Iron Salt Aerosol

Iron Salt Aerosols are naturally occurring iron compounds, mainly iron chloride, that are main cooling agents in the earth’s atmosphere. Iron chloride removes carbon dioxide and other greenhouse gases from the air, while also bringing extensive benefits for marine biology. Expanding ISA could be the single most economic, safe, easy and rapid contribution to reversing climate change.

Climate engineering by mimicking natural dust climate control: the iron salt aerosol method is a scientific article written by Franz Dietrich Oeste, Renaud de Richter and other scientific colleagues, published in 2017 by the European Geosciences Union in their peer reviewed journal Earth System Dynamics, available for free at https://www.earth-syst-dynam.net/8/1/2017/.  This article explains the ISA method in scientific detail, and contains an extensive list of references to other related scientific articles. 

ISA was one of the main natural cooling agents that expanded earth’s glaciers in the Ice Ages. During the ice ages the continents dried out, causing iron-rich dust to blow onto the oceans. This dust formed into aerosols and generated immense plankton production, due to the fact that iron is a key limiting nutrient for plankton growth. The iron in ice age dust removed about 50 parts per million of CO₂ and other greenhouse gases from the atmosphere, a natural feedback process that amplified global cooling.

By copying this natural process from the ice ages, production of ISA can become a safe, rapid and low-cost way to help reverse global warming. Natural and man-made sources now add about 100,000 tonnes of iron to the ocean each year. Doubling this existing rate using ISA would have a number of cooling benefits, while only adding a few grams of iron per square kilometer each day.

ISA firstly helps produce clouds as it reacts with moisture in the air. Creating more cloud means less light and heat gets through to the earth surface, cooling the land and sea through increased reflection and increasing rainfall. Sunlight acting on the ISA then releases chlorine, which depletes atmospheric methane, low level ozone, black carbon soot and other greenhouse gases.

The ISA falls with the rain to provide a safe, widely dispersed and productive micronutrient, increasing growth of plankton, continental plants and microbes. By enhancing ocean biological productivity, the ISA method sucks CO₂ out of the air and sea as a safe and inexpensive way to slow global warming and acidification. This removed carbon will either become part of the sediment at the ocean floor or recycle as biological material. 

More than sixty million square kilometres of the world ocean is anaemic, with very low iron levels, and will benefit from added iron. In these regions ISA can enable photosynthesis using up to 100,000 carbon atoms for each added iron atom.  Other regions also benefit from ISA through its various cooling effects.

ISA plumes can be generated by burning soluble iron compounds such as ferrocene in ships and power stations or on purpose-built platforms. Tiny particles of iron oxide will rise in hot combustion gases to a height of about one kilometer. The iron compounds stay in the air for a few days, where they react with naturally occurring hydroge chloride, mainly from sea-spray, forming iron chloride, a salt aerosol with many cooling impacts.

Alternatively, ISA can be generated locally, for example at coal mines, by spraying a mix of iron chloride and hydrogen chloride, in order to remove high concentrations of methane.

ISA could potentially remove up to twelve gigatons of CO₂ equivalent per year at an estimated cost below one dollar a tonne, by doubling the current level of iron in the air. This total is double the CO₂ reduction rate expected under the Paris Accord over the next decade, at a tiny fraction of the planned Paris cost, making ISA potentially the single most cost-effective climate change response available.

Scientific modelling indicates that ISA could safely begin to reverse global warming within a decade, while delivering essential local ecosystem protection, by global addition of 150,000 tonnes of iron to the atmosphere each year. Global use of the ISA method could provide a rapid, safe, low cost way to reverse climate change and protect biodiversity.

ISA can be implemented rapidly at scale in cooperation between commercial, government and scientific partners. Cooling benefits from ISA come equally from removing CO₂  and from other effects including methane removal and cloud formation. The methane removal is particularly beneficial since methane has short term global warming potential 28 times worse than CO₂ .

At global level, doubling the current natural addition of 150,000 tonnes of iron per year onto the ocean surface would have major immediate impact to cool the climate, using about one kilogram of iron per square kilometer per year in the large ocean regions with high nutrient and low chlorophyll.

ISA could increase krill and fish populations, reduce cyclone intensity, break down marine plastic and lower acidity.

ISA could help save the Great Barrier Reef and other threatened marine ecosystems, and could enable Australia to fully meet commitments under the Paris Accord at low outlay with major economic and ecological benefits.

By cooling the ocean water, ISA can protect coral reefs from bleaching and reduce warming risk to other threatened ecosystems.

Release of ISA from locations such as Macquarie Island could meet Australia’s emission reduction targets at a small fraction of current planned cost, while boosting Southern Ocean fish yields.

