Scientists Tighten PETM Timeline; Ocean Temps Rose 41F Over 20K Yrs @ 10% Of Current Carbon Increase

[hatrack]

Researchers have pinpointed the timing of the start of an ancient global warming episode known as the Paleocene-Eocene thermal maximum (PETM).

The early part of the Cenozoic era witnessed a series of transit global warming events called hyperthermals. The most severe of these was the PETM at the Paleocene-Eocene boundary, which took place around 56 million years ago. Over a 20,000-year period, ocean temperatures rose globally by about 41 degrees Fahrenheit.

The team said one possibility of this temperature rise is that these hyperthermals were driven by cyclic variations in the eccentricity of the Earth's orbit around the sun. Increased temperatures at the cycle peaks could have caused methane hydrate deposits in the deep sea to release large amounts of methane.

EDIT

Their analyses indicated that the onset of the PETM did not occur at the peak of a 400 thousand year cycle in the Earth's orbital eccentricity. "Compared to other early Eocene hyperthermals, it appears that the PETM was triggered by a different mechanism, and thus may have involved volcanism. However, a thorough test of this hypothesis will require further detailed dating studies," Adam said in a statement.

EDIT

http://www.redorbit.com/news/science/2064800/researchers_pinpoint_start_of_ancient_global_warming_episode/index.html?source=r_science

[phantom power]

1. Jesus fucking christ, 41F???

pardon me, as you were.

[pschoeb]

3. I think that's a typo at the news site, PETM was 11F not 41F

nt

[eppur_se_muova]

4. Thanks, that lessens the shock quite a bit.

But still -- 11F?? I hadn't ever heard of these "hyperthermals" before.

[wtmusic]

5. I've seen it quoted elsewhere as a 5°C rise

what some then (incorrectly) do is convert 5°C scalar to Fahrenheit to get 41°F.

[muriel_volestrangler]

7. Yep, 5°C - university press release here

The early part of the Cenozoic era, which started around 65.5 million years ago witnessed a series of transient global warming events called hyperthermals. The most severe of these was the PETM at the Paleocene–Eocene boundary, around 56 million years ago. Over a period of around 20,000 years, a mere blink of the eye in geological terms, ocean temperatures rose globally by approximately 5°C. There is evidence that the concentration of atmospheric carbon oxide increased, but the phenomena that triggered the event remain controversial.

http://www.soton.ac.uk/soes/news/2011/06/15_dating_an_ancient_episode_of_severe_global_warming.page

Pretty bad that RedOrbit, a site for Science, Space, Technology and Health News, can't convert Celsius to Fahrenheit properly.

[OKIsItJustMe]

2. Study here

http://dx.doi.org/doi:10.1029/2010GC003426

[wtmusic]

6. Air temperature at the poles was 50°F to 63°F

and temperatures at the equator at times rose above the boiling point of water.