1. OIL POLLUTION IN THE NORTH SEA – MULTI-DECADAL TRENDS
Dr Angela Carpenter
Visiting Researcher
University of Leeds

2. This presentation will review knowledge on oil pollution in the North Sea
Springer Handbook of Environmental Chemistry, Volume 41, brought together scientists, legal and policy experts, academic researchers and specialists in various fields relating to marine environmental protection, oil pollution and the North Sea

3. Marine pollution and its sources

4. The Law of the Sea and Marine Pollution
Marine pollution is defined, under Article 1(4) of UNCLOS, as being:
“the introduction by man, directly or indirectly, of substances or energy into the marine environment, including estuaries, which results or is likely to result in such deleterious effects as harm to living resources and marine life hazard to human health, hindrance to marine activities, including fishing, and other legitimate uses of the sea, impairment of quality for use of sea water and reduction of amenities.”

5. Sources of marine pollution – all types
The main sources of pollution, and their respective contribution to marine pollution load (by mass), are:
Land based (82%);
Vessel based (9%);
Dumping of waste at sea (8%); and
Off-shore activity (1%) – this includes oil and gas production.

6. Main sources of oil pollution at sea
Land-based sources include sewage outfalls, industrial discharges, runoff from urban storm-water
Vessel-based sources including accidental discharges, operational discharges and dumping. Pollution from vessels can include: oil, chemicals, lost cargo/ equipment, sewage, garbage, fumes and invasive exotic species.
Dumping is the deliberate and illegal disposal of wastes at sea. The operational oil spills found at sea as a result of illegal discharges include: engine room bilges and fuel oil sludge by merchant ships and other vessels, or oil cargo residues from tankers
Offshore activities such as oil and gas production which can generate pollution primarily through the use of oily drilling muds and by production blow outs.

7. Vessel-source oil pollution designations
Accidental spills – a tanker may sink, be involved in a collision, be grounded or have technical difficulties resulting in an oil leak at sea
Operational discharges – in some areas ships may discharge oil intentionally (and legally) as part of the operation of a ship.
Illegal discharges include:
operational discharges in areas where these are not permitted including the North Sea which is a Special Status Area under the MARPOL Convention and the Wadden Sea which is a Particularly Sensitive Area under that convention
Intentional (and operational) discharges where the concentration of oil in discharged waste exceeds 15 parts per million

8. Sources of oil inputs from oil & gas installations
DW is seawater used for ballasting storage tanks which is discharged to sea when oil is loaded into those tanks
Cuttings are solid material removed from drilled rock together with any solids and liquids derived from any adherent drilling fluids
Produced Water (PW) is water that comes from the reservoir as a by-product of oil and gas extraction
DW is seawater used for ballasting the storage tanks of offshore installations which is discharged into the sea when oil is loaded into those tanks
organic phase drilling fluids (OPF) and the discharge of OPF-contaminated cuttings [17]. OPFs are fluids which are an emulsion of water and other additives in which the continuous phase is a water-immiscible organic fluid of animal, vegetable or mineral origin.
PW is water that comes from the reservoir as a by-product of oil and gas extraction
Cuttings are solid material removed from drilled rock plus any solids or liquids in drilling fluids

9. How much oil enters the North Sea?
Total oil input (103 tonners/year) to the North Sea – 1993 Estimate
More recent estimates of the total amount of oil entering the North Sea range from 15,000 to 60,000 tonnes per year

10. Legal Framework for marine pollution
- International Measures
- North Sea Measures
- Some of the Actors involved

11. International Marine Pollution Conventions
The International Maritime Organization (IMO) has adopted over 25 Conventions including, in the field of marine pollution:
International Convention for the Prevention of Pollution from Ships, 1973, as modified by the Protocol of 1978 relating thereto (MARPOL 73/78)
International Convention Relating to Intervention on the High Seas in Cases of Oil Pollution Casualties (INTERVENTION), 1969
Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (London Dumping Convention - LDC), 1972
International Convention on Oil Pollution Preparedness, Response and Co-operation (OPRC), 1990
Protocol on Preparedness, Response and Co-operation to pollution Incidents by Hazardous and Noxious Substances, 2000 (HNS Protocol)
International Convention on the Control of Harmful Anti-fouling Systems on Ships, 2001

