Re: [geo] Warning over aerosol climate fix - BBC News

[Parminder Singh]

Overtopping dams and plunge pools on spillways create extreme hydraulic 
conditions that can cause rock scour and erosion downstream. Why not fill 
with olivine rocks.

Parminder Singh



On Tuesday, April 21, 2015 at 12:51:03 AM UTC+8, Ron wrote:
>
> Prof Schulling,  cc list:
>
> I hope you are correct.  We need every possible means of CDR.
>
> I have just learned of a new (February) rare comparison of the CDR (their 
> term: NET) options (under the phrase “Stranded Assets):
>
> http://www.smithschool.ox.ac.uk/research-programmes/stranded-assets/Stranded%20Carbon%20Assets%20and%20NETs%20-%2006.02.15.pdf
>  
> <http://www.smithschool.ox.ac.uk/research-programmes/stranded-assets/Stranded+Carbon+Assets+and+NETs+-+06.02.15.pdf>
>
> They have identified three approaches they call “No Regrets”, which become 
> NR-NET.  I am pleased that biochar is there - but I don’t think they have 
> yet fully captured biochar potential.  
>
> Your olivine approach is not one of the three - because of the high energy 
> costs of achieving small particles.  Could you respond to them?
>
> Ron
>
>
> On Apr 20, 2015, at 1:33 AM, Schuiling, R.D. (Olaf)  > wrote:
>
> I would like to express it better, what politicians should do:
> *“the best thing that politicians can do is to intensify the process that 
> has throughout the geological history of the Earth captured its CO2 and 
> stored it safely in rocks”* Olaf Schuiling
>  
> *From:* geoengi...@googlegroups.com  [
> mailto:geo...@googlegroups.com ] *On Behalf Of *Ronal W. 
> Larson
> *Sent:* maandag 20 april 2015 5:02
> *To:* Andrew Lockley
> *Cc:* Geoengineering
> *Subject:* Re: [geo] Warning over aerosol climate fix - BBC News
>  
> Andrew and list
>  
> 1.  Besides your message below being about Prof. Caldeira’s comments on 
> SRM, this is a nice reminder that a major “Geo”-related conference ended a 
> few days ago.  At:
> 
> http://meetingorganizer.copernicus.org/egu2015/sessionprogramme
>  I found about 40 oral and poster presentations on biochar and about the 
> same number with a biomass flavor.  This seems to be down a little from the 
> previous year, found at:
> 
> http://meetingorganizer.copernicus.org/egu2014/sessionprogramme
> Could those who attended give us a flavor for how the various SRM and 
> CDR/NET approaches were being viewed by conference attendees?  
>  
> 2.   I was surprised to see Prof.  Caldeira’s session had only 4 other 
> papers on SRM - none of which seemed particularly positive.
>  
> 3.  With apologies for bringing up the “only” subject again so soon, I 
> wonder if others see a disparity with the above statistics and a sentence 
> almost at the end below:
> *"The only thing a politician can do to start the planet 
> cooling is solar geoengineering.*
>  
> Ron
>  
>  
>  
> On Apr 17, 2015, at 3:16 PM, Andrew Lockley  > wrote:
>
>
> http://www.bbc.co.uk/news/science-environment-32334528
>
> By Simon Redfern
> Science writer
> 16 April 2015
> From the section Science & Environment
>
> Any attempts to engineer the climate are likely to result in "different" 
> climate change, rather than its elimination, new results suggest.
> Prof Ken Caldeira, of Stanford University, presented research at a major 
> conference on the climate risks and impacts of geoengineering.
> These techniques have been hailed by some as a quick fix for climate 
> change.
> But the impacts of geoengineering on oceans, the water cycle and land 
> environments are hotly debated.
> They have been discussed at a meeting this week of 12,000 scientists in 
> Vienna.
> Researchers are familiar with the global cooling effects of volcanic 
> eruptions, seen both historically and even back into the deep past of the 
> rock record.
> With this in mind, some here at the European Geosciences Union General 
> Assembly have been discussing the possible worldwide consequences of 
> pumping sulphate aerosols into the stratosphere to attempt to reflect 
> sunlight back into space and cool the planet.
> Planetary sunshade
> Two hundred years ago this month, the huge volcano Mount Tambora erupted 
> in Indonesia, throwing tonnes of gas and ash into the stratosphere.
> Maybe as much as 100 million tonnes of sulphur dioxide aerosols spread as 
> a blanket around the globe, acting like a planetary sunshade.
> Global temperatures plummeted, and across America and Europe 1816 became 
> known as the year without a summer.
> Such global cooling processes, but managed in a geoengineering solution, 
> have been touted by some as a possible mechanism to extricate the planet 
> from its path towards a warmer future.
> Solar radiati

