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Oceans and Climate Change: What We Think We Know

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Presentation on theme: "Oceans and Climate Change: What We Think We Know"— Presentation transcript:

1 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 Associates Oceans and Fisheries Consulting 4007 North Abingdon Street Arlington, Virginia, USA

2 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)

3 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

4 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

5 The Culprits Source: IPCC 2001

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

7 Temperature Obs: 1998 was hottest year in “Global average land and ocean temperature was the warmest on record for January (NOAA CDC 2002)” Proj: Ave. temp. to increase ° 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

8 Temperatures are Rising - Recently
Source: IPCC 2001

9 Temperatures are Rising
Source: IPCC 2001

10 Warming is Uneven Source: IPCC 2001

11 7 of 9 Models Agree on Warmer Winters & Summers in Northeast
Source: IPCC 2001

12 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 Currents and upwelling. Freshwater influx from the movements and melting of sea ice or ice sheets may lead to a weakening of the global thermohaline circulation, leading to cooling in the North Atlantic and possibly causing unpredictable instabilities in the climate system. There are competing arguments as to whether oceanic and coastal upwelling would increase or decrease. In any case, there is no ability to make reliable forecasts at the regional scale which governs the upwelling systems. Forces leading the oceans to vary in temperature and currents on decadal scales of natural variability are not well understood and are not well modelled.

13 Ocean Conveyer Belt Source: US National Assessment

14 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

15 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

16 Sea Level Rise Obs. show cm. rise since 1900; 1-2 mm/yr. 10X faster than previous 3K yrs. No acceleration detected Proj. is 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

17 The Oceans are Rising Source: IPCC 2001

18 Armored Coasts

19 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

20 7 of 9 Models Agree on Wetter Winters in Northeast
Source: IPCC 2001

21 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

22 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 Many of the changes affect predator - prey relationships

23 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 Fishers can follow fish, communities usually won’t-But there are economic,social and safety costs

24 Sensitivity Examples Species Societal
• 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 Species Species are defined by predator - prey relationships Fishers without ability to deal with increased vessel and gear demands--Storminess/safety, pursuit of fish Shift in economies and food sources in developing countries Societal

25

26 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 There are no compelling data to suggest a confluence of climate change impacts that would affect global marine production in either direction, These conclusions are dependent on the assumption that natural climate variability and the structure and strength of wind fields and ocean currents will remain about the same. If either changes, there would be significant impacts on the distribution of major fish stocks, though not on the global production [medium confidence]. National fisheries will suffer if institutional mechanisms are not in place that enable fishers to move within and across national boundaries [high confidence]. Subsistence and other small scale fishermen, lacking mobility and alternatives, are often most dependent on specific fisheries and will suffer disproportionately from changes

27 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 years. While overfishing has a greater effect on fish stocks than climate change today, progress is being made on the overfishing problem.

28 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 An impact ranking can be constructed. The following categories are listed in descending order of sensitivity, positive or negative, to climate change [medium confidence]. 1. Freshwater fisheries in small rivers and lakes, in regions with larger temperature and precipitation change; 2. Fisheries within Exclusive Economic Zones, particularly where access regulation mechanisms artificially reduce the mobility of fishing groups and fleets and their capacity to adjust to fluctuations in stock distribution and abundance; 3. Fisheries in large rivers and lakes; 4. Fisheries in estuaries, particularly where there are species without migration or spawn dispersal paths, or estuaries impacted by sea level rise or by decreased river flow; 5. High seas fisheries.

29 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) - Design and implement national and international fishery management institutions that recognize shifting species ranges, accessibility, and abundances and that balance species conservation with local needs for economic efficiency and stability. - Support innovation by research on management systems and aquatic ecosystems; - Expand aquaculture to increase and stabilize seafood supplies, to help stabilize employment, and carefully, to augment wild stocks; - In coastal areas, integrate the management of fisheries with other uses of coastal zones; - Monitor health problems (e.g., red tides, ciguatera, cholera) that could increase under climate change and harm fish stocks and consumers. Action Now that the documents are being distributed, it is time to turn to the action recommendations. For this Congress, I would argue for addressing only the first. I believe it is the most important. This recommendation, in bold above, seeks to build into resource management regimes the concept that fish abundances and distributions will change over time as a consequence of climate change and also that resource productivity and industrial capacity should be in balance. THIS APPROACH IS NEEDED NOW! Perhaps climate change awareness can serve as a vehicle to bring this essential message to the attention of political leaders and fishery managers. The natural variability in regional climate, that sometimes takes places over decades, represents greater (or as great) changes as will come with climate change. The only difference may be the permanance of the changes. If we can adapt our institutions to deal with climate change, we will have addressed the natural variability issues that plague many existing institutions and the industries they regulate.

30 Understanding Requires a Broad View Oceanwide Synchrony in Pacific Sardines and the North Pacific Index 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). Negative NPI Negative NPI 800 7 700 Peru/Chile 6 600 5 California Sardine Catch (Thousand Metric Tons) 500 California 4 Japan and Peru/Chile Sardine Catch (Million Metric Tons) 400 3 300 2 200 Japan 1 100 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 What comes first? Sources: U.S. GLOBEC, FAO North Pacific Index (Atmos. Pressure)

31 Where to get Information
Intergovernmental Panel on Climate Change (IPCC): NMFS Pacific Fisheries Env Lab U.S. Environmental Protection Agency (EPA): U.S. Global Change Research Program (USGCRP): UN Atlas of the Oceans: 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 IPCC Working Group I, Climate Change 2001: The Scientific Basis. Document of the Intergovernmental Panel on Climate Change


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