Download Fisheries and Climate Change: the IPCC Second Assessment

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
Intergovernmental
Panel on CC
• Mission: provide an authoritative
statement of scientific opinion on CC
• Several hundred scientists serve on 3 WG’s
• Broadly peer reviewed plus govm’t review
• WG I: science of climate change itself
• WG II: impacts and response strategies
• WG III: broad socioeconomic issues
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
Physical Changes
• Climate change will come with changes in
• temperature,
• circulation,
• sea level,
• ice coverage,
• wave climate, and
• extreme events,
• Affecting ecosystem structure & function
Temperature
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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
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
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
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
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
Precipitation
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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
UV-B
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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
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
Societal Sensitivities
• Species in more stable environments are
usually more valuable
• Fishers can follow fish, communities won’t
• Political borders or economics stop
pursuit
• Developing nations dependent on fish as
food or export earnings are most sensitive
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
Societal
• Temperatures above or below the stock’s 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
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
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.
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
Adaptation Options
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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)