Re: [geo] Warning over aerosol climate fix - BBC News

[Ronal W. Larson]

Prof Schulling,  cc list:

I hope you are correct.  We need every possible means of CDR.

I have just learned of a new (February) rare comparison of the CDR 
(their term: NET) options (under the phrase “Stranded Assets):
http://www.smithschool.ox.ac.uk/research-programmes/stranded-assets/Stranded%20Carbon%20Assets%20and%20NETs%20-%2006.02.15.pdf

They have identified three approaches they call “No Regrets”, which 
become NR-NET.  I am pleased that biochar is there - but I don’t think they 
have yet fully captured biochar potential.  

Your olivine approach is not one of the three - because of the high 
energy costs of achieving small particles.  Could you respond to them?

Ron


On Apr 20, 2015, at 1:33 AM, Schuiling, R.D. (Olaf)  wrote:

> I would like to express it better, what politicians should do:
> “the best thing that politicians can do is to intensify the process that has 
> throughout the geological history of the Earth captured its CO2 and stored it 
> safely in rocks” Olaf Schuiling
>  
> From: geoengineering@googlegroups.com 
> [mailto:geoengineering@googlegroups.com] On Behalf Of Ronal W. Larson
> Sent: maandag 20 april 2015 5:02
> To: Andrew Lockley
> Cc: Geoengineering
> Subject: Re: [geo] Warning over aerosol climate fix - BBC News
>  
> Andrew and list
>  
> 1.  Besides your message below being about Prof. Caldeira’s comments on SRM, 
> this is a nice reminder that a major “Geo”-related conference ended a few 
> days ago.  At:
> http://meetingorganizer.copernicus.org/egu2015/sessionprogramme
>  I found about 40 oral and poster presentations on biochar and about the same 
> number with a biomass flavor.  This seems to be down a little from the 
> previous year, found at:
> http://meetingorganizer.copernicus.org/egu2014/sessionprogramme
> Could those who attended give us a flavor for how the various SRM and 
> CDR/NET approaches were being viewed by conference attendees?  
>  
> 2.   I was surprised to see Prof.  Caldeira’s session had only 4 other papers 
> on SRM - none of which seemed particularly positive.
>  
> 3.  With apologies for bringing up the “only” subject again so soon, I wonder 
> if others see a disparity with the above statistics and a sentence almost at 
> the end below:
> "The only thing a politician can do to start the planet cooling 
> is solar geoengineering.
>  
> Ron
>  
>  
>  
> On Apr 17, 2015, at 3:16 PM, Andrew Lockley  wrote:
> 
> 
> http://www.bbc.co.uk/news/science-environment-32334528
> 
> By Simon Redfern
> Science writer
> 16 April 2015
> From the section Science & Environment
> 
> Any attempts to engineer the climate are likely to result in "different" 
> climate change, rather than its elimination, new results suggest.
> Prof Ken Caldeira, of Stanford University, presented research at a major 
> conference on the climate risks and impacts of geoengineering.
> These techniques have been hailed by some as a quick fix for climate change.
> But the impacts of geoengineering on oceans, the water cycle and land 
> environments are hotly debated.
> They have been discussed at a meeting this week of 12,000 scientists in 
> Vienna.
> Researchers are familiar with the global cooling effects of volcanic 
> eruptions, seen both historically and even back into the deep past of the 
> rock record.
> With this in mind, some here at the European Geosciences Union General 
> Assembly have been discussing the possible worldwide consequences of pumping 
> sulphate aerosols into the stratosphere to attempt to reflect sunlight back 
> into space and cool the planet.
> Planetary sunshade
> Two hundred years ago this month, the huge volcano Mount Tambora erupted in 
> Indonesia, throwing tonnes of gas and ash into the stratosphere.
> Maybe as much as 100 million tonnes of sulphur dioxide aerosols spread as a 
> blanket around the globe, acting like a planetary sunshade.
> Global temperatures plummeted, and across America and Europe 1816 became 
> known as the year without a summer.
> Such global cooling processes, but managed in a geoengineering solution, have 
> been touted by some as a possible mechanism to extricate the planet from its 
> path towards a warmer future.
> Solar radiation management would use stratospheric sulphate aerosols to dim 
> the Sun. Using a variety of climate models, Ken Caldeira, from the Carnegie 
> Institution for Science in Stanford, California, has investigated the likely 
> consequences of such geoengineering on agriculture across the globe.
> Mount Pinatubo
> Mount Pinatubo pumped 20 million tonnes of sulphur dioxide high into the sky 
> above the Philippines
> His research shows that while dimming could rapidl

