# Causes and consequences of Arctic amplification elucidated by coordinated multimodel experiments

## TL;DR

This paper explains how Arctic warming is amplified and its effects on weather patterns like the jet stream.

## Contribution

The study identifies specific climate responses to Arctic sea-ice loss using coordinated model experiments.

## Key findings

- Arctic sea-ice loss drives local warming and moistening in the troposphere.
- Jet stream and storm track shifts in the North Atlantic are linked to sea-ice loss.
- Model diversity helps constrain real-world climate responses to Arctic changes.

## Abstract

Human-induced warming is amplified in the Arctic, but its causes and consequences are not precisely known. Here, we review scientific advances facilitated by the Polar Amplification Model Intercomparison Project. Surface heat flux changes and feedbacks triggered by sea-ice loss are critical to explain the magnitude and seasonality of Arctic amplification. Tropospheric responses to Arctic sea-ice loss that are robust across models and separable from internal variability have been revealed, including local warming and moistening, equatorward shifts of the jet stream and storm track in the North Atlantic, and fewer and milder cold extremes over North America. Whilst generally small compared to simulated internal variability, the response to Arctic sea-ice loss comprises a non-negligible contribution to projected climate change. For example, Arctic sea-ice loss is essential to explain projected North Atlantic jet trends and their uncertainty. Model diversity in the simulated responses has provided pathways to observationally constrain the real-world response.

The Polar Amplification Model Intercomparison Project reveals robust jet stream and storm track responses to Arctic sea-ice loss that are separable from internal variability, and the model diversity provides pathways to constrain the real-world response