Aarhus University Seal / Aarhus Universitets segl

No. 71: Disko West. A strategic environmental impact assessment of hydrocarbon activities

Boertmann, D., Mosbech, A., Schiedek, D. & Dünweber, M. (Eds.) 2013. Disko West. A strategic environmental impact assessment of hydrocarbon activities. Aarhus University, DCE – Danish Centre for Environment and Energy, 306 pp. Scientific Report from DCE – Danish Centre for Environment and Energy No. 71.

Summary and conclusions

This document is a Strategic Environmental Impact Assessment (SEIA) of activities related to exploration, development and exploitation of hydrocarbons offshore West Greenland between 67° and 71°?N (= the Disko West area, Figure 1). The area was opened for licence applications in 2006 and seven licenses were granted by the Bureau of Minerals and Petroleum (BMP), in 2007 and 2008.

The SEIA has been carried out by DCE - Danish Centre for Environment and Energy- formerly known as National Environmental Research Institute (NERI) - and the Greenland Institute of Natural Resources (GINR).

The assessment area is shown in Figure 1. This is the region that potentially could be impacted by a large oil spill deriving from activities within the licence areas; although the oil could drift beyond the borders of this area. The area to the north of the assessment area is covered by another SEIA of hydrocarbon activities in the Baffin Bay (Boertmann & Mosbech 2011).

The environment

The physical conditions of the study area are briefly described focusing on oceanography and ice conditions, i.e. presence of icebergs and sea-ice in winter and spring.

The study area is situated within the Arctic region, with all the typical biological properties of this climatic region: a relatively simple food web from primary producers to top predators and with 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 planktonic algae, the primary producers in the food web. These are grazed upon by copepods, including the three Calanus-species which represent important key species in the food web in the assessment area.

Benthos is the fauna living on and in the seabed. Benthic macrofauna species are an important component of coastal ecosystems. They consume a significant fraction of the available production and are in turn an important food source for fish, seabirds and mammals. The benthic community has been studied in the coastal areas and offshore. Areas with high abundance and biomass of benthic species, e.g. bivalves have been identified (e.g. Store Hellefiskebanke).

The macroalgae are found along shorelines attached to hard and stable substrate, and may occur at a depth of more than 50 m. Biomass and production of littoral and sub-littoral macroalgae can be significant and are important for higher trophic levels of the food web. Studies concerning macroalgal diversity in the assessment area have been carried out, documenting the importance of this group in coastal waters.

In and on the underside of the sea-ice a specialised ecosystem exists: the sympagic flora and fauna. Algae living in and on the ice are grazed by small crustaceans, which sustain populations of polar cod which again are important food to ringed seals and seabirds

Sandeel occur also in dense schools on the banks (e.g. Store Hellefiskebanke) and are important prey for some species of fish, seabirds and baleen whales.

Fish, seabirds, marine mammals and humans represent the higher trophic levels in the marine environment, where polar bear and man are the top predators.

Seabirds are abundant with several species present in the study area. Many species breed in dense colonies along the coasts, seaducks assemble in certain fjords and bays to moult, and millions of seabirds migrate through the area on their passage between breeding sites in Northwest Greenland and Arctic Canada and winter grounds off Southwest Greenland and Newfoundland. Some of the most important species are northern fulmar, common eider, thick-billed murre and little auk. During their migration they depend on zooplankton and smaller fish, such as polar cod.

Thick-billed murre, common eider, black-legged kittiwake and ivory gull are all red-listed in Greenland due to declining, or in case of the common eider, previously declining populations. Furthermore, some of these species are designated as species of national responsibility (which means that the population in Greenland is so large that the local management of the species is vital to the global population), e.g. the little auk.

Marine mammals are significant components of the ecosystem. Four species of seal, walrus, 14 species of whale, and polar bear occur in the assessment area. The assessment area is particularly important to marine mammals in winter, because vulnerable species such as narwhal, white whale (beluga), bowhead whale, walrus, and polar bear occur in significant numbers.

Polar bear, walrus, bowhead whale, white whale and narwhal are all red-listed because their populations have been reduced by present or past hunting or are expected to decline because of climate change (especially polar bear).

Important areas and biological hotspots have so far been identified on Store Hellefiskebanke, particularly the shallow part with a high diversity of benthic animals, high densities of sandeels, very high concentrations of wintering king eiders, high numbers of wintering bearded seals and white whales and the most important winter site for walrus in West Greenland.

