Marine scientists warn gases 'may kill reefs in 40 years'

Cancun summit offers bleak prognosis of threat to world's corals from carbon emissions.

CANCUN, Mexico // Greenhouse gases are threatening coral reefs around the world, including those in the UAE, marine scientists warned during climate talks.

If humanity continues on its present course, some of the world's most vibrant reefs could be reduced to rubble by 2050, experts told the UN summit in Cancun.

The large amounts of carbon emissions pumped into the atmosphere are already changing the chemistry of the ocean and affecting the ability of reefs to grow, they said.

After 40 years, the process, called acidification, could be so advanced that reefs corrode.

"Ocean acidification, or should I say in our case, sea or even coastal acidification, has been increasing rapidly over the last two decades, surpassing the levels seen in the entire 150 years before that," said Dr Thabit al Abdessalaam, the director of the biodiversity management sector at the Environment Agency - Abu Dhabi.

Acidification "could be viewed as big a challenge as climate change itself", he added, speaking from the UAE.

Corals in the Arabian Gulf, which survive in high temperatures and salinity, have long been known for their resilience. Although no research has yet been done on how those corals were affected by acidification, it was logical to wander whether the added stress would harm them, Dr al Abdessalaam said.

"Perhaps, if we reduce the amount of effluents and eutrophication [when water receives excess nutrients, which stimulate plant growth that can cause algal blooms] and implement climate change adaptive measures at the local UAE level, it would help," he said.

A major part of any solution would be the reduction of carbon emissions - caused when fossil fuels were burned to produce energy, power industrial complexes and transport people.

Politicians and scientists in Cancun are trying to work out how to stop greenhouse gas concentrations from rising and keep them at a level no higher than 450 parts per million (ppm). Currently, concentrations worldwide are at 385ppm, the highest measurement since the beginning of the Industrial Revolution.

Achieving consensus on methods may prove impossible. Even if that happened, it would not be enough to save the oceans alone, experts said.

"The problem is, when they are talking at limiting carbon dioxide emissions at 450ppm, that will not be enough," Dr al Abdessalaam said.

Dr Carol Turley, a leading scientist on ocean acidification from the Plymouth Marine Laboratory in the UK, agreed.

"At 450ppm, there will still be significant ocean acidification," she said.

Dr Turley and other scientists in Cancun said that although acidification was connected to climate change, it should be tackled by politicians as a separate issue.

The Intergovernmental Panel on Climate Change (IPCC) will include acidification in its fifth assessment report, in 2014. The IPCC is the scientific body that informs the United Nations and the world's governments on the effects of carbon emissions.

Before politicians started negotiations, work had to be done by scientists, said Ellycia Harrould Kolieb, a marine scientist with Oceana, a non-governmental organisation.

One question experts must address is how to quantify acidification, so politicians could negotiate targets.

One way to measure the impacts might be the examination of "indicator species" such as squid and clownfish, which were proving very sensitive to the process. The sensory organs of clownfish, for example, become damaged, which makes them unable to smell predators.

"This can impact the survivability of those organisms," Ms Kolieb said.

Whatever the targets, humanity needed to act quickly, Dr Turley warned.

"Ocean acidification is happening now. It can be stabilised," she said. She added that failure to act would affect the oceans "for tens of thousands of years".