Merkel, F., Boertmann, D. & Mosbech, A. 2021. Davis Strait – an updated strategic environ- mental impact assessment of petroleum activities. Scientific Report from DCE – Danish Centre for Environment and Energy No. 439, 332 pp.
This document is an updated Strategic Environmental Impact Assessment (SEIA) of activities related to exploration, development and exploitation of oil and gas in the eastern Davis Strait (Merkel et al. 2012). The covered area is referred to as the Davis Strait assessment area and is situated between 62° N in the south and 67° N in the north and extends to the border of the Exclusive Economical Zone (EEZ) (Fig 1.1.1). The update is justified by the plan to open the area for ‘open door’ applications in November 2020.
The report has been prepared by DCE – Danish Centre for Environment and Energy and the Greenland Institute of Natural Resources (GINR) and funded by the Government of Greenland: The former Ministry of Industry, Energy, Science and Labour (today Ministry of Foreign Affairs and Energy) and the Environmental Agency for Mineral Resource Activities (EAMRA). The updated is based on published and unpublished sources made available since the first SEIA report in 2012.
The purpose of the SEIA is to provide updated information to support the decision process concerning potential future exploration and exploitation of oil and gas in the Greenland offshore areas of the Davis Strait. The presented information is also available for the companies operating in Greenland, for example for the preparation of Environmental Impact Assessments of their activities.
The SEIA is part of a series of five SEIAs covering the waters off entire West Greenland and Northeast Greenland, and the SEIA covering the adjacent waters to the north – the Disko West area – is also being updated.
The SEIA describes the environment – the physical rather briefly – and the biological in more detail. It describes nature conservation, threatened species and the human use of the living resources. It also gives a summary of contaminant levels as far as they are known. Based on that information, the potential environmental impacts of oil and gas activities (incl. oil spills) in the region are assessed. Finally, the report identifies research needs to be addressed to improve the data base for environmental impact assessments, authority regulation, oil spill response etc.
The different activities in a full life cycle of an oil field are briefly described and the environmental impacts of activities are as far as possible evaluated. However, as no oil have been exploited yet in Greenland and location of possible oil fields are unknown, it is difficult to evaluate effects and impacts from such activities, and the descriptions rely on experience from areas as similar as possible to the Greenland environment. These include the two large oil spills in the US (Exxon Valdez and Deepwater Horizon), the Norwegian SEIA of petroleum activities in the Barents Sea (Anon 2003) and the Oil and Gas Assessment by Arctic Council (AMAP 2010b). Note that the assessment does not assess the global climate impact of gasses released when potential oil and gas from Greenland fields is burned by consumers.
Due to the sea ice and weather conditions, exploration activities generally will take place in summer and autumn (June to November), while production will be a year-round activity.
The physical conditions of the study area are briefly described with focus on oceanography and ice conditions. The southern part of the assessment area generally has open water all year around, except for the most western part. In the north-western part sea ice is usually present from about February to May. During cold winters, ‘fastice’ is formed in the innermost parts of the fjords. Icebergs are occasionally present in late winter and early spring, but rarely encountered north of Fyllas Banke. This is explained by the pattern of currents, the bathymetry and the distant iceberg sources.
Among the most important features of the environment are the shallow-water banks along the west coast of Greenland. High water velocity at these banks creates strong upwelling, which in turn provides nutrients for sustained high primary productivity in these relatively shallow areas. Open drift ice can occur on the banks, but they are normally ice-free year-round, except for the Store Hellefiskebanke on the northern edge of the assessment area. The banks can sustain high productivity several months longer than the deep waters offshore. Another important feature of the area is the relationship between frontal hydrography, the marginal ice zone and plankton communities at the transition between the waters of Arctic and temperate origin. Moreover, there are physical and chemical differences between (the shallow and freshwater influenced) inshore and the offshore area. Therefore, physical processes in the frontal zones affect planktonic organisms in a number of ways, including nutrient entrainment, elevated primary and secondary production and plankton aggregation.
In general, the pelagic environment of the assessment area is characterised by low biodiversity (except for the benthos community) with often numerous and dense animal populations; a relatively simple food web from primary producers to top predators; and a few species playing a key role in the ecology of the region. The most significant ecological event in the marine environment is the spring bloom of phytoplankton (peaking in April/May), the primary producers in the food web. The phytoplankton bloom is trailing the receding ice edge and occurs all over the area. The phytoplankton are grazed upon by zooplankton, including the important copepods Calanus (mainly C. finmarchicus), which represent one of the key species groups in the marine ecosystem. Not only do the zooplankton transfer energy to consumers at higher trophic levels, such as fish, baleen whales and seabirds, but they also play a key ecological role in supplying the benthic communities with high quality food by means of their large and fast-sinking fecal pellet.
As the assessment area is situated within the sub-Arctic region, the marine environment is dominated by Atlantic species, such as the C. finmarchicus copepod. However, a recently discovered southward current along the South-west Greenland continental shelf, could imply that Arctic zooplankton will be more important in the offshore areas than at the more studied coastal sites. In addition, the biomass is expected to differ between offshore and inshore areas, with lower densities in the offshore areas.