The Disko Bay area is another biological hotspot, very importnat for breeding seabirds (several significant breeding colonies), for wintering and migrating marine mammals (narwhal, bowhead whale) and for northern shrimp and Greenland halibut (extensive fisheries).

A third important area, at least during winter, is the winter habitat for narwhals in central Baffin Bay.

These three areas are designated by IUCN as 'Ecologically and culturally Biologically Significant Areas' and is by Greenland proposed to PAME as  ‘Arctic marine areas of heightened ecological and cultural significance’ (Christensen et al. 2013).

The natural resources of the assessment area is utilised by the local human population, by subsistence and small-scale hunting (marine mammals and seabirds) and fishery in the coastal areas, and by a substantial commercial fishery in Disko Bay and on the banks.

Commercial fisheries represent the most important export industry in Greenland, and the main commercially exploited species within the assessment area are Greenland halibut, deep-sea shrimp and snow crab.

Tourism is a growing industry in Greenland and now counts as the third largest economic activity in the country. The number of guests staying in the Disko area, e.g. in Ilulissat is increasing a trend also seen in the numbers of tourists brought in by cruise ships. The coastal marine areas are an important asset for the tourist activities

For the assessment of the sensitivity and environmental impacts from petroleum activities, knowledge on background levels of contaminants such as hydrocarbons and heavy metals is important. Owing to long-range transport into the Arctic, the levels of certain contaminants, i.e. organochlorines, are high in Greenland, particular in the higher trophic level (e.g. whales, polar bears). In addition, new persistent pollutants, such as brominated flame retardants and perflouronated chemicals, have now appeared. Levels of petroleum compounds, including PAHs, are relatively low and are regarded as background concentrations, except in polluted areas such as harbours where higher levels can be found. The present knowledge concerning the relation between contaminant loads and biological impact, including sub-lethal health effects or impairments of biota, is still limited.

Climate change will have profound impacts on the ecosystems and their components in the Arctic. Changes in the distribution of species are to be expected, e.g. northward move of true Arctic species and more temperate species become more abundant, also in the assessment area. Alterations in the distribution and abundance of keystone species at various trophic levels could have significant and rapid consequences for the structure of the ecosystems with implications for its functioning but also for fisheries and hunting. For some species and populations, climate change may act as an additional stressor in relation to existing impacting factors, leading to higher sensitivity to oil spill incidents.


The assessment presented here is based on our present knowledge concerning the abundance and distribution of species and their tolerance and threshold levels toward human activities in relation to oil exploration and production. However, since the Arctic is changing due to climate change, conclusions and assessments may need to be adjusted in the future.

Normal operations – exploration

Exploration activities are temporary, probably lasting some years, involving different license areas. They will take place during the ice free seasons, i.e. summer and autumn. Seismic and site surveys have in recent years been conducted as late as November. Exploration drillings have to be terminated in the Disko West area by the end of September to provide an ice free window for relief drilling before sea-ice arrives.

If no commercial discoveries are made, activities will terminate and all installations be removed. If oil or gas is found, and appraisal shows it to economically feasible to exploit, activities will proceed for up to 50 years under a license.

During exploration activities, the main environmental impacts derive from 1) noise generated either by seismic surveys or the drilling platforms or 2) from cuttings and drilling mud if these are released to the sea during the drilling process.

Seismic surveys

Noise from a seismic survey has the potential to scare adult fish away from fishing grounds, but this effect is temporary and normal conditions will re-establish after some days or weeks after the seismic survey, time period depending on fish species.

The fishery at risk of impact from noise from seismic surveys in the assessment area is the Greenland halibut fishery. There is a risk of temporary (days or weeks) displacement of fish which may cause reduced catches in that period.

It is well known that seismic noise can scare away marine mammals, but it is expected that the effect of a single seismic survey is temporary and that seals and whales will return when a seismic survey have terminated. If displacement from traditional hunting grounds occurs, a temporary reduction in hunting yield must be expected.

The species most sensitive to noise from seismic surveys in the assessment area are the baleen whales (minke, fin and humpback whales) 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, white 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 expected to be 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 relatively small areas, may cause more severe temporary impacts on the marine mammals.

Noise from drilling rigs will also be temporary but locally more permanent than seismic surveys. The most vulnerable species in the assessment area are the whales and the walrus. 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.

Release of drilling mud

During drilling operations, drilling mud (if water based) and cuttings will be released to the seabed, resulting in local impacts on the benthic fauna. Mitigating such impacts include release of chemicals with low or no harm to the environment, as defined by OSPAR (HOCNF) standards. However, the knowledge on degradation and toxicity of even the environmentally safe chemicals under Arctic conditions is very limited, why use and discharge should be thoroughly monitored and evaluated, including further testing of degradation and toxicity.

