Asian Geographic2017

Optimistically, scientists do

not believe the tipping point of

irreversible change has yet occurred

As unpr edictable as the weather
Changes in ocean currents and precipitation patterns also
contribute to the frequency and intensity of extreme weather
events, which are predicted to become more common. Large
storms such as hurricanes and cyclones can cause significant
habitat loss, with increased storm surges resulting in
dramatic coastal erosion. The impact of large storms can be
devastating on both the environment and local communities.
El Niño events are also becoming more common,
warming the eastern and central Pacific above their
normal seasonal averages. El Niño events alter global
weather patterns, which affect extreme weather systems
worldwide. The potential increase in severe El Niño events
threatens ecosystems and could have large socio-economic
consequences. For example, 2016 saw the third mass global
coral bleaching event, resulting from warmer-than-normal
seawater, which was attributed to it being an El Niño year.
Bleaching is a stress response of corals, resulting in the
loss of their microscopic algae that they depend on for
energy production. Scientists believe that up to a third of
the northern Great Barrier Reef was lost from the El Niño
in 2016. With predictions that El Niño events will become
more frequent, the ability of the reef to recover is worrying,
especially when other climate impacts, such as ocean
acidification, are intensifying.

The Osteoporosis of the Sea
The oceans absorb atmospheric carbon dioxide, which
initiates chemical reactions that reduce seawater pH and
carbonate ions in seawater. pH is the scale used to measure
how acidic something is. The scale ranges from 0 to 14,
with the lower values measuring that which is more acidic.
Seawater is slightly basic (higher than seven on the pH scale)
meaning that the process of ocean acidification is a shift
towards pH neutral (pH equals seven) rather than acidic
conditions. The shift in chemistry also reduces the carbonate
ions in seawater, which are the fundamental building blocks
needed for marine organisms that have a calcium carbonate
shell or skeleton. The greater acidity also increases the risk of
dissolution, making ocean acidification “the osteoporosis of
the sea” – compromising the structural integrity of organisms
made of calcium carbonate.
The impact of climate change on the world’s oceans is
extensive. Collectively, the effects threaten to disrupt the
balance of the oceans’ ecosystems. Already, there are reports
of the poleward migration of marine organisms to cooler
waters where conditions are more optimal.

DR EMMA CAMP is a marine biologist who studies the

impacts of climate change on marine ecosystems. She works

at the University of Technology Sydney in the Climate Change

Cluster (C3). Emma is also a passionate diver, photographer

and conservationist, acting as an ambassador for preserving

biodiversity for the international charity Ibex Earth.

Unfortunately, not all species are capable of relocating;

many species face an increasing risk of extinction.

As scientists continue to understand and uncover the

planet’s responsive processes, we are seeing how intricately

balanced life on Earth is. Optimistically, scientists do not

believe the tipping point of irreversible change has yet

occurred. There is, however, an urgent need to implement

policies and practices to reduce carbon dioxide emissions, to

ensure the effects of climate change do not negatively change

our oceans. ag

IMAGE © COTTON COULSON/KEENPRESS

IMAGE © PETER ESSICK

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