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
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

Recruitment Genius: Commercial Vehicle Sales Executive

Negotiable: Recruitment Genius: Working with a set process to achieve profitab...

Recruitment Genius: Customer Service Executive

£30000 - £35000 per annum: Recruitment Genius: This company provides a number ...

Recruitment Genius: Facilities Coordinator

Negotiable: Recruitment Genius: A Facilities Coordinator is required to join a...

Recruitment Genius: Project Manager - Software House - PRINCE2, PMP

£35000 - £45000 per annum: Recruitment Genius: A dynamic, customer oriented Pr...

Day In a Page

Greece says 'No': A night of huge celebrations in Athens as voters decisively back Tsipras and his anti-austerity stance in historic referendum

Greece referendum

Greeks say 'No' to austerity and plunge Europe into crisis
Ten years after the 7/7 terror attacks, is Britain an altered state?

7/7 bombings anniversary

Ten years after the terror attacks, is Britain an altered state?
Beautiful evening dresses are some of the loveliest Donatella has created

Versace haute couture review

Beautiful evening dresses are some of the loveliest Donatella has ever created
No hope and no jobs, so Gaza's young risk their lives, climb the fence and run for it

No hope and no jobs in Gaza

So the young risk their lives and run for it
Fashion apps: Retailers roll together shopping and social networking for mobile customers

Fashion apps

Retailers roll together shopping and social networking for mobile customers
The Greek referendum exposes a gaping hole at the heart of the European Union – its distinct lack of any genuine popular legitimacy

Gaping hole at the heart of the European Union

Treatment of Greece has shown up a lack of genuine legitimacy
Number of young homeless in Britain 'more than three times the official figures'

'Everything changed when I went to the hostel'

Number of young homeless people in Britain is 'more than three times the official figures'
Compton Cricket Club

Compton Cricket Club

Portraits of LA cricketers from notorious suburb to be displayed in London
London now the global money-laundering centre for the drug trade, says crime expert

Wlecome to London, drug money-laundering centre for the world

'Mexico is its heart and London is its head'
The Buddhist temple minutes from Centre Court that helps a winner keep on winning

The Buddhist temple minutes from Centre Court

It helps a winner keep on winning
Is this the future of flying: battery-powered planes made of plastic, and without flight decks?

Is this the future of flying?

Battery-powered planes made of plastic, and without flight decks
Isis are barbarians – but the Caliphate is a dream at the heart of all Muslim traditions

Isis are barbarians

but the Caliphate is an ancient Muslim ideal
The Brink's-Mat curse strikes again: three tons of stolen gold that brought only grief

Curse of Brink's Mat strikes again

Death of John 'Goldfinger' Palmer the latest killing related to 1983 heist
Greece debt crisis: 'The ministers talk to us about miracles' – why Greeks are cynical ahead of the bailout referendum

'The ministers talk to us about miracles'

Why Greeks are cynical ahead of the bailout referendum
Call of the wild: How science is learning to decode the way animals communicate

Call of the wild

How science is learning to decode the way animals communicate