Effects of SAI on Tipping Points & Climate Impacts

Request for Proposals (RFP) ID: RE-1002

Please submit your proposal through this application form. You may download a PDF version of this RFP here. For any questions, please review the Q&A board before submitting your question via this form.

Key Dates

Funding Opportunity Details

Background

Reflective’s mission is to equip the world with the data and tools needed to make timely, informed decisions about stratospheric aerosol injection (SAI). In support of that mission, this two-part RFP seeks proposals to develop understanding of the interaction of SAI with (1) earth system tipping points, and (2) climate impacts.

The IPCC’s Seventh Assessment Report is now in preparation and will consider literature submitted by the end of March 2027. Its assessment of SAI will shape the field for years to come. It is therefore critical that the authors have access to the broadest and most robust evidence base possible. This RFP is intended to expand that evidence base by supporting fast-paced research that can be completed – and submitted for publication – within this timeline.

Topic 1: Tipping Points

Tipping points in the earth system represent major risks to human welfare (Lenton et al., 2019, Armstrong-McKay et al., 2022). For example, a collapse of the Atlantic Meridional Overturning Circulation (AMOC) would cause abrupt and large climate shifts, including cooling in Northern Europe and disruption to tropical precipitation, threatening global food security (Ritchie et al., 2020). Sunlight reflection interventions have been shown to reduce the changes in drivers of many tipping elements (Zhao et al., 2025), but research on the interaction of tipping with SAI is limited and large uncertainties remain.

The limited research on interactions between SAI and tipping elements is a problem because SAI has several characteristics which could drive novel responses from tipping elements, including:

• Altering global mean temperature while leaving atmospheric CO₂ concentrations largely unchanged
• Producing scenario-dependent meridional temperature gradients and regional climate responses
• Introducing novel temporal pathways of temperature change, including non-monotonic trajectories, and rapid rates of change (such as abrupt warming following termination)
• Reducing direct sunlight and UV radiation, while increasing diffuse radiation

Because of these features, the non-linear phenomena which drive tipping dynamics may respond differently to SAI than to greenhouse gas forced change, and may vary across different SAI implementation scenarios.

Topic 2: Climate Impacts

Climate impacts refer to the consequences of climate change for human and natural systems, including food security, human health, ecosystem responses, infrastructure and economic activity. While there has been significant research into climate impacts under SAI, comprehensive assessments remain limited. In many cases, we also lack a detailed understanding of how impacts vary with SAI strategy and of the relative contributions of different sources of uncertainty.

Research Goals

We seek proposals which address one or both of two topics: first, how SAI interacts with tipping elements and may increase or reduce the risk of abrupt or irreversible changes in the climate system; and second, how SAI affects climate impacts.

Across both topics, we will prioritize research that delivers one or both of the following:

1. Novel insights into processes which drive the response to SAI
2. Expansion of the scope of current assessments, for example, to consider scenario dependence, inter-model uncertainty, or under-researched tipping elements/impacts.

We welcome proposals that replicate, extend, or stress-test recent studies, particularly where newer SAI simulations or alternative injection strategies allow deeper insight.

Proposed studies should produce one or more of the following outputs:

Topic 1: Tipping Points

1. Understanding of the causal effects on tipping elements of the specific set of driving conditions expected under SAI.
2. Quantification of the scenario, injection strategy, and model dependence of SAI’s effects on tipping risks.
3. Assessment of the path dependence — or hysteresis — of tipping point responses to SAI.
4. Expansion of the existing evidence base to include new SAI-tipping interactions.

Proposals could address any earth system tipping elements – see the 2025 Global Tipping Points Report or Armstrong-McKay et al., (2022) for examples. Priority will be given to proposals which target tipping elements with global impacts, near-term urgency (i.e. low temperature thresholds and/or short timescales), or dynamics which suggest the response to SAI might differ substantially from the response to greenhouse-gas driven temperature change

Examples of projects which would be well aligned with this opportunity include:

• A holistic assessment of the response of tipping drivers to SAI (e.g. Zhao et al., 2025), using recent GeoMIP simulations to address inter-model uncertainty
• Idealized modelling of AMOC dynamics, used to understand the path and scenario dependence in its response to SAI
• An assessment of the multi-model range in drivers of West Antarctic Ice Sheet collapse across SAI simulations, exploring mechanisms underlying inter-model differences
• Driving vegetation models with earth system model forcings to effects of the unique combination of temperature, CO2 concentration, and direct/diffuse radiative fluxes under SAI on case study ecosystems, such as the Amazon or Boreal forests

