Twenty-five years after first warning that oil spills would wane while invasive species and climate impacts would surge, an international team revisits its coastal forecasts and finds many bull's-eyes, alongside surprising misses. Plastic pollution, ocean acidification, and sensory pollution have risen faster than imagined, even as strong treaties curbed chemicals like TBT. The scientists argue that shorelines remain “sentinels” for the global ocean and urge a blend of local action and sweeping accords such as a Global Plastics Treaty to keep future surprises in check.
What the scientists got right
  • Oil spills would decrease in frequency and quantity;
  • More food would be collected from rocky shores, both recreationally and commercially;
  • The global redistribution of non-native species would increase as global temperatures change;
  • A combination of agricultural intensification, and riverside and coastal urbanisation, would lead to increased sediment running into rivers, estuaries and seas.
What the scientists got partly right
  • The forecasts were insufficiently optimistic about reductions in the impacts of chemical compounds, such as tributyltin (TBT), which were subsequently the subject of international legislation;
  • Scientists were very aware of the influence of climate fluctuations, but didn’t fully appreciate the varied impacts they would have on species and ecosystems;
  • They also underestimated the importance of extreme weather events resulting from climate change;
  • Scientists correctly predicted an increase in coastal defence structures to tackle rising sea levels and stormier seas but underestimated their likely impacts on wider coastal ecosystems;
  • Recreational use of coastal areas has increased, but rather than having a solely negative effect it has actually led to people appreciating these regions more.
What the scientists got wrong
  • Coastlines are more vulnerable now to eutrophication - an increase in the concentration of nutrients such as nitrogen and phosphorus - than they were 25 years ago;
  • Concerns about the intensification of aquaculture, and particularly impacts from genetically modified organisms, have so far proved unfounded;
  • Anticipated harm to habitats as a result of offshore renewable energy installations has not materialized;
  • The impacts of ultraviolet radiation on coastal species were not fully appreciated.
What the scientists missed
  • The impacts of coastal mining;
  • Ocean acidification and its potential impact on marine species;
  • The effects of artificial light pollution;
  • The effects of noise pollution;
  • Extreme flood and drought events;
  • The scale and effects of plastic pollution;
  • The impacts of pharmaceutical contamination;
  • The combined effects of various environmental threats and chemical compounds.