12. North Sea Marine Pollution Legislation
Year
Legislation
1969
Agreement for cooperation in dealing with pollution of the North Sea by Oil (Bonn Agreement)
1972
Convention for the Prevention of Marine Pollution by Dumping from Ships and Aircraft (Oslo Convention)
1973
International Convention for the Prevention of Marine Pollution from Ships (MARPOL) and Protocols (MARPOL 73/78)
1974
Convention for the Prevention of Marine Pollution from Land-based Sources (Paris Convention)
1982
Memorandum of Understanding on Port State Control in Implementing Agreements on Maritime Safety and Protection of the Marine Environment (Paris MOU)
1983
Agreement for cooperation in dealing with pollution of the North Sea by Oil and other harmful substances (Bonn Agreement) – superseding 1969 Agreement
1992 (ratified 1998)
Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR Convention) which supersedes the Oslo and Paris Conventions

13. Some actors involved in North Sea Pollution Prevention

14. Where is the North Sea and who controls its waters?

15. The North Sea
The North Sea is situated on the continental shelf of North West Europe, opening into the Atlantic Ocean in the north and, via the English Channel, in the south west, and into the Baltic Sea in the east.
It lies between Norway, Denmark, Germany, the Netherlands, Belgium, France and the UK
It measures approximately 960 km North-South and 580 km East-West at its widest point
It has a surface area of approximately 750,000 km2

16. National zones under international law
Zone type
Distance from the coastal baseline mean water mark
Internal waters
Any waters, including estuaries, inland from baseline
Territorial waters
12 nautical miles offshore from the baseline
Contiguous zone
Between 12 and 24 nautical miles from baseline
EEZ
200 nautical miles from baseline
International waters
Waters outside any waters claimed by a country
Note: The nautical mile is approximately 15% longer than a standard mile

17. Boundaries of the North Sea in 1983
The North Sea was divided into sub-regions by the North Sea Task Force (NSTF) in 1983,
The NSTF was made up of the 8 North Sea states together with the Commission of the European Communities
The NSTF was established by ICES and the Oslo and Paris Commissions (OSPARCOM) to:
“… carry out work leading, in a reasonable timescale, to a dependable and comprehensive statement… [including] dispersion of contaminants … and effects of human activities in the North Sea”
Source: North Sea Task Force (1983)

18. Bonn Agreement Aerial Surveillance Zones and OSPAR Region Maps
Bonn Agreement zones (which now also includes Irish waters)
OSPAR Regions - Region II is the Greater North Sea

19. Monitoring Oil Pollution in the North Sea

20. Responsible bodies for oil pollution monitoring (1)
Bonn Agreement Secretariat
Responsible for administering the requirements of the Bonn Agreement including maintaining an aerial surveillance programme to detect spillages of oil and other harmful substances that can affect the marine environment. This uses aircraft from contracting parties with specialist equipment on board and also, since 2004, satellite surveillance data
The Oslo and Paris Commission (OSPAR)
One of the main roles of the OSPAR Commission is to monitor oil discharges from the offshore oil and gas industry in the North Sea, and more widely in the OSPAR Maritime Area

21. Responsible bodies for oil pollution monitoring (2)
European Maritime Safety Agency
The EMSA CleanSeaNet (CSN) Service offers a European satellite-based oil spill and vessel detection service to help identify pollution entering the marine environment from ships in EU waters
The EMSA also operates a SafeSeaNet (SSN) service using an automatic information system (AIS) to track ship movements - when a pollution incident is identified, SSN may help determine the source of that pollution
EMSA also provides an operational response service in the event of a pollution incident, with a network of oil spill response vessels (2 in the UK, 2 in Belgium) available to assist in clean-up activities within 24 hours of a spill occurring

