Feeds

10m years ago there was less CO2 - but the Earth was WARMER

Warmth and carbon 'decoupled': 'A surprising finding'

Build a business case: developing custom apps

Scientists are puzzled today by the discovery that millions of years ago levels of carbon dioxide in the atmosphere were lower - and yet, temperatures were higher than today's.

The revelations come in a new paper just published by hefty boffinry mag Nature, in which geoscientists probed the temperatures experienced by the Earth during the Miocene era - the period from 12 to 5 million years ago. The boffins write:

Comparatively little is known about the climate of the late Miocene (~12–5 Myr ago), an interval with pCO2 values of only 200–350  parts per million by volume but nearly ice-free conditions in the Northern Hemisphere and warmer-than-modern temperatures on the continents.

Today CO2 stands at 390 parts per million, well up on Miocene levels, and yet the planet - and in particular its oceans, engines of the climate - are significantly cooler. This wasn't known until now, as it is only recently that the team led by Jonathan P LaRiviere of UC Santa Cruz have looked into the matter. A statement from San Francisco State uni, where another of the scientists works, explains the methods used:

They used an organic compound called unsaturated alkenone as their "fossil thermometers." The compound is produced by tiny phytoplankton and preserved in cores of ocean sediment drawn from the mid-latitude Pacific Ocean basin. Ratios of the compound preserve a record of the water temperature in which the plankton lived.

The results of the study show that "sea surface temperatures were significantly warmer than today", according to San Francisco State University geosciences prof Petra Dekens. The Nature paper, indeed, states that in the boffins' opinion oceanic temperature and atmospheric carbon levels - generally considered to be firmly connected in today's climate science - were "decoupled".

"It's a surprising finding, given our understanding that climate and carbon dioxide are strongly coupled to each other," LaRiviere says.

"In the late Miocene, there must have been some other way for the world to be warm."

The paper suggests:

A relatively deep global thermocline, reductions in low-latitude gradients in sea surface temperature, and cloud and water vapour feedbacks may help to explain the warmth of the late Miocene.

It can be read (by subscribers) here. ®

Next gen security for virtualised datacentres

More from The Register

next story
Boffins attempt to prove the UNIVERSE IS JUST A HOLOGRAM
Is this the real life? Is this just fantasy?
China building SUPERSONIC SUBMARINE that travels in a BUBBLE
Shanghai to San Fran in two hours would be a trick, though
Our LOHAN spaceplane ballocket Kickstarter climbs through £8000
Through 25 per cent but more is needed: Get your UNIQUE rewards!
CRR-CRRRK, beep, beep: Mars space truck backs out of slippery sand trap
Curiosity finds new drilling target after course correction
SpaceX prototype rocket EXPLODES over Texas. 'Tricky' biz, says Elon Musk
No injuries or near injuries. Flight stayed in designated area
Galileo, Galileo! Galileo, Galileo! Galileo fit to go. Magnifico
I'm just a poor boy, nobody loves me. But at least I can find my way with ESA GPS by 2017
Astronomers scramble for obs on new comet
Amateur gets fifth confirmed discovery
prev story

Whitepapers

A new approach to endpoint data protection
What is the best way to ensure comprehensive visibility, management, and control of information on both company-owned and employee-owned devices?
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Maximize storage efficiency across the enterprise
The HP StoreOnce backup solution offers highly flexible, centrally managed, and highly efficient data protection for any enterprise.
How modern custom applications can spur business growth
Learn how to create, deploy and manage custom applications without consuming or expanding the need for scarce, expensive IT resources.
Next gen security for virtualised datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.