Dear all,

I have tried to summarise the arguments various people have made for not supporting the letter, listing six main issues below.

If this letter is successful in drawing the attention of John Holdren, then one would expect him to refer to the experts in various areas to check out the evidence and the arguments.  The recipients of this email include top experts on Arctic sea ice, climate modelling and geoengineering.  Other recipients have access to such experts.  So no doubt Holdren will get back to several of you and your colleagues.
 
We have had considerable discussion about the issues during the course of the past few years, particularly since the dramatic retreat of Arctic sea ice in September 2007.  It was at that time that I became extremely concerned about the positive feedback building up in the Arctic, and my concerns were confirmed in a briefing by David Wasdell and Peter Wadhams entitled “Accelerated Global Warming” at Tomorrow’s Company in February 2008 [1].  David impressed me by his understanding of the nature of positive feedback, and how it had been largely neglected by climate scientists, particularly in the 2007 IPCC report.  Peter added his knowledge and understanding of the Arctic sea ice, to present a very alarming picture of the situation.  David was keen to distinguish being alarmist from being honest about an alarming situation.  And the more I have looked into the science, the more alarmed I have become.
 
But I have been most puzzled by the reaction from scientists.  There has been a refusal to accept the danger of the situation and what can be done about it.  Perhaps I have been fundamentally wrong about some critical piece of evidence or crucial part of the argument.   I wish, I wish, that somebody could prove me wrong.  But I refuse to be comforted by a cosy consensus that seems to propagate the idea that there’s nothing to worry about.  For example it has been said, by a past government adviser at a House of Commons seminar, that we won’t need geoengineering for at least 30 years [2].  The Royal Society study on geoengineering didn’t address the Arctic sea ice problem at all [3].
 
So where could I be wrong?  What arguments are there against the letter to Holdren?
 
  1. Sea ice retreat could be much slower
 
This is the argument that the sea ice could last till well beyond 2050.  Certainly this is possible.  But can we bank on it, given the current evidence of sea ice volume decline?  Isn’t it wiser to take the precautionary approach and work on the assumption that the sea ice retreat will happen quicker than expected, rather than slower?
 
  1. Methane not a menace
 
Tom Wigley was concerned with this passage:
 
"... we can expect permafrost to release large quantities of methane, from as early as 2011 onwards, which will lead inexorably to runaway greenhouse warming and abrupt climate change."
 
It is now generally recognised that there is a vast amount of carbon locked in frozen structures within the Arctic region, and, as temperatures rise, it will emerge in ever increasing quantities. 
 
I replied to Tom in detail on 12th July, as follows:
 
If all carbon trapped in permafrost were released as CO2, it would triple CO2 in the atmosphere [1].  A significant proportion will be released as methane, which a much more potent greenhouse gas than CO2. 

Continued heating of the Arctic will inevitably lead to melting of permafrost.   This heating is accelerating due to positive feedbacks.  A major feedback is from the albedo change when sea ice is replaced by water [2].  As the sea ice retreats, we can expect methane to be released in ever larger quantities.  The global warming effect of the methane will lead to further methane release, and further warming, in what can be described as thermal runaway.  Abrupt climate change could then be expected.  Massive methane discharge is thought to have caused abrupt climate change in the past, "on a timescale less than a human lifetime" [3].
 
[1] Copenhagen Diagnosis, p21
http://www.ccrc.unsw.edu.au/Copenhagen/Copenhagen_Diagnosis_LOW.pdf

[2] Nature Letters
http://sciences.blogs.liberation.fr/files/arctique-ann%C3%A9es-2000-tures.pdf

[3] Clathrate gun hypothesis
http://en.wikipedia.org/wiki/Clathrate_gun_hypothesis
 
  1. Best to wait until things get worse
 
When you are fighting a fire, you don’t wait to see if the fire has taken hold.  If a patient is ill, with a significant chance of cancer, you don’t delay treatment.  The longer we wait to apply geoengineering, the less likely it is to succeed in cooling the Arctic.
 
  1. Geoengineering is too dangerous
 
One has to balance the risks of geoengineering against the risks of not geoengineering.  The latter are clearly so high that they almost certainly dwarf the possible adverse effects of geoengineering.  We’ve had a long discussion about this on the geoengineering list.  In particular, a few people have argued that SRM could adversely affect monsoons, but the modelling seems inconclusive as to the possible size of this effect and even its direction.
 