The macroalgae are found along shorelines attached to hard and stable substrate, and may occur at a depth of more than 50m. Biomass and production of littoral and sub-littoral macroalgae can be significant and are important for higher trophic levels of the food web as they provide substrate for sessile animals, shelter from predation, protection against wave action as well as currents and desiccation or are utilised directly as a food source. During the dark winter period when phytoplankton is absent, the kelp carbon becomes increasingly important as a food source for the macrofauna. In general, the production of kelp is high in the assessment area due to the year-round open water period in most of the area. Unique for the assessment area is the presence of seagrass, Zostera marina (a red listed species), which forms dense meadows on soft and sandy seabeds in fjord arms around Nuuk. Also, the coralline red algae Corallina officinalis is only found in the Nuuk area in Greenland. Further, loose-lying branched species of coralline red algae, rhodoliths, are present in the Nuuk area.
The seabed macrofauna (benthos) consume a significant proportion of the available production and, in turn, are an important food source for fish, seabirds and mammals. The assessment area has the largest number of historical sampling stations and holds more than 1000 registered species of benthic invertebrates. Recent studies have revealed a highly heterogenous substrate composition as well as local species richness of soft bottom infauna as high as >80 species/taxa per 0.1m2 grab sample. Species characterizing benthic VME’s (Vulnerable Marine Ecosystems, according to FAO criteria for vulnerability to bottom trawling) have been found several times, and recently Greenland’s first soft coral garden habitat was described within the assessment area and found to represent a true benthic VME-candidate, covering a 486 km2 area spanning ~60 km of continental slope.
Sea ice is a highly dynamic and extreme environment with large vertical variations in the ice in light conditions, temperature, salinity and nutrient availability. Organisms living inside the brine channels and at the bottom of the sea ice include viruses, bacteria, algae, ciliates, heterotrophic flagellates, amphipods and copepods. Studies conducted outside the assessment area show that the sea ice primary productivity is of great importance for the higher trophic levels in the Arctic food chain at times of the year where the pelagic and benthic productions are low. Studies conducted within the assessment area are largely missing, including studies of the ‘west-ice’ in the north-western part of the assessment area.
Fish fauna in the offshore areas, including the marine shelf, is dominated by demersal (bottom living) species such as Greenland halibut, Atlantic halibut, redfish, wolffish and several less commercially interesting species. For the Greenland halibut, which is highly important for the commercial fishery (see below), the main spawning ground is presumed to be located within the assessment area and is important for stock recruitment both within and outside the assessment area (Northwest Greenland and Canada). Sandeel occur in dense schools on the banks and are important prey for some species of fish, seabirds and baleen whales. In the coastal zone, three important species spawn: Atlantic cod, capelin and lumpsucker. The capelin is important prey for larger fish, marine mammals, seabirds and for human use. Both the Atlantic cod and lumpsucker (the eggs) are utilised on a commercial basis. Arctic char is also an important species of the coastal waters and is the target of much recreational fishing. Other species utilised in small-scale commercial or subsistence fisheries include Atlantic salmon, Atlantic halibut and wolffish.
Seabird colonies are numerous in the assessment area, but typically smaller in size compared with more northern breeding areas in West Greenland. In
total, 20 species are known as regular breeders in the assessment area and the highest density of colonies is found in the extensive archipelago between 63° and 66°, despite the fact that not all areas have been thoroughly surveyed for breeding birds. Two species are rare breeders to Greenland, the Atlantic puffin and the common murre, which are listed as vulnerable and endangered, respectively, on the Greenland Red list.
For 13 bird species the importance of the assessment area is classified as ‘high’ on a national or international scale due to the number of breeding, moulting or wintering birds (Tab. 3.7.1). The assessment area is especially important as a wintering area. It makes up a large proportion of the open water region in Southwest Greenland, where large numbers of seabirds from Russia, Iceland, Svalbard and Canada assemble from October to May. More than 3.5 million birds are estimated to winter in the coastal areas alone. The most abundant species are thick-billed murre, common eider, king eider and little auks. A large, but unknown number of seabirds also migrate through or winter in the offshore areas.
Marine mammals are significant components of the marine ecosystem. Five species of seal occur in the assessment area, of which harp seals are numerous throughout the area during most of the year. Another species, the harbour seal, is listed as critically endangered in Greenland. The northernmost part of the assessment area overlaps with the southern edge of a key wintering habitat for walruses. Among the whales, several baleen whales, such as minke whales, fin whales, humpback whales and sei whales, are seasonal inhabitants of the assessment area and relatively abundant. The area is part of their foraging area during summer and the distribution of the whales often correlates with their main prey: capelin, krill and sandeel. However, recent surveys from 2015 indicate a shift, or fluctuation, in the main distribution of minke, fin and humpback whales from West to East Greenland. The bowhead whale migrates through the assessment area in the period January-February towards feeding and possibly mating grounds just north of the assessment area. Several toothed whales are common in the assessment area: harbour porpoise, long-finned pilot whale, northern bottlenose whale and white-beaked dolphin. The southern wintering grounds of beluga whales and narwhals extend into the northern part of the assessment area. Polar bears occur during winter and spring, depending on and in association with the very variable sea ice cover.
