With support from multiple philanthropic partners, Spark is currently providing grants to the following groups as part of our Earth's energy imbalance research initiative.
Principal Investigators: Gavin A. Schmidt (NASA, Columbia University, USA), Kostas Tsigaridis (Columbia University, USA)
Co-Principal Investigators: Tim Andrews (UKMO, Leeds University, UK), Susanne Bauer (NASA, Columbia University, USA), Øivind Hodnebrog (CICERO, Norway), Hannah Liddy (Columbia University, USA), Michael Mayer (ECMWF, University of Vienna, Austria), Gunnar Myhre (CICERO, Norway), Hamish Prince (University of Vienna, Austria), Shiv Priyam Raghuraman (University of Illinois Urbana-Champaign, USA), George Tselioudis (NASA, Columbia University, USA)
Collaborators: Clare Singer (University of Colorado Boulder), Mark Zelinka (LLNL)
Summary: CERESMIP is a protocol for participating climate model groups to simulate the CERES period (2000 to 2024) with the goal of trying to match the observed trends and variability and diagnose the causes of the ongoing increase in the Earth’s Energy Imbalance. This protocol was proposed in 2023 and started in 2025 (as the appropriate input files were made available by the Coupled Model Intercomparison Project (CMIP) community). The main goal was to close a gap between the historical simulations in CMIP6 (which went only to 2014) and present day observations, by updating climate drivers to the present (at least 2024) and target the CERES satellite observations of the long-wave (LW), short-wave (SW) and net energy imbalance trends at the top of the atmosphere. We propose here to accelerate the completion of the CERESMIP among the interested modeling groups, enhance the analysis of these simulations, and address what can be inferred with respect to future climate change and the rate of warming. To that end we bring together an international set of motivated and experienced researchers on this topic to focus on these simulations and analysis, and plan for a workshop in December 2026 to finalise efforts to write these results up, and have them submitted for publication in time to be assessed in the upcoming Seventh IPCC Assessment Report (AR7).
Principal Investigators: George Tselioudis (NASA, Columbia University, USA), Paul Lerner (Columbia University, USA)
Co-Principal Investigators: Joseph Kelly (Columbia University, USA)
Summary: The large 21st century increase in the Earth’s Energy Imbalance (EEI), driven primarily by an increase in Absorbed Solar Radiation (ASR), is a major unresolved issue that is actively being investigated by the Earth science community. The proposed study addresses the issue of the increase in the Earth’s sunlight absorption, using trend attribution analysis and examining separately the regional trends over the global oceans that are the major contributors to the global ASR trend. This regionally separated analysis follows the premise that globally valid conclusions for the mechanisms causing the strong 21st century ASR trend can be structured only as a synthesis of the mechanisms operating in the different regions and climate regimes. We have already performed an analysis of the North Pacific Ocean, the dominant region of the global solar absorption increase, which shows that the dominant N. Pacific role occurs due to the confluence of three processes: a decrease in high and middle clouds caused by a poleward shift of the N. Pacific storm track, a decrease in low-cloud reflectivity and fraction caused by a decrease in cloud condensation nuclei, and a decrease in clear sky albedo caused by decreases in aerosol emissions. Analysis incorporating cloud controlling factors shows that the high and middle cloud fraction changes are driven by atmospheric dynamics and thermodynamics, while the low cloud fraction changes are driven by indirect aerosol effects. In addition, high and middle cloud fraction trends correlate with a poleward shift in the N. Pacific midlatitude storm track, pointing to a positive cloud feedback loop. In this project, we extend our N. Pacific analysis to the global domain, aiming to provide a synthesis and quantification of the processes responsible for the global 21st century ASR trend and examine the contribution of climate feedback processes affecting that trend.
Principal Investigators: Shiv Priyam Raghuraman (University of Illinois Urbana-Champaign, USA)
Co-Principal Investigators: Timothy Andrews (Leeds University, UK), Paulo Ceppi (Imperial College London, UK), Cristian Proistosescu (University of Illinois Urbana-Champaign, USA), Maria Rugenstein (Colorado State University, USA), Isla Simpson (NSF National Center for Atmospheric Research), Brian Medeiros (NSF National Center for Atmospheric Research), Clare Singer (University of Colorado Boulder, USA)
Co-Investigators: Benjamin Sanderson (CICERO, Norway), Marit Sandstad (CICERO, Norway), Chris Smith (International Institute for Applied Systems Analysis, Austria)
Summary: Previous work with climate models showed that anthropogenic radiative forcing and feedbacks from greenhouse gases, aerosols, clouds, and sea-ice changes caused an increase in Earth’s energy imbalance (EEI) over the last two decades. However, these models underestimate the observed trend in Earth’s energy imbalance. It is a high priority for the field to understand why the models are biased, because this result could imply that we are also underestimating future warming and extremes. The proposed research thus aims to answer two key questions: 1) How well do CMIP7 simulations represent observed trends related to EEI? and 2) What do observations of EEI imply for future warming? The first question will be tackled in four complementary approaches: use CMIP7 atmospheric and fully coupled simulations to investigate the impact of new model physics on trends in EEI, systematically investigate the processes behind the suite of radiative trends, conduct a targeted set of experiments in CESM2 and CESM3 to isolate the impact of aerosol forcing updates, and decompose the trends into atmospheric circulation-relevant regimes. The second question will be tackled in three complementary approaches: using emergent constraints to narrow the uncertainty in transient warming, using emergent constraints to narrow the uncertainty in long-term warming and feedbacks, and using climate model emulators that incorporate a realistic pattern effect to make more accurate predictions of future global warming. An international team of experts driven to answer these questions has been assembled. The team will submit the results for publication in journals in time to be considered part of the Intergovernmental Panel on Climate Change Seventh Assessment Report (IPCC AR7).
Principal Investigators: Gunnar Myhre (CICERO, Norway) and Øivind Hodnebrog (CICERO, Norway)
Summary: CERESMIP is a protocol for participating climate model groups to simulate the CERES period (2000 to 2024) with the goal of trying to match the observed trends and variability and diagnose the causes of the ongoing increase in the Earth’s Energy Imbalance. This protocol was proposed in 2023 and started in 2025 (as the appropriate input files were made available by the Coupled Model Intercomparison Project (CMIP) community). The main goal was to close a gap between the historical simulations in CMIP6 (which went
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