Warmer water temperatures
can result in coral bleaching.
When water is too warm,
corals will expel the algae
(Zooxanthellae) living in their
tissues, causing the coral
to turn completely whiteactivities – significantly reducing the levels of carbon dioxide
in the atmosphere, which helps to regulate the Earth’s
temperature. The absorption of this excess carbon dioxide,
however, causes a fundamental shift in seawater chemistry,
which ultimately results in the oceans becoming more acidic.
Warmer and more acidic oceans are the result of climate
change and are linked to numerous impacts that scientists
globally are still uncovering.
Wa r m e r Oc e a ns
The oceans have a high latent heat capacity, which means
they are very good at storing energy – so efficient, in fact, that
they have absorbed an estimated 93 percent of the additional
energy created from the greenhouse effect. This, combined
with the slow mixing time of the world’s oceans, means that it
can take up to a decade for changes in climate to alter ocean
temperatures. That being said, since the start of the 20th
century, there has been warming of the deep oceans, and an
increase in the global mean sea surface temperatures.
Rising sea level is a direct impact of ocean warming.
Warmer temperatures cause seawater to physically expand
(known as thermosteric sea level rise), while melting glaciers,
snow and ice add volume to the oceans (known as eustatic sea
level rise). Since the mid-19th century, sea level has risen at a
greater rate than the mean values from the last two millennia.
The consequence of this is that habitats are being lost – glacial
habitats that house animals such as the iconic polar bear are
diminishing, with the simultaneous effect of coastal habitats
being flooded. Scientific estimates suggest that sea level is
rising at a rate of 3.5 millimetres per year, a trend that threatensIMAGE © CATLIN SEAVIEW SURVEYff