Atmos. Chem. Phys., 18, 6535–6542, 2018 https://doi.org/10.5194/acp-18-6535-2018 © Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License. Cryosphere: a kingdom of anomalies and diversity Vladimir Melnikov1,2,3, Viktor Gennadinik1, Markku Kulmala1,4, Hanna K. Lappalainen1,4,5, Tuukka Petäjä1,4, and Sergej Zilitinkevich1,4,5,6,7,8 1Institute of Cryology, Tyumen State University, Tyumen, Russia 2Industrial University of Tyumen, Tyumen, Russia 3Earth Cryosphere Institute, Tyumen Scientific Center SB RAS, Tyumen, Russia 4Institute for Atmospheric and Earth System Research (INAR), Physics, Faculty of Science, University of Helsinki, Helsinki, Finland 5Finnish Meteorological Institute, Helsinki, Finland 6Faculty of Radio-Physics, University of Nizhny Novgorod, Nizhny Novgorod, Russia 7Faculty of Geography, University of Moscow, Moscow, Russia 8Institute of Geography, Russian Academy of Sciences, Moscow, Russia Correspondence: Hanna K. Lappalainen (hanna.k.lappalainen@helsinki.fi) Received: 17 November 2017 – Discussion started: 12 January 2018 Revised: 20 March 2018 – Accepted: 26 March 2018 – Published: 8 May 2018 Abstract. The cryosphere of the Earth overlaps with the 1 Introduction atmosphere, hydrosphere and lithosphere over vast areas ◦ with temperatures below 0 C and pronounced H2O phase changes. In spite of its strong variability in space and time, Nowadays the Earth system is facing the so-called “Grand the cryosphere plays the role of a global thermostat, keeping Challenges”. The rapidly growing population needs fresh air the thermal regime on the Earth within rather narrow limits, and water, more food and more energy. Thus humankind suf- affording continuation of the conditions needed for the main- fers from climate change, deterioration of the air, water and tenance of life. Objects and processes related to cryosphere soils, deforestation, acidification of ocean waters and biodi- are very diverse, due to the following basic reasons: the versity losses. The Grand Challenges are threatening the se- anomalous thermodynamic and electromagnetic properties curity of upcoming societies. As stated in the Earth System Manifesto, humankind only has a 40-year window to avoid of H2O, the intermediate intensity of hydrogen bonds and the wide spread of cryogenic systems all over the Earth. a collapse of the Earth system (https://www.atm.helsinki.fi/ However, these features attract insufficient attention from peex/images/manifesti_peex_ru_hub2.pdf). research communities. Cryology is usually understood as a Especially strong environmental changes are observed and descriptive discipline within physical geography, limited to are expected to go on during the next decades in North glaciology and permafrost research. We emphasise its broad Eurasia and the Arctic Ocean (IPCC, 2014). The rate of the interdisciplinary landscape involving physical, chemical and changes in the Arctic Region is higher than elsewhere in the world (Smith et al., 2015; IPCC, 2013). Furthermore, the biological phenomena related to the H2O phase transitions and various forms of ice. This paper aims to draw the atten- threats from climate change and deterioration of the envi- tion of readers to the crucial importance of cryogenic anoma- ronment are redoubled by restricted natural resources, unre- lies, which make the Earth atmosphere and the entire Earth strained migration tendencies, and uncertainties in political system very special, if not unique, objects in the universe. and socio-economic developments (Smith, 2010). The totality of environmental problems in relation to hu- man activities in North Eurasia (the area north of 45◦ N, in- cluding the Arctic Ocean and between the Atlantic and Pa- cific Oceans in terms of latitude) is addressed in the recently launched international program “Pan-Eurasian Experiment” Published by Copernicus Publications on behalf of the European Geosciences Union. 6536 V. Melnikov et al.: Cryosphere: a kingdom of anomalies and diversity (PEEX) aimed at responding to the Grand Challenges faced (Maeno, 1988). With its crystals built uniquely by hydrogen by European countries, as well as Russia and China (Lap- bonds, ice provides a standard for estimating these bonds. palainen et al., 2014; Kulmala et al., 2015). The PEEX Sci- The complexity of the ice structure and its non-equilibrium ence Plan (Lappalainen et al., 2016) focuses on the Polar phase transitions are sufficient for self-organising syner- and Arctic regions and, specifically, on the cryosphere in the getic behaviour and formation of stable macroscopic objects, context of modern challenges of the North Eurasian environ- like the classical snowflakes or drop clusters in atmospheric ment. clouds (Shavlov et al., 2011). Historically, cryosphere research has