Re: [geo] Warning over aerosol climate fix - BBC News

[Ronal W. Larson]

Nils,  cc list:

Thanks for this report; very helpful.  

I hope others will do the same.   

Few notes below.


On Apr 20, 2015, at 4:56 AM, Motoko  wrote:

> Dear Ron,
> 
> to 1.
> I attended only a few of the biochar presentations. From the program and the 
> presentation I it seemed that biochar has not been studied as a CE measure. 
> Most of the talk/posters were about soil enhancement. (BTW, it is the 
> international year of soil.) Some authors of CE-biochar papers have been 
> present but were not talking about CDR.
[RWL1:  Yes, (as you probably know but others may not) the emphasis in 
almost all biochar discussion venues is the same: soil productivity (mostly) 
improvements, rely anything on CDR/NET results or costs.  But there is zero 
conflict between these two aspects of biochar.  If one utilizes biochar for the 
former, this greatly helps the CDR analysis because the CDR/NET cost of the 
char falls and, for high value crops, has even become negative (first year 
payback)I’m afraid the few CDR/NET analysts haven’t understood yet how 
important the soil benefits are for increasing the use of biochar for CDR 
reasons.  I will send another message soon on a new such analysis.

> 
> There has also been a press conference with the some of the people that have 
> been at the CE session.
> http://meetingorganizer.copernicus.org/EGU2015/session/19804 
  [RWL1’:The direct URL for the 37-minute “solar geo” press conference 
video is 
 http://client.cntv.at/egu2015/PC6
The title of the press conference was “geoengineering”, but the terms CDR and 
NET never was mentioned, I think.  About 10 reporters.

Prof.  Caldeira does a good job in explaining the impacts of solar geo on plant 
growth.  
Dr.  Muri at 8:30 on thin high clouds.  Some good plots;  quite different 
predictions in two hemispheres.
Dr.  Korhonen at 15:00 gave a result I have not previously seen - that solar 
geoengineering is predicted to increase (NOT decrease) temperatures at high 
latitudes.  Also it seems a new cooling prediction of what happens with 
combined volcanic and solar-geo impacts.

Q1.  A good question to Ken at minute 21, saying here that his new 
results contradict previous predictions re latitude.

Q2 at 26:30 on expectations for solar Geo and the arctic.  Here is 
where Ken’s coupling of politicians and “only” occurs.  I now put emphasis on 
the “politician” portion of the statement.

Q3 at 31:30 related to public acceptance.

