Dear Eugene, Call me an extremist or an alarmist or what you like, from a scientists viewpoint the situation is extremely alarming, and hardly any scientist, even Prof Hansen, dares say just how alarming it is. This is the paralysis which is preventing the urgent action that's needed. And this action has now to include geoengineering because we have let the situation get so critical, with the Arctic sea ice in particular (but also permafrost, Greenland ice sheet, West Antarctic ice sheet, etc.). Let's not wait until it's actually too late to save the day and there is utter panic.
Regards, John ----- Original Message ----- From: Eugene I. Gordon To: [EMAIL PROTECTED] Sent: Tuesday, November 25, 2008 1:55 AM Subject: RE: [geo] Re: Tell Barack Obama the Truth -- The Whole Truth The objective is appropriate and well stated although I suspect, but do not know, that the climate scenario cited overstates the dangers and risks. This entire area of debate seems to be fraught with extremism. The realistic scenario is that the US goes forward with its emission reduction but others do not or do not succeed other than to add lots of wind. As regards the Manhattan geoengineering project, you recall I am certain that the Germans had a Manhattan project that did not succeed. Others may try their own and fail. But how do we deal with a U.S. generated geoengineering project that the rest of world rejects? -gene ------------------------------------------------------------------------------ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of John Nissen Sent: Monday, November 24, 2008 8:37 PM To: James Hansen Cc: geoengineering; Ken Caldeira; Stephen Salter; John Latham; [EMAIL PROTECTED] Subject: [geo] Re: Tell Barack Obama the Truth -- The Whole Truth Dear Professor Hansen, May I suggest that the situation is even more desperate than you suggest, but offer an opportunity for Obama to save the day through the "last resort" of geoengineering? In a recent paper you say: Paleoclimate data show that climate sensitivity is ~3°C for doubled CO2, including only fast feedback processes. These "fast feedbacks" include the albedo effect of Arctic sea ice. But the paleodata do not show the Arctic sea ice ever completely disappearing in summer. In fact the Arctic sea ice may have acted as a thermostatic control, preventing interglacial warming exceeding certain limits [1] and thus preventing its own disappearance. However we find ourselves today in a completely unprecedented situation. We have the possibility of summer disappearance within a few years - by 2012 or 2013 according to some experts [2] - thus breaking our own planetary thermostat. This will lead to significant feedback to global warming - in the range 0.4 to 1.6 Watts per square metre [3] - thus suggesting that climate sensitivity is underestimated. But it leads to much greater local warming - more than sufficient to cause massive methane release for frozen structures such as permafrost [4] - more than sufficient to destabilise the Greenland ice sheet and result in a metre or more of sea level rise this century [5]. What is more, the limits of interglacial warming may have protected vital carbon sinks, both terrestrial and oceanic. Thus the loss of Arctic sea ice could result in less than the current 50% of anthropogenic CO2 being absorbed, and again the climate sensitivity is adversely affected. The timescale for saving the Arctic sea ice is far shorter than the timescale for emissions reduction. Even removal of CO2 from the atmosphere by geoengineering could not conceivably be done quickly enough. Thus it seems that the only possibility to save the Arctic sea ice is through albedo engineering. However there are two methods which are feasible to quickly cool the Arctic region - one using stratospheric aerosols [6] and one using marine cloud brightening [7]. These could be used together, to increase the chance of success and allow some fine-tuning of the process, e.g. to minimise unwanted side-effects. Furthermore these methods could scaled up to halt warming globally, and protect the carbon sinks. No serious scientist is suggesting that geoengineering should be used exclusively, or as an excuse to avoid drastic emission cuts. Without such cuts, CO2 will cause ocean acidification. But the magnitude of the danger that we are in militates even more urgent cuts, and a more urgent move to low carbon economies around the world. So I absolutely support your efforts to have CO2 levels reduced to 350ppm or less. But albedo engineering is needed quickly. So my added conclusion is as follows. Barack Obama should be persuaded to set up a project to save the Arctic sea ice, with the focus, determination and urgency of the Manhattan project in WW2. This is the moral imperative. Failure is not an option. Kind regards, John Nissen Chiswick, London W4 +44 20 8742 3170 Email: [EMAIL PROTECTED] [1] The highest temperature of interglacials was little different from today's global mean. [2] A group of scientists are arguing that the summer sea ice is likely to be gone in 2012 or 2013. http://www.thewe.cc/weplanet/news/water/dramatic_melt_in_arctic_icecape.htm [3] Albedo effect on global warming (with complete disappearance of sea ice) of about 0.4 Watts per metre² is an estimate by Jeff Ridley of the Hadley centre, and about 1.6 Watts per metre² is my own - based on different assumptions. [4] David Lawrence, see for example: http://www.ucar.edu/news/releases/2008/permafrost.jsp [5] Your own warning. [6] Rasch, P. et al., 2008, An overview of geoengineering of climate using stratospheric sulfate aerosols. Phil. Trans. Roy. Soc A. [7] Salter et al, 2008, in same issue of Phil. Trans. Roy. Soc A ----- Original Message ----- From: James Hansen To: [EMAIL PROTECTED] Sent: Friday, November 21, 2008 11:35 PM Subject: Tell Barack Obama the Truth -- The Whole Truth To be removed from Jim Hansen's e-mail distribution, reply with REMOVE as subject. A draft write-up, Tell Barack Obama the Truth -- The Whole Truth, is at http://www.columbia.edu/~jeh1/mailings/20081121_Obama.pdf Criticisms are welcomed -- it was written pretty quickly as I am leaving this weekend for a long trip. Jim No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.175 / Virus Database: 270.9.9/1808 - Release Date: 11/23/2008 6:59 PM --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~----------~----~----~----~------~----~------~--~---
