scholarly journals Lifting options for stratospheric aerosol geoengineering: advantages of tethered balloon systems

2012 ◽  
Vol 370 (1974) ◽  
pp. 4263-4300 ◽  
Author(s):  
Peter Davidson ◽  
Chris Burgoyne ◽  
Hugh Hunt ◽  
Matt Causier
Keyword(s):  
Atmospheric Chemistry ◽  
Scale Up ◽  
High Refractive Index ◽  
Stratospheric Aerosol ◽  
Climatic Conditions ◽  
Solar Radiation Management ◽  
Tethered Balloon ◽  
Capital Costs ◽  
Delivery Options ◽  
Radiation Management

The Royal Society report ‘Geoengineering the Climate’ identified solar radiation management using albedo-enhancing aerosols injected into the stratosphere as the most affordable and effective option for geoengineering, but did not consider in any detail the options for delivery. This paper provides outline engineering analyses of the options, both for batch-delivery processes, following up on previous work for artillery shells, missiles, aircraft and free-flying balloons, as well as a more lengthy analysis of continuous-delivery systems that require a pipe connected to the ground and supported at a height of 20 km, either by a tower or by a tethered balloon. Towers are shown not to be practical, but a tethered balloon delivery system, with high-pressure pumping, appears to have much lower operating and capital costs than all other delivery options. Instead of transporting sulphuric acid mist precursors, such a system could also be used to transport slurries of high refractive index particles such as coated titanium dioxide. The use of such particles would allow useful experiments on opacity, coagulation and atmospheric chemistry at modest rates so as not to perturb regional or global climatic conditions, thus reducing scale-up risks. Criteria for particle choice are discussed, including the need to minimize or prevent ozone destruction. The paper estimates the time scales and relatively modest costs required if a tethered balloon system were to be introduced in a measured way with testing and development work proceeding over three decades, rather than in an emergency. The manufacture of a tether capable of sustaining the high tensions and internal pressures needed, as well as strong winds, is a significant challenge, as is the development of the necessary pumping and dispersion technologies. The greatest challenge may be the manufacture and launch of very large balloons, but means have been identified to significantly reduce the size of such balloons or aerostats.

scholarly journals Methods for Dispersal of Precipitated Calcium Carbonate for Stratospheric Aerosol Injection

2021 ◽  
Author(s):  
Armand Neukermans ◽  
Gary Cooper ◽  
Jack Foster ◽  
Lee Galbraith ◽  
Sudhanshu Jain
Keyword(s):  
Calcium Carbonate ◽  
Bulk Material ◽  
Scale Up ◽  
Stratospheric Aerosol ◽  
Complete Separation ◽  
Particle Mass ◽  
Solar Radiation Management ◽  
Precipitated Calcium Carbonate ◽  
Radiation Management ◽  
Stratospheric Aerosol Injection

AbstractTwo methods for the laboratory-scale formation of aerosols of nanosized particles of precipitated calcium carbonate (PCC), for potential use in Stratospheric Aerosol Injection (SAI), a Solar Radiation Management (SRM) technique, are described. The first uses the coarse fluidization of bulk PCC in a simple vessel, followed by dispersal using a commercially available two-fluid nozzle. The manufacturer’s measured particle mass distribution for the bulk material, and sprayed aerosol particle mass distributions are compared, indicating that the sprayed particles are well separated in spite of a notoriously problematic agglomeration tendency. The method is suitable for scale-up. A second dispersal method, useful for small laboratory experiments, using liquid carbon dioxide as a dispersant as well as spray propellant gave similar results. The mass mode diameters measured here (0.89 to 1.4 μm) differ from that stated by the manufacturer (0.7 μm), but the distributions are consistent in showing complete separation of the particles.

scholarly journals Africa's Climate Response to Solar Radiation Management With Stratospheric Aerosol

2020 ◽  
Vol 47 (2) ◽  
Author(s):  
Izidine Pinto ◽  
Christopher Jack ◽  
Christopher Lennard ◽  
Simone Tilmes ◽  
Romaric C. Odoulami
Keyword(s):  
Solar Radiation ◽  
Stratospheric Aerosol ◽  
Solar Radiation Management ◽  
Climate Response ◽  
Radiation Management

scholarly journals Stratospheric controlled perturbation experiment: a small-scale experiment to improve understanding of the risks of solar geoengineering

