Oceans and Climate Change:

What We Think We Know

Dr. John T. Everett

Project Manager, United Nations Atlas of the Oceans

Former IPCC Convening Lead Author (SAR) - Fisheries

Former Director, Division of Research, NOAA/NMFS

Ocean AssociatesOceans and Fisheries Consulting4007 North Abingdon StreetArlington, Virginia, USAJohnEverett@Comcast.Net

This Presentation

• Is based largely on the IPCC 1995 Report; Fisheries - Chapter 16. It is valid and best available

• The 2001 IPCC report of impacts is by region. There is little information specifically on marine fisheries

• The 2001 US National Assessment does not treat marine fisheries in depth (USNA)

• Physical changes reflect the 2001 IPCC report (IPCC 2001)

Intergovernmental Panel on CC

• Mission: provide an authoritative statement of scientific opinion on CC

• Broadly peer reviewed plus govm’t review

• Several hundred scientists serve on WG’s

•science of climate change itself

•impacts and response strategies

•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

The Culprits

Source: IPCC 2001

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

• Obs: 1998 was hottest year in 1000. “Global average land and ocean temperature was the warmest on record for January (NOAA CDC 2002)”

• Proj: Ave. temp. to increase 1.4-5.8° C by 2100

• High n. latitudes warm more than average

• Nights (2X) & 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

Temperatures are Rising - Recently

Source: IPCC 2001

Temperatures are Rising

Source: IPCC 2001

Warming is Uneven

Source: IPCC 2001

7 of 9 Models Agree on Warmer Winters & Summers in Northeast

Source: IPCC 2001

Currents & Upwelling

• Proj: A weakening of the global thermo-haline circulation may occur, reducing heat transport to the N. Atlantic

• Competing arguments on oceanic & coastal upwelling increase or decrease

• No reliable forecasts

• Forces driving natural variability not well understood

Ocean Conveyer Belt

Source: US National Assessment

Storms and El Niño

• Obs: No trends in storminess in last 50 years. Some regional trends in storminess in both directions

• The post 1989 period of ENSO activity seems unusually high, but may have happened before

• Proj: Changes in frequency & intensity of cyclones, storms, & El Niño uncertain

Ice Cover

• Obs: Two weeks less fresh ice in last ~125 yrs. No evident trend in sea ice in Antarctic.

• Proj: Glaciers and snow and ice coverage to continue retreat in N. hemisphere. Major loss of fresh & sea ice

• The NW Passage & N. Sea Route of Russia may have 100 days of shipping. 40% thinner summer Arctic ice since ~1960

• In the Antarctic, the main effect will be a retreat of the ice edge

• Ice coverage impacts ice-associated species, primary productivity, fishing and aquaculture

Sea Level Rise

• Obs. show 10-25 cm. rise since 1900; 1-2 mm/yr. 10X faster than previous 3K yrs. No acceleration detected

• Proj. is +11 - 77 cm by 2100; from thermal expansion & melting of ice. USNA*: +19” by 2100

• Regional variations due to wind and atmospheric pressure, ocean density, land motion, currents

• Wetlands will decrease; sharply where there is shore protection

• Higher wave energy; faster erosion

*USNA= US National Assessment

The Oceans are Rising

Source: IPCC 2001

Armored Coasts

Precipitation

• Obs show several %/decade greater air moisture & precip up 1%/decade in mid-high latitudes

• Proj: A few percent increase

• More extreme, heavier precip events

• This can affect water salinity, watershed flows, turbidity, pollutant loading and related factors

7 of 9 Models Agree on Wetter Winters in Northeast

Source: IPCC 2001

UV-B

• Other groups, not IPCC, study ozone depletion

• Obs: ozone losses up in mid-latitudes & Arctic

• Growth rates of several problem chemicals have slowed or stopped. Peak may be past

• Proj: ozone layer may return to normal about 2050

• In clear waters, UV-B penetrates tens of meters, damaging eggs, larvae and zooplankton

• In coastal waters, less than 1 meter

• Antarctic ozone hole is larger than Antarctica

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

• 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

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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

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.

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

CC Impact Ranking for Fisheries

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)

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Peru/Chile

California

Japan

Historical catches in the sardine fisheries of Japan, California and Peru-Chile exhibit parallel patterns, possibly in response to global-scale changes in climate (modified from Kawasaki, 1992).

Understanding Requires a Broad ViewOceanwide Synchrony in Pacific Sardines and the North Pacific Index

Negative NPI

Negative NPI

What comes first?Sources: U.S. GLOBEC, FAO 1998 North Pacific Index (Atmos. Pressure)

Where to get Information

•Intergovernmental Panel on Climate Change (IPCC): www.ipcc.ch/

•NMFS Pacific Fisheries Env Lab www.pfel.noaa.gov/research/climatemarine/

•U.S. Environmental Protection Agency (EPA): www.epa.gov/globalwarming

•U.S. Global Change Research Program (USGCRP): www.usgcrp.gov

•UN Atlas of the Oceans: www.oceansatlas.org

Primary References

Everett, J.T., E. Okemwa, H.A. Regier, J.P. Troadec, A. Krovnin, and D. Lluch-Belda, 1995: Fisheries. In: The IPCC Second Assessment Report, Volume 2: Scientific-Technical Analyses of Impacts, Adaptations, and Mitigation of Climate Change (Watson, R.T., M.C. Zinyowera, and R.H. Moss (eds.)]. Cambridge University Press, Cambridge and New York, 31 pp.

National Assessment Synthesis Team, 2001: Climate Change Impacts on the United States; The Potential Consequences of Climate Variability and Change Foundation. US Global Change Research Program, Washington www.usgcrp.gov

IPCC Working Group I, 2001. Climate Change 2001: The Scientific Basis. Document of the Intergovernmental Panel on Climate Change www.usgcrp.gov