ACSYS: A Scientific Foundation for the Climate and Cryosphere (CliC) Project

The cryosphere, derived from the Greek word cryo for “cold”, is the term which collectively describes the portions of the Earth’s surface where water is in solid form, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps and ice sheets and permafrost and seasonally frozen ground. Thus, there is a wide overlap with the hydrosphere. The cryosphere is an integral part of the global climate system with important linkages and feedbacks generated through its influence on surface energy and moisture fluxes, clouds, precipitation, hydrology, atmospheric and oceanic circulation. Through these feedback processes, the cryosphere plays a significant role in global climate and in climate model response to global change. The World Climate Research Programme (WCRP) established the Climate and Cryosphere (CliC) Project in 2000 as an evolution from the Arctic Climate System Study (ACSYS) with a global focus on the cryosphere and all its components in the Earth system. The CliC Project coordinates and enables research on (a) terrestrial cryosphere and hydroclimatology of cold regions with special focus on the carbon budget and permafrost, (b) ice masses and sea level which includes ice sheets, ice caps and glaciers, (c) the marine cryosphere and climate which includes all forms of sea ice and (d) the global predictions and the cryosphere to improve the prediction for regional climate models with the inclusion of cryospheric components.