - and puts film-goers at the heart of the action
Homeless Veterans appeal: MP says Coalition ‘not doing enough’

Homeless Veterans appeal

MP says Coalition ‘not doing enough’ to help
Larry David, Steve Coogan and other comedians share stories of depression in new documentary

Comedians share stories of depression

The director of the new documentary, Kevin Pollak, tells Jessica Barrett how he got them to talk
Has The Archers lost the plot with it's spicy storylines?

Has The Archers lost the plot?

A growing number of listeners are voicing their discontent over the rural soap's spicy storylines; so loudly that even the BBC's director-general seems worried, says Simon Kelner
English Heritage adds 14 post-war office buildings to its protected lists

14 office buildings added to protected lists

Christopher Beanland explores the underrated appeal of these palaces of pen-pushing
Human skull discovery in Israel proves humans lived side-by-side with Neanderthals

Human skull discovery in Israel proves humans lived side-by-side with Neanderthals

Scientists unearthed the cranial fragments from Manot Cave in West Galilee
World War Z author Max Brooks honours WW1's Harlem Hellfighters in new graphic novel

Max Brooks honours Harlem Hellfighters

The author talks about race, legacy and his Will Smith film option to Tim Walker
Why the league system no longer measures up

League system no longer measures up

Jon Coles, former head of standards at the Department of Education, used to be in charge of school performance rankings. He explains how he would reform the system
Valentine's Day cards: 5 best online card shops

Don't leave it to the petrol station: The best online card shops for Valentine's Day

Can't find a card you like on the high street? Try one of these sites for individual, personalised options, whatever your taste
Diego Costa: Devil in blue who upsets defences is a reminder of what Liverpool have lost

Devil in blue Costa is a reminder of what Liverpool have lost

The Reds are desperately missing Luis Suarez, says Ian Herbert
Ashley Giles: 'I'll watch England – but not as a fan'

Ashley Giles: 'I'll watch England – but not as a fan'

Former one-day coach says he will ‘observe’ their World Cup games – but ‘won’t be jumping up and down’
Greece elections: In times like these, the EU has far more dangerous adversaries than Syriza

Greece elections

In times like these, the EU has far more dangerous adversaries than Syriza, says Patrick Cockburn
Holocaust Memorial Day: Nazi victims remembered as spectre of prejudice reappears

Holocaust Memorial Day

Nazi victims remembered as spectre of prejudice reappears over Europe
Fortitude and the Arctic attraction: Our fascination with the last great wilderness

Magnetic north

The Arctic has always exerted a pull, from Greek myth to new thriller Fortitude. Gerard Gilbert considers what's behind our fascination with the last great wilderness