"The COP26 summit may come to be regarded as a failure or an important
milestone, but it certainly failed to address the “other” climate change
problem: ocean acidification.
With the exception of rising sea levels, climate change impacts on the oceans
have been treated as a peripheral matter at global climate change negotiations.
This marginalisation of the oceans largely continued at COP26.
But states, including New Zealand and Australia, nevertheless have an
obligation to prevent and mitigate excess carbon dioxide (CO₂) from entering
Almost four decades ago, 168 states signed up to the UN Convention on the Law
of the Sea (UNCLOS). Under this treaty, they must address CO₂ in the oceans
consistent with (but distinct from) their obligations under the climate regime.
Ocean acidification (OA) is caused by excess CO₂ in seawater. Atmospheric
concentrations of CO₂ have now reached 414ppm (from about 280ppm in 1750) and
the oceans are a major sink, having absorbed nearly half of all anthropogenic
emissions since the beginning of the Industrial Revolution some two centuries
But rising levels of CO₂ in the oceans change the acidity of seawater, measured
as pH. Ocean acidity has remained remarkably stable for more than 800,000
years, but has increased by about 30% in the last 200 years.
This has negative consequences for shell-forming organisms and coral reefs such
as the Great Barrier Reef in Australia. Recent research suggests it may also
affect the larvae of fish, including commercially important species such as
yellow fin tuna."
*** Xanni ***
Chief Scientist, Xanadu
Partner, Glass Wings
Manager, Serious Cybernetics