24th Pacific Science Congress (PSC-24)

The Tibetan Plateau (TP) has been warming more rapidly than the global average in the past few decades. Using 30-member ensemble of simulations from the CESM1 (the Community Earth System Model version 1) and outcomes from 47 CMIP6 models, the roles of anthropogenic forcing and internal variability in the recent rapid warming are investigated. Results suggest that, based on careful analyses of the CMIP6 multi-model simulations, the observed warming amplification of the TP is detectable and attributable to human influence, though with some negative contribution from NAT forcing. While the CESM1 ensemble-mean also indicates a significant anthropogenic contribution to surface air temperature (SAT) changes over the TP, it highlights a relatively strong effect of internal variability.
The absence of precipitation alongside the elevated temperatures resulted in 2022 being the hottest and driest summer on record on the TP since at least 1961. Event attribution study based on large-ensemble simulations from the HadGEM3-A-N216 attribution system revealed that anthropogenic forcing has, to some extent, promoted surface warming and increased variability in precipitation on the TP in summer, establishing conditions conducive for the 2022 CHDE from a long-term climate change perspective. The contribution of anthropogenic forcing to the probability of a 2022-like CHDE was 100%, implying that without anthropogenically induced global warming, a comparable CHDE akin to that observed in 2022 on the TP would not be possible.
These results underscore the need for improved understanding of internal variability processes, better data quality, and enhanced model simulations to better attribute the causes of amplified warming and changes in probability and intensity of extremes over the TP.
 

climate change;,Tibetan Plateau,;extreme event,;detection and attribution