Global Data Gaps in Our Knowledge of the Terrestrial Cryosphere

Abstract

The IPCC Special Report on Oceans and Cryosphere in a Changing Climate identified major gaps in our knowledge of snow and glacier ice in the terrestrial cryosphere. These gaps are limiting our ability to predict the future of the energy and water balance of the Earth's surface, which in turn affect regional climate, biodiversity and biomass, the freezing and thawing of permafrost, the seasonal supply of water for one sixth of the global population, the rate of global sea level rise and the risk of riverine and coastal flooding. Snow and ice are highly susceptible to climate change but although their spatial extents are routinely monitored, the fundamental property of their water content is remarkably poorly observed. Specifically, there is a profound lack of basic but problematic observations of the amount of water supplied by snowfall and of the volume of water stored in glaciers. As a result, the climatological precipitation of the mountain cryosphere is, for example, biassed low by 50–100%, and biases in the volume of glacier ice are unknown but are likely to be large. More and better basic observations of snow and ice water content are urgently needed to constrain climate models of the cryosphere, and this requires a transformation in the capabilities of snow-monitoring and glacier-surveying instruments. I describe new solutions to this long-standing problem that if deployed widely could achieve this transformation.

Contrasting Fate of Western Third Pole's Water Resources Under 21st Century Climate Change

“…The future water availability of the region, and even today's runoff regime, however, are both hotly debated and inadequately quantified. Challenges primarily stem from a lack of representative meteorological information in high elevations (Dahri et al., 2016; Immerzeel et al., 2015; Kan et al., 2018; Pritchard, 2021; Unger‐Shayesteh et al., 2013; Wortmann et al., 2018), inadequate representation of glacier‐hydrological process, and large spreads in future climate projections and downscaling approaches (Kraaijenbrink et al., 2017; Su et al., 2013), hindering a comprehensive understanding on the flow regime and future water availability in the mountainous TP (Pellicciotti et al., 2012; Ragettli et al., 2013, 2016). Precipitation regimes are poorly represented by in situ observations or multi‐sensor‐based gridded datasets across the TP region (Dahri et al., 2016; Immerzeel et al., 2015; Kan et al., 2018; Palazzi et al., 2013; Sun & Su, 2020; Sun, Su, He, et al., 2021; Tong et al., 2014; Wortmann et al., 2018) due to complex terrain, heterogeneous station networks, and diverse climate conditions across the region, and gridded products usually need correction before they can be used for hydrological modeling (Dahri et al., 2021; Li et al., 2020; Sun, Su, He, et al., 2021, Sun, Su, Yao, et al., 2021; Tong et al., 2014; Wortmann et al., 2018).…”

Land Surface Modeling in the Himalayas: On the Importance of Evaporative Fluxes for the Water Balance of a High‐Elevation Catchment

“…Studies on the spatial distribution of wind speed, relative humidity, cloud cover, and incoming shortwave radiation and precipitation would be beneficial to ongoing research for integrated catchment modeling. Whereas vertical temperature lapse rates can be extrapolated toward high altitudes with relative confidence due to a dense network of observations and a clear relationship with elevation, direct measurements to constrain the spatial distribution of precipitation are rare and generally limited to the lower zones of high‐elevation catchments (Pritchard, 2021; Winiger et al., 2005). Representing horizontal gradients in precipitation in such catchments would require reasonably high resolution reanalysis or atmospheric simulations (e.g., Collier & Immerzeel, 2015) which remains a future step for this work.…”

Knowledge Priorities on Climate Change and Water in the Upper Indus Basin: A Horizon Scanning Exercise to Identify the Top 100 Research Questions in Social and Natural Sciences

“…For example, only a handful of glaciers and rivers in the UIB are regularly revisited and directly measured (Arfan et al., 2019) and long‐term analyses are only possible in a few cases (Nüsser & Schmidt, 2021). Furthermore, our knowledge of the volume of water stored in glacier ice is poorly understood, as are estimates of snowfall (Pritchard, 2021). There is also a need for better data on socio‐demographic variables and human factors such as water demands, food demand, agricultural practices, cropping patterns, and infrastructure (Gioli et al., 2019; Rasul et al., 2019).…”