Essential Climate Variables – Global Glacier Change Data Indicate Continued Strong Ice Losses in 2015 and 2016
A Blog post by Isabelle Gärtner-Roer (WDS Scientific Committee member)
Changes in glaciers provide some of the clearest evidence of climate change, and as such they constitute key indicators and unique demonstration objects of ongoing climate change. Beside this scientific aspect, glacier changes have an impact on local hazard situations, regional water cycles, and global sea level.
The Global Terrestrial Network for Glaciers (GTN-G) is the framework for the internationally coordinated monitoring of glaciers in support of the United Nations Framework Convention on Climate Change. Within GTN-G, the World Glacier Monitoring Service affiliated at the University of Zurich, Switzerland (WGMS, WDS Regular Member)—which celebrated its 30th anniversary last year—is responsible for the collection and documentation of glacier fluctuations such as annual mass balances and length changes.
Figure 1. Mean annual mass balance of reference glaciers.
Latest mass balance data of the hydrological period 2014/15 and preliminary estimates for 2015/16 indicate continued strong ice losses. In fact, after 2002/03, 2014/15 is the second most negative year since the beginning of the monitoring program at WGMS (as shown in Fig. 1 for glaciers with long, continuous measurement programmes; the so-called 'reference glaciers'). This value is negative despite most of the glaciers in Norway and Iceland, as well as the few that are monitored in New Zealand and Antarctica, showing positive balances in the corresponding year (see Table 3 on this page). Since 1999/00, WGMS has already documented four years with a global mean ice thickness loss of more than 1000 millimetre water equivalent (mm w.e.). These new data show a continuation in the global trend of strong ice losses over the past few decades, and bring the cumulative average thickness loss since 1980 of the reference glaciers to almost 20.000 mm w.e.
As a Regular Member of the ICSU World Data System, WGMS publishes glacier data in a standardized format and makes them freely available to scientists, policy makers, and the wider public. Access is provided online through the 'Fluctuations of Glaciers Browser' and the 'Glacier App', as well as being consolidated in the 'Global Glacier Change Bulletin'.
Figure 2. Training course on glacier mass balance in La Paz, Bolivia (Photo: M. Zemp)
Upcoming challenges in glacier monitoring are very much related to the disintegration and vanishing of glaciers. Some of the glaciers under monitoring programmes disintegrate into several parts, while others—such as the Lewis Glacier on Mount Kenya—completely disappear. These issues demand continuous adaptation of monitoring strategies on both a local and global level. This is one reason why WGMS organizes training courses for Principal Investigators who perform glacier measurements and deliver their glacier data to WGMS. The last training course was held in 2016, with participants from Latin America (Mexico, Colombia, Ecuador, Peru, Bolivia, Chile, and Argentina) joining who are involved in ongoing mass balance programmes in their region (see Fig. 2). These participants were trained in both fieldwork and data analysis by an international team of experts in glacier monitoring and capacity building.
Our work relies on the cooperation and help of many scientists and observers throughout the world. We highly appreciate their long-lasting contributions in collaboration with our National Correspondents coordinating the collection of data in their country for submission to WGMS.