Could Sulphates Save the Planet?
This edition analyses two conflicting documents: a UN report which proposes releasing sulphates and the IMO’s low sulphur regulation to limit sulphates emissions, both to combat global warming
In a Nutshell
When I first read that the UN’s is considering options to repel solar radiation by darkening the skies, I thought I woke up in the middle of a conversation between Morpheus and Neo. However, it’s not a joke nor a movie script. Solar radiation management (SRM) is considered the ONLY solution on “politically relevant timescales” (p.14 of the report) to cool the Earth. Among the eight solutions, the one considered most viable is spraying the skies (technically called aerosol injection) with around 8-16 million tonnes of sulphate (SOx) to create a mist of reflective clouds at a cool (pun intended) cost of US$ 20 billion per year.
Aside from the casually dismissed potential negative consequences such as “changes in crop yields, changes in land and ocean ecosystem productivity, acid rain (if using sulphate)” (p.32), it struck me that I had heard of SOx before. In 2020, the International Maritime Organisation (IMO, a UN branch) introduced a regulation aimed at using cleaner fuels in shipping by reducing fuels’ sulphur content from 3.5% to 0.5%, or the equivalent of 8.5 million metric tonnes of SOx, thus contributing to avoiding more than 570,000 deaths worldwide between 2020-2025.
Thus, after reducing SOx emissions from shipping by 8.5 million tonnes TO SAVE THE PLANET, the UN plans to increase SOx emissions by 8-16 million tonnes TO SAVE THE PLANET. Besides asking the first obvious question - did the IMO cleaner fuel regulation make the effects of climate change worse by reducing SOx emisisons - the other question is, should ships switch to dirtier fuels to save the planet? I think I’m starting to see some cracks in the science.
What are SRMs?
Solar radiation management (SRM) is a class of climate engineering or solar geoengineering approaches, which refer to ways to reflect sunlight or to allow more of the Earth’s radiation to escape (p.10). Quite distinct from reducing greenhouse gases emissions, SRM approaches would work in parallel with emissions reduction programmes, should these programmes fail to establish in a timely manner or to deliver adequate results by providing a way to flatten the temperature curve – just have a look at these graphs:
The report considers several SRM approaches including stratospheric aerosol injection (SAI) with SOx, calcium carbonate or other substances, aerosol injection to increase cloud’s albedos, whitening urban roofs, genetically modifying crops to make them more reflective, and my personal favourite – covering the desert with a reflective blanket at a cost of several trillion dollars per year. These measures are considered at “planetary scale and need to last for decades or more to be effective” (p.5). While many of these interventions have been only theorised about or tested in laboratory environments, the next obvious step is clearly a widescale adoption because, clearly, the climate emergency is too urgent.
Why sulphates?
Of the SRMs considered, injection with sulphates or other aerosols seems to have a cost an order of magnitude smaller than the others, hence, unsurpingly, this approach was elaborated at length. The sulphate injection method is inspired from volcanoes, which expel sulphur into the atmosphere during eruptions, leading to noticeable cooling effects. The approach involves spraying sulphate particles into the stratosphere, presumably by airplane (chemtrail conspiracy theorists have been claiming this has been happening for years, did the UN just take inspiration from them?).
The sulphate injection approach seems one of the most sensible, although its challenges are largely overlooked. The report fails to consider how sulphate injection could be managed. With basic number crunching, a Boeing 747-8F freighter airplane can transport 139 tonnes of cargo. Spraying 8 million tonnes of SOx per year would require 57,500 flights, or 158 flights per day to spray all the SOx. All these flights would require up to 13 billion litres of aviation fuel (equivalent to 35 Mt CO2-e). Polluting the planet to save the planet. The report authors acknowledge some potential hazards while at the same time highlighting that the health, environmental and other consequences for large scale deployment are largely unknown. Are they?
Shipping to the Rescue!
The IMO 2020 regulation imposing a reduction in maritime fuels’ sulphur content from 3.5% to 0.5% seemed to specifically aim to curtail sulphates emissions due to their health and environmental impacts. According to the IMO:
“The new limit was forecast to lead to a 77% drop in overall sulphur oxide emissions from ships – a reduction equivalent to 8.5 million metric tonnes of SOx. Sulphur oxides are linked to asthma, pulmonary, cardiovascular and respiratory diseases. A study […] estimated that by not reducing the SOx limit for ships from 2020, the air pollution from ships would contribute to more than 570,000 additional premature deaths worldwide between 2020-2025. (Source)
Environmental effects of sulphates include acidification of surface water and soil, acid rain and fog that damage ecosystems, forests and plants. Very high concentrations of sulphates are toxic to cattle. Clearly, there were environmental and health reasons for reducing sulphate emissions. So, how are the same known, toxic compounds, in virtually the same quantities now touted as the ONLY option for the planet’s survival? And, given that sulphates have a cooling influence on climate change, did the IMO 2020 regulation worsen climate change effects?
The other aspect is cost. Sulphate injections are estimated to cost US$ 20 billion per year to increase SOx by 8 million tonnes. Compliance with IMO 2020 to decrease SOx emissions by 8.5 million tonnes was estimated to cost shipping companies between US$ 10 and 60 billion per year. So we need to pay to both decrease and increase the same emissions?
Here’s a crazy thought, shipping might actually save the day! Instead of 57,000 flights per year releasing 35 MT CO2-e, could shipping just revert to using the same “dirty” fuels as before in shipping? Ships tend to burn fuels in the ocean where not many people live, which is what the SAI programme is aiming for as well (“more of the sulphate from sulphate-aerosol SAI deployment would fall in the ocean or less-populated regions” p.18), extra emissions are avoided and shipping fuels become cheaper.
I recognise that this idea looks crazy, and it is! However, the idea is based on the UN’s logic, on the one hand its Environment Programme and on the other, the IMO. If these two agencies present two solutions with completely opposite measures - more SOx and less SOx respectively - but similar outcomes – saving the planet, maybe their logic isn’t particularly sound.
The Meta-Narrative
The UN report is an example of the meta-narrative that is extremely pervasive throughout the West, not only in relation to climate change but also other aspects such as pandemic response, future mobility, or cybersecurity and digital identity. If you read the summary of the solar radiation management justification below and replace the words in italics with healthcare, mobility or cybersecurity related terms, the story doesn’t change: the solution to the urgent problem at hand is ONE invariably global-scale intervention which MAY have the desired impact often with largely unknown long-term effects, yet the urgency of the problem mandates immediate action with little regard for the potential consequences.
Climate change poses a severe threat to the planet. In order to protect the planet and flatten the temperature curve, the only feasible solution is global-scale intervention through stratospheric aerosol injections. Research on such interventions has been ongoing for decades albeit mainly theoretical and in laboratory settings. These interventions may be needed for several decades, may have permanent, unintended consequences on health and the environment and will not replace conventional emissions reduction efforts. However, these are the ONLY chance we have to save the planet.