James E. Hansen: “Earth’s energy imbalance” GISS Lunch Seminar 20110413

This is a really interesting presentation by Dr. James Hansen (NASA GISS/Columbia) of the main points from a paper, now published as:

Hansen, J., Sato, M., Kharecha, P., and von Schuckmann, K.: Earth’s energy imbalance and implications, Atmos. Chem. Phys. Discuss., 11, 27031-27105, doi:10.5194/acpd-11-27031-2011, 2011.

The paper can be downloaded for free at the journal website  here. The reviewers’ comments are also available.

The slides Hansen show in the presentation are hard to see in the video, but the figures are all in the paper referenced above.

Hansen’s presentation is not primarily aimed towards the general public, but he explains many of basic concepts and assumptions that are made in the paper, so it is not too hard to follow the presentation, especially if you also read the paper.

 

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James Hansen, Eelco Rohling and Ken Caldeira at AGU11

Great short talks by James Hansen, Eelco Rohling and Ken Caldeira at a press conference briefing at the American Geophysical Union Fall Meeting 2011.

The powerpoint presentation is here: AGU_paleo_final (note that the order in the PPT is different from the video).

Some highlights from the video:

James Hansen argues in the talk that “The target that has been talked about in international negotiations for 2 degrees of warming is actually a prescription for long-term disaster.” (http://www.livescience.com/17340-agu-climate-sensitivity-nasa-hansen.html), and that previous warm periods were less than two degrees Celsius above preindustrial values  (image from Hansen & Sato (2011)).

Eelco Rohling argues that “in natural context, the ‘equilibrium’ sea level for current anthropogenic forcing is 25 ±3m higher than today” (see image above from the presentation by Rohling, it shows historical sea level corresponding to CO2 forcing) and that the previous interglacial was associated with very fast sea level rise rates, even above current sea level: “rates of rise above 0m of 1 to 2.5 m/century”.

Ken Caldeira talks about high climate sensitivity (“earth system sensitivity”): “Event 55 million years ago (PETM) suggests, with long-term feedbacks, 5.5 – 8 ⁰C ( 10 – 14 ⁰ F) per CO2-doubling” (image from the presentation).

Some of the papers that are discussed in the talks:

Hansen, J.E., and Mki. Sato, 2011: Paleoclimate implications for human-made climate change. In Climate Change: Inferences from Paleoclimate and Regional Aspects. A. Berger, F. Mesinger, and D. Šijači, Eds. Springer, in press.

Rohling EJ, Grant K, Hemleben Ch, Siddall M, Hoogakker BAA, Bolshaw M, Kucera M. High rates of sea-level  rise during the last interglacial period. Nature Geosci 2008; 1: 38-4. ngeo.2007.28

James Hansen
Director, NASA’s Goddard Institute for Space Studies, New York, New York, USA.

Eelco Rohling, 
Professor of Ocean and Climate Change, Southampton University, Southampton, United Kingdom.

Ken Caldeira
, Senior Scientist, Department of Global Ecology Carnegie Institutution of Washington, Stanford University, Stanford, California, USA.