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Physical Environment

Climate change affects the physical characteristics of UK coasts, seas, and surrounding oceans. Long-term observations show air and sea warming, sea-ice loss, ocean acidification and sea-level rise. These trends are expected to continue. For sea level, the latest UK projections show bigger changes than previously estimated, increasing the risk of coastal flooding and erosion. 

Links between climate change and wind, wave and storm activity around the UK remain less clear, although there is some suggestion that the most severe storms and significant wave heights have increased in recent decades. At the broader scale, ocean and atmospheric circulation may be changing in the North Atlantic, with potential implications for UK climate and extreme weather events. 

These physical changes have profound effects on marine ecosystems and people in the UK, which are explored through the ecosystem change and societal impact hubs.

Wider impact hubs can be accessed via:

UK seas show an overall warming trend, which is projected to continue over the coming century. Most models suggest an increase of over 3°C by the end of the century for high emission (RCP8.5) scenarios.
Dissolved oxygen concentrations will continue to decrease, as warming leads to reduced solubility, as well as an increase in the strength and duration of stratification.
Thermal stratification in UK shelf seas will continue to start earlier and end later in the year due to changes in air temperature. The strength of stratification is also projected to increase.
Most projections suggest that UK shelf seas, and the adjacent Atlantic Ocean, will be less saline than present, driven by ocean-circulation changes in response to climate change.
Mean sea level around the UK has risen by about 12–16 cm since 1900. Over the 21st Century, sea level is expected to continue to rise, with higher rates in the south compared to the north.
Climate change could affect storms and waves in the North Atlantic, but natural variability will continue to dominate in the near future.
Coastal erosion rate and extent in the UK is expected to increase in the future due to a combination of relative sea-level rise, reduced nearshore sediment supply, and impacts resulting from human activities and management.
A decline in pH (increasing acidity) is evident through the global ocean, and rates could increase in the second half of the century. For UK shelf seas, the rate of pH decline is higher in some coastal areas than others.
The Atlantic Meridional Overturning Circulation is projected to weaken this century due to climate change, but an abrupt shutdown is unlikely. Changes in shelf sea circulation are more uncertain.
The extent and thickness of Arctic sea ice continues to decrease, especially in summer months (May to September) and the area of thick, multiyear ice is in significant decline.