[Paper Review] Climate Engineering Responses to Climate Emergencies

Jason J. Blackstock, David S. Battisti+8 more|ArXiv.org|Jul 29, 2009

Climate Change and Geoengineering17 citations

TL;DR

This paper evaluates stratospheric aerosol injection as a rapid climate engineering response to abrupt climate emergencies, proposing a decade-long technical research agenda to reduce uncertainty. It identifies key risks and benefits of shortwave climate engineering, focusing on global cooling potential within one year, and establishes conceptual frameworks for assessing solar radiation management strategies.

ABSTRACT

Despite efforts to stabilize CO_2 concentrations, it is possible that the climate system could respond abruptly with catastrophic consequences. Intentional intervention in the climate system to avoid or ameliorate such consequences has been proposed as one possible response, should such a scenario arise. In a one-week study, the authors of this report conducted a technical review and evaluation of proposed climate engineering concepts that might serve as a rapid palliative response to such climate emergency scenarios. Because of their potential to induce a prompt (less than one year) global cooling, this study concentrated on Shortwave Climate Engineering (SWCE) methods for moderately reducing the amount of shortwave solar radiation reaching the Earth. The study's main objective was to outline a decade-long agenda of technical research that would maximally reduce the uncertainty surrounding the benefits and risks associated with SWCE. For rigor of technical analysis, the study focused the research agenda on one particular SWCE concept--stratospheric aerosol injection--and in doing so developed several conceptual frameworks and methods valuable for assessing any SWCE proposal.

Motivation & Objective

• To assess the feasibility and risks of shortwave climate engineering (SWCE) as a rapid response to abrupt climate emergencies.
• To develop a technical research agenda focused on stratospheric aerosol injection (SAI) to reduce uncertainty in SWCE outcomes.
• To create conceptual frameworks and analytical methods applicable to evaluating any SWCE proposal.
• To evaluate the potential for global cooling within one year using SAI as a palliative measure.
• To guide future research toward minimizing unintended environmental and societal consequences of climate engineering.

Proposed method

• Conducted a one-week technical review of proposed climate engineering concepts, focusing on SWCE methods.
• Selected stratospheric aerosol injection (SAI) as the primary case study for detailed analysis.
• Developed conceptual frameworks and analytical tools for assessing radiative forcing, atmospheric dispersion, and climatic impacts.
• Evaluated the potential for rapid global cooling via injection of reflective particles into the stratosphere.
• Used climate modeling and atmospheric physics to estimate radiative perturbations and stratospheric chemistry effects.
• Established criteria for measuring benefits, risks, and uncertainties in SWCE deployment.

Experimental results

Research questions

• RQ1 What is the potential for stratospheric aerosol injection to achieve global cooling within one year?
• RQ2 How can uncertainties in the climatic, environmental, and societal impacts of SAI be systematically reduced?
• RQ3 What are the key physical and chemical processes governing the dispersion and lifetime of injected aerosols?
• RQ4 How do SAI-induced changes affect regional precipitation patterns and ozone chemistry?
• RQ5 What governance and monitoring frameworks are necessary to support responsible research and potential deployment?

Key findings

• Stratospheric aerosol injection can potentially induce global cooling within less than one year, making it a viable rapid-response option for climate emergencies.
• The study identifies a 10-year technical research agenda to reduce uncertainty in SAI's climatic and environmental impacts.
• Key uncertainties include regional climate effects, stratospheric ozone depletion, and aerosol lifetime and distribution.
• The research establishes a framework for evaluating any SWCE method, not just SAI, enhancing methodological consistency.
• The study highlights the need for improved atmospheric modeling and observational monitoring to assess SAI risks.
• It concludes that while SAI offers a potential palliative response, it carries significant risks requiring rigorous scientific and governance oversight.