Nature protection and threatened species
The fjord Ikkattok and adjacent archipelagos near Paamiut are designated as wetlands of international importance under the intergovernmental environmental treaty, the Convention on Wetlands (the Ramsar Convention), also known as Ramsar sites.
Three areas within the assessment area are protected according to the Nature Protection Act. However, two of these are inland sites and will not be affected by offshore oil activities. The third site is the island of Akilia near Nuuk, which is close to the outer coast and protected due to geological interest (Fig. 4.1.1). Seven sites are protected as seabird breeding sanctuaries under the Bird Protection Executive Order and all seabird breeding colonies are protected from disturbing activities according to the same Order.
With reference to the Mineral Extraction Law, several areas are designated as ‘areas important to wildlife’ and here mineral (and hydrocarbon) exploration activities are regulated in order to protect wildlife. This include, for example, the most important seabird breeding colonies
Greenland issued in 2018 a new updated and enlarged list of threatened species – a red list. According to this, ten species of mammals, twelve birds and one fish species occurring in the assessment area are evaluated as threatened or near threatened (Tab. 4.3.1). The international red list from IUCN classify ten marine mammals and five birds from the assessment area as threatened or near threatened (Tab. 4.3.3)
Human impacts in the assessment area
The assessment area is impacted of several human activities and the SEIA gives a brief summary of some of these, as they can interact with the impact from oil and gas activities.
The levels of heavy metals (primary mercury) and POP’s (Persistent Organic Pollutants) are monitored coordinated by AMAP as they bio-accumulate in top predators including humans living from hunting and fishery. Especially mercury is a concern because the levels are relatively high and may increase in the assessment area. Lead have been decreasing and there is no temporal trend in Cadmium. The levels of POP’s are expected to decrease due to international regulation, but new contaminants are emerging from the industrialized areas in Europe, North America and Asia, and they appear also in Greenland.
The most toxic substances in oil are the PAH’s (Polycyclic Aromatic Hydrocarbons), but the levels are in general low in the assessment area, except close to harbours.
Contamination with plastic is increasing. Micro plastic (<5 mm) has been found everywhere in the Arctic environment, from plankton and whales. Macro (> 25 mm) and meso (5-25 mm) plastic have been found in the stomach of fish, birds, seals and whales. In addition, birds and marine mammals can become entangled in fishing gear made of plastic. The sources in the assessment area, are to a large degree local, but plastics are also transported to Greenland by ocean currents.
Human use – hunting and fishery
Human use of natural resources occurs throughout the assessment area; subsistence and small-scale use is extensive in the coastal areas, while there are substantial commercial fisheries in the offshore parts. Due to open water being present all year round in most coastal areas, commercial, subsistence and recreational hunting is possible throughout the year, except in legally closed seasons. Seabirds are among the most popular hunted resources and are bagged in large numbers, although gradually declining over the past two or three decades. The most important species are thick-billed murre and common eider. Seals are also harvested in large numbers in the assessment area. The skins are purchased and prepared for the international market by a tannery in South Greenland and the meat is consumed locally. The most important species is the harp seal. Walruses, belugas and narwhals are caught during winter and spring in the northern part of the assessment area and regulated by quotas.
Also harbour porpoises, minke whales, fin whales and humpback whales are caught in the assessment area, with harbour porpoise and minke whale as far the most numerous species. Minkes and humpback and fin whales are subject to annual quotas set by the IWC. Quotas also regulate polar bear catches, but only a few animals are shot every year in the assessment area.
Commercial fisheries represent the most important export industry in Greenland, accounting for 90% of the total Greenlandic export revenue (4.1 billion DKK in 2018). Greenland halibut, deep-sea shrimp and snow crab are the main commercially exploited species within the assessment area and annual catches make up a large proportion of total landings in Greenland, although the proportion of shrimps taken in the assessment area has decreased considerably in the last five years. More shrimps are now caught north of the assessment area. The Atlantic cod fishery has increased over the past decade, but recruitment appears to fluctuate quite a bit. Compared with historical levels (1960s) catches are still small. In the coastal area, various species are exploited on a small-scale commercial, subsistence or recreational basis, such as lumpsucker, wolffish, redfish, Atlantic cod, Greenland cod, capelin and Atlantic salmon.
Tourism is a growing industry in Greenland and now counts as the third largest economic activity in the country. The total number of guests in Greenland in 2019 was 105,000 or 266,000 ‘bed nights’, of which more than half went to the assessment area, especially Nuuk. In addition, cruise ships bring in tourists in ever increasing numbers. The coastal marine area is very important for tourist activity.
