Pantropical response to global warming and the emergence of a La Nina-like mean state trend

During the past century, the tropical Pacific Ocean has warmed significantly less than the other tropical oceans  in response to increasing greenhouse gases (GHGs). This La Nina-like warming trend in the observations is in stark contrast to the El Nino-like warming trend projected by the Coupled Model Intercomparison Project (CMIP) models for both the 20th and 21st century. A recent study by Zhang et al. (2019) proposes a new mechanism to help explain how enhanced Indian Ocean warming during the past century has reduced the Pacific warming response. A commentary paper (Lee et al., 2020) published in Geophysical Research Letters reviews the proposed mechanism in a broader perspective and discusses large-scale atmospheric responses in the Indian, Pacific and Atlantic basins and their interactions to increasing GHGs. This commentary paper also discusses how the future weakening of the Atlantic Ocean circulation may influence the Pacific warming response, emphasizing the interactive response of the pantropical atmosphere-ocean to increasing GHGs.

Figure: This figure summarizes the La Nina-like warming trend in the Pacific and associated atmospheric circulation anomalies observed during the 20th century, and the El Nino-like warming trend and associated atmospheric circulation anomalies projected for the 21st century by CMIP models.

Zhang, L.Han, W.Karnauskas, K. B.Meehl, G. A.Hu, A.Rosenbloom, N., & Shinoda, T. ( 2019). Indian Ocean warming trend reduces Pacific warming response to anthropogenic greenhouse gases: An interbasin thermostat mechanismGeophysical Research Letters4610882– 10890https://doi.org/10.1029/2019GL084088. https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL084088.

Lee, S.‐K.Kim, D.Foltz, G. R., & Lopez, H. ( 2020). Pantropical response to global warming and the emergence of a La Niña‐like mean state trendGeophysical Research Letters47, e2019GL086497. https://doi.org/10.1029/2019GL086497. https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL086497.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

Powered by WordPress.com.

Up ↑