Q4 at 35:15 on crop impact.  Repeat answer on Ken’s opening talk.
> 
> to 2.
> Conveners of the session have been Helene Muri, Simon Driscoll, and Peter 
> Irvine.
> The session seemed balanced. Some talked about the interlink of a volcanic 
> eruption and stratospheric SRM (Korhonen) or sea-level rise and SRM 
> (Applegate). I wouldn't call them in particular positive rather then very 
> negative.
RWL2:  Thanks.  The press conference didn’t include Applegate.  There are 
abstracts for all talks at the site given below;  I get a lot more from the 
video - and especially for the answers to the questions during the press 
conference.

There are other press conferences that may be relevant.  #3 is reported 
to include CCS.


Ron
> 
> Nils
> 
> 
> Am 20.04.2015 um 05:01 schrieb Ronal W. Larson:
>> Andrew and list
>> 
>> 1.  Besides your message below being about Prof. Caldeira’s comments on SRM, 
>> this is a nice reminder that a major “Geo”-related conference ended a few 
>> days ago.  At:
>>  http://meetingorganizer.copernicus.org/egu2015/sessionprogramme
>>  I found about 40 oral and poster presentations on biochar and about the 
>> same number with a biomass flavor.  This seems to be down a little from the 
>> previous year, found at:
>>  http://meetingorganizer.copernicus.org/egu2014/sessionprogramme
>> Could those who attended give us a flavor for how the various SRM and 
>> CDR/NET approaches were being viewed by conference attendees?  
>> 
>> 2.   I was surprised to see Prof.  Caldeira’s session had only 4 other 
>> papers on SRM - none of which seemed particularly positive.
>> 
>> 3.  With apologies for bringing up the “only” subject again so soon, I 
>> wonder if others see a disparity with the above statistics and a sentence 
>> almost at the end below:
>>  "The only thing a politician can do to start the planet cooling is solar 
>> geoengineering.
>>  
>> Ron
>> 
>> 
>> 
>> On Apr 17, 2015, at 3:16 PM, Andrew Lockley  wrote:
>> 
>>> http://www.bbc.co.uk/news/science-environment-32334528
>>> By Simon Redfern
>>> Science writer
>>> 
>>> 
>>> 

Emphasis added below
>>> “The only thing a politician can do to start the planet cooling is solar 
>>> geoengineering. If a catastrophic outcome does occur, the pressure to 
>>> deploy a scheme could be overwhelming.
>>> 


-- 
You received this message because you are subscribed to the Google Groups 
"geoengineering" group.
To unsubscribe from this group and stop receiving emails f

Re: [geo] Warning over aerosol climate fix - BBC News

[Motoko]

Dear Ron,

to 1.
I attended only a few of the biochar presentations. From the program and 
the presentation I it seemed that biochar has not been studied as a CE 
measure. Most of the talk/posters were about soil enhancement. (BTW, it 
is the international year of soil.) Some authors of CE-biochar papers 
have been present but were not talking about CDR.


There has also been a press conference with the some of the people that 
have been at the CE session.

http://meetingorganizer.copernicus.org/EGU2015/session/19804

to 2.
Conveners of the session have been Helene Muri, Simon Driscoll, and 
Peter Irvine.
The session seemed balanced. Some talked about the interlink of a 
volcanic eruption and stratospheric SRM (Korhonen) or sea-level rise and 
SRM (Applegate). I wouldn't call them in particular positive rather then 
very negative.


Nils


Am 20.04.2015 um 05:01 schrieb Ronal W. Larson:

Andrew and list

1.  Besides your message below being about Prof. Caldeira’s comments 
on SRM, this is a nice reminder that a major “Geo”-related conference 
ended a few days ago.  At:

http://meetingorganizer.copernicus.org/egu2015/sessionprogramme
 I found about 40 oral and poster presentations on biochar and about 
the same number with a biomass flavor.  This seems to be down a little 
from the previous year, found at:

http://meetingorganizer.copernicus.org/egu2014/sessionprogramme
Could those who attended give us a flavor for how the various SRM 
and CDR/NET approaches were being viewed by conference attendees?


2.   I was surprised to see Prof.  Caldeira’s session had only 4 other 
papers on SRM - none of which seemed particularly positive.


