Tropospheric Sulfur Emission Geoengineering. A Conjecture.

By Oscar A. Escobar

Florida, USA – Gt. January 21, 2016

CC BY-NC 4.0
Last Updated 1/27/2016

Most of the studies available to the public about sulfur injection as a method of SRM climate geoengineering focus on the stratosphere.  But a large gap in public information, if not knowledge, exist in regards to the possibility of tropospheric sulfur injection (or emission, rather) as a method for climate engineering; even though the concept has been expressed, as the following book excerpt states:^[1]

Geoengineering: Sulfur as Savior?

A tone of desperation is palpable in climate-change science when well-known people seriously propose that filling the stratosphere with sulfur dioxide may be the only way to stop run-away greenhouse warming. Do we really want to pump the stratosphere full of sulfur to shroud the surface from warmth, then live in a perpetual acid mist? Paul J. Crutzen of the Max Planck Institute for Chemistry in Germany, who won a Nobel Prize in 1995 for showing how industrial gases damage the Earth's ozone shield, advanced the idea anew in 2006, citing the "grossly disappointing international political response" to increasing evidence of global warming (Kerr 2006d, 401).

"We should treat these ideas like any other research and get into the mind-set of taking them seriously," said Ralph J. Cicerone, president of the National Academy of Sciences (Broad 2006). Most of these proposals involve geoengineering, large-scale rearranging of the Earth's environment to suit human needs. This idea "should not be taken as a license to go out and pollute," Cicerone said, emphasizing that most scientists believe that reducing greenhouse gases in the atmosphere should be the top priority. He added, however, that "Pin my opinion, he [Crutzen] has written a brilliant paper" (Broad 2006). Wallace S. Broecker, a geoengineering pioneer at Columbia University, also has proposed spreading tons of sulfur dioxide into the stratosphere, as erupting volcanoes occasionally do. The injections, he calculated in the 1980s, would require a fleet of hundreds of jumbo jets and, as a by-product, would increase acid rain (Broad 2006).

In a draft of his paper, Crutzen estimated the annual cost of his sulfur proposal at up to $50 billion, or about 5 percent of the world's annual military spending. "Climatic engineering, such as presented here, is the only option available to rapidly reduce temperature rises" if international efforts fail to curb greenhouse gases, Crutzen wrote. "So far," he added, "there is little reason to be optimistic" (Broad 2006). Supporters of this idea contend that any increase in sulfur at the Earth's surface would be small compared with the tons already being emitted from the smokestacks of coal-fueled plants (Broad 2006). Another proposed solution along the same lines involves the burning of sulfur in ships and power plants to form sulfate aerosols.

The possibility of this type of tropospheric geoengineering “unintended” or otherwise, has also been raised most recently by Oliver Morton in his book The Planet Remade: How Geoengineering Could Change the World:^[2]

But some of the mid-ocean sulphur comes from ships, and thus so does some planetary cooling. It has been calculated that the new emission standards the IMO is bringing into force this decade will reduce the cooling effects of global pollution by something like a third of a watt per square metre – a considerably greater effect, models would suggest, than that of all the carbon dioxide emitted by every generator and engine in the world over the same ten years. Those new standards will also, according to a companion analysis, save something in the region of 40,000 lives a year, because what is emitted over the mid-oceans does not stay over the mid-oceans; it is blown to shore, where it increases the damage done by pollution to susceptible lungs.

Do I think it realistic to imagine that the IMO might, as the result of a far-reaching envelope-stretching boundary-breaking debate, have come to a Crutzen-like grand bargain in which it sought to make good the cooling it was taking away by implementing a replacement brightening? Not really; but it remains striking – no, shocking – that as far as I can ascertain no one even mentioned the matter, even though the IMO’s own technical advisers used the term ‘geoengineering’ in some of their analyses. Conversations have to start somewhere, and that would have been a good place to start one.

