A team of scientists from Ohio State University led by Anne Carey analysed the chemical composition of water and sediment being washed out to sea by Taiwan’s longest river during 2004’s Typhoon Mindulle.

The findings, which were published in the journal Geology, showed that the Choshui River washed out almost 62 million tonnes of sediment, of which 508,000 tonnes was carbon captured by chemical weathering (the decomposition of silicate rock through exposure to carbon dioxide and water) – the equivalent of 95 per cent of the total amount of carbon the river carries each year.

This carbon will eventually become sedimentary rock and will remain out of the atmosphere for hundreds of millions of years. Knowing how much carbon is deposited off mountainous islands such as Taiwan, Papua New Guinea and New Zealand can help scientists who model climate change to estimate the planet’s overall carbon budget – how much carbon is in the atmosphere and how much is being taken from it.

Carey said that as this is the first study of its kind, further research was needed, but added: ‘With two to four typhoons happening in Taiwan per year, it’s not unreasonable to think that the amount of carbon sequestered during these storms could be comparable to the long-term annual carbon flux for the country.’

October 2008