3.  With apologies for bringing up the “only” subject again so soon, I 
wonder if others see a disparity with the above statistics and a 
sentence almost at the end below:
/"The only thing a politician can do to start the planet cooling is 
solar geoengineering./

Ron



On Apr 17, 2015, at 3:16 PM, Andrew Lockley > wrote:



http://www.bbc.co.uk/news/science-environment-32334528

By Simon Redfern
Science writer
16 April 2015
From the section Science & Environment

Any attempts to engineer the climate are likely to result in 
"different" climate change, rather than its elimination, new results 
suggest.
Prof Ken Caldeira, of Stanford University, presented research at a 
major conference on the climate risks and impacts of geoengineering.
These techniques have been hailed by some as a quick fix for climate 
change.
But the impacts of geoengineering on oceans, the water cycle and land 
environments are hotly debated.
They have been discussed at a meeting this week of 12,000 scientists 
in Vienna.
Researchers are familiar with the global cooling effects of volcanic 
eruptions, seen both historically and even back into the deep past of 
the rock record.
With this in mind, some here at the European Geosciences Union 
General Assembly have been discussing the possible worldwide 
consequences of pumping sulphate aerosols into the stratosphere to 
attempt to reflect sunlight back into space and cool the planet.

Planetary sunshade
Two hundred years ago this month, the huge volcano Mount Tambora 
erupted in Indonesia, throwing tonnes of gas and ash into the 
stratosphere.
Maybe as much as 100 million tonnes of sulphur dioxide aerosols 
spread as a blanket around the globe, acting like a planetary sunshade.
Global temperatures plummeted, and across America and Europe 1816 
became known as the year without a summer.
Such global cooling processes, but managed in a geoengineering 
solution, have been touted by some as a possible mechanism to 
extricate the planet from its path towards a warmer future.
Solar radiation management would use stratospheric sulphate aerosols 
to dim the Sun. Using a variety of climate models, Ken Caldeira, from 
the Carnegie Institution for Science in Stanford, California, has 
investigated the likely consequences of such geoengineering on 
agriculture across the globe.

Mount Pinatubo
Mount Pinatubo pumped 20 million tonnes of sulphur dioxide high into 
the sky above the Philippines
His research shows that while dimming could rapidly decrease global 
temperatures, high CO2 levels would be expected to persist, and it is 
the balance between temperature, CO2, and sunlight that affects plant 
growth and agriculture.
Exploring the regional effects, he finds that a stratospherically 
dimmed world would show increased plant productivity in the tropics, 
but lessened plant growth across the northerly latitudes of America, 
Europe and Asia.
It is easy to see how there might be geopolitical shifts associated 
with changes in regional food production across the globe.
"It's probably the poor tropics that stand to benefit and the rich 
north that stands to lose," said Prof Caldeira.
But what if geoengineered sulphate aerosols were, nonetheless, 
deployed and then a large volcanic eruption like Pinatubo in the 
Philippines took place? T

RE: [geo] Warning over aerosol climate fix - BBC News

[Schuiling, R.D. (Olaf)]

I would like to express it better, what politicians should do:
“the best thing that politicians can do is to intensify the process that has 
throughout the geological history of the Earth captured its CO2 and stored it 
safely in rocks” Olaf Schuiling

From: geoengineering@googlegroups.com [mailto:geoengineering@googlegroups.com] 
On Behalf Of Ronal W. Larson
Sent: maandag 20 april 2015 5:02
To: Andrew Lockley
Cc: Geoengineering
Subject: Re: [geo] Warning over aerosol climate fix - BBC News

Andrew and list

1.  Besides your message below being about Prof. Caldeira’s comments on SRM, 
this is a nice reminder that a major “Geo”-related conference ended a few days 
ago.  At:
http://meetingorganizer.copernicus.org/egu2015/sessionprogramme
 I found about 40 oral and poster presentations on biochar and about the same 
number with a biomass flavor.  This seems to be down a little from the previous 
year, found at:
http://meetingorganizer.copernicus.org/egu2014/sessionprogramme
Could those who attended give us a flavor for how the various SRM and 
CDR/NET approaches were being viewed by conference attendees?