An even more recent, presentation by Chuck Long from the US National Oceanic and Atmospheric Administration NOAA,  at the 2015 fall meeting of the American Geophysical Union AGU, titled “A23K-04: Evidence of Clear-Sky Daylight Whitening: Are we already conducting geoengineering?”.^[3] The presentation focused on the direct and indirect effects of aviation aerosols seems, in my view, to strengthen the concept of “Tropospheric Sulfur Injection as (unintended) geoengineering”. The presentation abstract reads:

Long et al. (2009, JGR 114) analyzed surface radiation data spanning 1995 through 2007 from several ARM and six SURFRAD sites across the continental US, and showed an average 8 Wm-2/decade brightening in all-sky downwelling SW. The study also showed a 5 Wm-2/decade increase in the clear-sky downwelling SW, an expected result of decreasing aerosol optical depths during the same time period (Augustine et al., 2008, JGR 113). However, the unexpected result of the Long et al. study is that the 5 Wm-2/decade increase occurred in the diffuse SW, while the direct SW remained virtually unchanged...opposite what is expected for aerosol direct effect due to decreases in aerosols. With detailed radiative transfer modeling and correlation with US FAA commercial flight hours through the same years, Long et al. suggested that while the decreased aerosols did increase the total SW, an increase in high, sub-visual contrail-generated ice haze repartitioned the increase into the diffuse SW component through large-mode particle scattering.

Subsequent attempts to investigate the veracity of this speculation using long time series of ARM Micropulse and Raman lidars data proved untenable due to instrument limitations and continuity issues. However, similar to using the red/blue ratio of pixel color amounts in processing color sky images to infer clouds, we have used clear-sky diffuse SW irradiance measurements from the Multi-Frequency Rotating Shadowband Radiometer (MFRSR) 870, 500, and 415 nm spectral channels to look at any possible trends suggesting "whitening" of the cloud-free skies over the ARM SGP site. We will present our preliminary findings to date of these investigations suggesting indeed that there has been an aggregate "whitening" of the sky conditions we typically consider to be "cloud free."

Augustine, J.A., G.B.Hodges, E.G.Dutton, J.J. Michalsky, and C.R.Cornwall (2008), An aerosol optical depth climatology for NOAA’s national surface radiation budget network (SURFRAD), J. Geophys. Res., 113, D11204, doi:10.1029/2007JD009504.

Long, C. N., E. G. Dutton, J. A. Augustine, W. Wiscombe, M. Wild, S. A. McFarlane, and C. J. Flynn (2009): Significant Decadal Brightening of Downwelling Shortwave in the Continental US, JGR, 114, D00D06, doi:10.1029/2008JD011263.

This presentation garnered what seems to be very limited press coverage,^[4] and virtually nonexistent reaction from civil society and environmental activists. Strange… given the controversial and pugnacious nature of the various debates surrounding the topic of geoengineering, particularly when it refers to climate justice, environmental concerns and moral hazard issues.

A short online debate has been documented in the ‘Geoengineering Google Group’,^[5] mostly centering on the definition of geoengineering, and whether or not the known effects of human industrial emissions could represent geoengineering. Chuck long is quoted:^[6]

“Chuck Long, from the US National Oceanic and Atmospheric Administration (Noaa), said that if his thinking was correct then what was occurring was an example of "accidental geoengineering".

"If you look up the definition of geoengineering, it includes large-scale manipulation of parts of the climate system or the environment, and I believe this ice haze from jet traffic does satisfy that requirement," he told reporters.”

On January 19, 2016, Slate magazine in partnership with New America, and Arizona State University on emerging technologies, public policy, and society; conducted a short online forum titled “These 2 Experts Will Answer Your Burning Geoengineering Questions”.^[7]  The two experts were Jeff Goodell a “contributing editor at Rolling Stone, a fellow at New America, and the author of How to Cool the Planet: Geoengineering and the Audacious Quest to Fix Earth’s Climate.” And “Raymond T. Pierrehumbert, who is the Halley professor of physics at the University of Oxford and has called geoengineering “barking mad.””

Here is the question I submitted and the answer by Raymond T. Pierrehumbert:

Question: How is the geoengineering debate impacted, in terms of climate justice, environment, moral hazard and research, by the following two facts? 1) A recent presentation by Chuck Long at the American Geophysical Union fall meeting argues that aviation emissions has been responsible for a form of ongoing SRM "accidental geoengineering." 2) Current anthropogenic annual sulfur emission are higher than five times the sulfur emitted by Mt. Pinatubo in 1991, and are currently emitted mostly in the Northern Hemisphere, with 98 vs. 6 Tg S year.