The use of oil based mud have until now been prohibited, but may in the future be allowed under strict regulation in order to prevent any release to the environment.

During exploration drilling, there is a risk of oil spills (see below).

Moreover, exploration drilling is an energy demanding process emitting large amounts of greenhouse gasses. The drilling of three wells in West Greenland in 2010 increased the Greenland contribution by 15?%.

Normal operations – development and production

Development and production activities are difficult to evaluate when their location and the level of activity are unknown. Overall, impacts will depend on the number of activities, how far they are scattered, and also on their durability. In this context cumulative impacts will be important to consider. The activities during development, production and transport are long-lasting, and there are several activities which have the potential to cause severe environmental impacts.

Emissions and discharges

The largest contribution to pollution from an oil field is expected to be the discharge of produced water (if not re-injected or transported to treatment facilities on land). Besides oil residues, produced water contains small amounts of acute toxic substances, radioactive substances, heavy metals, substances with hormone-disruptive capacity and plant nutrients. Some of these substances have the potential to bio-accumulate, but in general knowledge on long-term effects of release of produced water are limited.

There is concern regarding the environmental impacts of produced water, particularly if it is released under ice. In combination with limited turbulence in the surface layer, increased impacts could occur on ice communities or fish eggs, e.g. from polar cod which accumulate here. The most obvious way to mitigate effects of produced water is an effective cleaning before discharge or preferable re-inject it into the well.

Drilling activities also occur during most of the production period, why large amounts of muds and cuttings need to be disposed of. If released to the seabed more severe impacts on the bottom fauna are to be expected than during exploration because of the larger quantities released.

Development of an oil field and production of oil are energy-consuming activities which will contribute significantly to the Greenland emission of greenhouse gases. For example were the annual emissions from a single large Norwegian production field more than twice the current total Greenland CO2 emission. Several other environmentally harmfull substances will be emitted to the atmosphere, including NOx and VOC’s.

Also discharge of ballast water is of concern because of the risk of introducing non-native and invasive species. This is currently not a severe problem in the Arctic, but the risk will increase with climate change and the intensive tanker traffic associated with a producing oil field. However, this problem may be mitigated when the IMO convention on ballast water is ratified.


Similar to exploration activities there will be a risk of displacement of marine mammals from critical habitats during development and production. However, in this case the effects are long term or even permanent. Walrus and whales, particularly narwhal, white whale and bowhead whale are sensitive in this respect and may be permanently scared away from specific habitats with consequences for the populations. This could also impact hunters if quarry species are scared away from traditional hunting grounds.

Intensive helicopter flying has also the potential to displace seabirds and marine mammals from habitats (e.g. feeding grounds important for winter survival) as well as traditional hunting grounds, impacting on local people. Applying fixed flying lanes and altitudes will reduce impacts.

Placement of structures

Placement of offshore structures and infrastructure may locally impact seabed communities and there is a risk of devastate important feeding grounds particularly for walrus and king eider. In certain areas these structures may limit access to critical habitats and walrus is probably the most sensitive species in this respect, because the population is dependent on relatively few, shallow and localised benthic feeding areas such as Store Hellefiskebanke.

Inland structures primarily have aesthetical impacts on landscapes, but there is also a risk for obstruction of rivers with implications for anadromous Arctic char and of damage to coastal flora and fauna.

A specific impact on fisheries is the exclusion/safety zones (typically 500 m) which will be established around both temporary and permanent offshore installations. These will hamper fishery for Greenland halibut and northern shrimp.

Another effect of exclusion zones is that they act as sanctuaries, and in combination with the artificial reefs created by the subsea structures (Kaiser & Pulsipher 2005), attract fish and even seals.

Illuminated structures and the flame from flaring may attract seabirds during the dark hours with the risk of mass mortality on especially eiders and perhaps little auks.

There is also a risk for impacting the tourism in the assessment area, as large and obvious industrial installations and activities will compromise the impression of an unaffected Arctic wilderness, which is the main asset to cruise ship and other tourist operators.

Cumulative impacts

There is a risk of cumulative impacts in case several activities occur simultaneously or consecutive. Seismic surveys, for example, have a high potential to cause cumulative impacts, in particular on marine mammals. Cumulative impacts may also be caused in combination with other human activities, such as hunting.

