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So what do the world's coastlines look like in 2025? Scientists revisit turn-of-the-century forecasts

At the dawn of the millennium, a group of eminent scientists began compiling a list of the threats they felt were most likely to impact the world's rocky shorelines over the coming quarter of a century.

Published in 2002, it included forecasts that—among other things—pollution from oil spills would decrease, the number of invasive species across the world would rise, genetically-modified organisms would have harmful effects on the ocean, and the impacts of global climate change would be felt more intensely.

Now, 25 years on, the same academics—along with a larger and more wide-ranging team of international experts—have revisited their forecasts and discovered that many of them were correct, either in whole or in part, while others haven't had the impacts that were envisaged at the time.

They have also charted some of the other threats to have emerged and grown in significance since their original work, with notable examples including global plastic pollution, ocean acidification, extreme storms and weather, and light and noise pollution.

In doing so, they have also highlighted that while there are key issues they believe are likely to threaten the world's coastlines between now and 2050, others may also emerge that require varying levels of local and global action to try and tackle them.

The two studies were led by Professor Stephen Hawkins, Lankester Research Fellow at the Marine Biological Association, and co-authored by Professor Richard Thompson OBE FRS, Professor of Marine Biology at the University of Plymouth.

For the new study, in Marine Pollution Bulletin, they also collaborated with Dr. Kathryn O'Shaughnessy and other colleagues working at the Marine Biological Association and University of Plymouth and various other organizations in the UK, U.S., South Africa, Italy, Ireland, Chile, China and Monaco.

Collectively, they incorporated expertise in disciplines including climate change, marine biology, plastic pollution, light and noise pollution, and eco-engineering, demonstrating—the researchers say—the importance of factoring in multiple perspectives when discussing environmental threats.

Professor Hawkins, also an Emeritus Professor at the University of Southampton, said, "Our shorelines are sentinels for the global ocean and, for many people, their window to what is happening in our seas. Protecting their continued health is essential, but they are constantly facing multiple threats from land, sea and environmental change.

"Our two studies have shown that over the past 25 years, it is possible to forecast some of the challenges the planet might face in the future and to identify ways they might be addressed. However, there will always be things we can't foresee—and things that don't materialize as scientists might expect—and finding a balance will always be key to minimizing the impact we have on our planet."

Professor Thompson, recently named by TIME magazine among its 100 most influential people in the world for 2025, said, "In the past quarter of a century, most of the world has become more aware of the threats facing our planet.

"The key questions have always been around the best way of tackling them. Marine scientists have shown that a combination of global and local action can bring about positive change—the successful banning of tributyltin (TBT) by the International Maritime Organization in 2003 being a notable example.

"As international discussions continue around factors such as the Global Plastics Treaty and the most effective ways to reduce global warming, it is important that we recognize past environmental success and build on them."

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 urbanization, 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 defense 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.