Pierrehumbert: This isn’t “geoengineering.” These sort of effects are no different from other inadvertent things we do that affect the climate, including both greenhouse gas emissions, and emissions of sulfate pollution that form reflecting droplets in the atmosphere (aerosols). These are by-products of things we want to do (like fly, burn coal, etc.). Geoengineering, (or better “climate intervention”) is reserved for the case where the climate effect is not an inadvertent by-product, but rather the aim itself. By the way, sulfur dioxide injection is what’s proposed for albedo hacking that is done in the stratosphere, but the amount you’d need to inject over the ocean surface to cause a significant cloud change there makes even the geoengineering boosters blanche. For that reason, the proposals for low-level cloud modification generally involve sea-salt rather than sulfur dioxide. Still a bad idea, but we have to keep the actual scientific facts straight.

Speaking of blanching… I had included this reference to the “98 vs. 6 Tg S year” figures in my question, but it was omitted from the published version:

Approaches to Observe Anthropogenic Aerosol-Cloud Interactions, Johannes Quaas, 2015.^[8]

Although Mr. Pierrehumbert’s answer is very interesting. It does not resonate with me particularly because his statement “By the way, sulfur dioxide injection is what’s proposed for albedo hacking that is done in the stratosphere” may not be entirely accurate, as I have documented. But to the question of whether we are geoengineering or not, the best answer I have seen so far is the following:

“The question about geoengineering was interesting to me, because in some ways none of us would be here if in fact we weren’t already geoengineering this planet, that is the whole reason we are worried about it. The fact that we may have not intended to do it, the fact that we didn’t think about it rationally, ethically, nor was it part of our design; that is relatively immaterial from the point of view of the systems involved in the planet. It’s a geoengineered planet.”^[9]  Brad R. Allenby

Coming back to the original title of this article, “Tropospheric Sulfur Emission Geoengineering. A Conjecture”, I think that it would be helpful to investigate what proper scientific proposals of that sort may look like.  I imagine some may not be too different from what “we” are currently doing trough global aviation and shipping emissions. But that may also bring some very uncomfortable epiphanies.  No doubt a strong reason for some to continue to prefer barking mad ignorance.

And just in case… do I think deploying climate geoengineering is a good idea, and the only way to sustainable growth? No, particularly because I believe there are economic and energy alternatives to the fossil fuel economy that do not include ‘degrowth’!

But nevertheless one of the safest ways to know is… knowledge trough research.

Update:

A free acces model study about tropospheric ("In the set of model experiments considered here, we directly inject sulfate aerosols at a single model level at 12.1 km") emissions as geoengineering. Follow the link for the full study in pdf:

Could aerosol emissions be used for regional heat wave mitigation?http://www.atmos-chem-phys.net/13/6373/2013/acp-13-6373-2013.pdf

D. N. Bernstein1,2, J. D. Neelin2, Q. B. Li2, and D. Chen21Department of Soil and Water Sciences, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 76100, Israel
2Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, 405 Hilgard Ave., Los Angeles, CA 90095, USAdoi:10.5194/acp-13-6373-2013Abstract. Geoengineering applications by injection of sulfate aerosols into the stratosphere are under consideration as a measure of last resort to counter global warming. Here a potential regional-scale application to offset the impacts of heat waves is critically examined. Using the Weather Research and Forecasting model with fully coupled chemistry (WRF-Chem), the effect of regional-scale sulfate aerosol emission over California in each of two days of the July 2006 heat wave is used to quantify potential reductions in surface temperature as a function of emission rates in a layer at 12 km altitude. Local meteorological factors yield geographical differences in surface air temperature sensitivity. For emission rates of approximately 30 μg m−2 s−1 of sulfate aerosols (with standard WRF-Chem size distribution) over the region, temperature decreases of around 7 °C result during the middle part of the day over the Central Valley, one of the areas hardest hit by the heat wave. Regions more ventilated with oceanic air such as Los Angeles have slightly smaller reductions. The length of the hottest part of the day is also reduced. Advection effects on the aerosol cloud must be more carefully forecast for smaller injection regions. Verification of the impacts could be done via measurements of differences in reflected and surface downward shortwave. Such regional geoengineering applications with specific near-term target effects but smaller cost and side effects could potentially provide a means of testing larger scale applications. However, design considerations for regional applications, such as a preference for injection at a level of relatively low wind speed, differ from those for global applications. The size of the required injections and the necessity of injection close to the target region raise substantial concerns. The evaluation of this regional-scale application is thus consistent with global model evaluations, emphasizing that mitigation via reduction of fossil fuels remains preferable to considering geoengineering with sulfate aerosols.