Mitigation of environmental impacts

Careful planning concerning the placement of structures and establishment of transport corridors based on detailed background studies to localize sensitive ecosystem components will reduce inevitable impacts. Strict Health, Safety and Environment (HSE) procedures, application of the Precautionary Principle in combination with Best Environmental Practice (BEP), Best Available Technique (BAT) and international standards (OSPAR) will further contribute to reduce environmental impacts of both exploration and exploitation activities.


The accident due to the activities described above with most severe environmental consequences is a large oil spill. Such oil spills may occur either during drilling (blowouts) or from accidents during storing or transportation of oil. Nowadays, large oil spills are rare events due to the technical progress and the improving HSE policies. However, the risk cannot be eliminated and in an area with the presence of sea-ice and icebergs, such as Disko West, the probability of an accident is elevated.

Oil spill trajectory modelling carried out by DMI as a part of this SEIA showed that spills far from the coast (> 100 km) oil did not reach the coasts, while spills originating closer (< 48 km) had the potential to foul extensive stretches of the coast. This means that oil spills from activities in the three eastern blocks Puilasoq, Orsivik and Naternaq have a high probability of hitting sensitive coastlines throughout the assessment area.

Large oil spills have the potential to impact the marine ecosystem on all levels, from primary production to the top predators. A large oil spill represents a threat at population and even species level (AMAP 2010) and the impacts may last for decades as documented in Prince William Sound in Alaska. The lack of adequate response methods in ice-covered waters and the remoteness and lack of infrastructure in larger parts of the assessment area will add to the severity of an oil spill.

Oil in ice

In general, oil slicks occurring in the coastal zone are more harmful and cause longer-lasting effects than oil spills staying in the open sea. This applies also to the assessment area. Another especially vulnerable feature is ice covered waters. Spilled oil will be contained between the ice floes and on the rough underside of the ice. In this case, oil may be transported in an almost un-weathered state over long ranges and may impact the environment, e.g. seabirds and marine mammals, far from the spill site when the ice melts. Oil may also be caught along ice edges and in the shear zone where sensitive ‘Valued Ecosystem Components’ (VECs) aggregate, such as primary production, zooplankton, polar cod, seabirds and marine mammals. Particular concern has been expressed about polar cod stocks. This fish spawns in late winter, and the eggs accumulate just below the ice where spilled oil will also accumulate.

Moreover, knowledge on the behaviour of spilled oil in ice environments is still very limited and the technology for the clean-up of oil spills in ice-covered waters is inadequate and needs to be further developed (Brandvik et al. 2010).

Oil spills on sea surface

In open waters the impact of a surface oil spill on primary production, plankton and fish/shrimp larvae will be low in the assessment area due to expected large temporal and spatial variation of such events. There is, however, a risk of impacts (reduced production) on localised primary production areas; although overall production will probably not be significantly impacted. The same may be true for potential localised concentrations of plankton and fish/shrimp larvae if they occur in the uppermost part of the water column. But on a broad scale, no or only minor effects are expected on these ecosystem components. An exception could be polar cod, since higher concentrations of its eggs may occur under the ice and these will be at risk if oil accumulates below the winter ice.

Subsea oil spills

If subsea plumes of dispersed oil are generated in the Disko West area, impacts in the water column are to be expected for example on primary production, zooplankton and fish/shrimp larvae.

Impacts in the coastal zone

The coastal zone of the assessment area is particularly sensitive because of the high biodiversity present, including concentrations of breeding and moulting seabirds. The high sensitivity is also related to the fact that oil may be trapped in bays and fjords, e.g. around Disko Island, where high and toxic concentrations can build up in the water. Furthermore, local fishermen and hunters use the coastal zone of the assessment area intensively. There will be a risk of negative impacts on spawning concentrations of capelin in spring, Arctic char assembling outside their spawning rivers and on many seabird populations both in summer and migration periods. Long-term impacts may occur in the coastal zone if oil is buried in sediments, among boulders, in mussel beds or is imbedded in crevices in rocks. From such sites oil seeps and causes a chronic pollution which may persist for decades. In Prince William Sound in Alaska such preserved oil has caused long-term effects e.g. on birds utilising the polluted coasts and several populations have still not recovered.