2.   I was surprised to see Prof.  Caldeira’s session had only 4 other papers 
on SRM - none of which seemed particularly positive.

3.  With apologies for bringing up the “only” subject again so soon, I wonder 
if others see a disparity with the above statistics and a sentence almost at 
the end below:
"The only thing a politician can do to start the planet cooling is 
solar geoengineering.

Ron



On Apr 17, 2015, at 3:16 PM, Andrew Lockley 
mailto:andrew.lock...@gmail.com>> wrote:



http://www.bbc.co.uk/news/science-environment-32334528

By Simon Redfern
Science writer
16 April 2015
>From the section Science & Environment

Any attempts to engineer the climate are likely to result in "different" 
climate change, rather than its elimination, new results suggest.
Prof Ken Caldeira, of Stanford University, presented research at a major 
conference on the climate risks and impacts of geoengineering.
These techniques have been hailed by some as a quick fix for climate change.
But the impacts of geoengineering on oceans, the water cycle and land 
environments are hotly debated.
They have been discussed at a meeting this week of 12,000 scientists in Vienna.
Researchers are familiar with the global cooling effects of volcanic eruptions, 
seen both historically and even back into the deep past of the rock record.
With this in mind, some here at the European Geosciences Union General Assembly 
have been discussing the possible worldwide consequences of pumping sulphate 
aerosols into the stratosphere to attempt to reflect sunlight back into space 
and cool the planet.
Planetary sunshade
Two hundred years ago this month, the huge volcano Mount Tambora erupted in 
Indonesia, throwing tonnes of gas and ash into the stratosphere.
Maybe as much as 100 million tonnes of sulphur dioxide aerosols spread as a 
blanket around the globe, acting like a planetary sunshade.
Global temperatures plummeted, and across America and Europe 1816 became known 
as the year without a summer.
Such global cooling processes, but managed in a geoengineering solution, have 
been touted by some as a possible mechanism to extricate the planet from its 
path towards a warmer future.
Solar radiation management would use stratospheric sulphate aerosols to dim the 
Sun. Using a variety of climate models, Ken Caldeira, from the Carnegie 
Institution for Science in Stanford, California, has investigated the likely 
consequences of such geoengineering on agriculture across the globe.
Mount Pinatubo
Mount Pinatubo pumped 20 million tonnes of sulphur dioxide high into the sky 
above the Philippines
His research shows that while dimming could rapidly decrease global 
temperatures, high CO2 levels would be expected to persist, and it is the 
balance between temperature, CO2, and sunlight that affects plant growth and 
agriculture.
Exploring the regional effects, he finds that a stratospherically dimmed world 
would show increased plant productivity in the tropics, but lessened plant 
growth across the northerly latitudes of America, Europe and Asia.
It is easy to see how there might be geopolitical shifts associated with 
changes in regional food production across the globe.
"It's probably the poor tropics that stand to benefit and the rich north that 
stands to lose," said Prof Caldeira.
But what if geoengineered sulphate aerosols were, nonetheless, deployed and 
then a large volcanic eruption like Pinatubo in the Philippines took place? 
Three such eruptions occurred in the last century so the scenario seems likely.
Bad timing
Hannele Korhonen, of the Finnish Meteorological Institute, suggests that the 
climate impacts could be quite unexpected.
Her results indicate increased temperatures in the Southern Ocean and in 
northerly latitudes, as well as the mid-Pacific, but 

Re: [geo] Warning over aerosol climate fix - BBC News

[Ronal W. Larson]

Andrew and list

1.  Besides your message below being about Prof. Caldeira’s comments on SRM, 
this is a nice reminder that a major “Geo”-related conference ended a few days 
ago.  At:
http://meetingorganizer.copernicus.org/egu2015/sessionprogramme
 I found about 40 oral and poster presentations on biochar and about the same 
number with a biomass flavor.  This seems to be down a little from the previous 
year, found at:
http://meetingorganizer.copernicus.org/egu2014/sessionprogramme
Could those who attended give us a flavor for how the various SRM and 
CDR/NET approaches were being viewed by conference attendees?  

