Hurricanes 'can reduce CO2 levels'

Devastating hurricanes and typhoons could have one major benefit: reducing the amount of carbon in the atmosphere.

By Kate Devlin Last Updated: 7:15PM BST 19 Oct 2008

Scientists found that the storms act as a natural form of "carbon capture" by helping to trap carbon dioxide deep at the bottom of the ocean.
The more carbon dioxide is released into the atmosphere, the greater the number of strength of such storms, the study also suggests, although they will never rise to levels enough to reduce the current rate of global warming, the researchers warn.
However, the breakthrough will help scientists to improve their understanding of how the earth reacts to greenhouse gases and to tailor forecasts of the cycle more accurately.
The new study found that tropical cyclones, the umbrella term for hurricanes and typhoons, act as a counterbalance to increasing levels of carbon in the atmosphere.
These can be caused naturally, by events such as the eruption of volcanoes, as well as by man-made pollution.
The cyclones create large-scale floods which carry vast amounts of carbon, trapped in soil and vegetation, into rivers, the research found.
From there, housed in mounds of dirt and stones, the carbon is often dragged to the ocean, where is sinks to the floor, removed from the atmosphere.
Scientists from Britain, Japan and Taiwan studied deposits in Taiwan's LiWu river in the aftermath of floods caused by hurricanes and typhoons for the study, published in the journal Nature Geoscience.
They estimate that between 80 to 90 per cent of recent carbon deposits were carried there by floodwater.
The storms could provide the "optimum conditions" to bury carbon, the study found.
Robert Hilton, from Cambridge University, who was one of the scientists who led the study, said that the same effects would be seen on other islands including Japan, the Philippines, Cuba and Jamaica, where rivers could easily carry the carbon to the ocean.
"However, the rate at which this happens is around 100 to 1,000 times slower than the amount of carbon dioxide that is being pumped into the atmosphere by man's activity," he warned.
"Although we found that these tropical cyclones act as nature's way of trying to re-balance the amount of carbon in the atmosphere, they can only do so much."
He believes that the number and intensity of the storms will increase in relation to the amount of carbon dioxide released into the atmosphere.
"Other studies have already suggested that already the size of cyclones and their power is increasing in response to global warming."
However, he emphasised that cyclones were not the only natural process by which the earth brought its carbon dioxide levels into balance, and that the gas was also captured by processes including being buried in large limescale deposits, such as the White Cliffs of Dover.
"Carbon capture" has been hailed as a breakthrough in the quest for cleaner energy production.
Earlier this month the Environment Agency advised that no new coal-fired power stations should be built unless they could capture and store CO2, usually miles underground.