Medidas de Gestao das Pescarias Marinhas e Aquicultura 2019 The State of World Fisheries and Aquaculture 2018 | Page 147

THE STATE OF WORLD FISHERIES AND AQUACULTURE 2018
Assessing climate change impacts for fisheries
and aquaculture
In 2016, IPCC commissioned the Special report on
the ocean and cryosphere in a changing climate, to
be finalized in 2019, which will have a particular
focus on marine ecosystems and dependent
communities. At the same time, FAO
commissioned a report to update an earlier study
on the impacts of climate change for fisheries
and aquaculture (Cochrane et al., 2009). These
efforts recognize that the risks and
v ulnerabilities in the fisheries and aquaculture
sector, and in the communities that rely on it,
depend not only on predicted physical, chemical
and biological changes (and the likelihood of
their occurrence), but also on the v ulnerabilit y of
their contexts.
The Fifth Assessment Report of the
Intergovernmental Panel on Climate Change
(IPCC) includes the most comprehensive
summar y of the effects of climate change on
aquatic ecosystems and their resources (IPCC,
2014). The main risks for fisheries and
aquaculture are reasonably well understood: A
number of marine species, depending on their
mobilit y and habitat connection, are responding
to climate impacts by shifting their distributions
poleward and to deeper waters (see Box 16 and
Figure 38). The increased uptake of carbon dioxide
by oceans, resulting in higher water acidit y, is
also of particular concern for calcif ying
organisms in natural environments (including
mariculture facilities), although the full
ecosystem effects are still inconclusive.
Competition for water, changes in the water
cycle, increased frequency of storms and sea level
rise are all expected to affect both inland
fisheries and aquaculture industries (Seggel, De
Young and Soto, 2016).
Recent projections from the Inter-Sectoral
Impact Model Intercomparison Project (w w w.
isimip.org) have suggested that changes in
marine fisheries production may be just as
large as those in crop agriculture, which is
often claimed to be the sector most affected
by climate change. Furthermore, the
projections reveal decreases in both marine
and terrestrial production in almost 85
percent of coastal countries analysed, var ying
widely in their national capacit y to adapt
(Blanchard et al., 2017). These findings
underline the importance of responding to
climate change in a coordinated manner
across all food systems, to ensure
opportunities are maximized and negative
impacts reduced, and to secure food and
livelihood provision. Necessar y actions in
fisheries and aquaculture, as in agriculture,
must include effective governance, improved
management and conser vation, efforts to
maximize societal and environmental
benefits from trade, increased equitability of
distribution and innovation in food
production, and the continued development
of low-input and low-impact aquaculture.
A number of researchers have published
evidence to strengthen these arg uments.
Primar y production of the global ocean, on
which the marine food web and ultimately fish
rely, is expected to decline by 6 percent by 2100
and by 11 percent in tropical zones (Kwiatkowski
et al., 2017). Diverse models predict that by 2050,
the total global fish catch potential may var y by
less than 10 percent (Barange et al., 2014;
Cheung et al., 2010) depending on the trajector y
of greenhouse gas emissions, but with ver y
significant geographical variabilit y. While
impacts will be predominately negative in many
fisheries-dependent tropical regions,
opportunities will also arise in temperate
regions (Barange et al., 2014) (Figure 39).
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