Reflecting upon 10 years of geoengineering research: Introduction to the Crutzen + 10 special issue

Abstract

Ten years ago, Nobel laureate Paul Crutzen called for research into the possibility of reflecting sunlight away from Earth by injecting sulfur particles into the stratosphere. Across academic disciplines, Crutzen's intervention caused a surge in interest in and research on proposals for what is often referred to as "geoengineering"-an unbounded set of heterogeneous proposals for intentionally intervening into the climate system to reduce the risks of climate change. To mark the 10-year anniversary of the publication of Paul Crutzen's seminal essay, this special issue reviews the developments in geoengineering research since Crutzen's intervention and reflects upon possible future directions that geoengineering research may take. In this introduction, we briefly outline the arguments made in Paul Crutzen's (2006) contribution and describe the key developments of the past 10 years. We then proceed to give an overview of some of the central issues in current discussions on geoengineering, and situate the contributions to this special issue within them. In particular, we contend that geoengineering research is characterized by an orientation toward speculative futures that fundamentally shapes how geoengineering is entering the collective imagination of scientists, policymakers, and publics, and a mode of knowledge production that recognizes the risks that may result from new knowledge and that struggles with its own socio-political dimensions.

Evaluating climate geoengineering proposals in the context of the Paris Agreement temperature goals

“…In the context of their role in the Paris Agreement, and more generally in climate policy, climate geoengineering technologies may eventually become part of a significant socio-technical imaginary 146 – 148 , within which specific visions of the future are made to appear desirable, and which are influential on present political developments. Climate geoengineering is already entering the collective imagination 149 , e.g., as portrayed through media reports, and is also entering climate policy discussions, for instance through inclusion in the IPCC assessment reports 2 , and especially through the extensive reliance on CDR in low-carbon future scenarios analyzed by the IPCC 18 , 19 .…”

“…The significant ethical, legal, political and other social questions raised by hypothetical climate geoengineering interventions have been at the centre of attention since the early stages of the debate 148 , 161 . For instance, while a highly visible editorial on stratospheric aerosol injection (SAI) in 2006 (ref.…”

Ozone—climate interactions and effects on solar ultraviolet radiation

“…173,174 . Since then, several studies have discussed potential implications of such actions for the atmosphere and the biosphere, including side effects on stratospheric ozone and solar UV radiation 6,24,50,175 . Impacts on stratospheric ozone would occur through: (i) chemical effects of the increased aerosol loading, (ii) resulting changes in temperature and scattered solar radiation in the stratosphere, with corresponding changes photolysis rates, both of which will impact the ozone chemistry, and (iii) resulting changes in stratospheric circulation and transport.…”

The ‘Anthropocene Proposal’: A Possible Quandary and A Work-Around

“…In future, such a planetary technosphere may include deliberate scenarios of geoengineering the climate system [97][98][99][100]. Besides such scenarios, it is important to understand ongoing anthropogenic global change as driven by the cumulative effect of ordinary economic and social activities.…”