Ocean Acidification: The Other CO2 Problem
Ocean acidification (OA) is the quiet tsunami of
environmental degradation. Within a few decades, OA may
devastate some marine ecosystems and threaten the
productivity of our fisheries. When we burn oil, coal, or
gas, scientists have recently shown, we are transforming the
fundamental chemistry of the oceans, rapidly making the
water more acidic.
For more than 200 years, or since the industrial revolution
began, the concentration of carbon dioxide (CO2) in the
atmosphere has increased due to the burning of fossil fuels
and land use change (e.g. increased car emissions and
deforestation). During this time, the pH of surface ocean
waters has fallen by 0.1 pH units. The pH scale, like the
Richter scale, is logarithmic, so this change represents
approximately a 30 percent increase in acidity.
The ocean absorbs about 30% of the CO2 that is released in
the atmosphere, and as levels of atmospheric CO2 increase,
so do the levels in the ocean. When CO2 is absorbed by
seawater, a series of chemical reactions occur resulting in
the increased concentration of hydrogen ions. This increase
causes the seawater to become more acidic and causes
carbonate ions to be relatively less abundant.
Covering Ocean Acidification: Chemistry and Considerations
An Upwelling Crisis: Ocean Acidification
TED Talk (18+ Minutes)
Rob Dunbar: Discovering Ancient Climates in Oceans and Ice
Rob Dunbar hunts for data on our climate from 12,000 years
ago, finding clues inside ancient seabeds and corals and
inside ice sheets. His work is vital in setting baselines
for fixing our current climate -- and in tracking the rise
of deadly ocean acidification.
Ocean acidification on track to be among the worst of the last
300 million years
A new paper in Science examines the geologic record for
context relating to ocean acidification, a lowering of the
pH driven by the increased concentration of carbon dioxide
in the atmosphere. The research group (twenty-one scientists
from nearly as many different universities) reviewed the
evidence from past known or suspected intervals of ocean
acidification. The work provides perspective on the current
trend as well as the potential consequences. They find that
the current rate of ocean acidification puts us on a track
that, if continued, would likely be unprecedented in last
300 million years.
The authors conclude, "The current rate of (mainly fossil
fuel) CO2 release stands out as capable of driving a
combination and magnitude of ocean geochemical changes
potentially unparalleled in at least the last ~300 [million
years] of Earth history, raising the possibility that we are
entering an unknown territory of marine ecosystem change."
Greenhouse emissions similar to today's may have triggered
massive temperature rise in Earth's past
About 55.5 million years ago, a burst of carbon dioxide
raised Earth's temperature 5°C to 8°C, which had major
impacts on numerous species of plants and wildlife.
Scientists analyzing ancient soil samples now say a previous
burst of the greenhouse gas preceded this event, known as
the Paleocene-Eocene thermal maximum (PETM), and probably
triggered it. Moreover, they believe humans are pumping
similar levels of carbon dioxide into the atmosphere right
now, raising concerns that our own emissions may also
destabilize Earth's climate, triggering the planet to emit
devastating bursts of carbon in the future.
NOVA scienceNOW | Mass Extinction (13+ Minutes)
Host Neil deGrasse Tyson joins a team of investigators hot
on the trail of a mass murderer--one that knocked off its
victims 252 million years ago when it wiped out the majority
of life on our planet.
Five mass extictions--and what we can learn from them
So, are we currently in the middle of a mass extinction? If
we really are, this time the cause is not a meteorite impact
or volcanic eruptions. It is the work of a single species:
Homo sapiens. Habitat destruction and climate change from
rising carbon dioxide levels has driven extinction rates to
levels reminiscent of the mass extinctions of the ancient
The similarities between today and the past are uncanny. The
majority of past extinctions are associated with carbon
dioxide from volcanoes causing rapid global warming, which
led to a number of environmental cascade effects. The cause
may be different, but the results will be the same.