2014 ◽  
Vol 372 (2031) ◽  
pp. 20140059 ◽  
Author(s):  
John A. Dykema ◽  
David W. Keith ◽  
James G. Anderson ◽  
Debra Weisenstein
Keyword(s):  
Risk Assessment ◽  
Large Scale ◽  
Current Knowledge ◽  
Stratospheric Ozone ◽  
Full Range ◽  
Stratospheric Aerosol ◽  
Small Scale ◽  
Solar Radiation Management ◽  
Perturbation Experiment ◽  
Radiation Management

Although solar radiation management (SRM) through stratospheric aerosol methods has the potential to mitigate impacts of climate change, our current knowledge of stratospheric processes suggests that these methods may entail significant risks. In addition to the risks associated with current knowledge, the possibility of ‘unknown unknowns’ exists that could significantly alter the risk assessment relative to our current understanding. While laboratory experimentation can improve the current state of knowledge and atmospheric models can assess large-scale climate response, they cannot capture possible unknown chemistry or represent the full range of interactive atmospheric chemical physics. Small-scale, in situ experimentation under well-regulated circumstances can begin to remove some of these uncertainties. This experiment—provisionally titled the stratospheric controlled perturbation experiment—is under development and will only proceed with transparent and predominantly governmental funding and independent risk assessment. We describe the scientific and technical foundation for performing, under external oversight, small-scale experiments to quantify the risks posed by SRM to activation of halogen species and subsequent erosion of stratospheric ozone. The paper's scope includes selection of the measurement platform, relevant aspects of stratospheric meteorology, operational considerations and instrument design and engineering.

scholarly journals Radiative and climate impacts of a large volcanic eruption during stratospheric sulfur geoengineering

2015 ◽  
Vol 15 (15) ◽  
pp. 21837-21881 ◽  
Author(s):  
A. Laakso ◽  
H. Kokkola ◽  
A.-I. Partanen ◽  
U. Niemeier ◽  
C. Timmreck ◽  
...  
Keyword(s):  
Volcanic Eruption ◽  
Climate Model ◽  
Regional Climate ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Climate Impacts ◽  
Solar Radiation Management ◽  
Atmospheric Conditions ◽  
Concurrent Case ◽  
Radiation Management

Abstract. Both explosive volcanic eruptions, which emit sulfur dioxide into the stratosphere, and stratospheric geoengineering via sulfur injections can potentially cool the climate by increasing the amount of scattering particles in the atmosphere. Here we employ a global aerosol-climate model and an earth system model to study the radiative and climate impacts of an erupting volcano during solar radiation management (SRM). According to our simulations, the radiative impacts of an eruption and SRM are not additive: in the simulated case of concurrent eruption and SRM, the peak increase in global forcing is about 40 % lower compared to a corresponding eruption into a clean background atmosphere. In addition, the recovery of the stratospheric sulfate burden and forcing was significantly faster in the concurrent case since the sulfate particles grew larger and thus sedimented faster from the stratosphere. In our simulation where we assumed that SRM would be stopped immediately after a volcano eruption, stopping SRM decreased the overall stratospheric aerosol load. For the same reasons, a volcanic eruption during SRM lead to only about 1/3 of the peak global ensemble-mean cooling compared to an eruption under unperturbed atmospheric conditions. Furthermore, the global cooling signal was seen only for 12 months after the eruption in the former scenario compared to over 40 months in the latter. In terms of the global precipitation rate, we obtain a 36 % smaller decrease in the first year after the eruption and again a clearly faster recovery in the concurrent eruption and SRM scenario. We also found that an explosive eruption could lead to significantly different regional climate responses depending on whether it takes place during geoengineering or into an unperturbed background atmosphere. Our results imply that observations from previous large eruptions, such as Mt Pinatubo in 1991, are not directly applicable when estimating the potential consequences of a volcanic eruption during stratospheric geoengineering.

