Adaptation Actions for a Changing Arctic: Perspectives from the Barents Area

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Chapter 2 · Status of the natural and human environments

2.2.1.1 Climate The natural landscape and species present in the Barents area of today result mainly from the present climatic conditions combined with past events. For the whole of the northern hemisphere,ice-sheet advances during the LastGlacialMaximum played a significant role in forming the present landscape. Even though the extent and thickness of the ice cap are a subject of scientific discussion (Kullman, 2002; Birks et al., 2005), the period undoubtedly affected the Barents area. The lake-rich postglacial terrain is perhaps the most dominant feature in mainland areas, presenting a landscape with a lake density (number of lakes per 1000 km 2 ) more than four times that of areas not previously covered by glaciers (Smith et al., 2007).The climate of the terrestrial areas within the Barents area is heavily influenced by proximity to the sea and its high latitude.The Gulf Streamalsomakes the entire region far warmer than comparable circumpolar areas at these latitudes, and mainland Norway, Sweden and Finland are regularly defined as sub-Arctic rather thanArctic. Present-day mean annual temperature (Figure 2.2), estimated for the period 1960–2015 (see Benestad et al., 2016 for data and gridding), ranges from about -18°C at Novaya Zemlya (Russia) to about 6°C on the west coast of Norway. Temperature is estimated to have increased by 1–2°C over the period 1954–2003, with warming strongest in winter (ACIA, 2004). See Chapter 4 for further discussion. Present-day mean annual total precipitation (Figure 2.2) estimated for the period 1960–2015 (see Benestad et al., 2016 for data and gridding) also demonstrates a gradient, from about 1700 mm on the Norwegian west coast to about 100 mm on Svalbard andNovaya Zemlya (Russia).Precipitation is estimated to have increased by 8% over the last century (ACIA, 2004). See Chapter 4 for further discussion of changes in precipitation. Changes in winter climate, in particular winter warming events affect snow property. If followed by freezing temperatures the snow pack will increase in density and can generate ice layers in the snow. Such ice layers may limit access to forage by reindeer (Vikhamar-Schuler et al., 2016) as well as shelter and access to

food for small rodents living below the snow (Fuglei and Ims, 2008), thus affecting predators dependent on the rodents. See Chapter 4 for more discussion on snow.

2.2.1.2 Forest and tundra ecosystems

Forest/Taiga The taiga (often referred to as boreal forest in the USA and Canada) constitutes the most widespread forest ecozone (Figure 2.3) in the Barents area, covering 54% of the land area on the mainland. It is bordered by Scandinavian coastal conifer forests (west), Scandinavian Montane birch forest and grasslands (northwest and upwards in the highlands and mountains),Kola Peninsula tundra (north),Northwest Russian- Novaya Zemlya tundra (northeast), Urals montane tundra and taiga (east) and Sarmatic mixed forests (south), and by the Baltic andWhite Seas. The taiga summer is one to three months long with an average temperature of 10°C, although some areas, mainly in the west have a more humid continental climate with milder winters and longer summers.The mean annual temperature is generally between -5°C and 5°C, although actual temperatures may range from -54°C to 30°C. A typical winter day has a temperature of -20°C while a typical summer day has a temperature of 18°C. Precipitation is relatively low throughout the year, generally 200–750 mm, but can reach 1000 mm in some areas, occurring mainly as rain during summer months,but also as fog and snow. The flora comprises coniferous forests dominated by pine ( Pinus sylvestris ) in drier locations, often with an understory of juniper ( Juniperus communis ), spruce ( Picea abies and P . obovata ) and a significant mixture of birch ( Betula pubescens and B . pendula ). Siberian larch ( Larix sibirica ) is characteristic of the eastern parts of the ecozone. Besides birch, broadleaf trees of aspen ( Populus tremula ), willow ( Salix spp.), and rowan ( Sorbus aucuparia ) also occur.Many smaller herbaceous plants grow on the forest floor, such as ferns, as

Temperature, °C

Precipitation, mm/y

-200

0

200 400 600 800 1000 1200 1400 1600

2000 1800

-16 -14 -12 -10 -8 -6 -4 -2 0 2 4 6

Figure 2.2 Present-day mean annual temperature (left) and mean annual total precipitation (right) estimated for the period 1960–2015.The data are based on station records from the European Climate Assessment & Dataset (ECA&D) project with methodology as per Benestad et al. (2016).