In 2010, during research for a Master’s Degree in Climate Change at the Australian National University (ANU), I wrote a paper on the potential of Geoengineering as a means to combat the lacklustre political efforts being made to tackle carbon emissions on a global level. This was right after the failure of the 2009 United Nations Climate Change Conference (COP15), which was intended to demonstrate the political will of the nations of the world to solve what was being touted as the moral imperative of our time and our moral obligation to future generations.

What is striking when re-reading the paper is how little has changed in the nearly 9 years hence. While the Paris Agreement developed at COP21 in late 2015 has been signed by almost all nations of the world, with an aspirational goal of keeping temperature increases from pre-industrial levels to well below 2oC, carbon emissions have continued to grow. The IPCC’s most recent Special Report on 1.5 Degrees has caused more alarm bells to ring, and for possibly the first time, truly legitimised the need to bring Carbon Capture and Storage (CCS) solutions into the mainstream.

As the paper is long, I’ll break it into parts. Part I will be the background to Geoengineering as I saw it at the time. Part II will be the pros and cons. It’s my belief the paper is as relevant now as it was then – possibly even more so.

Geoengineering – Part I

With little progress being made on international agreements to reduce the greenhouse gas concentrations in the atmosphere causing Climate Change, alternative approaches are gaining in popularity. Geoengineering is one such approach. The International Panel on Climate Change (IPCC) refers to geoengineering as technological efforts to stabilize the climate system by direct intervention in the energy balance of the earth for reducing global warming (2007).   While other definitions differ slightly, in a broad sense it could be described as deliberate schemes to modify large-scale environmental systems. Even Climate Change itself is sometimes considered a global geoengineering experiment that alters the earth’s climate through increasing the stocks of greenhouse gases (GHGs) in the atmosphere, albeit inadvertently.

Belay Station - Articles (Geoengineering Proposals - University of Leeds)Geoengineering projects look at modifications that can take place in the oceans, atmosphere, and soils to assist or offset the climate change mitigation process. Most discussions of geoengineering are centred on how to offset the flows of carbon dioxide (CO2) into the atmosphere or how to enhance CO2 “sinks” in the oceans and on land. CO2 is long lived and the most dominant of the GHGs in terms of concentrations in the atmosphere and thus a primary focus. While it is theoretically possible to capture the other gases, very few geoengineering schemes have so far focused on methane, NO2, or hydrofluorocarbons.

Origins of Geoengineering:  The concept of modifying weather has been around for millennia (Schneider 2008). Interestingly, Soviet authors in the 1960s published an essay entitled “Man versus Climate”, with the desire to actually increase solar radiation to warm the country and divert rivers to improve land productivity. Conversely, a first reference to geoengineering-type solutions to combat global warming and climatic change was in 1965 in a report called “Restoring the Quality of Our Environment” (a document focused on pollutants and waste from increasing industrialisation, including the alteration of carbon dioxide concentrations in the atmosphere), by the US President’s Science Advisory Committee, which included several geoengineering concepts (though not the word geoengineering, itself), including dispersing reflective particles on large oceanic areas to increase the albedo effect and speculation about the use of clouds to counteract warming. And with increasing pessimism over agreements on conventional mitigation measures, witnessed by the post-2000 increases in CO2 emissions, and a concern that the tipping points that could significantly alter the earth’s climate system are close at hand, the academic and scientific community are increasingly showing support for geoengineering concepts, including private funding for trials of technologies such as oceanic iron fertilisation and maritime cloud seeding.

Belay Station - Articles (Geoengineering Methods - Climate Central)

In relation to Climate Change:  Geoengineering, as it relates to the Climate Change mitigation efforts, generally falls into two broad categories – first, Carbon Capture and Storage (CCS), which overlaps with bio-sequestration, such as CO2 removal technologies, like ocean iron fertilisation, burying biochar, and carbon dioxide air capture (e.g. “fake trees”); and secondly, Solar Radiation Management, defined as climate change mitigation by means other than reducing the net flow of GHGs into the atmosphere. It is the deliberate manipulation of the amount of the sun’s energy hitting the earth causing the earth to absorb less solar radiation. The focus of Solar Radiation Management is on either the earth’s surface albedo or on aerosols, both directly and through enhanced cloud cover.

A third category, Weather Modification, is sometimes noted, but often identified with adaptation techniques (e.g. cloud seeding for rain and the prevention of storm formations). A by-product of weather modification ideas, however, can also impact mitigation efforts. Bill Gates, for example, has filed patents for technology to stop hurricanes by bringing cold sea water up from the depths of the ocean to cool surface temperatures that would slow hurricane formations. The same upwelling concept could be used in mitigation as the colder water would add nitrogen and phosphorous rich nutrients to the surface, assisting in the capture of CO2 and “storing” it in the depths of the oceans when the colder water sinks.

Of these concepts, CO2 Extraction methods have been deemed preferable as they help return the climate system to its more natural state, but it’s a much slower means of controlling global temperatures. On the other hand, the potential of Solar Radiation Management as a climate change mitigation tool has been estimated to be quite high and can be deployed quickly in case of emergency. The aerosols (SO2) launched into the stratosphere by the Mount Pinatubo volcanic eruption in 1991, blocked a fraction of the sunlight from reaching earth and lowered global temperatures by about 0.5 degrees for the following two years. Similarly, it has been estimated that if the earth’s albedo, or the ability of the earth to reflect the sun’s energy, was increased by 0.5%, this could halve the effect of a doubling of CO2 concentrations in the atmosphere.

Belay Station - Articles (Geoengineering Ideas - Rosamund Pearce, Carbon Brief)The implementation of most Solar Radiation Management schemes, such as increasing aerosols in the sky, read as if created for a Science Fiction movie. Yet the proponents of such schemes are highly respected academics, scientists and engineers. Nobel Prize winning Dutch Chemistry Professor, Paul Crutzen, has proposed launching particles of sulphur into space to create a thin sunscreen around the earth. Arizona Professor, Roger Angel, has proposed launching a glass sunshield into space to deflect away a small portion of the sun’s rays. And British Atmospheric Physicist, John Latham and engineer, Stephen Salter, have designed a fleet of remote controlled yachts that would pump particles of seawater into the air to whiten clouds and enhance their reflectivity. It would only take roughly a 1% increase in the global albedo effect in order to offset GHG emissions. Schemes like this are thus not as far-fetched as may seem at first and are gaining some high profile backers. Bill Gates has donated $300,000 to support testing of Latham and Salter’s cloud whitening technology.

In addition, enhancing the Earth’s albedo, separate from actually blocking the sun’s energy from reaching Earth, is another area of potential, including painting towns white to provide greater reflection of the sun’s energy, and genetically engineering the colour of leaves on trees and crops. Land use management is also an important aspect of the Earth’s albedo, sometimes with conflicting results. While planting forests, for example, has a positive impact on extracting CO2 out of the atmosphere, the colour of forests is generally dark, thus increasing absorption of the sun’s energy, reducing the Earth’s albedo.

Geoengineering remains controversial in whatever form, with numerous disadvantages often being cited. Yet, the interest in geoengineering is growing, particularly among scientists (the number of scientific articles on the subject has grown substantially since 2002), the media, and some politicians. And will have to be taken seriously if more conventional avenues to emissions reduction fail.