CyI Colloquium: European climate dynamics over past centuries; new insights from temporal and spatial high resolution climate reconstructions & perspectives for the future
Knowledge of past climate helps addressing the question whether modern climate change is unprecedented in a long-term context and improves our understanding of the natural climate variability. The lack of widespread instrumental climate records, however, requires natural climate archives or ‘‘proxy’’ data such as tree-rings, ice cores, corals and documentary evidence to statistically reconstruct climate in past centuries. Considerable progress has recently been made in the estimation of past centuries hemispheric mean climate trends and in the employment of climate models to assess the roles of natural and anthropogenic forcing. It is found, that the warmth of the past decade for the Northern Hemisphere is likely anomalous in the context for more than a millennium.
Partly due to the sparseness of available proxy data, less progress has been achieved in identifying the spatial patterns as well as the causal factors behind them. Spatial field reconstructions provide insight into the mechanisms and forcings underlying the observed climate variability and are particularly important for their comparison with AOGCM integrations.
Past and future climate changes can have a strong seasonal dependency. For instance, volcanism, solar irradiance, greenhouse gases and anthropogenic aerosols, all influence the annual cycle in differing and complementary ways. Currently, annually resolved hemispheric temperature reconstructions do not provide information on regional-scale temperature and, especially, precipitation variability such as the intrinsic seasonal patterns of climate change as they have occurred in Europe. Extremes at regional scales, such as the European hot summer of 2003 or the cold winter of 1708/1709 exhibit much larger amplitudes than extremes at global scale, and they may thus markedly affect the local to regional natural environment, societies, and economies, including most vital aspects such as water supply and agriculture.
Further, better understanding of past climate change patterns and their causes is important for the validation of regional-to-continental scale climate projections which are relevant for the assessment of future climate change impacts.
We will present the current knowledge on multiproxy data and methodologies applied to reconstruct European climate change spanning the last few centuries. Special emphasis will be put on temperature variations, uncertainties, trends as well as extremes and associated impacts. Other aspects include the comparison or regional climate reconstructions with the output of forced (solar, volcanic, greenhouse gases) climate simulations and the contribution of natural external factors and human activities to European temperatures over the past half millennium.
The talk will conclude with the presentation of perspectives for future interdisciplinary research in the field of paleoclimatology.
