2025 Internship Project Overview

Arctic amplification (AA), the amplified surface temperature response in the Arctic relative to the global average, emerges under both CO2 increase and removal. Here, we investigate AA in a collection of CESM1 simulations subjected to various instantaneous CO2 increases (2x, 3x, 4x, 5x, 6x, 7x, 8x CO2) and, subsequently, instantaneous CO2 removal back to preindustrial levels. We find that AA is weaker following CO2 removal (cooling) compared to CO2 increase (warming). A feedback decomposition using radiative kernels reveals that the weaker AA during CO2 removal is primarily driven by changes in the albedo feedback, lapse rate, cloud feedbacks and atmospheric heat transport. Notably, our results contrast with previous findings showing stronger AA when CO2 is decreased below pre-industrial values. Together, these results indicate a state-dependent AA response to CO2 removal: AA is weaker when returning to preindustrial values but stronger when CO2 falls below preindustrial values. This state dependence suggests the potential for a delayed cooling response in the Arctic should CO2 removal occur in the current or future warmer climate.

ORGANIZATION/RESEARCH GROUP

The Vecchi Research Group, Department of Geosciences, Princeton University

LOCATION

Princeton, New Jersey

 

Interns

Khang Tran ’28
Major: Physics
Minor(s): Engineering Physics, Robotics
"This internship has been a very fruitful experience. Ivan was especially helpful as a mentor, and I got to learn a lot about geoscience research and the research process in general, how meticulous it is. I found the radiative kernels method most interesting, it holds a lot of explanatory power about climate phenomena. The moment when I found that Arctic amplification is weaker during CO2 removal, it was really exciting. This internship has sparked a fascination in me regarding numerical methods and scientific computing."

Click to view the end-of-project presentation

 

Gabriel Vecchi
Knox Taylor Professor of Geosciences, Professor in the High Meadows Environmental Institute

Mentors

  • Ivan Mitevski, Postdoctoral Research Associate, Geosciences