Global warming '30 times quicker than it used to be'
Friday 17 February 2006
Greenhouse gases are being released into the atmosphere 30 times faster than the time when the Earth experienced a previous episode of global warming.
A study comparing the rate at which carbon dioxide and methane are being emitted now, compared to 55 million years ago when global warming also occurred, has found dramatic differences in the speed of release.
James Zachos, professor of earth sciences at the University of California, Santa Cruz, said the speed of the present build-up of greenhouse gases is far greater than during the global warming after the demise of the dinosaurs.
"The emissions that caused this past episode of global warming probably lasted 10,000 years," Professor Zachos told the American Association for the Advancement of Science at a meeting in St Louis. "By burning fossil fuels, we are likely to emit the same amount over the next three centuries."
He warned that studies of global warming events in the geological past indicate the Earth's climate passes a threshold beyond which climate change accelerates with the help of positive feedbacks - vicious circles of warming.
Professor Zachos is a leading authority on the episode of global warming known as the palaeocene-eocene thermal maximum, when average global temperatures increased by up to 5C due to a massive release of carbon dioxide and methane.
His research into the deep ocean sediments suggests at this time about 4.5 billion tons of carbon entered the atmosphere over 10,000 years. This will be the similar amount of carbon released into the atmosphere from cars and industrial emissions over the next 300 years if present trends continue, he said.
Although carbon can be released suddenly and naturally into the atmosphere from volcanic activity, it takes many thousand of years for it to be removed permanently by natural processes. The ocean is capable of removing carbon, and quickly, but this natural capacity can be quickly overwhelmed, which is probably what happened 55 million years ago.
"It will take tens of thousands of years before atmospheric carbon dioxide comes down to pre-industrial levels," the professor said. "Even after humans stop burning fossil fuels, the effects will be long-lasting."
- 1 Saudi preacher who 'raped and tortured' his five -year-old daughter to death is released after paying 'blood money'
- 2 Mystery man who gave mum heart-warming note on train 'wanted to put a smile on her face'
- 3 Michelle Obama highlights harsh restrictions faced by Saudi women after meeting King Salman without wearing a headscarf
- 4 Mafia's wall of silence broken: Victim of Cosa Nostra's extortion rackets in its Corleone heartland co-operates with authorities for the first time ever
- 5 Amal Clooney gives excellent answer to fashion question at European Court of Human Rights
'We would evict Queen from Buckingham Palace and allocate her council house,' say Greens
Greece elections: Syriza and EU on collision course after election win for left-wing party
British Muslim school children suffering a backlash of abuse following Paris attacks
British grandmother Lindsay Sandiford faces execution by firing squad in Indonesia
Liberal Democrat minister defends comments suggesting immigration causes pub closures
9 reasons Greece's experiment with the radical left is doomed to failure
Negotiable: Tradewind Recruitment: This post arises as a result of the need to...
£120 - £150 per annum: Tradewind Recruitment: I am recruiting on instruction o...
£70000 per annum: Ashdown Group: Head of Finance - Financial Controller - Fina...
£24000 - £28000 per annum + benefits: Ashdown Group: Marketing Executive - Wim...