Fossil fuel emissions stunt coral growth

Fossil fuel emissions have been linked with reduced growth rates of coral reefs in a new study published in the Nature Geoscience journal.

Scientists say fine particles in the air from burning coal or volcanoes shade coral reefs from sunlight and cool the surrounding waters.

Corals are a vital part of ocean ecosystems. Up to 25% of species depend on them for food and shelter.

Research linking reef vulnerability to ocean acidification and climate change has gained a higher profile in recent years.

Scientists say this is the first study of its kind to make a connection between the concentration of particulate pollution in the atmosphere and reduced growth rates.

Scientists say their study shows coral reefs are sensitive to both carbon dioxide levels and regional aerosol emissions associated with industrialisation

“Particulate pollution or ‘aerosols’ reflect incoming sunlight and make clouds brighter,” said Dr Paul Halloran of the Met Office Hadley Centre.

“This can reduce the light available for coral photosynthesis, as well as the temperature of surrounding waters. Together these factors are shown to slow down coral growth.”

The authors used a combination of records retrieved from within the coral skeletons, observations from ships, climate model simulations and statistical modelling.

The analysis presented suggests coral growth rates in the Caribbean were affected by volcanic aerosol emissions in the early 20th century and by aerosol emissions caused by humans in the later 20th century.

Researchers say they hope this will lead to a better understanding of how coral growth may change in the future, taking into account future carbon dioxide levels and localised sources of aerosols such as industry or farming.

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