Lessons from a high-CO2 world: an ocean view from ∼ 3 million years ago
Dr. Sze Ling Ho from IONTU co-led a study involving an international team of scientists, including marine geologists (PlioVAR; https://pliovar.github.io/index.html) and paleoclimate modelers (PlioMIP2), to reconstruct the global sea surface temperature ~3 million years ago when the atmospheric CO2 level was similar to the lowest emission scenario (RCP2.6) adopted by the 5th IPCC report. Reconstructions based on geological proxies embedded in marine sediments show that, at the CO2 level that was 120 ppm higher than the pre-industrial value, the global surface ocean warmed by 2 to 3 degree Celsius, with a reduced meridional gradient due to enhanced warming in high latitudes. Further, the degree of global warming derived from geological data in marine sediments is weaker than that simulated by state-of-the-art climate models from Europe, North America, Japan and China. This implies that even under the lowest emission scenarios, future global warming at the end of the century may be stronger than that projected by climate models. The study is published in Climate of the Past and the findings will be included in the next IPCC report which is due for release in 2021.
McClymont*, E. L., Ford*, H. L., Ho*, S. L., Tindall, J. C., Haywood, A. M., Alonso-Garcia, M., Bailey, I., Berke, M. A., Littler, K., Patterson, M. O., Petrick, B., Peterse, F., Ravelo, A. C., Risebrobakken, B., De Schepper, S., Swann, G. E. A., Thirumalai, K., Tierney, J. E., van der Weijst, C., White, S., Abe-Ouchi, A., Baatsen, M. L. J., Brady, E. C., Chan, W.-L., Chandan, D., Feng, R., Guo, C., von der Heydt, A. S., Hunter, S., Li, X., Lohmann, G., Nisancioglu, K. H., Otto-Bliesner, B. L., Peltier, W. R., Stepanek, C., and Zhang, Z.. (2020) Lessons from a high-CO2 world: an ocean view from ∼ 3 million years ago, Clim. Past, 16, 1599–1615, https://doi.org/10.5194/cp-16-1599-2020. (* Corresponding author)
Interactive PlioVAR database: https://pliovar.github.io/km5c.html