22. Bonn Surveillance data - Oil Spills by zone
Belgium
Denmark
France
Germany
Netherlands
Norway
Sweden UK
Total
1990 65
130
362 26
180
763
1991 16 91 51
273 66 15
135
647
1992 60 27
202 98 6
191
719
1993 4 99
279
113
741
1994 82 10
122
283 80
147
736
1995 57 17 7
238 72
176
681
1996 42 13 5
121
247 93 21
108
650
1997 58 36 28
125
771 14 89
1181
1998 70 45
120
458 31 69
922
1999 61 74 22
118
450
884
2000 54 33 25
187 46 8 75
548
2001
114
266 64
676
2002 94 55
533
2003 47 53 23 9
2004 43 3
109
339
2005 71
263
2006 29 92
347
2007 37 85
319
2008
134 32 48 77
375
2009 34 30 19 38
200
2010
2011 40 20 24 18 50
216
2012
141
2013

23. Bonn Agreement data for Netherlands

24. Surveillance Data – all North Sea countries
Observed slicks are those that have been confirmed as mineral oil
Since 2004 satellite imagery has also been used to identify spills

25. Confirmed spills using satellite imagery & aerial surveillance
Year
Satellite imagery data
Aerial surveillance data
spills detected
Confirmed mineral oil
% confirmed
confirmed mineral oil
2004
378 46
12.17
540
429
79.44
2005
399 28
7.02
386
257
66.58
2006
407 86
21.13
478
347
72.59
2007
280 43
15.36
459
319
69.50
2008
700 90
12.86
559
375
67.08
2009
247 42
17.00
414
177
42.75
2010
411 29
7.06
238
57.49
2011
422 25
5.92
389
206
52.96
2012
509 31
6.09
227
136
59.91
2013
631 24
3.80
333
140
42.04

26. Source of confirmed oil spills

27. OSPAR Data - Operational discharges from oil & gas installations
Between 1984 and 1999 the main source of oil discharges was via cuttings
Since the early 2000s, the main sources of oil inputs to the sea have been inputs via PW and DW
The quantity of oil (in tonnes) discharged in PW fell from 13,892 tonnes in 2001 to 3,990 tonnes in 2012 – down over 70%
The quantity in DW fell from tonnes in 2001 to 61.4 tonnes in 2012 – down approx. 80%

28. Accidental oil spills from oil and gas installations
Accidental oil spills from oil and gas installations fell by around one third between 2004 and 2012 (Source: OSPAR)
around 60% of all spills were in UK waters
less than 5% of total oil discharges entering the North Sea came from accidental spills from rigs

29. EMSA Data - Satellite monitoring for oil spills
CleanSeaNet (CSN) is a European satellite-based oil spill and vessel detection service which fulfils the requirements of an EU Directive on ship-source pollution dated September 2005 (Directive 2005/35/EC)
CSN is an “Integrated Maritime Service” activity of the European Maritime Safety Agency (EMSA)
A number of satellites and their on-board sensors provide wide-area surveillance across all EU maritime zones, and can also be targeted to monitor specific locations or activities
CSN supplements existing surveillance systems nationally and regionally. In the North Sea, this means CSN satellite data supports the aerial surveillance activities of the Bonn Agreement

30. Sea area coverage of EMSA CleanSeaNet Satellite Imaging of the North Sea
- Data for 16 April January 2011
- There were 1-2 satellite images per month covering pale blue areas; more than 20 per month in the darkest blue areas
- Green squares represent satellite detections; yellow are detections which were checked; red are confirmed detections
Source: Adapted from EMSA (2011)