Topic 2: Climate Impacts

1. Quantitative, global assessments of the effect of SAI on a critical climate impact or set of impacts.
2. Mechanistic, process-level understanding of how SAI drives changes in one or more climate impacts.
3. Insight into how and why the response of one or more climate responses are expected to vary depending on injection strategy and magnitude.
4. Expansion of existing research to include assessment of scenario and model uncertainty
5. Quantification of the contributions of different drivers of uncertainty in climate impacts under SAI

Examples of projects which would be well aligned with this opportunity include:

• Globally comprehensive assessments of the SAI’s effects on:
  • Temperature-driven mortality and extreme heat exposure
  • Air pollution impacts on human health
  • Human health impacts of shortwave radiation changes
• Assessment of global and regional sea level rise (thermosteric and dynamic) under SAI, in a multi-model setting (e.g. in G6-1.5K-SAI simulations) or including land ice contributions
• A meta-analysis, synthesising evidence on the response of monsoons to SAI.

Methods

We welcome a variety of methodological approaches, including (but not limited to):

• Analysis of Earth System Model (ESM) simulations, such as the recent GeoMIP G6-1.5K-SAI and G6-1.5K-HiLLA experiments
• Domain-specific (offline) models, such as crop models and ice sheet models
• Idealized models of tipping dynamics and reduced complexity climate models
• Meta-analyses and review papers synthesising multiple lines of evidence to provide new insights

SAI simulations

All grantees will be welcome to use the Reflective Cloud to access SAI simulations and run analysis. This is a new community Jupyter Notebook platform developed by Reflective, and open to any SRM researchers (not just Reflective grantees), which provides free compute resources on AWS alongside a curated archive of SAI simulations (see below). Data from the recent G6-1.5K-SAI and G6-1.5K-HiLLA experiment are available on AWS via the Reflective Cloud, and this archive will be expanded to facilitate grantee requests where possible.

Eligibility

• This grant is open to academic institutions, non-profits, government-affiliated organizations, and similar groups. Individual researchers with appropriate resources may also apply.
• There are no restrictions on country of origin, and projects from the Global South are highly encouraged.
• Only one application may be submitted by the same research group.
• Proposals with experts across different disciplines and/or organizations are encouraged.
• For-profit organizations are eligible to apply as either a prime or sub-contractor, and must follow the same open-access guidelines as other organizations.

Application Process

1. If you have any questions, you may submit your question via this Q&A form or attend a live Q&A session from 8:15am - 9:15am PST on Wednesday, February 18th, 2026. Please register for the Q&A session here.
2. Submit a proposal by 11:59pm PST on Monday, March 2, 2026 using this form. A preview of application questions can be reviewed below.
3. Applications will undergo an initial eligibility screening before being sent to our external reviewers for a thorough evaluation using the criteria outlined below.
   1. Have someone in mind who would make a great peer reviewer for this proposal? Nominate them here!
4. We anticipate notifying applicants of the proposal outcome the week of April 13th, 2026 with an anticipated project start date of May 4, 2026.

Funding & Budget Considerations

Estimated Funding & Period of Performance

The 10-month performance period is intended to support completion of projects and the submission of a preprint by the March 2027 IPCC AR7 Working Group 1 literature cutoff date. Given the tight timeline between proposal outcome notification and grant start dates, we anticipate grantees needing to be able to start work prior to agreement finalization and first payments. If this would be problematic for you, please let us know in your proposal submission.

Please note, while the max award size is $150K, our goal is to maximize the breadth of research conducted under this grant and fund as many projects as possible. Projects with budgets above the max award size will not be immediately ruled out, but are discouraged and must be accompanied by sufficient justification of the costs.

Budget Categories

Applicants will be asked to fill out a budget workbook to outline project costs.

• Personnel: Includes salary & benefits for all personnel involved.
• Travel: Includes flights, accommodations, transportation and per diem for any travel required to complete the objectives of the grant.
• Equipment & Supplies: Items needed to complete the project
• Publications: we require grantees to submit papers to open access scientific journals. If the most relevant journal for your research is not open access, please provide further context in your proposal.
• Indirect: Costs not directly relevant to the project but important for operations. Please see Reflective’s indirect cost policy for more information.
• Miscellaneous/Other: Expenses that do not fit into the categories above (e.g. conference registration fees)