Climate scenarios for the Baffin Bay – Davis Strait region forecast local summertime air temperature increases of 1 to 4 °C by 2030 and 1.5 to 10 °C by 2080 (relative to 1986–2005), corresponding to an average surface water warming of 0.2 °C per decade over the next 50 year. In the northern region less sea ice will lead to a longer phytoplankton growing season, but, on the other hand, more precipitation and more freshwater from the melting Ice Sheet may lead to a stronger stratification of the water column, which could result in reduced nutrient supply from the deeper layers to the photic zone. The assessment area is, to some extent, already ice-free year-round, so future changes of the ecosystem is mainly expected to be caused by warming and possible changes in upwelling, stratification and mixing forces.
Implications for fisheries and hunting are likely to occur within the assessment area and future sustainability of human use will likely depend on flexible management plans, which will facilitate the use of new or alternative living resource. For some populations, climate change may act as an additional stressor in relation to existing impacting factors such as fishery or hunting, leading to higher sensitivity to oil spill incidents. Other populations may become more abundant and robust as a consequence of climate change. Species composition may also change, with some species disappearing or moving north, as currently observed for the northern shrimp, and other species moving in from the south, taking advantages of increasing water temperatures, like the Atlantic cod or the Atlantic mackerel.
To follow such changes, monitoring of and research in the ecosystems of the assessment area will be an important input to future ecosystem-based management of the human activities.
When the impacts of oil and gas activities shall be assessed, it is important to include cumulative impacts. These occur both between oil and gas related activities (e.g. multiple seismic surveys either simultaneously or consecutive) and with other human activities and climate change.
Assessment of oil and gas activities in the Davis Strait assessment area
The assessments presented here are based on our present knowledge concerning the distribution of species and their tolerance and threshold levels toward human activities in relation to oil exploration and production. However, the Arctic is changing due to climate change and this process seems to be accelerating. This means that conclusions and assessments may need to be adjusted in the future. Furthermore, a large part of the assessment area is poorly studied and increased knowledge may lead to additional adjustments.
The main environmental impacts of exploration activities derive from noise generated either by seismic surveys or the drilling platforms and from cuttings and drilling mud if these are released to the sea during the drilling process.
The species most sensitive to noise from seismic surveys in the assessment area are the baleen whales (minke, fin, sei and humpback) and toothed whales such as sperm and bottlenose whales. These may be in risk of being displaced from parts of their critical summer habitats. A displacement would also impact the availability of whales to hunters if the habitats include traditionally hunting grounds. Narwhals, beluga whales, bowhead whales and walruses are also sensitive to seismic noise, but their occurrence in the assessment area only overlaps briefly with the time in which seismic surveys would take place.
As seismic surveys are temporary, the risk for long-term population impacts from single surveys is low. But long-term impacts have to be assessed if several surveys are carried out simultaneously or in the same potentially critical habitats in consecutive years (cumulative effects). 3D seismic surveys, which are typically conducted in small areas, may cause more severe temporary impacts.
The fishery at risk of impact from noise from seismic surveys in the assessment area is the Greenland halibut fishery. The risk is temporary (days or weeks) displacement of fish and consequently reduced catches from the trawling grounds. Although the precise location of the Greenland halibut spawning grounds is not known, planning of seismic surveys in the area where spawning is expected to take place should consider avoiding overlap with the spawning period (early winter). The fishery for northern shrimp and snow crab will probably not be affected.
Noise from drilling rigs will also be temporary, but locally more permanent than seismic surveys. The most vulnerable species in the assessment area are cetaceans (whales and harbour porpoises) and the walruses. If alternative habitats are available to the whales no effects are expected, but if several rigs operate in the same region there is a risk of cumulative effects and displacement even from alternative habitats.
Drilling mud and cuttings that are released to the seabed. Due to environmental concerns oil-based mud is brought to land to be treated, while water-based mud is acceptable to release as long as the added chemicals are not hazardous. Within the assessment area local effects on the benthos are expected from discharging the water-based muds. Any drilling should be avoided in the most vulnerable areas. Baseline studies at drill sites must be conducted prior to drilling to document whether unique communities or species such as coldwater coral and sponge gardens are at risk of being harmed by increased sedimentation. Post-drilling studies should be carried out to document whether activities caused any specific effects. The most efficient way to reduce impacts on the seabed is a no release solution, where all the drilling waste is brought to land or re-injected into the well.
Exploration drilling is an energy-intensive process emitting large amounts of greenhouse gases. Even a single drilling will increase the Greenland contribution to global emissions significantly.
Finally, there is a risk of oil spills during exploration drilling (see below).
Assessment: development and production
Activities during development, production and transport are long-lasting and several activities have the potential to cause severe impacts on the environment. The impacts will depend on the number of activities, how far they are dispersed in the areas in question, and also on their duration. However, these impacts can be mitigated through thorough planning based on background information from the local environment, application of HSE-procedures (Health, Safety and Environment) and BAT (Best Available Technique) and BEP (Best Environmental Practice) and finally secured by strict authority regulation. There is however, a general lack of knowledge on cumulative and long-term impacts for example from the release of produced water even when applying the before mentioned initiatives.