Again the fire-fighting analogy comes in: if a building is on fire, your main concern is putting out the fire, not worrying about the damage to contents from fire extinguisher fluid.  However you will try to use effective extinguishing techniques that avoid damage to the furniture.  And you will certainly avoid techniques that could fan the flames.
 
  1. Geoengineering can’t be the only option
 
Unfortunately geoengineering does seem to be the only option to cool the Arctic and save the Arctic sea ice.  In the letter we say that “even if emissions could be cut to zero, the existing CO2 in the atmosphere would continue to warm the planet for many decades.”  Therefore there can be no cooling effect from emissions reduction.  CO2 removal would have to bring the level down below pre-industrial level to have a negative forcing on the climate – and that clearly cannot be done in the necessary time-scale.  So we are left with geoengineering as the only option.  Note that geoengineering can be defined as “deliberate intervention to change climate”, and this is what we need to do in the Arctic to cool it.
 
  1. We need more research on geoengineering
 
Having a project “of the intensity of the Manhattan project” does not rule out further research.  But it does stress that time is of the essence, to reduce the risk of being too late.  The risk of being too late is growing with all delay, due to growing effects of positive feedback.  Thus first task of the project would be work out a plan of attack, to maximise chances of success.  Research can continue in parallel with preparations for deployment.  A mix of different techniques will no doubt be considered – some more ready for deployment than others.  
 
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I hope everyone can now accept that the letter is grounded in good science and logical argument, as fitting to put to Professor Holdren. 

Put it another way.  Suppose this letter fails for lack of your support.  Can you imagine looking back from the future and thinking: “Wasn’t it a shame we screwed up the planet, when we knew we could have saved it, if only we’d pressed for geoengineering earlier”?

Best wishes,
 
John
 
[1] “Accelerated Global Warming”, see near bottom of this page:
http://www.tomorrowscompany.com/events.aspx
 
[2] Sir David King reported here:
http://blogs.nature.com/climatefeedback/2010/01/testing_geoengineering_a_catch_1.html
 
[3] Royal Society report ”Geoengineering the Climate”:
http://royalsociety.org/Geoengineering-the-climate/
 
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John Nissen wrote:

Dear Ron,

The letter argues that geoengineering is now our only hope - our only option to avoid sea ice disappearance and the possibility of catastrophic methane release - since only geoengineering can act quickly enough to cool the Arctic.  Procrastination will reduce chances of success, as well as increase chances of unmanageable side effects.

Cheers,

John

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Ron Lindsay wrote:
Please do not add my name to the letter.  I think geoengineering is a false hope and highly prone to unintended consequences.

    -- Ron


John Nissen wrote:

In view of the situation in the Arctic, I would be grateful for support for an open letter to John Holdren, along the following lines.  Please let me know whether you agree with this text and whether you'd be happy for me to add your name at the bottom.

Cheers,

John

---

To John P Holdren, the Director of the Office of Science and Technology Policy

Dear Dr Holdren,

The Arctic sea ice acts as a giant mirror to reflect sunlight back into space and cool the Earth. The sea ice has been retreating far faster than the IPCC predicted only three years ago [1]. But, after the record retreat in September 2007, many scientists revised their predictions for the date of a seasonally ice free Arctic Ocean from beyond the end of century to beyond 2030. Only a few scientists predicted this event for the coming decade, and they were ridiculed.

In 2008 and 2009 there was only a slight recovery in end-summer sea ice extent, and it appears that the minimum 2010 extent will be close to a new record [2].  However the evidence from PIOMAS is that there has been a very sharp decline in volume [3], which is very worrying.

The Arctic warming is now accelerating, and we can expect permafrost to release large quantities of methane, from as early as 2011 onwards, which will lead inexorably to runaway greenhouse warming and abrupt climate change.  All this could become apparent if the sea ice retreats further than ever before this summer.  We could be approaching a point of no return unless emergency action is taken.

We suggest that the current situation should be treated as a warning for us all. The world community must rethink its attitude to fighting global warming by cutting greenhouse gas emissions sharply. However, even if emissions could be cut to zero, the existing CO2 in the atmosphere would continue to warm the planet for many decades.  Geoengineering now appears the only means to cool the Arctic quickly enough.  A geoengineering project of the intensity of the Manhattan Project is urgently needed to guard against a global catastrophe.

Yours sincerely,

John Nissen

[Other names to be added here.]

[1] Stroeve et al, May 2007
http://www.smithpa.demon.co.uk/GRL%20Arctic%20Ice.pdf

[2] http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png

[3] http://nsidc.org/images/arcticseaicenews/20100608_Figure5.png

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