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Sea chemistry & salinity

With increasing CO2 in the atmosphere, levels of ocean acidity area likely to increase.

Projected changes in salinity vary with region but Changes in rainfall will affect coastal salinities.


Observed change

  • Measurements of surface waters in the Rockall Trough to the west of Ireland between 1991 and 2013 indicate increasing levels of acidity.
  • Decadal changes in levels of salinity levels have taken place with an unprecedented reduction in salinity levels observed in recent years in the north-east Atlantic.


Projected change

  • Estimates of future carbon dioxide levels indicate that by the end of this century the surface waters of the ocean could be nearly 150% more acidic, a condition not experienced for more than 20 million years.
  • Changes in salinity will vary with region. Changes in rainfall patterns will affect coastal salinities with implications for amongst others coastal dynamics, water column stability, water quality.

Climate status report for Ireland 2020, Camaro & Dwyer: climate observations & projections report