Emissions and discharges
Drilling will continue during development and production phases and drilling mud and cuttings will be produced in much larger quantities than during exploration. Discharges should be limited as much as possible by recycling and reinjection and only environmentally safe substances (such as the ‘green’ and ‘yellow’ substances classified by OSPAR) tested for toxicity and degradability under Arctic conditions should be permitted to be discharged. In Greenland the use of ‘black’ chemicals is not permitted and use of ‘red’ chemicals requires specific permission. Even the non-toxic discharges alter the sediment substrate and if these substances are released to the seabed impacts must be expected on the benthic communities near the release sites.
Produced water is by far the largest discharge to the environment, for example is the annual release on the Norwegian sector about 148 million m3. Even though produced water is cleaned and meet international standards, concern for long-term effects in the marine environment have been expressed. For example, produced water in ice covered areas may accumulate under the sea ice and here affect eggs and larvae of the ecological key species polar cod. The best way to mitigate such effects is a zero-discharge policy, where the produced water is re-injected.
Discharge of ballast water is also of concern as this carries the risk of introducing non-native and invasive species. Ballast water must therefore be handled and discharged subject to specific rules. The IMO ballast water management convention was adopted in 2017, and guidelines has been issued (IMO Link). All vessels and drilling units involved in hydrocarbon activities in Greenland should follow the IMO guidelines or the relevant Canadian regulations (Link). The problem with invasive species is currently not severe in the Arctic, but the risk will increase with climate change and the intensive tanker traffic associated with a producing oil field.
Development of an oil field and production of oil are energy-consuming activities that would contribute significantly to the Greenland emission of greenhouse gases. A single large Norwegian production field for example, release almost three times as much as the total Greenland CO2 emission of today.
Noise from drilling and the positioning of machinery, which will continue during the development and production phase, may potentially lead to permanent loss or displacement of important summer habitats for cetaceans, especially if several production fields are active at the same time. Noise from ships (incl. ice-breaking) and helicopters, which becomes more persistent than in the exploratory phase, can both affect marine mammals and seabirds. The most sensitive species within the assessment area are the colonial seabirds, bowhead whales, narwhals, beluga whales, minke whales, fin whales, harbour porpoises and walruses – species that may associate noise with negative events (hunting). Traditional hunting grounds may also be affected. Applying fixed flying lanes and altitudes will reduce impacts from helicopter noise.
Placement of structures
Placement of offshore structures and infrastructure may locally impact seabed communities and there is a risk of spoiling important feeding grounds – walrus is highly sensitive, but occurs mainly north of the assessment area. However, feeding areas for king eiders wintering at the shallow-water shelf banks (especially Fyllas Banke) may also be at risk. Inland structures may locally impact breeding birds; obstruct rivers, with implications for anadromous Arctic char; damage coastal flora and fauna; and have an aesthetic impact on the pristine landscape, which in turn may impact the local tourism industry.
A specific impact on fisheries is the exclusion/safety zones (typically 500 m) that will be established both around temporary and permanent offshore installations. These may affect some of the important fishing areas for Greenland halibut and northern shrimp.
Illuminated structures and flares may attract seabirds in the hours of darkness, and there is a risk of mass mortality especially for eiders and possibly little auks.
There will be a risk of cumulative impacts when several activities take place either simultaneously or consecutive. For example, seismic surveys have a high potential for cumulative impacts. Cumulative impacts may also occur in combination with other human activities, such as hunting, or in combination with climate change.
The best way of mitigating impacts from development and production activities is to combine a detailed background study of the environment (in order to locate sensitive ecosystem components) with careful planning of structure
placement and transport corridors. Subsequent application of BEP, BAT and compliance with international standards such as OSPAR and HOCNF can do much to reduce emissions to air and sea.
Assessment: Oil spill
The most environmentally severe accident from the activities described above would be a large oil spill. Accidental oil spills may occur either during drilling (blowouts) or from accidents when storing or transporting oil. Large oil spills are relatively rare events today and the global trend in spilled amounts of oil is decreasing. Nevertheless, the risk is evident and the environmental impacts from a large spill can be severe and long-lasting.
Oil spill simulations (examples of potential trajectories of oil spills) were carried out for six locations within the assessment area – three sites in the shelf-region and three sites further offshore (Fig. 8.3.1). In general, for the offshore simulations, the oil spill trajectory was towards the southwestern part of the assessment area, potentially affecting an offshore area between Greenland and Canada with a rough estimation of 70,000 km2.. Oil spilled in the shelf-region had a somewhat similar behavior, however, one simulation had a northgoing path before bending off towards southwest. In two of the shelf-region spill sites, the oil also affected the coast. In all simulations, small proportions of the oil (< 5%) could potentially reach the seabed.
