Paleoclimate data-model comparison and the role of climate forcings over the past 1500 years

The past 1500 years provide a valuable opportunity to study the response of the climate system to external forcings. However, the integration of paleoclimate proxies with climate modeling is critical to improving the understanding of climate dynamics. In this paper, a climate system model and proxy records are therefore used to study the role of natural and anthropogenic forcings in driving the global climate. The inverse and forward approaches to paleoclimate data–model comparison are applied, and sources of uncertainty are identified and discussed. In the first of two case studies, the climate model simulations are compared with multiproxy temperature reconstructions. Robust solar and volcanic signals are detected in Southern Hemisphere temperatures, with a possible volcanic signal detected in the Northern Hemisphere. The anthropogenic signal dominates during the industrial period. It is also found that seasonal and geographical biases may cause multiproxy reconstructions to overestimate the magnitude of the long-term preindustrial cooling trend. In the second case study, the model simulations are compared with a coral δ18O record from the central Pacific Ocean. It is found that greenhouse gases, solar irradiance, and volcanic eruptions all influence the mean state of the central Pacific, but there is no evidence that natural or anthropogenic forcings have any systematic impact on El Niño–Southern Oscillation. The proxy climate relationship is found to change over time, challenging the assumption of stationarity that underlies the interpretation of paleoclimate proxies. These case studies demonstrate the value of paleoclimate data–model comparison but also highlight the limitations of current techniques and demonstrate the need to develop alternative approaches.

Christian-Muslim Relations. A Bibliographical History Volume 6: Western Europe (1500-1600)

Christian-Muslim Relations. A Bibliographical History, volume 6 (CMR 6), covering the years 1500-1600, is a continuing volume in a history of relations between followers of the two faiths as it is recorded in their written works. Together with introductory essays, it comprises detailed entries on all the works known from this century. This volume traces the attitudes of Western Europeans to Islam, particularly in light of continuing Ottoman expansion, and early despatches sent from Portuguese colonies around the Indian Ocean. The result of collaboration between numerous leading scholars, CMR 6, along with the other volumes in this series, is intended as a fundamental tool for research in Christian-Muslim relations.