Global-warming Armageddon? It may be more likely than you thought
Calculations from Canadian and US scientists show runaway greenhouse effect is realistic possibility
Monday 29 July 2013
A runaway greenhouse Armageddon in which the oceans boil dry could theoretically happen on Earth, researchers claim.
The good news is that human activity on its own will probably not be enough to trigger such an end-of-the-world scenario in the near future.
Previously it was thought more energy from the sun would be needed for global warming on Earth truly to spin out of control.
But new calculations from Canadian and US scientists show that catastrophic warming can occur more easily than had been assumed.
For a planet receiving the same amount of solar radiation as the Earth, a runaway greenhouse effect is a realistic possibility.
The team, led by Colin Goldblatt from the University of Victoria in Canada, wrote in the journal Nature Geoscience: "The runaway greenhouse may be much easier to initiate than previously thought.
"A renewed modelling effort is needed, addressing both Earth and planetary science applications."
To see what might happen to the Earth if it was ever caught in the grip of runaway global warming, it is only necessary to look next door.
Venus, our closest neighbour in space, is believed to have experienced a runaway greenhouse effect in the past.
Shrouded in a dense carbon dioxide atmosphere, it has an average surface temperature of around 460C - hot enough to melt lead.
The new study used a simplified model which did not take into account the effect of clouds. But it still suggests that under certain atmospheric conditions a stable Earth could switch to a runaway greenhouse state.
Looking back in the Earth's history reveals past episodes of global warming, but none involving a runaway greenhouse effect. There is no clue to the size of any "safety margin", said the scientists.
A carbon dioxide greenhouse effect caused the "hothouse" climate of the Eocene period 55 million years ago, when the Earth underwent more warming than at any previous time in its history. Average global temperature rose by up to 4C, and palm trees grew in the Arctic.
Eocene atmospheric carbon dioxide levels and temperature were both higher than what is expected in the foreseeable future from man-made greenhouse gas emissions, without triggering a runaway effect.
"This implies that an anthropogenic (human-caused) runaway greenhouse is unlikely," the scientists wrote.
Dolphins ‘deliberately get high’ on puffer fish nerve toxins by carefully chewing and passing them around
Cow 'emissions' more damaging to planet than CO2 from cars
Gulf Stream is slowing down faster than ever, scientists say
Clash of the fiercest predators as shark eats polar bear
Malawi to burn its £5m ivory stockpile this week - and demonstrate its commitment to wildlife conservation
- 1 Tidal launch: The most pretentious lines from Alicia Keys' valedictory speech
- 2 Trevor Noah: Jon Stewart's replacement faces online criticism over 'anti-Semitic' tweets
- 3 Martha Stewart accuses Snoop Dogg of 'smoking for four hours' during Justin Bieber Roast
- 4 Gamers confess the worst things they've done in The Sims
- 5 Syrian child photographed 'surrendering to camera because she thought it was a gun'
Ukip supporters are 55 or older, white and socially conservative, finds British Social Attitudes Report
Street preacher quoting from the Bible fined for calling homosexuality an 'abomination'
Woman filmed launching racist tirade against men on the Tube for speaking in 'own lingo'
The West has it totally wrong on Lee Kuan Yew
David Cameron calls Labour 'hopeless, sneering socialists' while announcing 7-day NHS plans
Revealed: Putin's army of pro-Kremlin bloggers
Negotiable: Recruitment Genius: A rare and exciting role has arisen within thi...
£14000 - £16000 per annum: Recruitment Genius: A vacancy has arisen for a keen...
£14000 - £16000 per annum: Recruitment Genius: Due to expansion, this multi-ac...
£21000 - £34000 per annum: Recruitment Genius: This is an opportunity for an e...