[Terrapreta] expansion

[Greg and April]

< yawn >

Really?

Let's take a look.

K-T event ( now called the Cretaceous-Paleogene or K-Pg extinction  ) - 65M yrs ago.
End of the dinosaurs, and loss of 20% of marine life - mammals and birds hardly affected.
Most likely cause - asteroid ( supported by unusual iridium isotope levels in the boundary layer ).

Triassic-Jurassic event - 200M yrs ago.
At least 50% extinction of all known species.    Some studies indicate that at least with marine animals, decrease in diversity was caused more by a decrease in speciation than by an actual increase in extinctions.
Most likely cause - massive volcanic eruptions.

Permian-Triassic event - 250M yrs ago.
Largest known extinction.    96% of all known marine species and 70% of land species.    Actually 2 separate events about 5M yrs apart, and with the final event accounting for 80% of the marine life with the greatest losses in marine invertebrates and the rest during the preceding event. 
Most likely cause - multiple, starting with massive volcanic eruption ( Siberian Traps ), causing anoxic conditions due to POSSABLE ( but unsupported ) CO2 increases, which allowed anaerobic bacteria to thrive, which produced large amounts of atmospheric hydrogen sulfide.    Supporting evidence is not only the extinction of animal live, but the very unusual declines in plant populations of the period, which have otherwise thrived on occasions where CO2 is believed to increased causing climate change.

Late Devonian event - 360M yrs ago.
Took from between 500,000 - 15M yrs to happen, and is unknown if it is one large or several smaller extinction events, but current studies indicate that it's actually a series of events over a 3M yr period.    Some believe that it's more an issue of a decrease in speciation rather than an actual increase in extinctions.    Affected mostly the marine community.    Estimates of 57% of genera and 75% of species affected ( marine in both cases ), but these are only estimates due to lack of good biosphere surveys of the life forms.   
Most likely cause - unknown.    What is known for sure is that there is wide spread anoxia in the oceans and allot of carbon is being buried during this event ( many if not most oil deposits in the US come from this event ), thus indicating that atmospheric CO2 is decreasing.

Ordovician-Silurian event - 444M yrs ago.
49% of species affected.
Most likely cause - still under study, some indication that a glacial age is involved, with multiple rises and falling of sea level.    CO2 levels are known to have fallen just prior to this event. 

Cambrian-Ordovician event - 488M yrs ago.
The first major extinction event accounting of 49% of species.


So on one hand, we have you claiming extinction levels of 95%+ of all known species ( including plants ) due to global warming, caused by CO2 in the atmosphere due to the actions of man, and on the other hand, we have record of known extinction events, that never exceed aprox 80% in a worst case situation ( few of which involve plants ), and most of which account for <60% of species.    Further, few of the events support warming due to CO2 increases, and of those that do, the carbon & oxygen isotopes do not support the theory, but in only one or two cases.


Massive extinctions ( including plants ) due to temperature rise from increased CO2 is not supported by most fossil records.    Quite the opposite in fact, most fossil records with one or two exceptions, show an increase in plant life when CO2 and temperature have both gone up.


Have fun.


Greg H.
 
 
  ----- Original Message ----- 
  From: Sean K. Barry 
  To: Terra Preta ; Greg and April 
  Sent: Monday, June 02, 2008 17:59
  Subject: Re: [Terrapreta] expansion


  The estimates of percent species loss due to temperature increases as large as 9 degrees C are documented in the fossil record.  Why don't you see if you can cite a source for that?


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