A Review of Geoengineering in 2017

Before delving into specific geoengineering methods and discussing the debates surrounding them, I thought it would be a good idea to make a post providing some background information on geoengineering and the extent to which it is currently being utilised.


What is geoengineering?

Geoengineering is defined as the ‘deliberate large-scale manipulation of the planetary environment to counteract anthropogenic climate change’ (Royal Society, 2009, p. 77). Keith (2000) notes the importance of intent and scale within the definition; the manipulation of the environment must be the primary goal of an action to be considered geoengineering as well as continental to global in scale.

The term ‘geoengineering’ was first used by Victor Marchetti in his paper describing the injection of carbon dioxide (CO2) into sinking thermohaline currents which would spread it across the deep ocean, effectively disposing of it (Marchetti, 1977).

Geoengineering methods can fall into two categories:

1. Carbon Dioxide Removal (CDR) or Carbon Geoengineering
• These are methods which (as the name suggests) aim to remove CO2 and other greenhouse gases from the atmosphere.
• Examples include afforestation, the use of biomass energy with carbon capture and storage (CCS), accelerated weathering (both land and ocean-based), ocean fertilisation, and the direct capture of CO2 from the air (Caldeira et al., 2013).
2. Solar Radiation Management (SRM) or Solar Geoengineering
• These are methods which are much more controversial as they aim to reflect a proportion of the Sun’s energy back to space to reduce warming on Earth rather than tackling the root cause of climate change (anthropogenic greenhouse gas emissions).
• Examples include space-based approaches (e.g. solar mirrors), injection of aerosols into the stratosphere, cloud brightening, and modifying the surface of the earth to increase albedo (Caldeira et al., 2013).

Many of these examples will be examined in greater depth in later blog posts, but this post is aimed at providing an overarching view of the techniques and the categories into which they fall.

Figure 1: A diagram illustrating many of the proposed geoengineering techniques from both Carbon Dioxide Removal (CDR) and Solar Radiation Management (SRM). (Source: http://sitn.hms.harvard.edu/flash/2016/engineering-earth-fight-climate-change/).

What is the current extent of geoengineering on Earth?

The map shown below in Figure 2 created by ETC Group gives a very comprehensive overview of the various geoengineering projects taking place across the world (with a full resolution PDF available here and a table of references given here).

Figure 2: A map illustrating the geoengineering developments and studies carried out over the past 50 years across the world. (Source: http://www.etcgroup.org/content/world-geoengineering/).

In short, several CDR methods are currently being undertaken with particular attention being given to afforestation and bio-energy with carbon capture and storage (BECCS). The Royal Society (2010) identified BECCS as a method capable of reducing global carbon dioxide concentrations by between 50 and 150 ppm. Several ocean fertilisation studies have also been undertaken, with the most recent project being the highly controversial ‘Haida Gwaii project’ which involved the dumping of 120 tonnes of iron sulphate into the Pacific Ocean in an attempt to create a phytoplankton bloom and so increase ocean CO2 uptake, with the resulting ‘success’ of a created bloom and increased fish counts becoming a hotly debated topic (Strutton, 2012).

Much less research has gone into SRM methods utilising outdoor experimentation, instead largely focusing on modelling and laboratory work. A key exception to this is a project ran by Harvard University which aims to launch a balloon to spray between 100 g and 1 kg of ‘material’ at 20 km altitude to create an air mass of 1 km length and 100 m diameter, with the balloon then being used to assess the resulting changes in light scattering and chemistry (Dykema et al., 2014). This project is known as the Stratospheric Controlled Perturbation Experiment (SCoPEx) and has already drawn wide criticism despite assurances that the amount of ‘material’ (which will comprise of calcium carbonate and possibly sulfates) are negligible.

An Inconvenient Introduction

I first properly learned about geoengineering during my time spent abroad at UCLA last year. Specifically, during a course called within the Earth, Planetary, and Space Sciences department called Earth’s Energy: Diminishing Fossil Resources and Prospects for a Sustainable Future. The professor discussed space mirrors (among other methods) as potential ways of reducing the impacts of anthropogenic climate change, causing an onslaught of questions from slightly angered students in the class.

During my time at UCLA, I also kept up a blog describing my experiences and what I had learned, so it is interesting to return to regular posting after having the summer off!

I chose geoengineering as a topic because it is something that I am interested in but currently know very little about besides the one controversial lecture in America. It appears that the criticism is not strictly limited to Los Angeles, however, during my research on this topic I have read articles with scathing comment sections highlighting the flaws of suggested methods.

I aim to research geoengineering using a variety of sources and clearly present what I have learned in a series of blog posts. Hopefully, by doing this, I will form my own opinion on its viability to mitigate the consequences of anthropogenic climate change as well as influence or challenge the views of any readers!