Dr. Lockley and ccs
I generally agree with your comments and offer the following as something
directly related to arctic/antarctic/methane/time bomb issues - the topic of
this thread..
The following is only a personal follow-up to conversations on this list about
a week ago re Dr. Seitz's "Bright Water" article.. This exercise was performed
(solely by myself) so our discussion on doing something about arctic methane
release doesn't end prematurely. ..I have had no conversations re this Table
with Dr. Seitz (who is cc'd).
The following is my tentative "Bright Water" version of the Table given by Dr.
Robock earlier (citation given and reproduced in full a week ago). My
explanatory comments are(hopefully all) in bold in square brackets, shown as
deletions, or in separate identified subsections. . Numbering has been added to
aid in further dialog and for easier attribution in the final summary
comparison..But mostly this follows Dr. Robock's original. All - please
consider this a rushed, first draft.
Table 1 Benefits and risks of stratospheric "B right water" geoengineering
Benefits
a. From Dr. Robock's list
1. Cool planet [ limited, at least at first, to targeted polar regions]
2. Reduce or reverse sea ice melting [Primary motivation]
3. Reduce or reverse land ice sheet melting Likely marginal benefit, but
maintains symmetry.
4. Unexpected benefits [Maintains symmetry]
b. Adding items that might be listed by proponents
5. Can advance technology for reducing evaporative water loss from reservoirs
and aquaducts
6. Risks are highly localized and likely measurable
7. Can implement rapidly, so might give time to avoid tipping point due to
methane release
8. Low cost.
c. Reversing some listed by Dr. Robock as risks for the stratospheric approach)
9. Can stop effects quickly
10. Known hand on the thermostat
11. Does not degrade terrestrial optical astronomy
12. Does not affect stargazing
13. Does not affect satellite remote sensing
d. The following are non-benefits or marginal benefits for "Bright Water", but
not necessarily large scale or probable, as originally listed by Dr. Robock.
Reduce or reverse sea level rise
Increase plant productivity
Increase terrestrial CO 2 sink
Beautiful red and yellow sunsets
Risks (Retaining order from Dr. Robock)
a. Original list (some seem duplicative)
Drought in Africa and Asia
1. Perturb ecology with more diffuse radiation
Ozone depletion
Whiter skies
Less solar energy generation
Degrade passive solar heating of buildings
2.Environmental impact of implementation
Rapid warming if stopped
Cannot stop effects quickly
3 .Human error
4. Unexpected consequences
Whose hand on the thermostat?
Degrade terrestrial optical astronomy
Affect stargazing
Affect satellite remote sensing
The following seem to be less certain as risks, retained for symmetry
5. Commercial control
6. Military use of technology
7. Conflicts with current treaties
8. Moral hazard—the prospect of it working would reduce drive for mitigation
9. Moral authority—do we have the right to do this?
Summary
For Stratospheric: Benefits - 8; Risks - 20
For “Bright Water” Benefits -13; Risks - 9
Tentative Conclusion by RWL – “Bright Water” is worth exploring further for
both polar regions.
RWL Part B - Further interesting recent articles on the methane threats in the
Antarctic
1. This one says there is more of a possible methane threat in the Antarctic
than I had thought likely
http://www.nature.com/news/2010/100903/full/news.2010.442.html
2. This week's article in PNAS by Wayne Z. Trivelpiece, has same thrust re
methane and existing Antarctic ice melt.
"Variability in krill biomass links harvesting and climate
warming to penguin population changes in Antarctica"
http://www.pnas.org/content/early/2011/04/06/1016560108.full.pdf+html
The last sentence shows an interesting unexpected result, somewhat pertinent to
items in the above Table:
"Long thought to be ecological winners in the climate-warming scenario
(1–5), the chinstrap penguin instead may be among the most
vulnerable species affected by a warming climate"
End RWL for 14 April
----- Original Message -----
From: "Andrew Lockley" <[email protected]>
To: [email protected]
Cc: "geoengineering" <[email protected]>
Sent: Wednesday, April 13, 2011 3:40:22 PM
Subject: Re: [geo] Fw: Scientists should communicate: the methane time bomb
Of particular interest to geoengineers in this paper is the comment that
warming penetrates into hydrate sediments in a time-delayed but irreversible
fashion. Once a warming pulse is transmitted into the sediment, later cooling
does not prevent the eventual heating and dissociation of the clathrates in the
sediments.
It is therefore clear that we have a window for geoengineering, after which a
particular sediment block is inevitably doomed. If it is a large block, then
serious climate change is committed - regardless of the overlying temperature.
An ice covering may assist in the retention of the released methane, but
released it ultimately will be.
We urgently need to constrain the errors and uncertainties in this process.
A
On 13 April 2011 09:39, John Gorman < [email protected] > wrote:
----- Original Message -----
From: Veli Albert Kallio
Sent: Tuesday, April 12, 2011 8:56 PM
Subject: RE: Scientists should communicate: the methane time bomb
This Royal Society paper on role of methane is instrumental and anyone involved
in methane debate should read it.
Kr, Albert
>From John Gorman
A very interesting paper. The first thing that caught my eye was;
Harvey & Huang (1995) carried out a detailed evaluation of the potential impact
of
clathrate destabilization with global warming. Clathrate stability depends
crucially
and very nonlinearly on the amount of warming: less than 4 ◦ C warming means
that
comparatively little clathrate is released; however, when warming is 10 ◦ C,
large
amounts of methane are liberated.(page 603)
reassuring if one has the figure of 0.7 deg C in mind but very worrying if one
realises that Arctic amplification means that we are almost at 4 deg in the
arctic now and 2 deg global avaeage means eight or ten degrees in the arctic
and Antarctic. (one pager Arctic Amplification attached)
More later.
john gorman
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