Assessing the direct occupational and public health impacts of solar radiation management with stratospheric aerosols

Abstract

Geoengineering is the deliberate large-scale manipulation of environmental processes that affects the Earth’s climate, in an attempt to counteract the effects of climate change. Injecting sulfate aerosol precursors and designed nanoparticles into the stratosphere to (i.e., solar radiation management [SRM]), has been suggested as one approach to geoengineering. Although much is being done to unravel the scientific and technical challenges around geoengineering, there have been few efforts to characterize the potential human health impacts of geoengineering, particularly with regards to SRM approaches involving stratospheric aerosols. This paper explores this information gap. Using available evidence, we describe the potential direct occupational and public health impacts of exposures to aerosols likely to be used for SRM, including environmental sulfates, black carbon, metallic aluminum, and aluminum oxide aerosols. We speculate on possible health impacts of exposure to one promising SRM material, barium titanate, using knowledge of similar nanomaterials. We also explore current regulatory efforts to minimize exposure to these toxicants. Our analysis suggests that adverse public health impacts may reasonably be expected from SRM via deployment of stratospheric aerosols. Little is known about the toxicity of some likely candidate aerosols, and there is no consensus regarding acceptable levels for public exposure to these materials. There is also little infrastructure in place to evaluate potential public health impacts in the event that stratospheric aerosols are deployed for solar radiation management. We offer several recommendations intended to help characterize the potential occupation and public health impacts of SRM, and suggest that a comprehensive risk assessment effort is needed before this approach to geoengineering receives further consideration.

Climate engineering to mitigate the projected 21st-century terrestrial drying of the Americas: Carbon Capture vs. Sulfur Injection?

“…The utility of sulfur injection as a means to mitigate climate change has been long suggested (e.g., Crutzen 2006, Robock et al, 2009Niemeier and Tilmes, 2017), but some potential drawbacks have also been identified (Pongratz et al, 2012;Keller et al, 2014;Effiong and Neitzel, 2016;Irvine et al, 2017). For example, a notable downside of sulfur injection (mostly designed to be initiated from the Tropics to offset the higher intensity of solar radiation there), is that it tends to over-cool the Tropics, while under-cooling the polar warming due to the amplified greenhouse gas effect (Moore et al, 2014).…”

Complementing CO<sub>2</sub> emission reduction by solar radiation management might strongly enhance future welfare

“…For comparison, building and installing enough solar cells to meet global energy demand would, at current prices, cost about USD 250 trillion, although prices are decreasing rapidly (Cassedy and Grossman, 2017). However, apart from moral issues (Robock et al, 2009), sulfate SRM may have damaging effects on human health (Effiong and Neitzel, 2016) and the environment (Pitari et al, 2014;Ward, 2009) that are still poorly understood (Irvine et al, 2017). A sudden discontinuation of SRM will cause rapid warming ("termination shock") to levels dictated by greenhouse-gas concentrations (Brovkin et al, 2009;Matthews and Caldeira, 2007), which could put more stress on ecosystems and societies than a gradual warming (Trisos et al, 2018).…”

Best Scale for Detecting the Effects of Stratospheric Sulfate Aerosol Geoengineering on Surface Temperature

“…Mimicking large volcanic eruptions, SAI involves deliberate injections of stratospheric sulfate aerosols or their precursor, sulfur dioxide (SO 2 ), to increase Earth's albedo, thereby reducing the amount of incoming solar radiation and lowering surface temperatures. Using climate models, studies have shown that tropical SAI could effectively counteract global warming (e.g., Jones et al, ; ), although it could simultaneously bring unintended effects to the climate system (e.g., Aquila et al, ; Ferraro et al, ; Pitari et al, ), society (e.g., Preston, ; Svoboda et al, ), and human health (e.g., Eastham, ; Effiong & Neitzel, ).…”

“…HadGEM2-ES injected 5 Tg/year of SO 2 into the lower stratosphere globally to achieve a global distribution of stratospheric sulfate aerosols amid a lack of realistic stratospheric dynamics (Jones et al, 2010). None of the models have interactive stratospheric ozone chemistry (Eyring et al, 2013 climate system (e.g., Aquila et al, 2014;Ferraro et al, 2014;Pitari et al, 2014), society (e.g., Preston, 2013;Svoboda et al, 2011), and human health (e.g., Eastham, 2015;Effiong & Neitzel, 2016).…”