Most of the ways we use the sea are influenced by weather and many rely on oceanic and atmospheric processes. From the direct provision of fish for food to the indirect need to protect coasts, the marine climate is an important driver of economic activity. The link between our uses of the sea and its climate is intimate so it is very likely that the climate change we have already experienced in the 20th century has had an impact on productivity. However, it is difficult to separate out the influence of climate from changes in practices, management and direct pressures such as fishing, which tend to dominate developments in marine industries.

In this section we consider only the potential impacts of climate change on the different economic sectors. The subsequent section will discuss the role of the sea in helping to mitigate climate change.

Aquaculture

There are likely to be some major impacts on UK aquaculture beyond the current decade. Rising sea temperatures could lead to an increase in the prevalence of illness and parasites, and in the frequency of harmful algal and jellyfish blooms. Increased temperature or ocean acidification (for shellfish) may affect the suitability of species for farming. Changes in waves and winds could lead to escapes of farmed species through equipment failure.

Fisheries

As sea temperatures rise, cold-adapted species such as cod and herring – both of which are already heavily exploited and thus vulnerable to climatic variability – are likely to suffer poorer recruitment, and changes in growth patterns, in some sea areas around Britain and Ireland. In the longer term, the prevalence of southerly species in UK waters is likely to increase and provide opportunities to exploit species such as seabass, red mullet and John Dory. Fishing fleets may themselves be affected directly by climate change if storms become more severe making conditions more dangerous.

Leisure and recreation

Climate change is already increasing the frequency of months when conditions are more comfortable for tourists in north-west Europe than in the Mediterranean. Warmer seas and milder air temperatures are likely to increase participation in marine leisure and recreation. An increase in the length of the tourist season would attract more visitors to the coast and open up new destinations. The extent and participation in watersports, especially those involving full immersion (e.g. surfing, SCUBA diving and swimming) is likely to increase under warming conditions. However, any increased frequency of ‘extreme’ events such as storms and severe rainfall could discourage tourists, Kite surfers and disrupt travel, utilities and marine leisure services. Rising sea level and any increase in storm severity could also damage infrastructure, while an increase in the severity of rainstorms could increase run-off, leading to lowered water quality. Warming seas could alter the distribution of marine species of importance to marine wildlife watching and angling.

Kite surfers at Lowestoft

© Crown copyright 2010

Offshore infrastructure

Climate change is likely to affect all forms of offshore infrastructure, including oil and gas installations, pipelines and cables, renewable energy structures and future efforts to store CO₂ beneath the seabed. Rising sea level and possible increases in waves and winds may put greater stresses on some structures in the marine environment, while changes to currents could result in altered patterns of scour around the legs and supports of offshore installations. Any increase in storminess could also affect air and sea access to offshore installations and pose operational issues for health and safety and maintenance.

Maritime transport and ports

Reduced Arctic sea-ice cover may enable the opening of trade routes, reducing the time taken to transport cargo between Asia and Europe and increasing shipping trade. Changes in weather patterns could result in changes to other shipping routes due to storm activity. Any increase in the severity of storms could also increase the strain on quayside flooding, damage to port infrastructure, cargo and timetables. The costs of maintaining navigation channels may also change.