Emissions of CO2 driving rapid oceans 'acid trip'
Human emissions of carbon dioxide are increasing the levels of acidity in the oceans at rates not seen for millions of years, scientists say.
|Corals and marine life around the world are threatened by the massive acidification of sea water as a result of C02 gases|
The world's oceans are becoming acidic at an "unprecedented rate" and may be souring more rapidly than at any time in the past 300 million years. The oceans are thought to have absorbed up to half of the extra CO2 put into the atmosphere in the industrial age. Corals all over the world are threatened. Acidification had already caused a 30% loss of species in some ocean ecosystems and scientists predict acidification could increase by 170% by 2100.
Researchers conclude that human emissions of CO2 are clearly to blame: human activities are adding 24 million tonnes of CO2 to oceans every day. The addition of so much carbon has altered the chemistry of the waters. Since the start of the industrial revolution, the waters have become 26% more acidic. Prof Jean-Pierre Gattuso, from CNRS, the French national research agency: "My colleagues have not found in the geological record, rates of change that are faster than the ones we see today."
What worries the scientists is the potential impact on many ocean species including corals. Studies carried out at deep sea vents already show a 30% loss of biodiversity. The effect of acidity is currently being felt most profoundly felt in the Arctic and Antarctic oceans. The more acidic they become, the more damaging they are to the shells and skeletons of marine organisms. The researchers say that by 2020, ten percent of the Arctic will be inhospitable to species that build their shells from calcium carbonate. By 2100 the entire Arctic will be a hostile environment Prof Gattuso: "In the Southern Ocean, we already see corrosion of pteropods which are like sea snails, in the ocean we see corrosion of the shell. "They are a key component in the food chain, they are eaten by fish, birds and whales, so if one element is going then there is a cascading impact on the whole food chain."
The scientists also warn that the economic impact of the losses from aquaculture could be huge - the global cost of the decline in molluscs could be $130bn by 2100 if emissions of CO2 continue on their current pathway. Adding alkaline substances such as crushed limestone to the waters has been mooted as a potential way of mitigating the worst impacts of acidification, but this would only have a limited effect. Marine protection zones would also give some short term benefit, but the scientists say that in the long term only significant cuts in emissions will slow the progress of acidification.
Full article see from Matt McGrath
BBC News http://www.bbc.co.uk/news/science-environment-24904143