Large oil spills have the potential to impact all levels in the marine ecosystem, from primary production to the top predators. A large oil spill represents a threat at population and maybe even species level and the impacts may last for decades, as documented for Prince William Sound in Alaska. For some populations oil spill mortality can to an extent be compensatory (be partly compensated by reduced natural mortality due to less competition), while for others it will largely be additive to natural mortality. Some populations may recover quickly while others will recover to pre-spill conditions very slowly, depending on their life strategies and population status. For species which are vulnerable to oil spills and are also harvested, oil spill impacts could be mitigated by managing the harvest wisely and sustainably. The lack of efficient response methods in partly ice-covered waters and remoteness will add to the severity of an oil spill.
For this impact assessment the offshore areas are divided into eight sub-areas and classified according to their sensitivity to oil spill, taking into account the relative abundance of species/species groups; species or population specific oil sensitivity values; oil residency; human use; and a few other parameters. During all seasons the offshore areas closest to the coastal zone covering the shelf bank areas are among the most sensitive areas. These areas are especially important for migrating/wintering seabirds, human use of northern shrimp and snow crab, and as foraging areas for baleen whales. During spring and winter the southwest corner of the assessment area is also classified as highly sensitive to oil spill due to extensive Greenland halibut fishery and whelping areas for hooded seals in the western pack ice in March and April.
A comparison of seasons, based on absolute sensitivity values and averaged across all offshore areas, shows that winter is most sensitive to oil spill, closely followed by spring and autumn, while summer is least sensitive to oil spill. The main reason for this difference is the large number of wintering/migrating seabirds during winter, spring and autumn, which are all very sensitive to oil (especially auks and seaducks).
The coastal zone of the assessment area is even more sensitive to oil spill due to a higher biodiversity and due to the fact that oil may be trapped in bays and fjords where high and toxic concentrations can build up in the water. There is the potential for a number of negative impacts – on spawning concentrations of fish, such as capelin and lumpsucker, in spring; Arctic char assembling outside their spawning rivers; and on many seabird populations in summer, during migration periods and especially in winter when seabirds from a variety of breeding locations in the North Atlantic gather in Southwest Greenland. Long-term impacts may occur in the coastal zone if oil is buried in sediments or among boulders, in mussel beds or is imbedded in crevices in rocks. Oil seeps from these sites and causes chronic pollution which may persist for decades. In Prince William Sound in Alaska such preserved oil has caused negative long-term effects on e.g. birds utilising the polluted coasts and some populations have not recovered. The coastal zone is also of crucial importance for local hunters and fishermen, and in the case of an oil spill, these activities may be adversely affected by closure zones and/or by changed distribution patterns of the targeted species. The tourist industry in the assessment area will probably also be impacted negatively by oil exposure in the coastal area.
Another vulnerable feature is the winter/spring period with ice-covered waters in the northern and western part of the assessment area. Spilled oil would be contained between the ice floes and on the rough underside of the ice. However, oil in ice may be transported in an almost un-weathered state over long distances and when the ice melts may impact the environment, e.g. fish larvae, seabirds and marine mammals, far from the spill site. Oil may also be caught along ice edges and in marginal ice zones with sensitive aggregations such as primary producers, seabirds and marine mammals.
In general, accidents are best mitigated by careful planning, strict Health, Safety and Environment (HSE) procedures and application of the Precautionary Principle in combination with BEP, BAT and international standards (OSPAR). However, knowledge of the behaviour of spilled oil in ice environments is very limited and the technology for cleaning up oil spills in ice-covered waters is inadequate and in need of further development.
Primary production and zooplankton
It is assessed that the impact of a surface oil spill in the assessment area on primary production and zooplankton in open waters will be low due to the large temporal and spatial variation in these events and occurrences. There is, however, a risk of impacts (reduced production) in localised primary production areas and the spring bloom will be the most sensitive period. However, if a large subsea plume of dispersed oil in toxic concentrations occurs, stronger impacts than from a surface spill must be expected, especially on primary producers, zooplankton and fish/shrimp larvae.
Fish and crustacean larvae
In general, eggs and larvae of fish and crustacean are more sensitive to oil than adults and may theoretically be impacted by reduced annual recruitment with some effect on subsequent populations and fisheries for a number of years. Atlantic cod is especially sensitive as their eggs and larvae can be concentrated in the upper 10m of the water column, whereas larvae of shrimp and Greenland halibut, for instance, are found deeper and would therefore be less exposed to harmful oil concentrations from an oil spill at the surface. However, a subsea blowout with the properties and quantities of the Deepwater Horizon spill (more than 800,000 tonnes, the largest peace-time marine oil spill ever) may expose eggs and larvae over much larger areas and depth ranges and may potentially also impact the recruitment and stock size of other species, such as shrimp, Greenland halibut, snow crab and sandeel.
Bottom-living organisms such as bivalves and crustaceans are vulnerable to oil spills; however, no effects are expected in the open water unless oil sinks to the seabed. In shallow waters (< 10-15m), highly toxic concentrations of hydrocarbons can reach the seafloor with possible severe consequences for local benthos and thereby also for species utilising the benthos – especially common eider, king eider, long-tailed duck, bearded seal and walrus. A subsea spill with the size and properties of the spill from the Deepwater Horizon in the Mexican Gulf has the potential to impact the seabed communities in deep waters too.