Allowable Expenses

• Personnel
  • For academic faculty on an academic year salary in PI or co-PI roles, the grant can provide up to one month of summer salary support and related benefits. These salary funds are not substitutional (cannot be used to relieve a university of salary costs) and cannot be used to reduce teaching loads below the departmental norm.
  • For staff and research scientists in PI or co-PI roles, the grant can provide salary support and related benefits.
  • For staff and research scientists not in PI or co-PI roles, as well as postdoctoral, graduate and/or undergraduate research assistants, the grant can provide salary support and related benefits, including graduate student tuition.
• Travel
  • Domestic or international travel for project members for scientific purposes (including conferences and meetings) per the travel policies of the awardee institution.
    • As a general rule of thumb, Reflective will sponsor travel for one project team member to one conference in a 12 month period. Exceptions may be made with sufficient justification.
  • Support for visitors and collaborators, including domestic and international travel.
• Research equipment, supplies, and other expenses directly related to the research, including publication expenses and professional membership dues.
• Up to 20% of funds may be allocated as indirect costs. Reflective’s indirect cost policy can be viewed here.
• For any publications associated with Reflective funded research, we require grantees to submit to open access scientific journals. If the most relevant journal for your research is not open access, please provide further context in your proposal.

Funding Dispersal Mechanism

Grant amounts are finalized during negotiations with award recipients. At the start of the grant term, Reflective will disburse 50% of the agreed upon award amount and the remaining 50% will be disbursed approximately halfway through the project period. If a significant portion of funds are unused at the end of the term, Reflective may require the return of such funds.

Data, Reporting and Final Deliverables

Data and Resources Provided

To support proposed research, the following data and computational resources will be made available to successful applicants:

• Climate Model Simulation Outputs: Researchers will have access to SAI simulation data from a variety of Earth system models and scenarios, including from the ARISE-SAI high-altitude global deployment experiments in CESM2 and UKESM1, as well as the more recent G6-1.5K-SAI and G6-1.5K-HiLLA simulations. To the extent possible, and where data is not already easily available by other routes, Reflective will facilitate access to needed model outputs by adding them to our archive stored on AWS associated with the Reflective cloud. We invite applicants to describe in the Application what use, if any, they would make of these simulations, and what outputs, including the desired variable and temporal resolution, they would need to support their research. If a particularly high data volume output is required, please briefly explain its necessity. If specific, limited, additional ESM simulations would be critical to a project, applicants are welcome to indicate this and Reflective will try to facilitate collaborations with modeling groups. Applicants can submit questions to the Reflective team via the Q&A form.
• Cloud-Based Computational Platform: Researchers will be granted accounts on a cloud-hosted JupyterHub environment pre-configured for SAI data analysis. This platform provides browser-based Jupyter Notebook access to the above datasets and common analysis libraries, along with sufficient computing resources to handle large climate model outputs. The cloud platform eliminates the need for proposers to have local high-performance computing infrastructure; it allows teams to interactively explore data, run analysis code, and collaborate in a centralized workspace. Use of this platform is encouraged to ensure reproducibility and to lower technical barriers for all research teams.

Open-Access Guidelines

• We require work to be published as open-access.
• The underlying outputs—code, data, presentations, etc.—must be openly published (i.e. code on GitHub and data on Zenodo or the Reflective Cloud repository).
• Consistent with our 501(c)(3) status, grant funds may not be used for the purposes of commercial technology development, marketing communications, business development activities, or any other activities directed at generating a profit.
• We will require grantees to pledge not to assert any IP developed under Reflective grants through ARIA’s patent pledge (still in development).

Reporting Requirements

Awardees will be required to submit a mid-point report and a final report along with any promised deliverables.

Evaluation Criteria

Initial Eligibility Screening

The first phase of evaluation is an eligibility screening. This screening will include checks for the following:

• Eligible organization/institution type
• Within budget guidelines of the RFP
• Within project period of performance guidelines of the RFP
• High level check on alignment with RFP Goals

Peer Review Evaluation

Applications that pass the eligibility screening will be evaluated by at least two peer reviewers with relevant areas of expertise, where possible. The areas of evaluation are as follows:

• Impact & Technical Feasibility
  • Level of alignment with RFP goals
  • Evaluation of how the project will move forward our understanding of the climate impacts of SAI and its interaction with earth-system tipping elements
  • Inclusion of novel research areas, including but not limited to:
    • Projects that analyze global climate impacts of SAI on a region-by-region scale
    • Analyses of the mechanistic drivers behind SAI effects, including specific characteristics of SAI that could drive novel, non-linear responses in tipping point drivers
    • Multi-model analyses and why the models differ
    • Scenario dependence analyses and drivers of this dependence
    • Hysteresis in tipping points under SAI
    • Quantitative analyses of the relative importance of different physical and chemical drivers of uncertainty
• Technical Feasibility and Work Plan Efficacy
  • Feasibility and appropriateness of the proposed approach/methodology
  • Evaluation of the reasonableness of the budget and timeline and whether the project team has the resources and capabilities needed to complete the work
  • Evaluation will consider the balance of feasibility and novelty, and we encourage a more detailed risk management plan for any particularly high-risk projects.
• Overall feedback
  • Strengths of the proposal
  • Potential weaknesses of the proposal
  • Additional risks

Application Content Requirements

Proposal Content

Each proposal must include the information outlined in this section. We strongly recommend using the section headers described below, but you may alter/modify this to suit the needs of your project. Proposals should be submitted in PDF format and have a max 5 pages including figures, data, and visuals.

