Increasing CO2 concentration in the atmosphere leads to acidification of marine waters. Ocean acidification is relatively predictable with pH decreasing ~0.02 per decade, whereas changes in coastal pH can be 10 times larger due to changing inputs of nutrients and organic matter from land and warming. Despite that most organisms affected by acidification inhabit the coastal zone, status and trends of coastal acidification as well as possible consequences for marine life are largely overlooked. At present, coastal acidification is not consistently monitored and reported in Nordic countries. The TRIACID project has developed indicators, which are applicable to assess acidification and its potential consequences, provided that pH and other parameters of the carbonate system are monitored. It is recommended to increase focus on this emerging environmental problem.