Regional geoengineering using tiny glass bubbles would accelerate the loss of Arctic sea ice
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Alan Robock ☮
Oct 8, 2022, 9:51:11 AM10/8/22
to Geoengineering
Webster, M. A., & Warren, S. G. (2022). Regional geoengineering
using tiny glass bubbles would accelerate the loss of Arctic sea
ice. Earth's Future, 10, e2022EF002815.
https://doi.org/10.1029/2022EF002815
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022EF002815
Abstract
Arctic sea ice might be preserved if its albedo could be increased. To this end, it has been proposed to spread hollow glass microspheres (HGMs) over the ice. We assess the radiative forcing (RF) that would result, by considering the areal coverages and spectral albedos of eight representative surface types, as well as the incident solar radiation, cloud properties, and spectral radiative properties of HGMs.
HGMs can raise the albedo of new ice, but new ice occurs in autumn and winter when there is little sunlight. In spring the ice is covered by high-albedo, thick snow. In summer the sunlight is intense, and the snow melts, so a substantial area is covered by dark ponds of meltwater, which could be an attractive target for attempted brightening. However, prior studies show that wind blows HGMs to the pond edges.
A thin layer of HGMs has about 10% absorptance for solar radiation, so HGMs would darken any surfaces with albedo >0.61, such as snow-covered ice. The net result is the opposite of what was intended: spreading HGMs would warm the Arctic climate and speed sea-ice loss.
If non-absorbing HGMs could be manufactured, and if they could be transported and distributed without contamination by dark substances, they could cool the climate. The maximum benefit would be achieved by distribution during the month of May, resulting in an annual average RF for the Arctic Ocean of -3 Wm-2 if 360 megatons of HGMs were spread onto the ice annually.
Abstract
Arctic sea ice might be preserved if its albedo could be increased. To this end, it has been proposed to spread hollow glass microspheres (HGMs) over the ice. We assess the radiative forcing (RF) that would result, by considering the areal coverages and spectral albedos of eight representative surface types, as well as the incident solar radiation, cloud properties, and spectral radiative properties of HGMs.
HGMs can raise the albedo of new ice, but new ice occurs in autumn and winter when there is little sunlight. In spring the ice is covered by high-albedo, thick snow. In summer the sunlight is intense, and the snow melts, so a substantial area is covered by dark ponds of meltwater, which could be an attractive target for attempted brightening. However, prior studies show that wind blows HGMs to the pond edges.
A thin layer of HGMs has about 10% absorptance for solar radiation, so HGMs would darken any surfaces with albedo >0.61, such as snow-covered ice. The net result is the opposite of what was intended: spreading HGMs would warm the Arctic climate and speed sea-ice loss.
If non-absorbing HGMs could be manufactured, and if they could be transported and distributed without contamination by dark substances, they could cool the climate. The maximum benefit would be achieved by distribution during the month of May, resulting in an annual average RF for the Arctic Ocean of -3 Wm-2 if 360 megatons of HGMs were spread onto the ice annually.
Russell Seitz
Oct 8, 2022, 4:55:07 PM10/8/22
to geoengineering
"If non-absorbing HGMs could be manufactured, and if they could be transported and distributed without contamination by dark substances, they could cool the climate. "
I agree, especially since in contrast to the floating glass microspheres Webster and Warren reject, the solar radiation absorbance of the air in microscopic bubbles is roughly four orders of magnitude smaller than that of glass.
Jessica Gurevitch
Oct 8, 2022, 8:21:04 PM10/8/22
to russel...@gmail.com, geoengineering
This sort of thing sounds like it could potentially be a real danger to Arctic organisms. Anything they might consume could kill animals or have other effects in disrupting ecosystems. One would need to be very careful and have a lot of information about its potential effects on living systems before thinking about implementing or even field testing anything of this type.
Sent from my iPhone
On Oct 8, 2022, at 4:55 PM, Russell Seitz <russel...@gmail.com> wrote:
"If non-absorbing HGMs could be manufactured, and if they could be transported and distributed without contamination by dark substances, they could cool the climate. "
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Russell Seitz
Oct 9, 2022, 1:54:42 AM10/9/22
to geoengineering
Jessica, you err in eliding my 'Bright Water ' paper in Climatic Change with using HGM's to reflect sunlight- air bubbles don't need glass envelopes to provide Mie scattering. can do can do here is what I wrote Webster & Warren on October 6
"As I quite agree with your conclusion : "If a method could be devised to manufacture completely non-absorbing HGMs, and if they could be transported and distributed over the Arctic without contamination, they would be able to cool the climate. "
May I beg to point out that hydrosol generation,as proposed in my Climatic Change article fulfills that criterion, because the air in microbubbles absorbs roughly six orders of magnitude less solar energy out to the water cutoff than industrial glass.
Microbubbles are nothing more or less than than the H without the GM.
Sea brightening to mitigate global warming was first proposed by Roger Revelle and Wally Broecker in a 1965 White House report ( excerpt attached) , but the economic attraction of using white pigments — Mie theory delivers a lot of albedo for very little mass, pales in comparison to their environmental downside- white acrylic paint is a microplastic nightmare.
