Geoscience Reference
In-Depth Information
which an estimated 1 million species live, and pro-
vide food, income, and coastal protection and well-
being for around 500 million people throughout
tropical coastal areas of the world (Hoegh-Guldberg
et al
. 2008 ).
Polar, subpolar, and deep-sea ecosystems are also
at risk as ocean acidii cation will be most severe
there (Orr
et al.
2005 ; Guinotte
et al.
2006 ; Turley
et al.
2007 , 2010a ; Steinacher
et al.
2009 ) and organ-
isms playing important roles in those ecosystems
are particularly vulnerable, for example the mollusc
Limacina helicina
, a key link in the polar and subpo-
lar food chain, or the deep-water coral
Lophelia per-
tusa
( Maier
et al
. 2009), which is key in creating
important deep-sea ecosystems.
Shallow productive seas are also vulnerable (e.g.
Blackford and Gilbert 2007; Feely
et al.
2008 ), with a
growing list of organisms which may be affected by
ocean acidii cation in a number of ways at some
stage during their life history. As many of these pro-
vide food (Table 13.1) there may be a risk to food
security (see Box 13.1 ).
The world's eyes were on Copenhagen in
December 2009 where the 15th Conference of the
Parties (COP15) to the UN Framework Convention
on Climate Change (UNFCCC) met to negotiate
future agreements for mitigating climate change. A
binding agreement was not reached, rather 'The
Copenhagen Accord', according to which the
increase in global temperatures should be no greater
than 2°C, was agreed by most parties although there
was no i rm resolution to reduce CO
2
emissions.
The accord was effectively one of intent only and is
not legally binding, parties to the accord merely
agreed to 'take note' of it.
Post-Copenhagen, as the world moves towards
the next round of negotiations, it seems sensible to
take into account not only the impact of CO
2
emis-
sions on the climate, but also its impacts on ocean
chemistry and the value of the oceans.
as much weight in policy decisions. However, in
1997, marine ecosystem services were estimated to
have a total value of US$21 trillion per annum, rep-
resenting 63% of the total value of earth's ecosystem
services of US$33 trillion (Costanza
et al.
1997 ).
Whilst the accuracy of this i gure has been hotly
debated, there is no doubt that the marine environ-
ment accounts for a substantial proportion of the
world's ecosystem services.
13.3.1
Provision of food and food products
The Food and Agriculture Organization (FAO) of
the United Nations has monitored world i sheries
since 1950. The term 'i sh' includes i ni sh and other
creatures of oceanic origin that are consumed by
humans, including molluscs, crustaceans, echino-
derms, and many other smaller animal groups.
These invertebrates make up 15% of global marine
catch.
Fish provide 16% of annual protein consump-
tion for around 3 billion people worldwide
( Fig. 13.2; FAO 2003 ), and global i sh production in
2004 was valued at US$150 billion per annum
(Kite-Powell 2009). Fish is the primary protein
source for about 1 billion people. In low-income
food-dei cient countries i sheries can make up 22%
of animal protein consumption, whilst in many
coastal communities the percentage can be consid-
erably higher ( FAO 2003 ).
Food consumption per person varies globally
(Fig. 13.2) and is related to need, availability, geog-
raphy, and wealth. Seasonality plays a part too;
when other food sources are unavailable, i sh may
be the only animal protein food available. The
importance of small-scale i sheries in particular for
food security is emphasized by the FAO (2005).
About 38 million people worldwide are employed
in i sheries, 95% of whom live in developing coun-
tries where i sh are often one of the cheapest protein
sources available. Fish are not required simply for
protein, but are also rich in essential fatty acids,
micronutrients, and trace elements. In local subsist-
ence communities, i sh may also provide a small
income stream enabling the import of other staples
such as rice.
The demand for i sh protein has increased
with the growing human population, resulting in
13.3
Valuing the oceans
It is difi cult and controversial to put a monetary
value on ecosystem services because they are nei-
ther fully a part of commercial markets nor as easily
quantii able as economic services or manufacturing
output. For this reason they do not currently carry