been developed in the frame of physical geography with the major focus on glaciology and permafrost research. The present paper at- 4 Glaciation tracts the attention of the broad geoscience community of Glaciation is the most impressive cryogenic phenomenon on physicists, chemists, biologists and, prospectively, astro- Earth. Currently, ice covers more than 10 % of the Earth’s physicists to topical problems related to ice, snow and cold surface, but the area of glaciation was much larger in some in a wider interdisciplinary context, beyond the present con- periods of the Earth’s history. Traces of early Proterozoic ventional understanding (see above). glaciations (Huron, about 2300 myr ago) are found on all modern continents, which is evidence of global glaciation, 2 Cryosphere and cryogenic anomalies even taking into account the drift of continents. About 300 myr ago a large part of Gondwana was covered by ice Cold regions and natural phenomena related to cold are of- (John, 1979). ten described with terms using the prefix “cryo”, meaning The exact cause of glaciations remains debatable but their “cold”. The totality of phenomena on the Earth related to or cyclic nature is beyond doubt. The complex pattern of glacial linked with snow, ice or ice-like products (such as gas hy- cycles cannot be explained solely by orbital forcing of eccen- drates) comprises the Earth’s cryosphere (Fig. 1) – a com- tricity, obliquity, and precession that change in Milankovitch plex synergic system with self-organised constituents, which cycles (Milankovic,´ 1939), but also correlates with global ge- maintains the heat and mass exchange with the environment ological events. and spreads over the atmosphere, the hydrosphere, the litho- Glaciation obviously reduces the area of rocks exposed to sphere and the biosphere (Melnikov and Gennadinik, 2011). wind erosion and causes progressive CO2 increase though a The large extent of cryogenic objects, their variability in more active respiration of bacteria, which recycle dead or- space and time, as well as the discontinuity of the cryosphere, ganics at less active photosynthesis. This, in turn enhances have inspired development of special management technolo- the greenhouse effect of the atmosphere and thus increases gies. Such technologies, taking into account the stabilising the temperature. Due to this negative feedback, oscillations and bio-protective effects of ice, rooted in specific proper- in the cryosphere correlate with phases of global greenhouse ties of ice, have become applicable to the areas outside high gas and temperature cycles. There is also a positive feed- latitude and low temperature regions (Melnikov et al., 2010). back that controls ice surfaces waxing and waning (Le Hir Recent investigations of the cryosphere have yielded dis- et al., 2008). In particular, the increasing albedo may have covery and scientific description of a number of unique been responsible for the strongest glaciation about 800 myr natural objects and phenomena called “cryogenic anoma- ago, the “Snowball Earth” (Kirschvink et al., 1997). The ob- lies”. Below we consider examples of recently investigated served recent shrinking of areas covered by glaciers is often cryogenic anomalies, tentatively divided into six groups: ice attributed to anthropogenic factors, which became a real geo- structure, glaciation, ocean, atmospheric ice and water, biota logical force in the 20th century (Vernadsky, 1965). The true and cold and rates of processes. extent of this effect will be clear in the near future. The very existence of ice sheets changes the composition and physical properties of the lithosphere, the hydrosphere, 3 Ice structure and the atmosphere. Moving ice transports great amounts of material and, at the same time, preserves the entrained ob- Being a compositionally simple material, ice possesses di- jects. During glaciations, crust becomes denser, volcanism verse anomalous properties. It can exist in seventeen phase increases, ice sheets extended to the troposphere change the states, out of which eleven states are clearly expressed. This atmospheric composition and circulation, sea level falls and diversity is expressed in physico-chemical and biological climate changes. After the ice retreats, the formerly frozen processes, and in the types of precipitation: one type for rain, territories experience isostatic rebound and terrain smooth- eight types for snow, and two mixed water–ice types (Eisen- ing, changes in landscapes, such as formation of rivers and berg and Kauzman, 1975). There are paradoxically differ- lakes and changes in biota, such as species composition. ent properties brought together in ice: it is at the same time elastic and plastic, crystalline and amorphous, semiconduct-