Which is why I never proposed using particles of any sort to improve sea surface albedo. The Bright Water paper explains why it is not necessary to do so, and I hope that if you read it you will understand why I am dismayed by your elision of my work and the frankly idiotic Ice 911 project. "
hak...@encs.concordia.ca
Oct 9, 2022, 2:05:14 AM10/9/22
to Russell Seitz, geoengineering
I am not sure I understand this.
Are you saying solar absorptance of the air in the microscopic bubbles
are less than 0.0001?
Hashem
Quoting Russell Seitz <russel...@gmail.com>:
> "If non-absorbing HGMs could be manufactured, and if they could be
> transported and distributed without contamination by dark substances, they
> could cool the climate. "
>
> I agree, especially since in contrast to the floating glass microspheres
> Webster and Warren reject, the solar radiation absorbance of the air in
> microscopic bubbles is roughly four orders of magnitude smaller than that
> of glass.
> On Saturday, October 8, 2022 at 9:51:11 AM UTC-4 Alan Robock wrote:
>
>> Webster, M. A., & Warren, S. G. (2022). Regional geoengineering using tiny
>> glass bubbles would accelerate the loss of Arctic sea ice. *Earth's
>> Future*, 10, e2022EF002815. https://doi.org/10.1029/2022EF002815
>>
>> https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022EF002815
>>
>> *Abstract*
Are you saying solar absorptance of the air in the microscopic bubbles
are less than 0.0001?
Hashem
Quoting Russell Seitz <russel...@gmail.com>:
> "If non-absorbing HGMs could be manufactured, and if they could be
> transported and distributed without contamination by dark substances, they
> could cool the climate. "
>
> I agree, especially since in contrast to the floating glass microspheres
> Webster and Warren reject, the solar radiation absorbance of the air in
> microscopic bubbles is roughly four orders of magnitude smaller than that
> of glass.
> On Saturday, October 8, 2022 at 9:51:11 AM UTC-4 Alan Robock wrote:
>
>> Webster, M. A., & Warren, S. G. (2022). Regional geoengineering using tiny
>> Future*, 10, e2022EF002815. https://doi.org/10.1029/2022EF002815
>>
>> https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022EF002815
>>
>> *Abstract*
>> Arctic sea ice might be preserved if its albedo could be increased.
>> To this end, it has been proposed to spread hollow glass microspheres
>> (HGMs) over the ice. We assess the radiative forcing (RF) that would
>> result, by considering the areal coverages and spectral albedos of eight
>> representative surface types, as well as the incident solar radiation,
>> cloud properties, and spectral radiative properties of HGMs.
>> HGMs can raise the albedo of new ice, but new ice occurs in autumn
>> and winter when there is little sunlight. In spring the ice is covered by
>> high-albedo, thick snow. In summer the sunlight is intense, and the snow
>> melts, so a substantial area is covered by dark ponds of meltwater, which
>> could be an attractive target for attempted brightening. However, prior
>> studies show that wind blows HGMs to the pond edges.
>> A thin layer of HGMs has about 10% absorptance for solar radiation,
>> so HGMs would darken any surfaces with albedo >0.61, such as snow-covered
>> ice. The net result is the opposite of what was intended: spreading HGMs
>> would warm the Arctic climate and speed sea-ice loss.
>> If non-absorbing HGMs could be manufactured, and if they could be
>> transported and distributed without contamination by dark substances, they
>> could cool the climate. The maximum benefit would be achieved by
>> distribution during the month of May, resulting in an annual average RF for
>> the Arctic Ocean of -3 Wm-2 if 360 megatons of HGMs were spread onto the
>> ice annually.
>>
>>
>
>> To this end, it has been proposed to spread hollow glass microspheres
>> (HGMs) over the ice. We assess the radiative forcing (RF) that would
>> result, by considering the areal coverages and spectral albedos of eight
>> representative surface types, as well as the incident solar radiation,
>> cloud properties, and spectral radiative properties of HGMs.
>> HGMs can raise the albedo of new ice, but new ice occurs in autumn
>> and winter when there is little sunlight. In spring the ice is covered by
>> high-albedo, thick snow. In summer the sunlight is intense, and the snow
>> melts, so a substantial area is covered by dark ponds of meltwater, which
>> could be an attractive target for attempted brightening. However, prior
>> studies show that wind blows HGMs to the pond edges.
>> A thin layer of HGMs has about 10% absorptance for solar radiation,
>> so HGMs would darken any surfaces with albedo >0.61, such as snow-covered
>> ice. The net result is the opposite of what was intended: spreading HGMs
>> would warm the Arctic climate and speed sea-ice loss.
>> If non-absorbing HGMs could be manufactured, and if they could be
>> transported and distributed without contamination by dark substances, they
>> could cool the climate. The maximum benefit would be achieved by
>> distribution during the month of May, resulting in an annual average RF for
>> the Arctic Ocean of -3 Wm-2 if 360 megatons of HGMs were spread onto the
>> ice annually.
>>
>>
>
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