Sunday, March 31, 2013

Atmospheric CO2

As mentioned in this morning's post about the documentary SWITCH, the film does not account for accelerating levels of atmospheric CO2. The predictions of switching over to combinations of renewable, nuclear and conventional fuel sources is not presented with a CO2 analysis - will it change the graph below? In which direction?

When I see papers written by researchers from the organizations listed below it is hard for me to see a conspiracy in the works. Further research may suggest other interpretations and that can be considered when available. In the mean time this seems like an appropriate filter for discussions about the future/impact of fuel and energy sources.
Here is a link to the following abstract of a paper cited by

Target Atmospheric CO2: Where Should Humanity Aim?

James Hansen* 1,2, Makiko Sato 1,2, Pushker Kharecha 1,2, David Beerling 3, Robert Berner 4, Valerie Masson-Delmotte 5, Mark Pagani 4, Maureen Raymo 6, Dana L. Royer 7 and James C. Zachos 8
1 NASA/Goddard Institute for Space Studies, New York, NY 10025, USA
2 Columbia University Earth Institute, New York, NY 10027, USA
3 Dept. Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
4 Dept. Geology and Geophysics, Yale University, New Haven, CT 06520-8109, USA
5 Lab. Des Sciences du Climat et l’Environnement/Institut Pierre Simon Laplace, CEA-CNRS-Universite de
Versailles Saint-Quentin en Yvelines, CE Saclay, 91191, Gif-sur-Yvette, France
6 Dept. Earth Sciences, Boston University, Boston, MA 02215, USA
7 Dept. Earth and Environmental Sciences, Wesleyan University, Middletown, CT 06459-0139, USA
8 Earth & Planetary Sciences Dept., University of California, Santa Cruz, Santa Cruz, CA 95064, USA

Paleoclimate data show that climate sensitivity is ~3°C for doubled CO2, including only 
fast feedback processes. Equilibrium sensitivity, including slower surface albedo feedbacks, is 
~6°C for doubled CO2 for the range of climate states between glacial conditions and ice-free 
Antarctica. Decreasing CO2 was the main cause of a cooling trend that began 50 million years ago, 
the planet being nearly ice-free until CO2 fell to 450 ± 100 ppm; barring prompt policy changes, 
that critical level will be passed, in the opposite direction, within decades. If humanity wishes to 
preserve a planet similar to that on which civilization developed and to which life on Earth is 
adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be 
reduced from its current 385 ppm to at most 350 ppm, but likely less than that. The largest 
uncertainty in the target arises from possible changes of non-CO2 forcings. An initial 350 ppm 
CO2 target may be achievable by phasing out coal use except where CO2 is captured and adopting 
agricultural and forestry practices that sequester carbon. If the present overshoot of this target CO2
is not brief, there is a possibility of seeding irreversible catastrophic effects.