scholarly journals Heterogeneous reaction of N<sub>2</sub>O<sub>5</sub> with airborne TiO<sub>2</sub> particles and its implication for stratospheric particle injection

2014 ◽  
Vol 14 (4) ◽  
pp. 4421-4456 ◽  
Author(s):  
M. J. Tang ◽  
P. J. Telford ◽  
F. D. Pope ◽  
L. Rkiouak ◽  
N. L. Abraham ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Climate Model ◽  
Heterogeneous Reaction ◽  
High Refractive Index ◽  
Heterogeneous Reactions ◽  
Solar Radiation Management ◽  
Particle Injection ◽  
Stratospheric Chemistry ◽  
Radiation Management ◽  
The Impact

Abstract. Injection of aerosol particles (or their precursors) into the stratosphere to scatter solar radiation back into space, has been suggested as a solar-radiation management scheme for the mitigation of global warming. TiO2 has recently been highlighted as a possible candidate particle because of its high refractive index, but its impact on stratospheric chemistry via heterogeneous reactions is as yet unknown. In this work the heterogeneous reaction of airborne sub-micrometre TiO2 particles with N2O5 has been investigated for the first time, at room temperature and different relative humidities (RH), using an atmospheric pressure aerosol flow tube. The uptake coefficient of N2O5 onto TiO2, γ(N2O5), was determined to be ∼ 1.0 × 10−3 at low RH, increasing to ∼ 3 × 10−3 at 60% RH. The uptake of N2O5 onto TiO2 is then included in the UKCA chemistry climate model to assess the impact of this reaction on stratospheric chemistry. While the impact of TiO2 on the scattering of solar radiation is chosen to be similar to the aerosol from the Mt. Pinatubo eruption, the impact of TiO2 injection on stratospheric N2O5 is much smaller.

scholarly journals What is the limit of stratospheric sulfur climate engineering?

2015 ◽  
Vol 15 (7) ◽  
pp. 10939-10969 ◽  
Author(s):  
U. Niemeier ◽  
C. Timmreck
Keyword(s):  
Sulfur Dioxide ◽  
Solar Radiation ◽  
Radiative Forcing ◽  
Stratospheric Aerosol ◽  
Solar Radiation Management ◽  
Aerosol Layer ◽  
Aerosol Model ◽  
Model Studies ◽  
Radiation Management ◽  
Business As Usual

Abstract. The injection of sulfur dioxide (SO2) into the stratosphere to form an artificial stratospheric aerosol layer is considered as an option for solar radiation management. The related reduction in radiative forcing depends upon the amount injected of sulfur dioxide but aerosol model studies indicate a decrease in forcing efficiency with increasing injection magnitude. None of these studies, however, consider injection strengths greater than 10 Tg(S) yr-1. This would be necessary to counteract the strong anthropogenic forcing expected if "business as usual" emission conditions continue throughout this century. To understand the effects of the injection of larger amounts of SO2 we have calculated the effects of SO2 injections up to 100 Tg(S) yr-1. We estimate the reliability of our results through consideration of various injection strategies, and from comparison with results obtained from other models. Our calculations show that the efficiency of the aerosol layer, expressed as the relationship between sulfate aerosol forcing and injection strength, decays exponentially. This result implies that the solar radiation management strategy required to keep temperatures constant at that anticipated for 2020, whilst maintaining "business as usual" conditions, would require atmospheric injections of the order of 45 Tg(S) yr-1 which amounts to 6 times that emitted from of the Mt. Pinatubo eruption each year.

scholarly journals Heterogeneous reaction of N<sub>2</sub>O<sub>5</sub> with airborne TiO<sub>2</sub> particles and its implication for stratospheric particle injection

2014 ◽  
Vol 14 (12) ◽  
pp. 6035-6048 ◽  
Author(s):  
M. J. Tang ◽  
P. J. Telford ◽  
F. D. Pope ◽  
L. Rkiouak ◽  
N. L. Abraham ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Climate Model ◽  
Heterogeneous Reaction ◽  
High Refractive Index ◽  
Heterogeneous Reactions ◽  
Solar Radiation Management ◽  
Particle Injection ◽  
Stratospheric Chemistry ◽  
Radiation Management ◽  
The Impact

