Near-term climate risks and sunlight reflection modification: a roadmap approach for physical sciences research

Abstract

Current impacts and escalating risks of climate change require strong and decisive action to reduce greenhouse gas (GHG) emissions. They also highlight the urgency of research to enhance safety for human and natural systems, especially for those most vulnerable. This is reflected in two recent US National Academies of Science, Engineering, and Medicine studies that recommended a national focus on advancing our understanding of how to manage urgent current and future climate risks, and the study of approaches for increasing the reflection of sunlight from the atmosphere to reduce global warming, a process referred to as sunlight reflection modification (SRM). Here, we build on these recommendations by proposing a roadmap approach for the planning, coordination, and delivery of research to support a robust scientific assessment of SRM to reduce near-term climate risks in a defined timeframe. This approach is designed to support the evaluation of SRM as a possible rapid, temporary, additive measure to reduce catastrophic impacts from anthropogenic climate change, not as a substitute for aggressive GHG mitigation. Assessing SRM is proposed to be undertaken in the context of climate hazard risks through 2050, weighing the impacts associated with likely climate change trajectories against scenarios of possible SRM implementations. Provided that research is undertaken openly and that scientific resources are made widely available, the transparency of the process and the evidence generated would contribute to the democratization of information, participation by diverse stakeholders, more informed decision-making, and better opportunities for all people to weigh SRM options against climate change risks.

Exploring potential atmospheric methane removal approaches: an example research roadmap for chlorine radical enhancement

“…Roadmaps are used in climate research to define knowledge gaps, needs, and associated outputs as they relate to interdependencies and timelines (e.g. Wanser et al, 2022;Maesano et al, 2022;Aschwanden et al, 2021;Ocean Visions, 2023), particularly in instances that benefit from integrated, interdisciplinary research. A coordinated, thorough, and sciencebased approach is needed to ensure that resources are used efficiently, stakeholders and interdisciplinary teams are engaged on appropriate timelines, and efforts are focused towards sequenced research questions and milestones.…”

On Nucleation Pathways and Particle Size Distribution Evolutions in Stratospheric Aircraft Exhaust Plumes with H2SO4 Enhancement

“…Nevertheless, because of the challenges of cutting emissions at adequate rates and the long lifetime of greenhouse gases, the necessity to understand the full range of options available for protecting the safety of human and natural systems has been emphasized in a recent report by the US National Academies of Sciences, Engineering and Medicine . Solar radiation modification/management (SRM) has received increasing attention as a transitionary tool for limiting the global surface temperature increase below 1.5 °C and buying time for carbon emission reduction and removal. − The effectiveness and potential risks of stratospheric aerosol injection (SAI) in modifying Earth’s climate have been studied using global models, − but little attention has been given to plume processes that are not resolved in global models.…”

“…2 Solar radiation modification/management (SRM) has received increasing attention as a transitionary tool for limiting the global surface temperature increase below 1.5 °C and buying time for carbon emission reduction and removal. 2 − 6 The effectiveness and potential risks of stratospheric aerosol injection (SAI) in modifying Earth’s climate have been studied using global models, 7 − 9 but little attention has been given to plume processes that are not resolved in global models.…”

A Numerical Modeling Study on the Earth’s Surface Brightening Effect of Cirrus Thinning

“…Overall, our understanding of the solar radiation modification side effects is still in its early stages. In order to gain confidence about geoengineering deployments, it is crucial that we conduct in-depth evaluations of the benefits and harms associated with using solar radiation modification techniques [51][52][53][54].…”