Jim Hansen on “The Threat to the Planet”


Jim Hansen’s presentation (6.6 MB) this summer at the SOLAR 2006 Conference on Renewable Energy in Denver, which he has made available on his Columbia University Web site, integrates a wide range of scientific findings on global climate change with forthright and striking statements about their implications.  Government officials should pay attention to this assessment.

Earlier this year Bush administration political operatives made an unsuccessful attempt to muzzle climate scientist Jim Hansen, director of the NASA Goddard Institute for Space Studies.  Dr. Hansen is now speaking freely about his analysis of the threat of dangerous global climate change.  This in itself is a success story.  We would like to see more federal climate scientists both able and willing to put forward an assessment of the climate change problem to a wider audience. 

But overcoming overt censorship is just one necessary step.  We still need to have policymakers and the public pay attention to the analysis, seek to understand it, and give it their most serious consideration.  The President saw fit to meet over lunch with science fiction novelist Michael Crichton, author of State of Fear, a piece of pseudo-scientific drivel steeped in the views of the global warming denial machine.  We wonder: Are any high government officials having lunch with Jim Hansen and other leading climate scientists?

Hansen’s presentation begins with 12 pages of text, which annotates 52 pages of slides, including scientific charts.  It should be generally accessible to most attentive non-technical readers.  See also his book and movie review, “The Threat to the Planet,” in the New York Review of Books.  His Columbia University Web site contains valuable documents, as does his NASA Web site.

Hansen prefaces his SOLAR 2006 presentation document with the disclaimer: “These are personal opinions, based in part on information in subsequent charts.” The text accompanying the title slide reads:

1. The Threat to the Planet
A. We are near a tipping point.  If global emissions of GHGs [greenhouse gases] continue on a BAU [business-as-usual] course for even another decade, it may become practically impossible to avert climate changes with devastating consequences.
B. That may seem surprising, because global warming is just reaching a level that it is beginning to have effects that are noticeable.  Yet because of the inertia of the climate system and the inertia of our energy systems that produce GHGs (e.g., power plants, transportation systems, buildings) there is additional climate change in the pipeline.
C. It is possible, with practical steps, to level out the rate of GHG emissions over the next decade.  Further steps could reduce emission 25-30% by mid-century and 60-80% by the end of the century, keeping global temperature within the range of the warmest interglacial periods of the last million years.  Global warming, over and above that in 2000 could be kept <1C, and, although that level of warming may have significant impacts, it would not yield global chaos.
D. However, we are not taking the practical steps needed to level out GHG emissions. Continued BAU, with growth of emissions that Energy departments like to claim are inevitable, will bring known positive feedbacks into play, producing what is literally a different planet. We can say that for certain, i.e., with confidence much greater than 99%.
E. We still have a window of opportunity, but if we do not take it, if we hand our children a planet with climate change that is out of control, history will judge us severely. Our descendants will have little reason to forgive us — we should have known better. We can no longer claim that we were ignorant and did not understand the system.

The concluding slide (#41) reads:

As it appears that the world may pass a tipping point soon, beyond which it will be impossible to avert massive future impacts on humans and other life on the planet:
Who Bears (Legal/Moral) Responsibility?
Special Interests?
U.S. Politicians?
5a.  Today’s U.S. public?
5b.  U.S. Children/Grandchildren?
Who will pay?

The text accompanying the concluding slide:

A. My opinion is that all of the first five bear moral responsibility, some more than others.  But none of these are likely to bear financial responsibility.  That will be passed on to our children and grandchildren. 
B. The United States especially, but also Australia (and perhaps Canada, if they renege on the Kyoto Protocol), should be expected to pay damages, because we blocked international efforts to achieve an alternative scenario.
C. I am not sure about legal responsibilities, e.g., whether residents of island nations can successfully file suits when they have to abandon their homes.  Will our children have to pay the bill?
D. Moral responsibility is clear, however.  We cannot claim that we did not understand the consequences of our actions.  We can only pretend that we do not understand.

Read the presentation that is bracketed by these statements.

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