This
is one effect that is measuring up well. Our atmospheric bench mark
is about to cross the 400 point and the anthropomorphic linkage
appears unassailable. Thus the steady measurable rise in Arctic
ocean acidity when it is a natural trap and natural sink at the same
time conforms powerfully.
That
it may also have coincided also with a modest rise in Ocean
temperatures needs to be kept in mind but not as securely as these
two linkages.
The
anthropomorphic effect of CO2 production will naturally peak over the
next generation and then enter a precipitous decline. The generation
after that will see a huge draw down of CO2 as the Sahara Desert and
the Middle East generally is completely reforested. So in the long
term we more at risk to sustain fossil fuel burning to deliberately
maintain a high CO2 level.
The
Arctic has lost almost all its multiyear ice and will continue in
this mode until the oceanic heat inputs change.
Arctic Ocean
'acidifying rapidly'
By Roger Harrabin
6 May 2013
http://www.bbc.co.uk/news/science-environment-22408341
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Scientists from the
Arctic Monitoring and Assessment Programme (AMAP) monitored
widespread changes in ocean chemistry in the region.
They say even if CO2
emissions stopped now, it would take tens of thousands of years for
Arctic Ocean chemistry to revert to pre-industrial levels.
Many creatures,
including commercially valuable fish, could be affected.
They forecast major
changes in the marine ecosystem, but say there is huge uncertainty
over what those changes will be.
It is well known that
CO2 warms the planet, but less well-known that it also makes the
alkaline seas more acidic when it is absorbed from the air.
Absorption is particularly fast in cold water so the Arctic is
especially susceptible, and the recent decreases in summer sea ice
have exposed more sea surface to atmospheric CO2.
The Arctic's
vulnerability is exacerbated by increasing flows of freshwater from
rivers and melting land ice, as freshwater is less effective at
chemically neutralising the acidifying effects of CO2.
The researchers say
the Nordic Seas are acidifying over a wide range of depths - most
quickly in surface waters and more slowly in deep waters.
The report’s
chairman, Richard Bellerby from the Norwegian Institute for Water
Research, told BBC News that they had mapped a mosaic of different
levels of pH across the region, with the scale of change largely
determined by the local intake of freshwater.
“Large rivers flow
into the Arctic, which has an enormous catchment for its size,” he
said.
“There’s slow
mixing so in effect we get a sort of freshwater lens on the top of
the sea in some places, and freshwater lowers the concentration of
ions that buffers pH change. The sea ice has been a lid on the
Arctic, so the loss of ice is allowing fast uptake of CO2.”
This is being made
worse, he said, by organic carbon running off the land – a
secondary effect of regional warming.
“Continued rapid
change is a certainty,” he said.
“We have already
passed critical thresholds. Even if we stop emissions now,
acidification will last tens of thousands of years. It is a very big
experiment.”
The research team
monitored decreases in seawater pH of about 0.02 per decade since the
late 1960s in the Iceland and Barents seas.
Chemical effects
related to acidification have also been encountered in surface waters
of the Bering Strait and the Canada Basin of the central Arctic
Ocean.
Scientists estimate
that the average acidity of surface ocean waters worldwide is now
about 30% higher than before the Industrial Revolution.
The researchers say
there is likely to be major change to the Arctic marine ecosystem as
a result. Some key prey species like sea butterflies may be harmed.
Other species may thrive. Adult fish look likely to be fairly
resilient but the development of fish eggs might be harmed. It is too
soon to tell.
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