Scientists worried about 'unprecedented' changes in oceans

By Denise Donnebaum Sep 20, 2011, 17:22 GMT

Brussels - 'Most things in the oceans are hidden, but what happens there also changes our life on land,' says marine biologist Katja Philippart.

She is part of a team of scientists who put together the results of more than 100 European Union-financed research projects from the past few years for the sea research project, Clamer.

Philippart warns of heavy flooding, storms and fishermen without work. Her colleague Carlo Heip, director of the Royal Netherlands Institute for Sea Research, speaks with equal alarm about the dangers for coastal cities, including cholera.

These and other developments are part of a new 200-page report on climate change that especially looks at the consequences for the oceans.

Oceans are changing at an unprecedented speed, the report states. As icebergs are melting, the sea level and temperature are rising ever faster.

'We can no longer stop climate change. We took this path a long time ago,' the researchers say. The consequences of climate change are reversible only over the long term, 'maybe in decades or even centuries.'

In the past 25 years alone, the average temperature of oceans has increased 10 times as quickly as in the last century.

Worldwide, an average temperature increase of 2 degrees Celsius on the water surface is expected by the end of the 21st century. The North Sea should see a rise of 1.7 degrees, while the Baltic Sea will get 2 to 4 degrees warmer.

Some of the most dangerous bacterial pathogens feel at home in warmer waters. Researchers have determined that higher temperatures favour the spread of a certain bacteria from the vibrion species, which also causes cholera.

Heip said that means a potential threat for coastlines. Health costs could soar if humans eat contaminated seafood, according to the report.

The warming of the seas will also have other consequences. Many fish species are moving further north where the water is colder.

'The south is therefore losing some of its commercial fish, such as the cod,' Philippart says. The cod is in danger of dying out even in the Baltic Sea.

Fish migrations will not only disturb the ecosystem. Fisheries in southern Europe will have to deal with smaller catch totals, while the north - Greenland, Iceland and Norway - must prepare for just the opposite, and fishermen will need to adjust to the new conditions.

Melting sheets of ice and glaciers are also creating uncertainty. While the sea level has risen on average 1.8 millimetres per year over the past century, it has risen more drastically since 1993, with an annual increase of about 3.3 millimetres.

'An increase of 80 to 200 centimetres could wipe out entire countries,' according to the report.

Coastal cities are threatened by rising sea levels and Heip said they could run into big difficulties.

Cities such as Hamburg in Germany, although not directly on the ocean, could be hit with flash floods along the Elbe or immense rainfall - all of which will become more probable for northern Germany, France, Denmark, southern England and Eastern Europe.

'Those are not just scenarios for the far-off future. All that has long been happening,' Philippart says.

'Not everything is bad. Things just change. But we need to be aware of these changes and get prepared,' says Heip. 'We need to continue observing the oceans.'