2.   I was surprised to see Prof.  Caldeira’s session had only 4 other papers 
on SRM - none of which seemed particularly positive.

3.  With apologies for bringing up the “only” subject again so soon, I wonder 
if others see a disparity with the above statistics and a sentence almost at 
the end below:
"The only thing a politician can do to start the planet cooling is 
solar geoengineering.
 
Ron



On Apr 17, 2015, at 3:16 PM, Andrew Lockley  wrote:

> http://www.bbc.co.uk/news/science-environment-32334528
> 
> By Simon Redfern
> Science writer
> 16 April 2015
> From the section Science & Environment
> 
> Any attempts to engineer the climate are likely to result in "different" 
> climate change, rather than its elimination, new results suggest.
> Prof Ken Caldeira, of Stanford University, presented research at a major 
> conference on the climate risks and impacts of geoengineering.
> These techniques have been hailed by some as a quick fix for climate change.
> But the impacts of geoengineering on oceans, the water cycle and land 
> environments are hotly debated.
> They have been discussed at a meeting this week of 12,000 scientists in 
> Vienna.
> Researchers are familiar with the global cooling effects of volcanic 
> eruptions, seen both historically and even back into the deep past of the 
> rock record.
> With this in mind, some here at the European Geosciences Union General 
> Assembly have been discussing the possible worldwide consequences of pumping 
> sulphate aerosols into the stratosphere to attempt to reflect sunlight back 
> into space and cool the planet.
> Planetary sunshade
> Two hundred years ago this month, the huge volcano Mount Tambora erupted in 
> Indonesia, throwing tonnes of gas and ash into the stratosphere.
> Maybe as much as 100 million tonnes of sulphur dioxide aerosols spread as a 
> blanket around the globe, acting like a planetary sunshade.
> Global temperatures plummeted, and across America and Europe 1816 became 
> known as the year without a summer.
> Such global cooling processes, but managed in a geoengineering solution, have 
> been touted by some as a possible mechanism to extricate the planet from its 
> path towards a warmer future.
> Solar radiation management would use stratospheric sulphate aerosols to dim 
> the Sun. Using a variety of climate models, Ken Caldeira, from the Carnegie 
> Institution for Science in Stanford, California, has investigated the likely 
> consequences of such geoengineering on agriculture across the globe.
> Mount Pinatubo
> Mount Pinatubo pumped 20 million tonnes of sulphur dioxide high into the sky 
> above the Philippines
> His research shows that while dimming could rapidly decrease global 
> temperatures, high CO2 levels would be expected to persist, and it is the 
> balance between temperature, CO2, and sunlight that affects plant growth and 
> agriculture.
> Exploring the regional effects, he finds that a stratospherically dimmed 
> world would show increased plant productivity in the tropics, but lessened 
> plant growth across the northerly latitudes of America, Europe and Asia.
> It is easy to see how there might be geopolitical shifts associated with 
> changes in regional food production across the globe.
> "It's probably the poor tropics that stand to benefit and the rich north that 
> stands to lose," said Prof Caldeira.
> But what if geoengineered sulphate aerosols were, nonetheless, deployed and 
> then a large volcanic eruption like Pinatubo in the Philippines took place? 
> Three such eruptions occurred in the last century so the scenario seems 
> likely.
> Bad timing
> Hannele Korhonen, of the Finnish Meteorological Institute, suggests that the 
> climate impacts could be quite unexpected.
> Her results indicate increased temperatures in the Southern Ocean and in 
> northerly latitudes, as well as the mid-Pacific, but cooling in African and 
> Asian mid-latitudes.
> Regional weather patterns would still change, as they did after Tambora in 
> 1816, with similar widely felt disruption.
> "Deploying solar radiation management methods would lead to a completely new 
> climate state with enhanced greenhouse effect and reduced solar radiation," 
> said Korhonen, adding: "There are great uncertainties, related especially to 
> the regional climate impacts of solar radiation manage