Abstract. Injection of aerosol particles (or their precursors) into the stratosphere to scatter solar radiation back into space has been suggested as a solar-radiation management scheme for the mitigation of global warming. TiO2 has recently been highlighted as a possible candidate particle because of its high refractive index, but its impact on stratospheric chemistry via heterogeneous reactions is as yet unknown. In this work the heterogeneous reaction of airborne sub-micrometre TiO2 particles with N2O5 has been investigated for the first time, at room temperature and different relative humidities (RH), using an atmospheric pressure aerosol flow tube. The uptake coefficient of N2O5 onto TiO2, γ(N2O5), was determined to be ~1.0 × 10−3 at low RH, increasing to ~3 × 10−3 at 60% RH. The uptake of N2O5 onto TiO2 is then included in the UKCA chemistry–climate model to assess the impact of this reaction on stratospheric chemistry. While the impact of TiO2 on the scattering of solar radiation is chosen to be similar to the aerosol from the Mt Pinatubo eruption, the impact of TiO2 injection on stratospheric N2O5 is much smaller.

Governing the Sun

2019 ◽  
Vol 9 (2) ◽  
pp. 19-34
Author(s):  
Klaus Radunsky ◽  
Tim Cadman
Keyword(s):  
Carbon Dioxide ◽  
Carbon Capture ◽  
Emerging Technologies ◽  
Carbon Capture And Storage ◽  
Stratospheric Aerosol ◽  
Solar Radiation Management ◽  
Mitigation And Adaptation ◽  
Governance Systems ◽  
Solar Geoengineering ◽  
Radiation Management

Governments have previously sought to reduce climate-change-inducing concentrations of carbon dioxide in the earth’s atmosphere through mitigation and adaptation activities, with limited success. New approaches are being explored, such as negative emissions technologies, including carbon dioxide removal, as well as solar geoengineering, also known as solar radiation management, or modification. This article outlines these emerging technologies focusing on bioenergy, carbon capture and storage, and stratospheric aerosol injection, and explores some of the challenges they pose. Prevention of emissions and their reliable, safe, and environmentally benign removal remain the best options. Robust governance systems and a careful, unbiased, and knowledge-driven assessment of the risks of these emerging technologies are required before they are implemented any further.

Stratospheric aerosol particles and solar-radiation management

2012 ◽  
Vol 2 (10) ◽  
pp. 713-719 ◽  
Author(s):  
F. D. Pope ◽  
P. Braesicke ◽  
R. G. Grainger ◽  
M. Kalberer ◽  
I. M. Watson ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Aerosol Particles ◽  
Stratospheric Aerosol ◽  
Solar Radiation Management ◽  
Radiation Management

State Responsibility for Environmental Harm from Climate Engineering

Climate Law ◽  
2015 ◽  
Vol 5 (2-4) ◽  
pp. 142-181 ◽  
Author(s):  
David Reichwein ◽  
Anna-Maria Hubert ◽  
Peter J. Irvine ◽  
Francois Benduhn ◽  
Mark G. Lawrence
Keyword(s):  
Large Scale ◽  
Stratospheric Aerosol ◽  
Legal Responsibility ◽  
Environmental Harm ◽  
Solar Radiation Management ◽  
State Responsibility ◽  
Climate Engineering ◽  
Trade Offs ◽  
Increased Risk ◽  
Radiation Management

Some have proposed that climate-engineering methods could be developed to offset climate change. However, whilst some of these methods, in particular a form of solar-radiation management referred to as stratospheric aerosol injection (sai), could potentially reduce the overall degree of global warming as well as some associated risks, they are also likely to redistribute some environmental risks globally. Moreover, they could give rise to new risks, raising the issue of legal responsibility for transboundary harm caused. This article examines the question of international accountability of states for an increased risk of environmental harm arising from a large-scale climate intervention using sai, and the legal consequences that would follow. Examination of the applicability of customary rules on state responsibility to sai are useful for understanding the limitations of the existing accountability framework for climate engineering, particularly in the context of global environmental problems involving risk-risk trade-offs and large uncertainties.

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