<a href="https://www.greenlifestylemag.com.au/blogs/jumpycrawl#">Postcards from Copenhagen</a>

Postcards from Copenhagen

John Pickrell, on the ground at the Copenhagen Conference

Global warming's evil twin

Oceana ad

According to the Secretariat of the Convention on Biological Diversity the acidity of seawater will increase by 150% by 2050, which is a rate of change not seen in 20 million years.

Credit: Oceana

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G is happy to see that the problem of ocean acidification, which threatens Australia's Great Barrier Reef, has a high profile around the edges of the U.N.'s Copenhagen climate talks.

Ocean acidification - described by the head of the U.S. National Oceanic and Atmospheric Administration (NOAA) as "global warming's evil twin" - has been recognised as a big problem by scientists for a decade or so now, but has only recently started to get the coverage it deserves in the mainstream media (with stories hitting the BBC, the Telegraph and the Daily Mail this week).

Anthropogenic carbon dioxide is building up in the atmosphere, but it has also been dissolving into the oceans, slowly making them more acidic. This makes calcium carbonate - used by marine animals such as corals and snails to build their shells and skeletons - much less available in seawater. It's already making it more difficult for them to grow, and is having profound negative effects on a variety of sea life.

According to a review of research launched in Copenhagen by the Secretariat of the Convention on Biological Diversity (CBD), acidity will increase by 150% by 2050, which is a rate of change not seen in at least 20 million years.

"The only pathway in which you retain ecosystems like coral reefs is one that brings greenhouse gasses like carbon dioxide to below 350 parts per million (ppm) [in the atmosphere] in the long term," says Ove Hoegh-Guldberg an expert on corals at the University of Queensland. "It's important that we try to minimise any further rise in greenhouse gasses and keep well below 450 ppm. The message is that those changes that appear to be very subtle are incredibly important for humans and they must be part of this dialogue here in Copenhagen, because there is so much at stake."

A clever advertising campaign, funded by the NGO Oceana, is plastered all over Copenhagen's transport system - it makes the point that governments should aim for 350 ppm if we are to have much hope of saving diverse marine ecosystems we take for granted today.