The effects of aggressive mitigation on steric sea level rise and sea ice changes   总被引：1，自引：0，他引：1  

J. Körper  I. Höschel  J. A. Lowe  C. D. Hewitt  D. Salas y Melia  E. Roeckner  H. Huebener  J.-F. Royer  J.-L. Dufresne  A. Pardaens  M. A. Giorgetta  M. G. Sanderson  O. H. Otterå  J. Tjiputra  S. Denvil 《Climate Dynamics》2013,40(3-4):531-550

With an increasing political focus on limiting global warming to less than 2 °C above pre-industrial levels it is vital to understand the consequences of these targets on key parts of the climate system. Here, we focus on changes in sea level and sea ice, comparing twenty-first century projections with increased greenhouse gas concentrations (using the mid-range IPCC A1B emissions scenario) with those under a mitigation scenario with large reductions in emissions (the E1 scenario). At the end of the twenty-first century, the global mean steric sea level rise is reduced by about a third in the mitigation scenario compared with the A1B scenario. Changes in surface air temperature are found to be poorly correlated with steric sea level changes. While the projected decreases in sea ice extent during the first half of the twenty-first century are independent of the season or scenario, especially in the Arctic, the seasonal cycle of sea ice extent is amplified. By the end of the century the Arctic becomes sea ice free in September in the A1B scenario in most models. In the mitigation scenario the ice does not disappear in the majority of models, but is reduced by 42 % of the present September extent. Results for Antarctic sea ice changes reveal large initial biases in the models and a significant correlation between projected changes and the initial extent. This latter result highlights the necessity for further refinements in Antarctic sea ice modelling for more reliable projections of future sea ice.  相似文献   

Summer air temperature,reconstructions from the last glacial stage based on rodents from the site Taillis-des-Coteaux (Vienne), Western France     

Aurélien Royer  Christophe Lécuyer  Sophie Montuire  Jérôme Primault  François Fourel  Marcel Jeannet 《Quaternary Research》2014

The oxygen isotope composition of phosphate from tooth enamel of rodents (δ¹⁸O_p) constitutes a valuable proxy to reconstruct past air temperatures in continental environments. This method has been applied to rodent dental remains from three genera, Arvicola sp., Microtus sp. and Dicrostonyx sp., coming from Taillis-des-Coteaux, Vienne, France. This archaeological site contains an exceptionally preserved sedimentary sequence spanning almost the whole Upper Palaeolithic, including seven stratigraphic layers dated from 35 to 17 cal ka BP. The abundant presence of rodent remains offers the opportunity to quantify the climatic fluctuations coeval of the various stages of human occupation of the site. Differences between δ¹⁸O_p values of Arvicola sp. and Microtus sp. teeth are interpreted as the result of heterochrony in tooth formation as well as differences in ecology. Mean δ¹⁸O_p values of Microtus sp. are preferentially used to reconstruct summer air temperatures, which range from 16.0 ± 3.7 to 19.1 ± 3.1°C throughout the sedimentary sequence; however, the highest variability is observed during the last glacial maximum.  相似文献