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By Mark Turner

Newcomers to the world of geoengineering are confronted by a cornucopia of words.

Dozens of terms, describing multiple technologies (or families of technologies), sometimes used differently by different communities, make this a daunting subject to get to grips with. They can also lead to misperceptions and miscommunication.

Even the word ‘geoengineering’ is a point of contention, with some ambiguity over what technologies it should refer to (see: How do we categorise carbon removal?). Guidance to deconstruct this word salad is one of the top requests we receive at C2G2.

This is no simple task. Every term brings with it values and assumptions that could affect the debate; choosing one or another is not a neutral decision.

Over the coming months we hope to expand our glossary, to show in more detail how and where different terms are used, and to highlight some of their implications. Before that, however, we needed to gain clarity on the terms we ourselves used, and to be transparent about how we did that.

As a first step, we reached out to a broad group of friends from academia, climate communications, environmental NGOs, faith groups, international organisations, media and science, and asked their advice. Around two dozen responded, often with great rigour and insight.

Even with our limited sample, it was clear this is an area where reasonable minds disagree; in some cases, quite sharply. For some communities, this was old ground, the subject of long-standing debate (albeit without resolution). For others, it was all brand new. Our initial consultation highlighted how deliberate terminology choices could become an ideological battleground as the geo-governance debate goes mainstream.

After analyzing the responses, and consulting our Advisory Group, we settled on our own basic approach. This may change over time, but we thought it might be helpful for others to understand why we chose what we did. It is not C2G2’s role to make these choices for anyone else, but we think it important to point out that they exist.

1. ‘Geoengineering’ or disaggregate?

Our first decision we whether it was useful to use a single umbrella term to describe the large spectrum of climate intervention technologies.

The term geoengineering – also known as climate geoengineering, climate intervention, climate engineering – is broadly understood as meaning “intentional large-scale human interference in the earth system to combat climate change.” The twin keys here are the intentionality, and the scale.

It refers to two broad families of technology: those which deal with reflecting back solar radiation, and those which deal with removing greenhouse gases. While both families share some features, they are quite different in their practical implementation and effect, and the necessary governance frameworks.

Opinion was split on the utility of lumping them under one umbrella or not. Some argued that the term led to confusion (mixing up quite different technologies). Others thought it was useful in indicating all these technologies mark a major shift in humankind’s relationship with the planet.

‘Geoengineering’ has the added complication as the term widely used by chemtrails conspiracy theorists, to describe what they believe to be secret government spraying programmes already underway. Associating that with, for example, afforestation, could have a chilling effect.

Conclusion: In public discussions and advocacy, C2G2 will wherever possible describe the specific technology (or family of technology), rather than use the umbrella term.

2. Taking greenhouse gases from the air

Respondents generally believed it was useful to have a single category for technologies to reduce atmospheric greenhouse gases, despite the diversity of techniques that covers. (Some land, some ocean-based,  some with mostly local impacts, some transboundary.)

Choices included: carbon (dioxide) removal, negative emissions technologies (as used by IPCC), greenhouse gas removal, and carbon geoengineering. Recent discussions have also suggested some new frames, such as enhanced mitigation, atmospheric pollution clean-up or waste management.

Opinions varied considerably, although the IPCC term ‘negative emissions technologies’ was generally thought to be less helpful. Some respondents felt ‘clean-up’ frames could bring more players to the debate. But that was felt to be a step too far for C2G2, which aims to be impartial.

Conclusion: C2G2 will refer to this family of technologies as ‘carbon removal’, for the sake of simplicity and descriptive power.

3. Reflecting back sunlight

Respondents also agreed it was useful to have one category for proposed technologies to reflect more sunlight back into space, thereby creating a net cooling effect.

Candidates include albedo modification, solar radiation management, radiation modification measures, radiative forcing geoengineering, solar geoengineering, and some new suggestions, such as sunlight reduction/reflection, or extreme adaptation.

Again, opinions varied, but two thoughts emerged: that the most commonly used term ‘solar radiation management’ was not very accessible, and potentially misleading, while the term geoengineering – and its associated connotations – was in this context quite helpful.

While the sunlight reflection frame was interesting, and may emerge organically, C2G2 decided that it was not our place to explore or promote it at present.

Conclusion: C2G2 will refer to this family of technologies as ‘solar geoengineering’, whilst remaining aware of all the associations the term brings with it.

Next steps

These decisions were only a first step in navigating the complex world of geoengineering terminology, but a useful exercise to focus our minds. Many other terms will require exploration – and it is likely that many new frames will emerge.

To that end, we would welcome any thoughts or suggestions as to how we can usefully move forward. What other products would help you and your audiences navigate these difficult waters? Would a printed booklet be useful/appropriate? Video explainers? Should we consider a more substantial and academically rigorous survey?

As ever, please feel free to leave comments below, or get directly in touch.