The acid question on our oceans

The steady acidification of the world’s seawater over the next few decades will create oceans full of winners and losers, a conference in Hobart has heard.

The gathering of some of the region’s leading climate change experts was told oceans would reach a carbon saturation tipping point within 50 years and nobody knew what might happen then.
Ocean acidification is caused by man-made carbon dioxide emissions.

Dr Will Howard of the Antarctic Climate and Ecosystems Co-operative Research Centre said research pointed to significant changes in marine life such as plankton, corals and urchins before even deep cuts to emissions could have an effect.

“Some organisms won’t be able to produce shells without expending a lot more energy,” he said.

“What that means for the whole ecosystem is still most unclear. We’re into uncharted territory.

“Even if we somehow magically cut our emissions to zero now, the ocean would still continue to absorb carbon dioxide from the atmosphere.

“There’s a long set of time lags in the system which put a premium on acting early.”

Dr Howard said this week’s conference would try to identify where research should be directed.

CSIRO marine scientist Bronte Tilbrook said what was already known about ocean acidification was troubling.

“Indications are that we will see some fairly significant changes in the ecosystem,” Dr Tilbrook said.

“Under the CO2 emissions scenarios — and it’s the high ones we seem to be tracking at present — in about 2060 we’ll cross a chemical threshold in the Southern Ocean where one form of calcium carbonate will become chemically unstable.

“It’s very early days to say there will be a decline in (fishery) production or an increase — some species will do better, we just don’t know if they’re going to be of much value for the ecosystem.”

David Killick, Mercury, 3 June 2008. Article.

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