ple, by studying past environmental and national security agreements, the siting and deployment of large-scale technology, and the conditions under which cooperation or conflict develops. Further research can help elucidate when and what type of governance might be useful not only for deployment but also for field experiments that can be reasonably expected to involve risks of negative consequences. Decisions about intentional interventions in the climate system require not only an understanding of the physical climate system response but also how these climate responses affect differentially vulnerable people and things people need or care about such as food and water security.

Improve detection and attribution of climate change so as to provide an adequate baseline of observations of the “nonengineered” system with which to compare observations of the “engineered” system. Just as it is a nontrivial exercise to quantitatively attribute observed climate change among different climate forcing agents, distinguishing the effects of intentional climate intervention from other causes of climate change to ascertain the effectiveness of SRM approaches is a nontrivial task. Detection and attribution of climate change, and evaluation of all actions taken to respond, including initial testing, will require enhanced observing systems and analyses covering a wide array of climate and other environmental variables, especially more complete observations of energy flows in Earth’s climate system. In particular, preparations are needed to carefully observe the effects of the next major volcanic eruption.

Measure and evaluate public attitudes and test communication approaches to effectively inform and engage the public in decision making. Past experience with large and potentially dangerous technologies (or technologies perceived as dangerous) shows the importance of involving the public in advancing ideas and deliberations regarding testing or deployment of climate engineering approaches (see references above). However, little is known at this time about how different publics would perceive such large-scale interventions, what their attitudes are, how they should be engaged, and how best to communicate the complex issues concerning climate engineering. Also, attitudes and communicative approaches are likely to change over time and require periodic reassessment.

Develop an integrated research effort that considers the physical, ecological, technical, social, and ethical issues related to srm. Much of the research and observations needed to advance the scientific understanding of SRM approaches are also needed to advance general understanding of the climate system and related human and environmental systems. Examples of dual-purpose research include studies of the climate effects of aerosols, cloud physics, and how ecosystems, ocean circulation, permafrost, and ice sheets respond to changes in temperature and precipitation.