RE: [geo] Solar geoengineering must take temperature debt into account - Andreas Oschlies

2018-02-23 Thread Douglas MacMartin 
Isn’t this trivially obvious?  Yes, when decisions are ultimately made, they 
should explicitly consider the risks of any choice (to deploy or not, how much 
to deploy, etc).  I’ve never heard a single person argue that we shouldn’t take 
the risks of solar geoengineering into account.

 

(And, of course, any rational engineer tries to identify strategies to reduce 
the probability of occurrence and the severity of impact, e.g., ensure multiple 
countries are capable of sustaining a deployment.)

 

From: geoengineering@googlegroups.com [mailto:geoengineering@googlegroups.com] 
On Behalf Of Andrew Lockley
Sent: Saturday, February 24, 2018 1:37 PM
To: geoengineering 
Subject: [geo] Solar geoengineering must take temperature debt into account - 
Andreas Oschlies

 

Poster's note: others challenge these arguments. Parker and Irvine dispute the 
vulnerability of solar geoengineering to anything less than eg a nuclear war. 
Keith et al. suggest it can be temporarily deployed 


https://www.nature.com/articles/d41586-018-02203-x

 


Solar engineering must take temperature debt into account


Andreas Oschlies


*
*
*

  
<https://www.nature.com/magazine-assets/d41586-018-02203-x/d41586-018-02203-x.pdf>
 PDF version

Solar geoengineering is a proposed method of climate engineering that aims to 
reduce global warming using an artificial ‘sunscreen’ of aerosols in Earth’s 
high atmosphere. As planning of the first field experiments gets under way, any 
potential risks associated with the technology must be transparently assessed 
and not downplayed or dismissed. One such risk of solar geoengineering is its 
‘temperature debt’ — the planetary heating that would arise if maintenance of 
the artificial sunscreen was discontinued.

Modelling suggests that most of the world’s population could benefit from this 
temporary sunscreen, compared with the adverse effects of unabated climate 
change (a questionable reference state, in my view). However, models also 
reveal the alarming rise in temperatures that could occur if the screen of 
short-lived aerosols should suddenly cease to function for any reason in the 
presence of high concentrations of long-lived greenhouse gases (see  
<http://dx.doi.org/10.1073/pnas.0700419104> H. D. Matthews and K. Caldeira 
Proc. Natl Acad. Sci. USA104, 9949–9954; 2007). This rapid warming would pose a 
severe risk to ecosystems and society.

Even with the best planning to ensure steady operation of the technology, its 
continuous safe functioning and maintenance cannot be guaranteed. Yet it could 
take hundreds of years to safely phase out solar geoengineering and achieve the 
same degree of cooling by reducing greenhouse-gas concentrations. It is 
therefore imperative that, in the absence of a fail-safe mode for solar 
geoengineering, the temperature debt is fully accounted for in any assessments 
of this technology.

Nature 554, 423 (2018)

doi: 10.1038/d41586-018-02203-x

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[geo] Solar geoengineering must take temperature debt into account - Andreas Oschlies

2018-02-23 Thread Andrew Lockley 
Poster's note: others challenge these arguments. Parker and Irvine dispute
the vulnerability of solar geoengineering to anything less than eg a
nuclear war. Keith et al. suggest it can be temporarily deployed

https://www.nature.com/articles/d41586-018-02203-x

Solar engineering must take temperature debt into account
Andreas Oschlies

   -
   


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   -
   


 PDF version


Solar geoengineering is a proposed method of climate engineering that aims
to reduce global warming using an artificial ‘sunscreen’ of aerosols in
Earth’s high atmosphere. As planning of the first field experiments gets
under way, any potential risks associated with the technology must be
transparently assessed and not downplayed or dismissed. One such risk of
solar geoengineering is its ‘temperature debt’ — the planetary heating that
would arise if maintenance of the artificial sunscreen was discontinued.

Modelling suggests that most of the world’s population could benefit from
this temporary sunscreen, compared with the adverse effects of unabated
climate change (a questionable reference state, in my view). However,
models also reveal the alarming rise in temperatures that could occur if
the screen of short-lived aerosols should suddenly cease to function for
any reason in the presence of high concentrations of long-lived greenhouse
gases (see H. D. Matthews and K. Caldeira *Proc. Natl Acad. Sci.
USA*104, 9949–9954;
2007 ). This rapid warming would
pose a severe risk to ecosystems and society.

Even with the best planning to ensure steady operation of the technology,
its continuous safe functioning and maintenance cannot be guaranteed. Yet
it could take hundreds of years to safely phase out solar geoengineering
and achieve the same degree of cooling by reducing greenhouse-gas
concentrations. It is therefore imperative that, in the absence of a
fail-safe mode for solar geoengineering, the temperature debt is fully
accounted for in any assessments of this technology.

Nature 554, 423 (2018)
doi: 10.1038/d41586-018-02203-x

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