There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
The ocean has been shielding the earth from the worst effects of rapid climate change
by absorbing excess carbon dioxide from the atmosphere. This absorption of CO2 is
driving the ocean along the pH gradient towards more acidic conditions. At the same
time ocean warming is having pronounced impacts on the composition, structure and
functions of marine ecosystems. Warming, freshening (in some areas) and associated
stratification are driving a trend in ocean deoxygenation, which is being enhanced
in parts of the coastal zone by upwelling of hypoxic deep water. The combined impact
of warming, acidification and deoxygenation are already having a dramatic effect on
the flora and fauna of the oceans with significant changes in distribution of populations,
and decline of sensitive species. In many cases, the impacts of warming, acidification
and deoxygenation are increased by the effects of other human impacts, such as pollution,
eutrophication and overfishing. The interactive effects of this deadly trio mirrors
similar events in the Earth's past, which were often coupled with extinctions of major
species' groups. Here we review the observed impacts and, using past episodes in the
Earth's history, set out what the future may hold if carbon emissions and climate
change are not significantly reduced with more or less immediate effect.