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."
2014 is warmest year since records began - and third wettest
Dolphins ‘deliberately get high’ on puffer fish nerve toxins by carefully chewing and passing them around
The top 10 weirdest animal mating rituals
The ugliest animals on earth: Blobfish, axolotl and proboscis monkey battle it out to be named least attractive beast
Global warming hiatus could be down to changing Atlantic currents
- 1 'Alien thigh bone' on Mars: Excitement from alien hunters at 'evidence' of extraterrestrial life
- 2 West poised to join forces with President Assad in face of Islamic State
- 3 Mother fed her daughter tapeworms to make her skinny for pageant
- 4 Pamela Anderson rejects ice bucket challenge because of ALS experiments on animals: 'Mice had holes drilled into their skulls'
- 5 ALS ice bucket challenge co-founder Corey Griffin drowns, aged 27
Richard Dawkins on babies with Down Syndrome: 'Abort it and try again – it would be immoral to bring it into the world'
Scottish independence: English people overwhelmingly want Scotland to stay in the UK
Isis threat: Cameron wants an alliance with Iran
Michael Brown shooting: Chaos erupts on the streets of Ferguson after autopsy shows teenager was shot six times – twice in the head
Disgusting, frustrating, but intriguing: how the country really feels about its politicians
Bin bag full of cats' heads discovered near Manchester's Curry Mile
£30000 - £45000 per annum: Harrington Starr: A global investment management fi...
£65000 - £75000 per annum: Harrington Starr: Senior Network Engineer-(CCIE, CC...
£70000 - £80000 per annum: Harrington Starr: Senior Network Analyst - (CCIE, C...
£60000 - £80000 per annum: Harrington Starr: Senior Network Engineer-(Design, ...