Impacts of Climate Change on Agriculture - Climate Resilient Agriculture for Ensuring Food Security - page 73

will also be affected. The impacts, both positive
and negative, will depend on the region and lati-
tude. There is increasing evidence that global
warming is already modifying the distribution of
marine species. Warmwater species are being dis-
placed towards the poles and experiencing
changes in their size and the productivity of their
habitats.

4.8 Fisheries and Aquaculture

The impacts of the accumulation of GHGs in the
atmosphere and water relate to a number of phys-
ical phenomena including gradual changes in
water temperature, acidifi cation of water bodies,
changes in ocean currents, and rising sea levels.
These physical changes affect ecological func-
tions within aquatic systems and the frequency,
intensity, and location of extreme weather events
(Cochrane et al. 2009 ). A range of impacts on
fi sheries and aquaculture, both direct and indi-
rect, can be expected. These are illustrated in
Table 4.13 .
Ecosystem productivity is likely to be reduced
in most tropical and subtropical oceans, seas, and
lakes. In high-latitude ecosystems, productivity
is likely to increase. Physiological and behavioral
processes of fi sh and the organisms they feed on

4.8.1 Predicted Changes

in Fisheries Catch Potential
During 2005-2055 Under
a Higher GHG Emissions
Scenario

Tropical countries could face up to a 40 % drop
in catch potential. High-latitude regions could
enjoy as much as a 30-70 % increase in catch
potential.
How would the current top fi shing countries
fare under this scenario? The model predicted
that, by 2055, exclusive economic zones (EEZ)
average catch potentials in Nordic countries [such
as Greenland (Denmark), Iceland, and Norway]
would increase by 18-45 % and in the Alaskan
(USA) and Russian Pacifi c EEZ by around 20 %.
In most EEZs around the world, catch potentials
would decline by various degrees, with Indonesia
having the largest projected decline: over 20 %
across the 45 species currently targeted within its
EEZ (Cheung et al. 2009 ).
Rising sea levels will have an impact on fresh-
water fi sheries and aquaculture. On the other
hand, higher sea levels may also create new envi-
ronments and opportunities for the fi sheries and
aquaculture sector (e.g., for coastal aquaculture
and mangrove development). Increased frequency
and intensity of storms could directly endanger
infrastructure used for fi sheries and aquaculture.
Inland, the impacts on freshwater fi sheries and
aquaculture are also expected to be signifi cant
with increased variability in rainfall patterns as
well as air and water temperatures affecting the
productivity of rivers, lakes, and fl ood plains. For
aquaculture, broader changes in hydrological con-
ditions and seasonal changes in temperature, pH,
salinity, and ecosystem health are all expected to

Table 4.13 Potential climate change impact pathways
for fi sheries and aquaculture
GHG
accumulation and
global warming
changes Areas affected Impacts

• Ocean currents
• El Niño
Southern
• Oscillation
• Sea-level rise
• Rainfall
• River fl ows
• Lake levels
• Thermal
structure
• Storm severity
• Storm
frequency
• Acidifi cation

Production
ecology

Species composition,
production and
yield, distribution
and seasonality,
disease and other
disruptions, coral
bleaching,
calcifi cation

Fishing,
aquaculture,
and postharvest
operations

Safety and security,
effi ciency and costs,
infrastructure
security

Communities
and livelihoods

Loss and damages
to assets, risks
to life and health,
vulnerability
and confi dence,
displacement
and confl ict

Wider society
and economy

Costs of mitigation
and adaptation,
social and market
impacts, water,
and other resource