• Section 1: Abstract (~0.5 pg)
  • Include the project title, project duration, which topic this project aligns with, budget, and a brief description of the research goals and final deliverables.
• Section 2: Technical Description (~2-3 pg)
  • Research Goals: Explain in detail what your research goals are for this proposal and your motivation for pursuing them. Describe how this research will significantly advance our understanding of SAI’s interaction with tipping points and/or climate impacts and how it aligns with the RFP’s research goals.
  • Methodology: Provide details on your intended methodology, including scientific rationale and/or references to support it. This should include an explanation of any existing simulations or data you intend on utilizing in your research, if applicable.
  • Timeline & Milestones: Please provide an estimated timeline for the project, including specifics about when you expect to complete certain milestones.
  • Final Deliverables: Please describe the final deliverable(s) for your project.
    • Note: In the spirit of promoting open, faster science, we require grantees to pre-print immediately and to publish in open-access journals. We also encourage grantees to consider how else to disseminate results beyond journals and can provide direct technical support for building and maintaining “living data products” — continuously updated, openly accessible datasets and workflows that automatically incorporate new data and make scientific outputs easy for others to reuse and extend.
  • Risks & Mitigation Strategies: Please share any risks that could derail the timeline, budget, or ability to deliver the project deliverables and how you will mitigate said risks.
    • Note: We recommend table format for this.
• Section 3: Project Team & Budget (~1-1.5 pg)
  • Team: Share the background of each project team member, their affiliation, and what they will contribute to the project. Where possible, please include some indication of how much time the person will commit (e.g. full-time, part-time, advisor etc.)
    • Note: We recommend doing this in table format
  • Resources: ​​Please describe the resources, tools, software, and technology available to you/the team for this project.
  • Budget Justification: Please provide narrative context on your budget workbook including details like how budget amounts were calculated and what travel/conferences are included and why.
• Section 4: Current and Pending (<0.5 pg)
  • Current grants, including project goals, timelines, and any overlap with this proposal.

Application Form Questions

The following is a copy of the application form to help you prepare your application materials in advance. The software we use will save a copy of your responses locally to your computer and browser, but we recommend preparing your responses beforehand in a separate document before submission. Questions marked with an asterisk are required.

Section 1: Applicant Details

1. Organization Type*
   1. University/Academic Institution
   2. Non-profit/NGO
   3. Government-affiliated organization
   4. Other
2. Organization/Institution Name*
3. Primary Principal Investigator (PI) Title*
4. PI First Name*
5. PI Last Name*
6. PI Email Address*
7. How did you hear about this funding opportunity?*
8. What regions are represented on your project team?*
   1. Africa
   2. Asia
   3. Europe
   4. Latin America & Caribbean
   5. U.S./Canada
   6. Middle East
   7. Oceania

Section 2: Project Proposal

1. Project Title*
2. Which overall research question(s) from the RFP does your proposal address?*
   1. Climate Impacts
   2. Tipping Points
3. Please submit a proposal outlining answers to the questions described in the “Proposal Content” section of the RFP. All proposals must be in PDF format and a max of 5 pages (including figures, data, and visuals).*
4. Please upload ONE file with the resumes/CVs of all project team members with the PI as the first resume in the file. Please submit as a PDF*
   1. Max 2 pages per resume/CV in the file.
5. What regions are represented on your project team?*
   1. Africa
   2. Asia
   3. Europe
   4. Latin America & Caribbean
   5. U.S./Canada
   6. Middle East
   7. Oceania
6. How long will your project take (in months)?*
7. What is your total budget for this project?*
8. Upload your budget justification workbook* (make a copy of and fill in this template)
9. What areas of expertise in a peer reviewer would be most relevant for your proposal? (select all that apply)*
   1. Aerosols and Air Quality
   2. Arctic Climate
   3. Atmospheric Chemistry
   4. Atmospheric Dynamics
   5. Coral Reefs
   6. Cryosphere
   7. Earth System Modeling
   8. Ecology
   9. Extreme Weather
   10. Health Impacts
   11. Ocean Carbon
   12. Permafrost
   13. Physical Oceanography
   14. SAI
   15. Sea Ice
   16. Tipping Points
   17. Other
10. Do you have anyone in mind who would make a good peer reviewer for a proposal like yours?
    1. If yes, you’ll be asked for the reviewer’s title, first, last name, and email address.