Impacts from a surface spill on adult fish stocks in the open sea are not expected. The situation is different however in coastal areas, where high and toxic oil concentrations can build up in sheltered bays and fjords resulting in high fish mortality (see above). Once more, a large subsea blowout could represent an exception as far as low impact is concerned. Considerable plumes of dispersed oil can occur in the water column from a subsea blowout and may impact the fish both directly or through the food chain. Greenland halibut would be exposed in both ways, because they move up from the seabed to the pelagic waters to feed.
An oil spill in the open sea will affect fisheries mainly by means of temporary closure in order to avoid contaminated catch. Closure time would depend on the duration of the oil spill, weather, etc. The offshore fishery for Greenland halibut within the assessment area is large and a closure zone would probably extend further west and cover Canadian fishing grounds too. The reason is that Greenland halibut moves considerable distances over a very short time and contaminated (tainted) fish may move out of the assessment area and be caught far from a spill site.
The assessment area is also among the most important fishing grounds in Greenland for northern shrimp and snow crab, and closure zones may also have significant economic consequences for this section of the fishing industry.
Oiled coastal areas would also be closed for fisheries for a period – the duration of the closure would depend on the behaviour of the oil. There are examples of closure for many months due to oil spills, particularly if oil is caught in sediments or on beaches. The commercial inshore fishery targets primarily lumpsucker and local populations of Atlantic cod, while capelin form part of the subsistence and recreational fishery.
Seabirds are extremely vulnerable to oil spills in the marine environment as they usually spend much time at the surface where most oil spills occur. Their plumage is highly sensitive to oil, as only small amounts can destroy its insulation and buoyancy properties. Exposed birds usually die from hypothermia, starvation, drowning or intoxication. In the assessment area the coastal zone is particularly sensitive as high concentrations of seabirds are found all year around. A substantial number of these birds, including breeding birds, moulting birds as well as wintering birds, are associated with habitats along the highly exposed outer coastline. In these areas, oil spill response is hampered by remoteness, the complex coastal morphology and the often harsh weather conditions. The seabird species most vulnerable to oil spills are those with low reproductive capacity (low population turnover), a trait especially found among auks, fulmars and many seaducks. These species, e.g. thick-billed murres, little auks, eiders and long-tailed ducks, winter in the assessment area in large numbers as Southwest Greenland constitutes an international wintering area for seabirds from a range of breeding locations in the North Atlantic.
During autumn and winter, a number of species are also at risk further offshore in the assessment area, including the shelf areas; although birds tend to be more dispersed in the open water compared to coastal habitats. Some of the important species include northern fulmar, black-legged kittiwake, puffin, little auk, thick-billed murre, black guillemot and king eider. Especially the king eider is vulnerable in the offshore area as the birds assemble in large dense flocks on the shallow-water shelf banks during winter (Fyllas Banke and Store Hellefiskebanke). A major oil spill in these areas could seriously affect this population.
Polar bears and seal pups are highly vulnerable to direct oiling and even short exposures can be lethal, as the oil affects the insulation properties of the fur. There are seal whelping areas in the assessment area (see below), while polar bears are associated with the Davis Strait pack ice, of which the extent lying within the assessment area varies.
Whales, seals and walruses are vulnerable to surface oil spills. The baleens of the baleen whales may become smothered with oil. This may lead to toxic effects and injuries in the gastrointestinal tract if oil is ingested. There is also the potential for inhalation of oil vapours and direct contact of the oil with eye tissues. The extent to which marine mammals actively avoid an oil slick and also how harmful the oil would be to fouled individuals is uncertain. However, observations indicate that at least some species do not perceive oil as a danger and have repeatedly been reported to swim directly into oil slicks.
Marine mammal species affected by an oil spill during winter in the assessment area could include bearded seal, hooded seal, ringed seal, harbour seal, bowhead whale, narwhal, white whale, polar bear, harbour porpoise, walrus, bottlenose whale and sperm whale. Harbour seals are especially vulnerable as they are endangered in Greenland, and hooded seals too, because whelping patches are located in the eastern Davis Strait pack ice. Marine mammals that use the area as a feeding ground during summer include harp seal, hooded seal, ringed seal, harbour seal, fin whale, humpback whale, minke whale, sei whale, harbour porpoise, white beaked dolphin, bottlenose whale, sperm whale, and pilot whale. Blue whale occurs only rarely in the assessment area but is vulnerable due to its very small population.
Mitigation and oil spill response
It is recommended that environmental impacts from oil and gas activities are mitigated by including detailed background knowledge on the environment in the planning of the activities. It is further recommended to combine this information with BAT, BEP, international standards (e.g. OSPAR) and guidelines (Arctic Council) to ensure that pollution from discharges to sea and atmosphere are kept within acceptable limits and minimise the risk of accidents. If the regulation of activities is based on detailed background knowledge, it allows for exchanging the precautionary principle with empirical knowledge to the benefit of both operators and the environment.