Humans are causing the sixth planetary extinction. Creating new ocean biomass aims to help stop the collapse of biodiversity.  To return our planet to the stable climate our ancestors enjoyed for the last ten thousand years of the Holocene era, about a trillion tonnes of carbon must eventually be converted from CO₂ and methane into biological and other stable forms. Increasing ocean biomass by accelerating natural photosynthesis is a primary effective strategy to achieve this climate restoration goal, replicating natural planetary cooling mechanisms. ISA is a significant and easily deployed starting point on this long road, with annual potential to remove more than ten gigatons of CO₂  equivalent.

In replicating how the earth cooled down in the ice ages, ISA mimics an entirely safe natural process, with rewards expected to far outweigh risks. Environmental safety of ISA can only be determined through small scale scientific field trials.

A stepped process of testing ISA for atmospheric, marine ecosystem and continental impacts, including through field monitoring, measurement and computer modelling, can ensure the safest approach to ensuring ISA effects are well understood. The impacts of ISA should be thoroughly measured and tested in small scale coastal scientific field trials and subjected to computer modelling before any larger deployment, in accordance with United Nations protocols. ISA trials must be rigorously committed to the highest levels of safety at each stage of development, through application of best practices to safeguard the environment, the health and safety of the public and those at work on the project.

Desktop analysis indicates very low risk of adverse events from ISA. Hypothetical risks from the related process of adding iron sulphate to the ocean include growth of unwanted algae and jellyfish species, change to ocean oxygen levels, shifts in the location of plankton in the ocean, and rapid return of captured carbon to the air. ISA field trials will assess these and other identified issues. Safety factors reducing any risk include the miniscule level of ISA addition in any location, planned adherence to strict scientific process, and the fact that ISA replicates beneficial natural cooling processes.

Research and development of ISA can reduce the dangers resulting from failure to control global warming. Investing in research and development to create knowledge is a far safer path than just banning ISA because of hypothetical untested risks.

Our models indicate ISA can remove carbon for less than a dollar a tonne of CO₂ equivalent, and possibly much less than that.

The low ISA cost would bring many times its value in economic and environmental benefits for industries including shipping, fishing, tourism, insurance, energy and plastics, making investment in ISA very attractive as a least cost carbon abatement strategy.

A recently published literature review of carbon removal options from The University of Michigan found typical prices in the order of $10-$60 per tonne of CO₂. The ISA costings are around 1% of these benchmark figures.

A tonne of the main ISA input ferrocene costs about USD $10,000. A tonne of ferrocene could remove ten thousand tonnes of carbon dioxide equivalent, at cost of one dollar per tonne of abatement or less.  That cost is orders of magnitude below other carbon removal methods under discussion. In the large regions of the world ocean that have high nutrients and low chlorophyll (HNLC), ISA could be many times more efficient than this dollar a tonne estimate.

Cost of ISA generation at the ferrocene market price of US$ 10,000 per tonne produces annual ISA costs of US$ 1.5 billion to finance the burial rate of up to six gigatons of CO₂  per year. This is twenty five US cents for each tonne of CO₂  removal alone, not including other cooling effects. Adding the likely equal cooling impact of removing CO₂ equivalents, plus the albedo cooling effect, halves this cost estimate to US twelve cents per tonne of CO₂e. Locating ISA in areas of lower uptake could increase the overall estimated unit price to about one dollar per tonne of CO₂e.

Since publication of the Oeste et al journal article in 2017, supporters of the proposal to test ISA in the field have been discussing how to do a thirty-day scientific field trial in coastal waters to measure ISA effects. We are now seeking scientific, commercial and political support and funding for an Australian field trial in Bass Strait, between Victoria and Tasmania, and have developed a detailed initial test proposal to discuss with investors, scientists, regulators and the public.

After evaluating a range of possible initial trial locations, Bass Strait appears the best place in the world for a first small ISA trial in terms of logistics, cost, safety and regulation. Bass Strait could be an entry point that can generate scientific and public understanding and interest, preparing for more comprehensive later trials, with easy management by scientists based in Victoria and Tasmania. Bass Strait location options include offshore oil platforms or the Spirit of Tasmania vessels that cross Bass Strait every day between Melbourne and Devonport.  Tests in the Southern Ocean and the Coral Sea could follow an initial proof of concept in Bass Strait, given that these deep marine locations are logistically more challenging.

