Simone,

Not reading German, I don't know precisely what is in the story.

What I said to the reporter is that if the aerosol layer similar to that of
Mt Pinatubo were sustained, it would produce a cooling of about 3 K.

This is based on estimates of Mt Pinatubo producing around 4 W / m2 of
radiative forcing (cf. Crutzen, 2006?), which is similar to a CO2 doubling
-- and 3 C per CO2 doubling is in the middle of the range of estimates for
climate sensitivity. So, this is just a back-of-envelope calculation.

A question of course, given particle aggregation and so on, is whether such
a layer could be sustained.

Best,

Ken


On Thu, Jun 28, 2012 at 6:37 PM, Simone Tilmes <[email protected]> wrote:

> Dear Ken,
>
> in the article you stated that Mt Pinatubo is assumed to result in a
> global cooling of about 0.5 degree. It is also stated in the text of the
> article that the amount of aerosols emitted, if they would stay in the
> stratosphere for a longer time period, would result in a 3 degrees global
> cooling. Could you point me to the study you are referring to that
> calculates this amount of cooling if injecting volcanic aerosols of the
> amount of Mt Pinatubo?
>
> Cheers, Simone
>
>
>  Ken
>>
>> It should follow from your argument about the land-sea temperature
>> difference reducing precipitation on land that a technique which had the
>> initial effect of cooling the sea would be more attractive.  If it were
>> also possible to have a frequency response shorter than the monsoon
>> cycle we could play useful tricks about the phase of operations relative
>> to the monsoon season.
>>
>> Stephen
>>
>> Emeritus Professor of Engineering Design
>> Institute for Energy Systems
>> School of Engineering
>> Mayfield Road
>> University of Edinburgh EH9  3JL
>> Scotland
>> Tel +44 131 650 5704
>> Mobile 07795 203 195
>> www.see.ed.ac.uk/~shs
>>
>>
>> On 28/06/2012 06:27, Ken Caldeira wrote:
>>
>>> pdf attached.
>>>
>>> http://www.nzz.ch/wissen/**wissenschaft/sonnenschutz-**
>>> fuer-die-erde-1.17282213<http://www.nzz.ch/wissen/wissenschaft/sonnenschutz-fuer-die-erde-1.17282213>
>>>
>>>
>>> _______________
>>> Ken Caldeira
>>>
>>> Carnegie Institution for Science
>>>
>>> Dept of Global Ecology
>>> 260 Panama Street, Stanford, CA 94305 USA
>>> +1 650 704 7212 [email protected]
>>> <mailto:kcaldeira@**carnegiescience.edu <[email protected]>>
>>> http://dge.stanford.edu/labs/**caldeiralab<http://dge.stanford.edu/labs/caldeiralab>@kencaldeira
>>>
>>> *Currently visiting * Institute for Advanced Sustainability Studies
>>> (IASS) <http://www.iass-potsdam.de/>
>>> *and *Potsdam Institute for Climate Impact Research (PIK)
>>> <http://www.pik-potsdam.de/>***in Potsdam, Germany.*
>>>
>>>
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