[1] Johansen, Bruce E., (2009-11-03) The Encyclopedia of Global Warming Science and Technology (Pg 270-271), Greenwood.

[2] Morton, Oliver (2015-11-03) The Planet Remade: How Geoengineering Could Change the World (p. 296), Princeton University Press. Google Play, U.S. Edition.

[3] AGU Fall Meeting, 2015, A23K-04: Evidence of Clear-Sky Daylight Whitening: Are we already conducting geoengineering? - Retrieved online on January 21, 2016 from https://agu.confex.com/agu/fm15/meetingapp.cgi/Paper/59257

[4] Kiel, 2015 December 26, [press review] Media responses to Charles Long on "Unintentional Geoengineering" - Retrieved online on January 21, 2016 from http://www.climate-engineering.eu/single/items/press-review-media-responses-to-charles-long-on-unintentional-geoengineering.html

[5] Rau, G. (2015, December 16) "Accidental" Geoengineering? [Blog topic] Retrieved online January 21, 2016 from https://groups.google.com/forum/#!topic/geoengineering/2AASwDEgumg

[6] Amos Jonathan, 2015 December 16, Jet traffic linked to ice haze, Retrieved online on January 21, 2016 from http://www.bbc.com/news/science-environment-35109198

[7] Slate (2015 January 19) These Two Experts Answered Your Burning Geoengineering Questions, Retrieved online on January 21, 2016 from http://www.slate.com/articles/technology/future_tense/2016/01/jeff_goodell_and_raymond_t_pierrehumbert_take_questions_about_geoengineering.html

[8] Quaas, J. (2015) Approaches to Observe Anthropogenic Aerosol-Cloud Interactions. Springer Link. Retrieved online on January 21, 2016 from http://link.springer.com/article/10.1007/s40641-015-0028-0/fulltext.html

[9] Allenby, B. R. (2007, October 9) Earth Systems Engineering and Management, MIT Video. Retrieved online on July 7, 2013 from http://video.mit.edu/watch/earth-systems-engineering-and-management-9306/

Cómo Es Que Ya Le Estamos Haciendo Geoingeniería A Nuestro Planeta (Traducción)

Por Christina Boyes

Diciembre 21, 2015

Traducido por Oscar Escobar – Enero 13, 2016

Florida, USA - Gt

Fuente:

How We're Already Geoengineering Our Planet - Real Clear Science - Dec 21, 2015

http://www.realclearscience.com/articles/2015/12/21/how_were_already_geoengineering_our_planet_109487.html

Cuando la mayoría de nosotros pensamos en la geoingeniería de la atmósfera, pensamos en las prácticas intencionales como la siembra de nubes.  Sin embargo dos científicos están desafiando esa idea.  Ellos creen que ya estamos haciendo geoingeniería en los cielos sobre nosotros, aunque de manera accidental.  El Dr. Martin Wild de Suiza ETH Zurich y el Dr. Chuck Long de la NOAA están estudiando el problema desde dos direcciones, pero sus resultados conducen a conclusiones similares.

