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

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Chapter 10 · Synthesis

In terrestrial ecosystems, climate change impacts depend on a combination of temperature changes, snow cover changes and specific weather conditions. Seasonal snow cover plays a critical role in the hydrological regime and for plant and animal life. Snow depth has declined in inland regions but increased in coastal areas.Another observed trend is towards earlier snow-free dates (Chapter 2). In winter, the impacts of climate change are likely to be most pronounced when there is a sudden switch from sub- zero temperatures to conditions above freezing, and when temperatures fluctuate around freezing creating so-called rain-on-snow events. The long-term ecological implications of a warmer terrestrial environment are related to higher biomass production and changes in community structure. Arctic plants and animal species will be challenged by the spread of invasive species and new incidences of pests and diseases, particularly from 2030 onwards (Chapter 6). In some cases, such shifts may affect the structure and functioning of entire ecosystems,with implications for conservation management. In the Barents area, warming combined with changes in hydrology has already led to tall shrubs expanding their range, while mosses and lichens are declining. There are also changes in forest vegetation, with a shift from boreal evergreens to deciduous species (Chapter 6). Forest ecosystems are also increasingly affected by pest outbreaks and forest fires, with implications for forestry that require adaptive responses (Chapter 9). Freshwater ecosystems include lakes, rivers and wetlands that support large populations of migratory birds, provide drinking water and food, and regulate the flow of water within the landscape. Climate change drives changes in water flow and thawing permafrost, but these are also influenced by a range of other factors such as hydropower generation (especially dams), roads and pipelines (with direct impacts on peatlands), building, open pit mining, unregulated traffic, and surface contamination. Adaptation needs relate to changes in flood risk, movement of contaminants, and impacts on fish populations. In the Barents area, large rivers support major recreational fisheries and related businesses as well as subsistence fishing (Chapter 6). In the marine environment, a warmer climate entails warmer and less saline water, changes in sea-ice extent and thickness, and changes in sea level (Chapter 4). Ocean acidification is another concern (Chapter 4 and Browman, 2016). The reduction in sea ice and northward retreat of the ice edge is a major driver of change for marine species and ecosystems, especially those directly associated with the sea ice. Changes include increased phytoplankton productivity in previously ice-covered waters and the expansion of boreal zooplankton species at the expense of Arctic zooplankton species (Chapter 6). Whether increased productivity at the base of the food web translates into more abundant populations of fish and marine birds depends on many other factors, such as the timing of access to food,pressure fromharvesting,shifts in the spatial distribution of species, and ecological interactions.

Annika E. Nilsson

Bleiken wind farm, Västerbotten county, Sweden

Marine mammals within the Barents area are affected by the changes in community structure linked to the declining sea ice and are also sensitive to pollution and disturbance by human activities. Changes in seabird and marine mammal populations can serve as indicators of ecosystemhealth.They also have direct impacts on those local economies that rely on such species (i.e. tourism operators, hunters) (Chapter 5). Significant environmental challenges are associated with the spread of new species, from migration or through ballast water (Chapters 2 and 6).At a regional and sub-regional level, commercial fishing, increased transport of oil by tankers, and discharge of ballast water are considered the strongest ecological threats (Chapter 6).Other activities and sources of environmental impact in the region tend to be more localized. Changes in the marine environment also affect the coast. In addition to sea-level rise, reduced sea ice in combination with wind can result in significantly higher waves and storm surges, which is a challenge for coastal infrastructure.However,future projections are uncertain.This is because the land is still rising in some areas (as it continues to readjust to the disappearance of the heavy Fennoscandian ice sheet after the last glaciation) and because impacts depend on the nature of the coastline (low-lying erosion-prone coastlines versus steep rocky cliffs) as well as on the location and quality of coastal infrastructure. Changes in ecosystemswill in turn affect ecosystemservices,but the translation fromecosystem impacts to effects on ecosystem services alsodependon adaptation actions andonother changes in the social context. Chapter 2 highlights likely increases in wood production, summer outdoor recreation and species richness, and likely decreases in winter outdoor recreation and native Arctic species that have high cultural value (e.g. for hunting). Many other changes in ecosystem services are uncertain owing to a lack of knowledge about future species interactions, changes in land-use, and tourist behavior.