Arctic Amplification in the Past 22,000 Years

Arctic amplification (AA) refers to a key climatic mode that Arctic regions are warming faster than Northern Hemisphere average in global warming context. In recent years, many efforts have been made to explore AA’s physics on decadal to centennial timescales. But its long-term variability, which could provide scientists more clues and insights in investigating its mechanism, still remains unknown due to lack of observations.

Here, we present some preliminary results from a transient modeling work covering the last 22,000 years by using NCAR CCSM3, and compare our results with millennium reconstructions as well as centennial reanalysis. It is shown that AA is a solid and robust mode throughout the past 22,000 years with a typical ratio around 2.47, especially when the change of NH temperature is greater than 0.5 K/100a. Our findings suggest that AA can be linked to comprehensive air-sea-ice coupling process in polar areas as response to huge natural external forcing, like glacial-to-interglacial scale, rather than just minor anthropogenic forcing in the last century or even internal noise within climate system.

This study presents a more complete picture of AA’s long-term variability on the timescales far beyond anthropogenic influences, which broaden our views and improve our understanding of modern climate changes at high-latitudes and polar regions.