Impacts on the seabed

Bottom-living organisms such as bivalves, crustaceans or fish (sandeels) are vulnerable to oil spills; however, no effects are expected in the open water unless oil sinks to the seabed. In shallow waters (

Impacts on fish

Impacts from a surface spill on adult fish stocks in the open sea are not expected. But if an oil spill occurs in ice-covered waters there is a risk to polar cod populations. This is an ecological key species and significant impacts on polar cod stocks may be transferred up in the food web (to other fish, seabirds and marine mammals). Another exception is a subsea spill. This could impact both the fish directly or through the food. Greenland halibut will also be exposed in both ways because they move up in the pelagic waters to feed.

Impacts on seabirds

In open waters, seabirds are usually more dispersed than in coastal habitats. However, in the assessment area there are some very concentrated and recurrent seabird occurrences in polynyas and in the shear zone. Post breeding concentrations of staging birds (as thick-billed murres, Box 4) may also be vulnerable. Such concentrations of seabirds are extremely sensitive to oil spills and population effects may occur in case of oil in one of these open-water habitats. The most vulnerable species are thick-billed murre, little auk and king eider. Several nationally red-listed species occur in the marine environment and will be exposed to potential oil spills. The little auk is moreover a national responsibility species, because a vast majority of the world population is found within the assessment area, where a major oil spill could seriously affect the viability of the species.

Impacts on marine mammals

Among the marine mammals the polar bear is sensitive to oiling, and several individuals may become fouled with oil in case of a large oil spill in the marginal ice zone. The impact of an oil spill may add to the general decrease expected for the polar bear stocks (therefore red-listed both nationally and internationally) as a consequence of reduced ice cover (global warming) and long-term over-exploitation.

Whales, seals and walruses are also vulnerable to oil spills, particularly if they have to surface in oil slicks. Baleen whales may get their baleens smothered with oil and ingest oil. The extent to which marine mammals actively will avoid an oil slick and also how harmful the oil will be to fouled individuals, but whales have been observed moving directly into oil spills. White whales, bowhead whales and walruses are especially sensitive because they all have small or declining populations. Oil spills (and disturbance) may therefore have disproportionably high impacts on these populations. These species are also listed on the Greenland Red List.

The assessment area is particularly important to many whales (e.g. narwhal, white whale, humpback whale, bowhead whale) because their main food intake takes place (on an annual basis) here, even though they only spend a limited time of their annual cycle here. Effects from oil spills (and disturbance) may therefore have disproportionably high impacts on the populations.

Recent studies indicate that whales and seals are very sensitive to inhaling oil vapours, and particularly narwhals, white whales and bowhead whales could be vulnerable during an oil spill in winter when the availability of open waters is limited by the sea-ice. Walruses and other seals living in the ice may also be vulnerable in this respect. There is also a risk of indirect impacts on walrus and bearded seal populations through contamination of benthic fauna, especially at shallow (

Impacts on fisheries and hunting

An oil spill in the open sea will affect fisheries mainly by means of temporary closure in order to avoid contamination of catches. Closure time will depend on the duration of the oil spill, weather, etc. Even though the offshore fisheries for Greenland halibut within the assessment area is small (compared to other Greenland fisheries for this species), a closure zone probably will extend further south and cover a much larger area, including both Greenland and Canadian fishing grounds. In this combined fishing ground approx. 13,000 t are taken annually.

The northern shrimp fishery in the assessment area is on a national scale very important and economic consequences can be significant in case of closure.

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 inshore fishery for Greenland halibut within the assessment area is important on a national scale, and a closure of these fishing areas will have significant economic consequences.zHunting in oil spill impacted areas can be affected by closure zones and by changed distribution patterns of quarry species.

Impacts on tourism

The tourist industry in the assessment area will probably also be impacted negatively by a large oil spill.

Long term impacts

In case an oil spill hits the coasts, long term effect of residual oil caught in the beach sediments must be expected, as described from the Prince Williams Sound. Here oil from the Exxon Valdez spill on 1989 still is present in such habitats and still impacts the environment.


Oil spills shall be prevented and avoided. This is done primarily by high HSE levels, knowledge on the risks and by applying the Best Available Technique (BAT) and Best Environmental Practice (BEP) principles. If a spill occurs, efficient contingency plans shall be in place including access to adequate equipment and oil spill sensitivity maps where the most sensitive areas have been identified.

Information needs

Since the first edition of this SEIA a number of studies have been carried out to provide biological data which can be used in an operational context, i.e. for NEBAs, EIAs, sensitivity mapping and regulation of activities. These studies are listed in Section 12. However, many more biological topics have to be covered to provide adequate data for operational purposes, and a number of studies – both of local character, but also some which have a more general arctic outreach – are proposed in Section 12.