Abstract
Most climate projections represent volcanic eruptions as a prescribed constant forcing based on a historical average, which prevents a full quantification of uncertainties in climate projections. Here we show that the contribution of volcanic forcing uncertainty to the overall uncertainty in global mean surface air temperature projections reaches up to 49% in 2029, and is comparable or greater than that from internal variability throughout the 21st century. Furthermore, compared to a constant volcanic forcing, employing a stochastic volcanic forcing reduces the probability of exceeding 1.5 °C warming above pre-industrial level by at least 5% for high climate mitigation scenario, and enhances the probability of negative decadal temperature trends by up to 8%. Intermediate to high climate mitigation scenarios are particularly sensitive to the choice of future volcanic forcing implementation. We recommend the use of either a stochastic approach or prescribed constant forcing levels that sample volcanic uncertainty in future climate simulations.
| Original language | English |
|---|---|
| Article number | 236 |
| Number of pages | 10 |
| Journal | Communications Earth & Environment |
| Volume | 6 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Dec 2025 |
Bibliographical note
Funding Information:M.M.C. is supported by the Croucher Foundation and The Cambridge Commonwealth, European & International Trust through a Croucher Cambridge International Scholarship, and the Joseph Needham Foundation for Science and Civilisation through a Joseph Needham Merit Scholarship. M.M.C. and T.J.A. acknowledge support from the Camborne School of Mines Trust International Travel Bursary and the Department of Earth and Environmental Sciences of the University of Exeter. T.J.A. acknowledges funding from the Coupled Model Intercomparison Project International Project Office (PO 4000136906) and the European Space Agency\u00A0(Project \u201CVolcanic Forcing for CMIP\u201D, contract number 4000145911/24/I-LR). C.S. was funded by a NERC/IIASA Collaborative Research Fellowship (NE/T009381/1) and Horizon Europe under Grant Agreements 101081369 (SPARCCLE) and 101081661 (WorldTrans).
Funding Information:
M.M.C. is supported by the Croucher Foundation and The Cambridge Commonwealth, European & International Trust through a Croucher Cambridge International Scholarship, and the Joseph Needham Foundation for Science and Civilisation through a Joseph Needham Merit Scholarship. M.M.C. and T.J.A. acknowledge support from the Camborne School of Mines Trust International Travel Bursary and the Department of Earth and Environmental Sciences of the University of Exeter. T.J.A. acknowledges funding from the Coupled Model Intercomparison Project International Project Office (PO 4000136906) and the European Space Agency (Project \u201CVolcanic Forcing for CMIP\u201D, contract number 4000145911/24/I-LR). C.S. was funded by a NERC/IIASA Collaborative Research Fellowship (NE/T009381/1) and Horizon Europe under Grant Agreements 101081369 (SPARCCLE) and 101081661 (WorldTrans).
Publisher Copyright:
© The Author(s) 2025.