Iron Salt Aerosol Australia Pty Ltd has been established to coordinate government and scientific and commercial partner involvement in the Australian field trials. Our team includes Dr Franz Dietrich Oeste and Dr Renaud de Richter, co-authors of the ISA journal article, and Robert Tulip and John Macdonald, the Australian contacts working to arrange scientific field trials and analysis. Franz and Renaud are chemical engineers, Robert is a former official in AusAID and the Department of Foreign Affairs and Trade, and John was a leading Australian architect. We are passionate about practical ways to stop global warming, and see ISA as the single best way that Australia can contribute to local and global action to limit climate change.

The primary research on ISA has been managed by Dr Franz Dietrich Oeste over the last twenty years, detailed in his 2017 journal article published with co-authors including Dr Renaud de Richter. Australia’s Deakin University plans to support PhD research on ISA, mainly addressing how ISA can remove marine pollution, as a main academic engagement with the field trial. We hope to employ a Post-Doctoral Fellow through Deakin University to provide technical management of the field trial planning, implementation and reporting. The involvement of Deakin University has potential to include work in legal aspects, engineering, chemical science and environmental monitoring.

Initial approvals to proceed with project design from responsible government authorities are a precondition for further project commitment and expenditure of funds. Activities in Bass Strait are controlled by State and Federal regulation, involving a range of authorities with approval jurisdictions, ensuring compliance with relevant expectations. Overall project approval will be sought in stages, beginning with a broad project plan, discussing any concerns and refining detailed operational plans.  Our initial field trials proposed under this project will fully comply with the United Nations London Protocol requirement that testing of iron fertilisation should be limited to scientific trials in coastal waters. We initially propose mainly to measure atmospheric effects, rather than the marine effects observable in the deep ocean.

Recognising the potential strong public interest in the field trials, governance standards for the project will include clear processes for decisions, public access to information about planned activities and demonstrated compliance with Australia’s environmental laws. The project is rigorously committed to transparent and accountable standards of governance. We commit to the application of best practices for project planning and delivery, involving high levels of professional expertise and consultation, including in work with partner organisations and stakeholders and in project communications.

The new European Sentinel 5P Satellite is expected to be the primary monitoring system, measuring atmospheric and ocean effects, working together with scientific institutions including universities and government instrumentalities. The project is rigorously committed to effective, detailed, accurate and transparent monitoring of activities and impacts at each stage of development. We commit to the application of best practices for modelling, gathering and analysis of data for our project, monitoring all environmental effects and operational processes.

The European Space Agency launched the Sentinel 5P satellite in October 2017 to map and measure gas concentrations such as ozone, methane and aerosols. This satellite can help to observe ISA plumes with high precision and quantify their depletion effects on methane, ozone and numerous other chemicals in the atmosphere. Satellite location data will then be correlated to sea surface temperature reduction and increased chlorophyll A production by phytoplankton. Other satellites and ground based activities could also assist with monitoring.

For the first trial planned in Bass Strait, we aim to gather data about the atmospheric cooling effects of ISA by measuring depletion of chemicals including methane (CH4), volatile organic compounds (VOCs), ozone (O3), nitrous oxide (NO2), hydrochlorofluorocarbons (HCFC) and soot aerosol, as well as cloud formation and cloud brightness. Bass Strait has no iron deficiency, but the influence on phytoplankton can be measured to indicate possible results in subsequent tests in iron deficient waters. The temperature effects within the ISA plume and beyond will indicate expected cooling effects. We plan to test a range of precursor iron chemicals including ferrocene, at different fuel mixes, temperatures and concentrations. This Bass Strait trial will indicate ISA potential to cool sensitive locations such as the Great Barrier Reef, where later tests aim to prove a cost-effective method to prevent coral bleaching.

ISA appears to be far better value as a climate change response than reducing emissions, burying CO2 or reflecting sunlight.  The key theme emerging from our work is that ISA could be orders of magnitude superior to other proposed climate protection methods. This superiority is across primary criteria of cost, safety, speed, ease of implementation, natural precedent and effectiveness. These modelled effects require field tests to confirm or adjust the predictions.

ISA improves upon previously proposed methods of ocean iron fertilization in areas of cost, risk, effectiveness and ease of deployment at scale. ISA is suited to both local and global use, providing iron in extremely low and even concentration with cooling benefits both in the air and in the water. Previously studied methods of ocean iron fertilization spread liquid iron sulphate onto smaller regions of the ocean's surface, and did not bring ISA co-benefits such as methane removal and cloud formation. A key benefit of ISA is that it does not require any local concentration of iron, but operates systemically, reducing the anaemia of the world ocean. Spreading iron through the air as a salt aerosol enhances the concept of ocean iron fertilization and is likely to prove the safest single contribution to cooling the climate.

Franz Dietrich Oeste and Ernst Ries are owners of