Fisheries and Climate Change: the IPCC Second Assessment

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Fisheries and Climate Change the IPCC Second
Assessment
Dr. John T. Everett IPCC Convening Lead Author -
Fisheries National Marine Fisheries
Service National Oceanic and Atmospheric
Administration United States Department of
Commerce
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Intergovernmental Panel on CC

• Mission provide an authoritative statement of
  scientific opinion on CC
• Several hundred scientists serve on 3 WGs
• Broadly peer reviewed plus govmt review
• WG I science of climate change itself
• WG II impacts and response strategies
• WG III broad socioeconomic issues

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Fisheries Lead Authors
Dr. John T. Everett, CLA Dr. Daniel Lluch Belda
Washington, USA La Paz, BCS, Mexico Dr. Andre
Krovnin Dr. Henry A. Regier Moscow, Russia
Toronto, Canada Dr. Ezekiel Okemwa Jean-Paul
Troadec Mombasa, Kenya Brest, France
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Physical Changes

• Climate change will come with changes in
• temperature,
• circulation,
• sea level,
• ice coverage,
• wave climate, and
• extreme events,
• Affecting ecosystem structure function

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Temperature

• Ave. temp. to increase 1-3.5 C by 2100
• High n. latitudes warm more than average
• Nights winters warm more than average
• Ocean changes lag land by 10 years
• Exceptions delay or cooling in belt around
  Antarctica and in high N. Atlantic
• In high latitudes, the growing period and
  productivity should increase

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Currents Upwelling

• A weakening of the global thermohaline
  circulation may occur
• Competing arguments on oceanic coastal
  upwelling increase or decrease
• No reliable forecasts
• Forces driving natural variability not well
  understood

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Storms and El Niño

• Changes in frequency intensity of cyclones,
  storms, El Niño uncertain
• No trends in storminess in last 50 years
• Some regional trends in storminess in both
  directions
• The post 1989 period of ENSO activity seems
  unusual, but may have happened before

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Ice Cover

• Major loss of fresh sea ice (up to 50 )
• The NW Passage N. Sea Route of Russia may have
  up to 100 days of shipping
• In the Antarctic, the main effect will be a
  retreat of the ice edge
• No evident trend in sea ice at either pole
• Ice coverage impacts ice-associated species,
  primary productivity, fishing and aquaculture

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Sea Level Rise

• Up 15-95 cm by 2100
• From thermal expansion melting of ice
• Regional variations due to wind and atmospheric
  pressure patterns, ocean density differences,
  land motion, currents
• Obs. show 10-25 cm. rise since 1900
• No acceleration has been detected
• Wetlands will decrease sharply where there is
  shore protection

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Precipitation

• A few percent increase
• More concentrated in time
• Increases in low and high latitudes
• Greater evaporation in mid-latitudes
• This can affect water salinity, watershed flows,
  turbidity, pollutant loading and related factors

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UV-B

• Other groups, not IPCC, study ozone depletion
• Problem chemicals should peak about 2000
• The ozone layer may return to normal about 2050
• In clear waters, UV-B penetrates tens of meters
• In coastal waters, less than 1 meter
• Antarctic ozone hole is larger than Antarctica
• Ozone losses are up in mid-latitudes and the
  Arctic
• Growth rates of several chemicals have slowed or
  stopped

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Species Sensitivities
Changes temperature, sea level, river flows,
salinity, currents, winds, storms, and
variability Species are dependent on one or
more of above Species can move rapidly if
habitat and paths exist Fish are cold-blooded.
Life processes, like growth, are faster when
warmer (within limits) Many species have narrow
ecological niches, but there are many species to
fill niches Small changes cause large
disruptions to a species Mixes will change
until stability is reestablished
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Societal Sensitivities
Species in more stable environments are usually
more valuable Fishers can follow fish,
communities wont Political borders or
economics stop pursuit Developing nations
dependent on fish as food or export earnings are
most sensitive
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Sensitivity Examples
Scallop and fish eggs that rely on a gyre to
return them to their habitat on a certain day or
week Fish eggs in streams or on the sea floor
that require a minimum current speed for
oxygenation Species that require an influx of
freshwater to induce spawning or to kill
predators Temperatures above or below the
stocks lethal limit Immobility of communities
dependent on one species Societies without
money to buy other foods Fishers unable to deal
with new vessel/gear demands
Species
Societal
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Important Findings

• Freshwater fisheries and aquaculture at mid to
  higher latitudes should benefit
• Saltwater fisheries should be about the same
• Fishery areas and species mix will shift
• Changes in abundance more likely near ecosystem
  boundaries
• National fisheries will suffer if fishers cannot
  move within and across national borders
• Subsistence/small scale fishermen suffer most

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Important Findings-2

• CC impacts add to overfishing, lost wetlands and
  nurseries, pollution, UV-B, and natural variation
  
• Inherent instability in world fisheries will be
  exacerbated by a changing climate
• Globally, economic and food supply impacts should
  be small. Nationally, they could be large
• Overfishing is more important than CC today the
  relationship should reverse in 50-100 years.

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CC Impact Ranking for Fisheries
1. Small rivers and lakes, in areas of higher
temperatures and less rain 2. Within EEZs,
particularly where fishers cannot follow
migrating fish 3. In large rivers and lakes 4. In
estuaries 5. High seas
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Adaptation Options

• Establish management institutions that recognize
  shifting distributions, abundances and
  accessibility, and that balance conservation with
  economic efficiency and stability
• Support innovation by research on management
  systems and aquatic ecosystems
• Expand aquaculture to increase and stabilize
  seafood supplies and employment, and carefully,
  to augment wild stocks
• Integrate fisheries and CZ management
• Monitor health problems (e.g., red tides,
  ciguatera, cholera)