Oil spill contingency and response
The environmental risk of large oil spills can be minimized by applying the highest health, safety and environmental standards (HSE) combined with the highest technical standards (BEP and BAT). However, the risk of oil spills is always present and a fast, robust and efficient oil spill response must be in place to counteract spilled oil. Three methods have been used to counter act oil spills. Mechanical recovery, chemical dispersion and in situ burning.
Mechanical recovery was not efficient during the two large oil spills in the US. The method is moreover difficult to apply in harsh weather conditions and when the oil is to be recovered from waters with ice. It is moreover labour demanding and requires extensive logistics.
Chemical dispersion requires fast response before the oil is too weathered to be dispersed. Cold conditions can extend the operational window for dispersion. Dispersion transfer the oil from the sea surface to the water column, where it can affect organisms, which would not be affected from surface oil. The method requires a comparative analysis of environmental pros and cons, a SIMA (Spill Impact Mitigation Assessment) before it can be applied. Dispersion will also facilitate natural degradation of the oil, which in Greenland waters, however, seems often to be of limited use, because of low nutrient availability.
In situ burning has proven promising under arctic conditions, where stable ice can act as barrier to oil on the surface. The method has, however, only been tried under test conditions, and it is questionable if it can be applied in dynamic drift ice, such as the sea ice in the assessment area.
The three response methods have their own environmental impacts. Mechanical recovery can in coastal habitats impact flora and fauna, dispersing agents have their own toxic impacts and in situ burning sends large amounts of soot into the atmosphere and leaves residues on surface and seabed. These environmental impacts shall be weighed to the impacts from the oil itself, on a strategic level (Environment & Oil Spill Response tool, EOS), and in an operational situation by a SIMA.
Recommendations from DCE and GINR on area restrictions
The DCE and GINR recommendations on area restrictions for oil exploration (hydrocarbon licence) in this strategy period are based on three selection criteria: 1) Areas already appointed as especially valuable areas on a national scale, in terms of ecological and biological value and sensitivity to oil spills, or new valuable and sensitive areas identified in this assessment, 2) the distance to the coast and the sensitivity of the coastline, because it is difficult to protect the coast in a nearshore spill and 3) the probability of ice, because effective oil spill methods in drift ice do not exist.
None of the especially valuable areas (criteria 1) previously identified on a national scale is located within the Davis Strait assessment area. Among the important areas identified or confirmed within the assessment area (and not covered by criteria 2 and 3), is an offshore area consisting of a soft coral garden. This area is also recommended as a candidate for area restriction. With respect to criteria 2, DCE /GINR recommend to consider a coastal protection zones corresponding to zones used in northern Norway, and DCE/GINR propose a 65 km coastal protection zone in three areas with high biological value and high sensitivity, namely the fjords and surroundings of Nuuk, the fjords and surroundings of Maniitsoq and an area south of Sisimiut. For the remaining coastline DCE/GINR recommend a 35 km protection zone. Concerning ice cover (criteria 3), DCE and GINR recommend to consider allowing oil activity only if the ice cover is below a certain value, which we recommend to be somewhere in between the one defined by the Norwegian criteria of 15% ice frequency and the 30% mean sea ice cover in March (see Chapter 9).
There is a general lack of knowledge on many of the ecological components and processes in the Davis Strait area. Identification of knowledge gaps for environmental management and regulation of future oil activities in the Davis Strait is presented in Chapter 9. To manage future oil activities, more information is required in order to: a) assess, plan and regulate activities to minimise the risk of impacts; b) identify the most sensitive areas and update the Oil Spill Sensitivity Atlas; c) establish a baseline to use in ‘before and after’ studies for impacts from any large oil spills.
Glossary to some terms used in the SEIA
Environmental pressures: These are the results of specific human activities in the environment. The activities can for example be hunting and fishing, shipping or mineral extraction and on a larger scale also climate change. The term ‘stressor’ is often used in this context.
Environmental impact or only impact is the way a specific pressure act on the environment. It is less specific than effect, and used in the sense of impact on an environmental element for example the impacts of a seismic survey on the population of narwhals. See also environmental effect.
Environmental effect or only effect is the result of a specific impact for example the toxic effect of a chemical in the drilling mud or the effect of noise generated by a seismic survey, such as displacement or temporal hearing loss. See also environmental impact. Effects and impacts are to some extend synonyms.
Sensitive: This is an intrinsic characteristic of the ecological elements (organisms, processes – VEC’s), independent of human activities. For example, narwhals are particularly sensitive to underwater noise. See also vulnerable, a term which sensitive to some degree overlaps with in meaning.
Vulnerable: This term includes the risk of being exposed to an impact, why it is a combination of being sensitive and risk of being impacted. For example, narwhals – because they are sensitive to underwater noise – will be vulnerable to a planned seismic activity. See also sensitive, a term, which vulnerable to some degree overlaps with in meaning.
Environmental risk: This describes the likelihood and consequence of an impact on the environment as a result of a human activity, for example from exploration drilling.