New evidence on sea levels and fish behaviour underlines urgency of climate action

Posted on 08 July 2010    
The baby Nemo of film fame would not be able to find the way home in a carbonated ocean, a study found
© Jurgen Freund
Gland, Switzerland: New evidence suggesting sea levels will rise to double expected levels this century and that fewer baby fish will grow successfully to maturity in more acidified oceans underline the urgent need for decisive action on climate change, WWF said today.

The Australian Earth Sciences Convention has heard that cores drilled up to two kilometers below the Antarctic ice have outlined an earth with a similar climate to the warmer earth projected in current climate assessments.

The new evidence was presented by Professor Tim Naish, director of New Zealand’s Antarctic Research Centre, recently named a lead author for the next climate change assessment from the Intergovernmental Panel on Climate Change (IPCC).

It supports other recent modeling suggesting an average sea level rise this century of one metre or more – double the upper estimate issued by the IPCC.

“Given many climate models predict the planet will warm by the same two to three degrees over the next 50 to 100 years, scientists need to urgently understand how temperature changes will affect the polar ice sheet and the speed of likely change,” Professor Naish said.

“A couple of degrees of temperature change can lead to quite dramatic changes across the world.”

Nemo wouldn’t be able to find way home in a carbonated ocean, study finds

Some 150 million people live within a one metre elevation from sea level and much greater numbers would be vulnerable to impacts that include higher storm surges and saline intrusion into coastal aquifers supplying water and supporting food production..

“New studies are all the time painting an ever-worsening picture of what we are facing with climate change,” said Gordon Shepherd, interim leader of WWF’s global climate deal. “And what we are facing is not just worse projections for impacts we know about but left fielders that we never anticipated.

“For instance, the same conference has heard that baby fish will become more vulnerable to predators as oceans acidify in the process of absorbing excess CO2.”

“This is another threat joining an already long list of climate change threats to our food supplies.”

The ocean acidification study, conducted by Australia’s highly regarded Centre of Excellence for Coral Reef Studies, found that as carbon levels rise and ocean water acidifies, the behaviour of baby fish changes dramatically.

The behaviours of concern include being attracted to predators rather than cautious of them and a decreased sense of smell. Early experiments using clown fish – the Nemo of the film – found them unable to find their way home in carbonated water.

Overall, the behavioural changes decrease larval fish chances of survival by 50 to 80 per cent.

The baby Nemo of film fame would not be able to find the way home in a carbonated ocean, a study found
© Jurgen Freund Enlarge

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