31. EMSA CSN First Generation Data by North Sea State, 2007-2011
Year
Country
2007
2008
2009
2010
2011
Totals by country*
Belgium 86
136
105
107 6
440
Denmark**
320
621
581
594 65
2181
Germany**
273
497
485
544 56
1855
Netherlands
197
334
264
281 35
1111
Norway~ 85
383
373
333 44
1218
Sweden**
365
628
631
591 42
2257 UK
343
590
508
582 55
2078
* Totals by country are for the period 16 April 2007 to 31 January 2011
**In the case of Denmark, Germany and Sweden, the number of acquisitions included images covering their Baltic Sea regions
~ In the case of Norway the number of acquisitions also covered the north of the country, including the Barents Sea

32. Annual number of satellite detections for North Sea States & average number per image
Year
Country
2007
2008
2009
2010
2011
Totals by country*
Belgium
5 (0.06)
12 (0.09)
5 (0.05)
6 (0.06) 28
Denmark
62 (0.19)
131 (0.21)
92 (0.16)
86 (0.14) 1
372
Germany
59 (0.22)
117 (0.24)
61 (0.13)
50 (0.09) 2
289
Netherlands
80 (0.41)
189 (0.57)
121 (0.46)
109 (0.39)
501
Norway**
13 (0.15)
82 (0.21)
39 (0.10)
23 (0.07)
158
Sweden
99 (0.27)
178 (0.28)
121 (0.19)
48 (0.08) 9
455
UK**
142 (0.41)
241 (0.41)
185 (0.36)
136 (0.23) 14
718
*Totals by country are for the period 16 April 2007 to 31 January 2011
** Includes detections from ships and oil installations
NOTE: Average number of detections per image appears in brackets. As figures for 2011 are for 1 month only there is no average

33. Beached Bird Surveys as a monitoring tool
Systematic surveys of beach-cast corpses of birds (‘beached bird surveys’) have been used for many decades to highlight and document the adverse effects of oil pollution on wild birds (notably seabirds and coastal waterbirds)
Beached bird surveys are now seen as a valuable, independent, and cost-effective instrument (given a massive volunteer input to search beaches for dead birds) to monitor levels of chronic oil pollution around the North Sea
As one of the OSPAR Ecological Quality Objectives (EcoQOs) for the North Sea, the proportion of oiled Common Guillemots among those found dead or dying on beaches is listed under Issue 4 (Seabirds), EcoQO element (f)
OSPAR EcoQO = the average proportion of oiled Common Guillemots should be <10% of the total found dead over a period of at least 5 years

34. Spatial pattern in oil rates (% oiled) beached birds found around the North Sea
(a) 1970s and early 1980s – auks (mostly guillemots and razorbills)
Source: Furness & Camphuysen, 1997
(b) Late 1980s and 1990s – common guillemots
Source: Stowe, 1982

35. Some National Case Studies
Belgium
Denmark
The Netherlands

36. National Case Study: Belgian Waters (1)
The Belgian part of the North Sea is situated NE of the Dover Strait, in the immediate vicinity of the two biggest ports of Europe, Rotterdam and Antwerp.
There are over 150,000 ship movements per year - or 400 ship movements a day - in the central Traffic Separation Scheme that goes through the Dover Strait
There are also almost 60,000 ship movements in other maritime traffic routes in Belgian waters
The dense and complex maritime traffic situation in and around Belgian waters creates a major maritime safety risk as well as a major risk for deliberate and accidental marine pollution from ships
Since 1985, 28 maritime accidents took place in and around the waters of Belgium, mainly collisions, which resulted in accidental marine pollution by oil (23) or a significant risk thereof (5)
Most of the accidents resulted in minor to medium accidental oil outflows – i.e. of less than 100 m³ or in the order of a few 100 m³ of oil released in the marine environment