Long es delgado y de mayor edad, con el pelo del color de las nubes que estudia. Pero al pasar dos minutos hablando con él, uno queda impresionado con su energía ilimitada y su rostro juvenil.  Long estudia los cristales de hielo en la atmósfera y cómo han cambiado en tamaño y número con el tiempo. Él no mira las nubes como usted y yo las definiríamos – él está más interesado en que tan blancos son los espacios entre esas nubes y si se están volviendo más blancos.  El  'Fenómeno Cielo Despejado' (clear sky phenomenon) es el término usado para describir lo que él está examinando, pero parece que nuestros cielos 'despejados' a veces no son tan despejados. Eso es más que una cuestión de estética. El número de cristales de hielo en nuestros cielos 'claros' va en aumento - y Long cree saber por qué.

En las décadas hasta e incluyendo los años 1970 y 80, los niveles de contaminantes en aerosol aumentaron de forma constante. Estas partículas grandes fueron responsables de fenómenos como la lluvia ácida, enfermedades respiratorias, y en ciudades como la Ciudad de México, de aves cayendo del cielo. Gracias a los esfuerzos de todo el mundo, a partir de la década de 1990, los niveles de contaminación atmosférica industrial se redujo significativamente... pero el efecto sobre la radiación solar que llega a la superficie fue diferente a lo esperado si los aerosoles eran la única fuente del brillo. Ese es el misterio que capturó la atención de Long.

Utilizando los datos capturados durante décadas de investigación y evaluando cuidadosamente para asegurarse de que era válida, confiable y obtenida consistentemente a través del tiempo, Long fue capaz de hacer seguimiento a una tendencia de brillo gradual que no se correlaciona con los datos de aerosol para sus sitios de muestreo. Las vías de tráfico aéreo comercial y las estelas de propulsión a chorro asociadas, sin embargo, se correlacionaron bien. Long ve una explicación plausible en el depósito de cristales de hielo en las estelas [de condensación de los motores] a chorro que dejan, después que se disipan, una capa delgada y sin embargo importante de pequeños cristales subvisuales de hielo [en forma] "cirros".

El estado actual de la investigación de Long es limitado. Los instrumentos LiDAR más comúnmente utilizados no son lo suficientemente sensibles como para recoger la información que necesita durante el día, y no hay ninguna atenuación o abrillantado para observar por la noche; no hay luz solar. Incluso cuando el LiDAR es lo suficientemente potente como para recoger los datos que necesita, los instrumentos no duran décadas, por lo que la consistencia de datos en un problema. Otros instrumentos plantean problemas similares – los globos meteorológicos con sensores de humedad, por ejemplo, sólo tiene unos seis segundos para recopilar los datos que necesita de las capas delgadas de cristales de hielo que dejan los aviones.

Aunque él está seguro de que hay mucha investigación que queda por hacer sobre la neblina de hielo creada por los aviones de propulsión a chorro y otro tráfico aéreo, hay algo de lo que Long está convencido.  "ESTAMOS cambiando los componentes del sistema climático a través de la actividad de la contaminación* industrial humana.  Sí, efectivamente, la actividad humana puede y está afectando el clima." Los efectos de algunas estelas de aviación a chorro pueden parecer insignificantes si tenemos en cuenta el tamaño y la complejidad de nuestra atmósfera, pero son – así lo cree Long - claramente visibles en los datos.

El Dr. Wild de ETH no está restringido por las mismas limitaciones instrumentales como lo está Long. Su trabajo se centra en 'todo el cielo' “all-sky”, lo que abarca fenómeno de cielo claro y despejado. En Suiza, el oscurecimiento causado por la presencia de sulfatos y otros aerosoles en el cielo mantuvo el retroceso de los glaciares al mínimo durante décadas. Con aire más claro en la década de 1990, comenzó un rápido deshielo de los glaciares. Hubo considerablemente menos contaminación del aire, pero también hubo glaciares más pequeños.

La investigación de Wild, publicada recientemente en la revista Science, detalla las alzas en la radiación solar total que alcanzan la superficie (es decir, el 'brillo') que él y sus colegas detectaron, a partir de mediados de la década de 1980. En las décadas anteriores, se observaron caídas importantes en la cantidad de radiación solar directa que golpea la superficie de la Tierra. La naturaleza del enfriamiento de los aerosoles ya se entendía, sobre todo en contextos de la contaminación muy pesada del aire, muy como se ve en algunas partes de Asia.  Lo que es nuevo en la investigación del Wild es la presencia de un período de brillo después de la tendencia de oscurecimiento global observado durante las últimas décadas. La limpieza de sulfatos y otros aerosoles está trabajando, así lo parece. Pero acarrea un precio - más radiación llegando a la superficie de la Tierra significa más energía en el sistema, por lo tanto un mayor calentamiento.

