Download The North East Atlantic and Climate Change – Vulnerability Analysis

Agenda Item 4
OSPAR 05/4/ -E
Original: English only
OSPAR CONVENTION FOR THE PROTECTION OF THE MARINE ENVIRONMENT OF THE
NORTH-EAST ATLANTIC
MEETING OF THE OSPAR COMMISSION (OSPAR)
MALAHIDE (IRELAND): 27 JUNE – 1 JULY 2005
The North East Atlantic and Climate Change
– Vulnerability Analysis –
-Addendum to OSPAR 05/04/10-
Presented by WWF
In relation to OSPAR paper OSPAR 05/4/10 - This paper presents the initial results from the WWF
workshop on the Vulnerability Analysis of the North East Atlantic Shelf to Climate Change. This
pertains to the work of most of the OSPAR Commission’s subsidiary bodies in a cross-cutting way.
Introduction
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This paper summarises the preliminary findings of a two day workshop which took place 16 th and 17th
June 2005. Ecologists, oceanographers and atmosphere experts shared best knowledge and provided expert
opinion to predict the impacts of climate change on the North East Atlantic Shelf Marine Ecoregion. Of
particular note from the initial collation of this work are following observations.
Sea surface temperature
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Sea surface temperature has already risen by 0.6oC around the UK coast over the last 100 years and is
forecast to increase by as much as 4.5 oC by the end of the century. The predicted effects are:

Phytoplankton production occurs all year and peak blooms are occurring earlier;

Species composition for all fauna and floral groups is showing changes as southern species are
becoming more frequent and extending their range and northern species contracting in geographical
spread;

Biomass changes, for example Calanus copepods and reduced net primary productivity of
phytoplankton in some areas;

Breeding failures and recruitment are occurring, for example sand eels and sea bird colonies.
Trophic mismatch is occurring or will do so in the future; and

Periodic stratification and associated deoxygenation of the water column may occur in semienclosed water bodies.
Storm surges and sea level rise
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The amount of sea level rise in the North East Atlantic is presently 1 mm/yr but forecast to increase
by as much as 86 cm by the end of the 21st century. Even if greenhouse gas emissions were stabilized today,
sea level rises would continue for the next 1000 years. Similarly, storm surge events are predicted to
increase in size and frequency, for example one UKCIP scenario (medium-high emissions) predicts the 1.5
m storm surge frequency (Immingham) will change from a 1 in 150 year event to a 1 in 7 year event. The
predicted effects are:
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OSPAR Commission
OSPAR 05/4/ -E

Coastal habitats, particularly saltmarshes and mudflats are at risk of damage and reduction in extent;

Fauna, such as terns and seals may lose breeding habitat;

Sandbanks populated by, for example, sand eels may become less habitable; and

Biogenic reefs could be damaged and not able to recover.
Ocean circulation
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A great deal of uncertainty remains about how patterns of water movement might change over this
century (Hughes, workshop presentation) although the position currently held by the majority of
oceanographers is that to a large extent the existing patterns of currents will remain but their relative
strength and variability could change. Ongoing research and modeling is investigating this matter further.
North Atlantic Oscillation index
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Meteorological drivers, as characterized by the North Atlantic Oscillation (NAO) index: Weather
conditions have been predominantly milder and wetter, with associated stronger westerly winds and
associated increase in sea surface waves, in recent years as a consequence of a positive NAO index (Hughes,
workshop presentation). Though the pattern of change in the value of the index, and hence the cycling of
mild and cold annual-scale weather conditions, remains approximately decadal, the underlying (likely) trend
is toward a more positive mean.
Methane hydrates
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Release, from permafrost in high latitudes, of methane gas from previously trapped methane hydrates
due to rises in sea level and sea and air temperature is understood to already be taking place. Release of
methane hydrates from deep sea reservoirs is not considered a threat at present but remains a prospect in
future centuries.
Acidification
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The pH of the sea has reduced from 8.3 to 8.2 with predictions suggesting an ongoing decline for at
least the remainder of this century to 7.6. Uncertainty remains, but small reductions in pH are predicted to
have impacts upon:

Growth and mortality of calcareous fauna and flora such as coccolithopohres, echinoderms, maerl
and molluscs. Some biological affects occur at pH 8.0.

Viability of fish eggs and larvae;
Conclusions
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The most significant initial conclusions are as follows:

Increase in sea surface temperature is the primary driver of change in community composition,
productivity and functionality;

Acidification is a fundamental concern to all parts of the ecosystem, with the potential to disrupt the
functionality and viability of all parts of the ecosystem;

Methane hydrates are already melting in coastal areas in the northern north east Atlantic, and this
constitutes a positive feedback emchanism to climate change from the marine environment; and

The North Sea in particular may be subject to the greatest amount of influence from climate change
pressures.
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