Author: Michael Zemp

Publisher:

Published: 2012

Total Pages: 72

ISBN-13: 9783855432615

"Information about ongoing glacier changes was already being collected internationally as early as 1894. In the beginning, the focus was on compiling and publishing findings relating to glacier front variations, in the hope that long-term glacier monitoring would give insight into processes affecting the formation of the Ice Ages. Since then, the datasets and goals of international glacier monitoring have evolved and multiplied. Glaciers have become the icon of global warming, which has resulted in an increasing demand for data and information about their global and regional distribution and changes. Modern monitoring strategies have been designed to provide quantitative and understandable information in connection with questions about process understanding, change detection, model calibration and validation, as well as environmental impacts. As such, monitoring can be regarded as the data backbone for scientific research. However, in spite of the early start of internationally coordinated glacier monitoring and its contemporaneous evolution within the glaciological sciences, the relevance of long-term glacier monitoring has not yet been fully acknowledged by the scientific community and funding agencies. It is to fill this gap in understanding that the present work undertakes to demonstrate the relevance of glacier monitoring, and its ability to complement scientific studies, on a local, mountain, and global scale. Based on 14 publications with essential contributions by this author, this work provides an overview of the historical background and present context of glacier monitoring, and the relevant organizations, strategies, and datasets. In the thematic main part, the methodological implementation of these concepts is presented, including exemplary results at different spatio-temporal scales integrating in-situ and remote sensing measurements, and numerical modeling. This is followed by a first effort to measure the relevance of internationally coordinated glacier monitoring. In this way, the present work provides a comprehensive summary of monitoring concepts, the results from recent distribution and glacier change studies, and an outlook on the corresponding key tasks for the coming decade(s). The internationally coordinated monitoring efforts over more than a century have resulted in an unprecedented dataset of information about spatial glacier distribution and changes over time. These datasets are readily available and include reconstructed glacier changes extending back into the Little Ice Age and the Holocene, direct observations of annual front variation dating back to the late 19th century, six decades of annual and seasonal mass balance measurements, and a preliminary world glacier inventory for the 1970s, based mainly on aerial photographs and maps, with detailed information on more than 100,000 glaciers. This latter inventory task continues through the present day, now based mainly on satellite images. These datasets document that the retreat from the Little Ice Age moraines is a worldwide and centennial trend showing increasing ice loss since the mid 1980s, with intermittent periods of glacier re-advances at regional and decadal scale. When looking at individual fluctuation series, one finds a high rate of variability and sometimes widely contrasting behavior of neighboring ice bodies. Reviewing the extensive literature available on process understanding and numerical modeling of glaciers, it becomes evident that, given current climate change scenarios, the ongoing trend of worldwide and rapid ice loss may lead to the deglaciation of large sectors of many mountain ranges during the present century. This will most probably trigger secondary impacts on global sea level rise, regional hydrologic regimes and landscape evolution, and local hazard situations beyond known historic and Holocene experience. Such rapid environmental changes require that the international glacier monitoring efforts make use of swiftly developing new technologies, such as remote sensing and geo-informatics, and relate them to the more traditional field observations, in order to tackle the challenges of the 21st century in a more effective way." Résumé de l'auteur.