Temporal and spatial structure of multi-millennial temperature changes at high latitudes during the Last Interglacial

Abstract

a b s t r a c tThe Last Interglacial (LIG, 129e116 thousand of years BP, ka) represents a test bed for climate model feedbacks in warmer-than-present high latitude regions. However, mainly because aligning different palaeoclimatic archives and from different parts of the world is not trivial, a spatio-temporal picture of LIG temperature changes is difficult to obtain.Here, we have selected 47 polar ice core and sub-polar marine sediment records and developed a strategy to align them onto the recent AICC2012 ice core chronology. We provide the first compilation of high-latitude temperature changes across the LIG associated with a coherent temporal framework built between ice core and marine sediment records. Our new data synthesis highlights non-synchronous maximum temperature changes between the two hemispheres with the Southern Ocean and Antarctica records showing an early warming compared to North Atlantic records. We also observe warmer than present-day conditions that occur for a longer time period in southern high latitudes than in northern high latitudes. Finally, the amplitude of temperature changes at high northern latitudes is larger compared to high southern latitude temperature changes recorded at the onset and the demise of the LIG.We have also compiled four data-based time slices with temperature anomalies (compared to presentday conditions) at 115 ka, 120 ka, 125 ka and 130 ka and quantitatively estimated temperature uncertainties that include relative dating errors. This provides an improved benchmark for performing more robust model-data comparison. The surface temperature simulated by two General Circulation Models (CCSM3 and HadCM3) for 130 ka and 125 ka is compared to the corresponding time slice data synthesis. This comparison shows that the models predict warmer than present conditions earlier than documented in the North Atlantic, while neither model is able to produce the reconstructed early Southern Ocean and Antarctic warming. Our results highlight the importance of producing a sequence of time slices rather than one single time slice averaging the LIG climate conditions. Crown

Stable isotope compositions of speleothems from the last interglacial – Spatial patterns of climate fluctuations in Europe

“…The event is generally explained as resulting from a freshwater influx from melting ice sheets that induced a reduction in the Atlantic Meridional Overturning Circulation (AMOC) and associated cooling in the northernmost parts of the Atlantic realm. However, the event was not homogeneous in the entire North Atlantic as shown by the temperature anomaly distributions compiled by Capron et al (2014).…”

“…10) such as the Greenland ice core δ 18 O data (North Greenland Ice Core Project members, 2004; using the GICC05 age scale of Wolff et al, 2010) and selected stable isotope compositions and sea surface temperature reconstructions derived from North Atlantic deep sea sediment cores Sánchez-Goñi et al, 2012;Galaasen et al, 2014). It should be noted here that dating of deep sea records is a challenging task (e.g., Drysdale et al, 2009), and the North Atlantic region may behave heterogeneously with respect to temperature anomalies during climate change events (Capron et al, 2014) that must be kept in mind during the evaluation. The selected records demonstrate that the period of low δD values in the BAR-II record was associated with climate changes in the wider region.…”

The last interglacial climate: comparing direct and indirect impacts of insolation changes

“…Following the results presented in the previous section, we will compare the simulated response to proxy records for temperature, North Atlantic ocean circulation, sea ice cover, and North African precipitation. Capron et al (2014) have compiled a collection of temperature proxy records covering the last interglacial. The dataset consists of several time slices; including 125 ka employed here.…”

“…Changes in the orbital configuration and thus the insolation resulted in global warming of up to 2 °C compared to pre-industrial conditions, with more pronounced warming at high latitudes (CAPE-Last Interglacial Project Members 2006;Masson-Delmotte et al 2013;Capron et al 2014). Due to the nature of the forcing, the last interglacial is not a perfect analogue for future greenhouse gas driven warming.…”

“…Continued improvements of GCMs and increased availability and quality of proxy records (Capron et al 2014;Govin et al 2015) give reason for continued investigation of the last interglacial. Using the state-of-the-art EC-Earth climate model, we have designed a series of experiments to investigate the last interglacial climate and the mechanisms behind the warming.…”