Half a Century of Measurements of Glaciers on Axel Heiberg Island, Nunavut, Canada

We illustrate the value of longevity in high-latitude glaciological measurement series with results from a programme of research in the Expedition Fiord area of western Axel Heiberg Island that began in 1959. Diverse investi­gations in the decades that followed have focused on subjects such as glacier zonation, the thermal regime of the polythermal White Glacier, and the contrast in evolution of White Glacier (retreating) and the adjacent Thompson Glacier (advancing until recently). Mass-balance monitoring, initiated in 1959, continues to 2011. Measurement series such as these provide invaluable context for understanding climatic change at high northern latitudes, where in-situ information is sparse and lacks historical depth, and where warming is projected to be most pronounced.Nous illustrons la valeur de la longévité en ce qui a trait à une série de mesures glaciologiques en haute latitude au moyen des résultats découlant d’un programme de recherche effectué dans la région du fjord Expédition du côté ouest de l’île Axel Heiberg, programme qui a été entrepris en 1959. Diverses enquêtes réalisées au cours des décennies qui ont suivi ont porté sur des sujets tels que la zonation des glaciers, le régime thermique du glacier White et le contraste entourant l’évolution du glacier White (en retrait) et du glacier Thompson adjacent (qui s’avançait jusqu’à tout récemment). La surveillance du bilan massique, qui a été amorcée en 1959, se poursuit jusqu’en 2011. Les séries de mesure de ce genre fournissent un précieux contexte permettant de comprendre le changement climatique qui se produit dans les hautes latitudes du Nord, là où il y a peu d’information sur place, où la profondeur historique est mince et où le réchauffement devrait être le plus prononcé

Integrating risks of climate change into water management

[No abstract available

Basic theory behind parameterizing atmospheric convection

Last fall, a network of the European Cooperation in Science and Technology (COST), called “Basic Concepts for Convection Parameterization in Weather Forecast and Climate Models” (COST Action ES0905; see http://w3.cost.esf.org/index.php?id=205&action_number=ES0905), organized a 10-day training course on atmospheric convection and its parameterization. The aim of the workshop, held on the island of Brac, Croatia, was to help young scientists develop an in-depth understanding of the core theory underpinning convection parameterizations. The speakers also sought to impart an appreciation of the various approximations, compromises, and ansatz necessary to translate theory into operational practice for numerical models

Integrating risks of climate change into water management

The Working Group II contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change critically reviewed and assessed tens of thousands of recent publications to inform about the assess current scientific knowledge on climate change impacts, vulnerability and adaptation. Chapter 3 of the report focuses on freshwater resources, but water issues are also prominent in other sectoral chapters and in the regional chapters of the Working Group II report as well as in various chapters of Working Group I. With this paper, the lead authors, a review editor and the chapter scientist of the freshwater chapter of the WGII AR5 wish to summarize their assessment of the most relevant risks of climate change related to freshwater systems and to show how assessment and reduction of those risks can be integrated into water management

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

Estimating the glacier contribution to sea-level rise for the period 1800-2005

In this study, a new estimate of the contribution of glaciers and ice caps to the sea-level rise over the period 1800-2005 is presented. We exploit the available information on changes in glacier length. Length records form the only direct evidence of glacier change that has potential global coverage before 1950. We calculate a globally representative signal from 349 glacier length records. By means of scaling, we deduce a global glacier volume signal, that is calibrated on the mass-balance and geodetic observations of the period 1950-2005. We find that the glacier contribution to sea-level rise was 8.4 ± 2.1 cm for the period 1800-2005 and 9.1 ± 2.3 cm for the period 1850-2005

Twentieth-century global-mean sea-level rise: is the whole greater than the sum of the parts?

Confidence in projections of global-mean sea level rise (GMSLR) depends on an ability to account for GMSLR during the twentieth century. There are contributions from ocean thermal expansion, mass loss from glaciers and ice sheets, groundwater extraction, and reservoir impoundment. Progress has been made toward solving the ‘‘enigma’’ of twentieth-century GMSLR, which is that the observed GMSLR has previously been found to exceed the sum of estimated contributions, especially for the earlier decades. The authors propose the following: thermal expansion simulated by climate models may previously have been underestimated because of their not including volcanic forcing in their control state; the rate of glacier mass loss was larger than previously estimated and was not smaller in the first half than in the second half of the century; the Greenland ice sheet could have made a positive contribution throughout the century; and groundwater depletion and reservoir impoundment, which are of opposite sign, may have been approximately equal in magnitude. It is possible to reconstruct the time series of GMSLR fromthe quantified contributions, apart from a constant residual term, which is small enough to be explained as a long-term contribution from the Antarctic ice sheet. The reconstructions account for the observation that the rate of GMSLR was not much larger during the last 50 years than during the twentieth century as a whole, despite the increasing anthropogenic forcing. Semiempirical methods for projecting GMSLR depend on the existence of a relationship between global climate change and the rate of GMSLR, but the implication of the authors’ closure of the budget is that such a relationship is weak or absent during the twentieth century