37. National Case Study: Belgian Waters (2)
Operational slick distributions:
Red – 1991 to 1998
Green – 1999 to 2005
Blue – 2006 to 2013
Location of oil slicks found in the Bonn surveillance area over the years
Source: Schallier and Van Roy (2015)

38. National Case Study: Danish Waters (1)
The Danish sector of the North Sea region is regulated at multiple levels:
from international conventions such as UNCLOS and MARPOL,
by regional agreements such as the OSPAR Convention and the Bonn Agreement,
by EU legislation such as the Directive such as the EU Offshore Directive, and
through bilateral and trilateral agreements with its neighboring countries (Germany and the Netherlands)
Thousands of ships pass between the North Sea and Baltic Sea through the Skagen each month, including large oil tankers, ships carrying dangerous and potentially polluting cargoes, as well as international cruise ships
Responsibility for aerial surveillance and for combating oil spills at sea lies with Danish Defence Command

39. National Case Study: Danish Waters (2)
The sea area off Skagen (outlined top centre), is a bottleneck for sea traffic between the Baltic and North Sea
Source: Christensen & Carpenter (2015)

40. National Case Study: Netherlands Waters (1)
The Netherlands are situated in the most southern part of the North Sea (a shallow shelf sea in the NE Atlantic).
Shipping lanes running along the Dutch coast form important maritime connections between major shipping harbours in Germany (Hamburg, Bremen), The Netherlands (Amsterdam, Rotterdam), & Belgium (Antwerp).
The Dutch sector of the Continental shelf (~51-56°N latitude, °E longitude) has a surface area of approximately 57,000 km²
About 150 oil or gas production platforms, all connected by underwater pipelines to transport oil /gas from the wells towards processing plants on land, are situated in the Dutch sector of the North Sea, and a particularly high number is situated around 53°-54°N latitude, 3°-4°30’E longitude

41. National Case Study: Netherlands Waters (2)
Radar identified spots (unidentified slicks, possibly pollution but substance unknown) per grid cell/hour – Dutch Continental Shelf
Within the Southern North Sea, chronic marine oil pollution was a highly significant issue, at least until sometime in the 1980s
Oil rates of stranded seabirds were exceptionally high in an international context
Chronic oil pollution (a mix of hydrocarbon entering the seas from shipping, offshore and coastal exploration and production and other sources) was a major problem
discharges from ships and leakages from platforms and rigs were the main culprits leading to seabird mortality and polluted shorelines in the Southern North Sea
The number of detected oil slicks per hour of surveillance has declined steadily since the early 1990s
shorelines are now normally clean and will be more or less clean throughout the year (ignoring some relatively minor pollution incidents)
the oil rates in stranded seabirds has declined significantly

42. Conclusions

43. Conclusions (1)
There has been a decline in the annual total number of oil spills occurring in the North Sea over more than two decades from all sources.
Some agreed discharges from oil installations are still permissible - these make up the main input in recent years.
From aerial surveillance data, the ratio of observed slicks to flight hours fell from 0.22 slicks/flight hour in 1999 to 0.04 slicks per flight hour in 2010.
The majority of slicks are quite small - between 1998 and 2010 around 80% of identified slicks were less than 1 m3 in size (other than in 2002 when 74% were less than 1 m3).
Legal measures at international, regional, EU and national levels mean that operational discharges are much more strictly controlled.

44. Conclusions (2)
Monitoring activities have increased the possibility of a discharge being quickly identified.
Accidental spills from ships are now very infrequent due to better ship designs and anti-collision measures in the region’s busy shipping lines.
BUT - illegal discharges remain a problem (highlighted by some beached bird survey data for example).
Tools to rapidly identify spills at sea (aerial surveillance, satellite imagery), confirm whether a spill is oil or not, identify vessels in the region of a spill (AIS, EMSA SSN, for example), and match a spill sample with oil from a potential source), should further drive down intentional, illegal pollution in the North Sea, as the risk of a polluter being caught, prosecuted and fined has increased.

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