Wild está preocupado por el presupuesto global de energía, y la forma en que la variación de la luz del sol en la superficie lo afecta a todo, desde el ciclo del agua hasta la radiación solar. Él no ve ninguna incertidumbre en cuanto a la presencia de la geoingeniería humana, aunque sea accidental. También entiende la posibilidad de que su trabajo podría ser malinterpretado por el público en general, como abogando la contaminación del aire, pero se apresura a declarar que hacer geoingeniería intencionalmente en nuestra atmósfera vertiendo más aerosoles en ella es una mala idea.

"Siete millones de personas mueren cada año como resultado de la contaminación del aire." Dice él, "A pesar de que vemos una tendencia de enfriamiento que resulta de los sulfatos y otros aerosoles en la atmósfera, cuando miramos al hemisferio sur, donde la contaminación de los aerosoles es relativamente inexistente, hay una tendencia al calentamiento general que se atribuye a los (GEI) gases de efecto invernadero...  Se necesita contrarrestar ambos. No se puede utilizar uno para compensar por el otro, y se pueden causar un montón de otros problemas si se entra en ese pacto con el diablo... No podemos contaminar el aire para compensar por el calentamiento de efecto invernadero”.

Como Long, Wild reconoce que su trabajo demuestra una clara relación entre el comportamiento humano y la cantidad de radiación solar que llega a la superficie. Los aerosoles que estudia son considerablemente más pequeños que los cristales de hielo en la investigación de Long, pero ambos realizan funciones similares. Reducen la cantidad de luz directa que llega a la superficie, aumentan la cantidad de radiación difusa, y alteran el balance energético del planeta, algo que tiene implicaciones de largo alcance en múltiples sectores - desde la producción de energía solar y la energía hidroeléctrica a la función global del ciclo del agua.

[La compañía] Crayola podría tener que dar el nombre de 'cielo azul' a un tono más claro si el blanqueamiento del cielo despejado continúa, pero esa no es la única consecuencia potencial de este fenómeno. Conforme nuestros cielos crecen más blancos reflejan más luz hacia el espacio y proporcionan menos energía para los campos de colectores solares que dependen de la luz solar directa. Los cielos más blancos también pueden dar lugar a temperaturas más frías.

La geoingeniería, aunque sea accidentalmente, es una cosa del presente. Los seres humanos ya están afectando el ciclo hidrológico de la Tierra en formas medibles. Reconocer un impacto humano en la atmósfera coincide con las propuestas para reflejar la luz solar para enfriar la Tierra - algo propuesto en los últimos documentos del Consejo Nacional de Investigación de EE.UU. También le da a los científicos la oportunidad de estudiar, potencialmente, el impacto de este tipo de geoingeniería antes de abrazarla activamente como un medio directo para cambiar el calentamiento del clima de la Tierra.

*El texto en inglés dice “solution” o sea solución, creo que en este contexto quisieron decir “polution” o sea contaminación.

Otras lecturas:

Sesión de la reunión de otoño del Sindicato Americano de Geofísica (AGU por sus siglas en inglés):

A23K-04: Evidence of Clear-Sky Daylight Whitening: Are we already conducting geoengineering?

Evidencia de Blanqueamiento de la luz diurna de cielos despejados: 

¿Estamos ya haciendo geoingenieria?

https://agu.confex.com/agu/fm15/meetingapp.cgi/Paper/59257

[press review] Media responses to Charles Long on "Unintentional Geoengineering"

Reacciones de la prensa a la presentación de Charles Long sobre "Geoingeniería Un-intencional)

http://www.climate-engineering.eu/single/items/press-review-media-responses-to-charles-long-on-unintentional-geoengineering.html