AOSC Seminar by Dr. Ming Cai, 9/12/2024
AOSC Seminar
Ming Cai
Florida State University
Title
A New Paradigm for Principles-Based Adept Predictions of Global Warming from Climate Mean States
Abstract
Distinguishing anthropogenic warming from natural variability in observations and reducing uncertainty in global warming projections by climate models remain critical challenges for climate scientists. In our work, we present a groundbreaking principle-based framework for adept predictions of the global mean warming and its spatial pattern in response to external energy perturbations from climate mean states without running climate models or relying on statistical trend analysis.
When applied to the observed climate mean state of 1980-2000, our framework accurately predicts the global warming observed from 1980-2000 to 2000-2020, with a prediction of 0.403 K compared to an observed value of 0.414 K. Our predictions from the preindustrial mean climate states of individual CMPI6 models yields a similar median global mean warming to their warming projections under the abrupt 4×CO2 scenario (5.4 K versus 5.6 K), but with noticeably less inter-model spread. Our predictions not only exhibit a high map correlation skill comparable to that of each individual CMIP6 model for the observed warming, but also capture the temporal pace of their warming projections under 1% annual CO2-increasing scenario.
The success of our global warming prediction from climate mean states under any given scenarios of CO2 increasing without running climate models is built on the following two innovations. One of them is our recent discovery of nature’s climate feedback 'circuit' associated with temperature feedback. The other is that we extract the information of surface energy amplification by non-temperature feedback from the ratio of downward longwave energy emission from the atmosphere to solar energy absorbed by the surface in climate mean states. The product of amplification rates by temperature and non-temperature feedbacks corresponds to the total amplification of energy perturbations at the surface caused by CO2 increasing. Temperature feedback yields a 6.6-fold global mean amplification, while non-temperature feedback contributes an another 2.3-fold amplification. This results in a total 15.8-fold increase in the global mean of CO2-induced energy perturbations at the surface. The energy balance between the enhanced thermal emission from the surface and the total external energy input perturbations amplified by temperature and non-temperature feedback determines the global surface warming in response to CO2 increasing.
Bio
Prof. Cai received professional training from the Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign, where he obtained his M.S. in 1985 and Ph.D. in 1990. Then, he came to the University of Maryland, and worked as a Research Associate first, and then Assistant and Associate Research Scientist. In 2003, he took an Associate Professor position in the Department of Meteorology, Florida State University. After spending three years as Program Director of Climate and Large-Scale Dynamics at the National Science Foundation, he rejoined the Florida State University as a full professor.
Prof. Cai works on the areas of climate dynamics, theory of global change, linear/nonlinear dynamics of large-scale atmospheric motions, dynamics of tropical cyclones, short-time climate variability, global mass circulation theory and its applications for climate predictions and projections. He has authored/co-authored about 120 peer-reviewed journal papers. Prof. Cai has also served as Editor of the Journal of Atmospheric Sciences (2010 - 2016).
Contact
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AOSC Seminar
Pre-seminar refreshment: N/A
Seminar: 3:30-4:30pm, Room: ATL 2400(only when in-person)
Meet-the-Speaker: 4:30-5:00pm, Room: ATL 3400(only when in-person) [For AOSC Students only]
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