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Normalized Global Warming and Occurrence of Heat Waves (Invited Presentation)

Presentation Date
Tuesday, January 12, 2021 at 1:10pm
Authors

Author

Abstract

Most global warming studies have focused on surface air temperature trends. Here we use four observational annual mean temperature datasets to quantify global warming normalized by internal variability from 1960-2019. Compared with the raw trends showing Arctic amplification, the normalized trends show a tropical amplification over land, and they are more strongly correlated with record-breaking hot years. While the trends are higher over land, northern hemisphere record-breaking hot years occur more frequently over ocean. These events also occur more frequently over southern hemisphere tropical land than over mid- and high latitudes. These marine heatwaves and tropical land heatwaves should receive more attention (e.g., for early warning systems) due to their impacts on ecosystem, environment, and health. Most of the 17 CMIP5 and 15 CMIP6 Earth system models perform poorly compared with observations; the ensemble mean results are better but they still fail to reproduce the observed large differences in normalized trends and record-breaking events between land and ocean.

Funding Program Area(s)