Contrasting northern and southern European winter climate trends during the Last Interglacial

J Sakari Salonen,Maria Fernanda Sánchez-Goñi,Hans Renssen,Anna Plikk

doi:10.1130/g49007.1

Abstract

Abstract The Last Interglacial (LIG; 130–115 ka) is an important test bed for climate science as an instance of significantly warmer than preindustrial global temperatures. However, LIG climate patterns remain poorly resolved, especially for winter, affected by a suite of strong feedbacks such as changes in sea-ice cover in the high latitudes. We present a synthesis of winter temperature and precipitation proxy data from the Atlantic seaboard of Europe, spanning from southern Iberia to the Arctic. Our data reveal distinct, opposite latitudinal climate trends, including warming winters seen in the European Arctic while cooling and drying occurred in southwest Europe over the LIG. Climate model simulations for 130 and 120 ka suggest these contrasting climate patterns were affected by a shift toward an atmospheric circulation regime with an enhanced meridional pressure gradient and strengthened midlatitude westerlies, leading to a strong reduction in precipitation across southern Europe.

Highlights

The Last Interglacial (LIG; ca. 130–115 ka; roughly coincident with marine isotope stage 5e) is an important case study for the response of the climate system to changes in climate forcing, with negligible human impact and only slight changes in total greenhouse gas forcing, but some of the largest anomalies in orbitally driven insolation forcing during the past million years (Berger and Loutre, 1991). This combination of factors led to the last known instance of warmer than preindustrial global temperatures in geological history, with average global annual sea-surface temperature estimated at +0.5 ± 0.3 °C above preindustrial (1870–1889 CE) levels (Hoffman et al, 2017) and summer surface warming reconstructed at up to 4–5 °C over Arctic land areas (CAPE–Last Interglacial Project Members, 2006), with the global surface temperature anomaly estimated at approximately +0.8 °C (Fischer et al, 2018)
In Europe, ensembles of transient climate model simulations show poor agreement in winter temperature trends, and often opposite trends compared to available proxy data, while for summer, individual models and proxy data show a consistent early LIG temperature maximum in mid- and high latitudes (Brewer et al, 2008; Bakker et al, 2013; Salonen et al, 2018)
To elucidate European winter climate evolution during the LIG, we present a data–modeling synthesis with high-resolution climate proxy archives spanning along the Atlantic seaboard from southern Iberia to the Arctic

Summary

Introduction

The Last Interglacial (LIG; ca. 130–115 ka; roughly coincident with marine isotope stage 5e) is an important case study for the response of the climate system to changes in climate forcing, with negligible human impact and only slight changes in total greenhouse gas forcing, but some of the largest anomalies in orbitally driven insolation forcing during the past million years (Berger and Loutre, 1991). In Europe, ensembles of transient climate model simulations show poor agreement in winter temperature trends, and often opposite trends compared to available proxy data, while for summer, individual models and proxy data show a consistent early LIG temperature maximum in mid- and high latitudes (Brewer et al, 2008; Bakker et al, 2013; Salonen et al, 2018).

Results

Conclusion