Presentation on theme: "Oceans and Climate Change: What We Think We Know"— Presentation transcript:
1Oceans and Climate Change: What We Think We Know Dr. John T. EverettProject Manager, United Nations Atlas of the OceansFormer IPCC Convening Lead Author (SAR) - FisheriesFormer Director, Division of Research, NOAA/NMFSOcean AssociatesOceans and Fisheries Consulting4007 North Abingdon StreetArlington, Virginia, USA
2This PresentationIs based largely on the IPCC 1995 Report; Fisheries - Chapter 16. It is valid and best availableThe 2001 IPCC report of impacts is by region. There is little information specifically on marine fisheriesThe 2001 US National Assessment does not treat marine fisheries in depth (USNA)Physical changes reflect the 2001 IPCC report (IPCC 2001)
3Intergovernmental Panel on CC Mission: provide an authoritative statement of scientific opinion on CCBroadly peer reviewed plus govm’t reviewSeveral hundred scientists serve on WG’sscience of climate change itselfimpacts and response strategiesbroad socioeconomic issues
4Fisheries Lead Authors Dr. John T. Everett, CLA Dr. Daniel Lluch BeldaWashington, USA La Paz, BCS, MexicoDr. Andre Krovnin Dr. Henry A. RegierMoscow, Russia Toronto, CanadaDr. Ezekiel Okemwa Jean-Paul TroadecMombasa, Kenya Brest, France
6Physical Changes Climate change will come with changes in temperature, circulation,sea level,ice coverage,wave climate, andextreme events,Affecting ecosystem structure & function
7TemperatureObs: 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 2100High n. latitudes warm more than averageNights (2X) & winters warm more than averageOcean changes lag land by 10 yearsExceptions: delay or cooling in belt around Antarctica and in high N. AtlanticIn high latitudes, the growing period and productivity should increase
8Temperatures are Rising - Recently Source: IPCC 2001
117 of 9 Models Agree on Warmer Winters & Summers in Northeast Source: IPCC 2001
12Currents & UpwellingProj: A weakening of the global thermo-haline circulation may occur, reducing heat transport to the N. AtlanticCompeting arguments on oceanic & coastal upwelling increase or decreaseNo reliable forecastsForces driving natural variability not well understoodCurrents 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.
13Ocean Conveyer BeltSource: US National Assessment
14Storms and El NiñoObs: No trends in storminess in last 50 years. Some regional trends in storminess in both directionsThe post 1989 period of ENSO activity seems unusually high, but may have happened beforeProj: Changes in frequency & intensity of cyclones, storms, & El Niño uncertain
15Ice CoverObs: 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 iceThe NW Passage & N. Sea Route of Russia may have 100 days of shipping. 40% thinner summer Arctic ice since ~1960In the Antarctic, the main effect will be a retreat of the ice edgeIce coverage impacts ice-associated species, primary productivity, fishing and aquaculture
16Sea Level RiseObs. show cm. rise since 1900; 1-2 mm/yr. 10X faster than previous 3K yrs. No acceleration detectedProj. is cm by 2100; from thermal expansion & melting of ice. USNA*: +19” by 2100Regional variations due to wind and atmospheric pressure, ocean density, land motion, currentsWetlands will decrease; sharply where there is shore protectionHigher wave energy; faster erosion*USNA= US National Assessment
19PrecipitationObs show several %/decade greater air moisture & precip up 1%/decade in mid-high latitudesProj: A few percent increaseMore extreme, heavier precip eventsThis can affect water salinity, watershed flows, turbidity, pollutant loading and related factors
207 of 9 Models Agree on Wetter Winters in Northeast Source: IPCC 2001
21UV-B Other groups, not IPCC, study ozone depletion Obs: ozone losses up in mid-latitudes & ArcticGrowth rates of several problem chemicals have slowed or stopped. Peak may be pastProj: ozone layer may return to normal about 2050In clear waters, UV-B penetrates tens of meters, damaging eggs, larvae and zooplanktonIn coastal waters, less than 1 meterAntarctic ozone hole is larger than Antarctica
22Species 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 reestablishedMany of the changes affect predator - prey relationships
23Societal 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 sensitiveFishers can follow fish, communities usually won’t-But there are economic,social and safety costs
24Sensitivity 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 demandsSpeciesSpecies are defined by predator - prey relationshipsFishers without ability to deal with increased vessel and gear demands--Storminess/safety, pursuit of fishShift in economies and food sources in developing countriesSocietal
26Important FindingsFreshwater fisheries and aquaculture at mid to higher latitudes should benefitSaltwater fisheries should be about the sameFishery areas and species mix will shiftChanges in abundance more likely near ecosystem boundariesNational fisheries will suffer if fishers cannot move within and across national bordersSubsistence/small scale fishermen suffer mostThere 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
27Important Findings-2CC impacts add to overfishing, lost wetlands and nurseries, pollution, UV-B, and natural variationInherent instability in world fisheries will be exacerbated by a changing climateGlobally, economic and food supply impacts should be small. Nationally, they could be largeOverfishing 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.
28CC Impact Ranking for Fisheries 1. Small rivers and lakes, in areas of higher temperatures and less rain2. Within EEZs, particularly where fishers cannot follow migrating fish3. In large rivers and lakes4. In estuaries5. High seasAn 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.
29Adaptation OptionsEstablish management institutions that recognize shifting distributions, abundances and accessibility, and that balance conservation with economic efficiency and stabilitySupport innovation by research on management systems and aquatic ecosystemsExpand aquaculture to increase and stabilize seafood supplies and employment, and carefully, to augment wild stocksIntegrate fisheries and CZ managementMonitor 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.ActionNow 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.
30Understanding Requires a Broad View Oceanwide Synchrony in Pacific Sardines and the North Pacific IndexHistorical 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 NPINegative NPI8007700Peru/Chile66005California Sardine Catch(Thousand Metric Tons)500California4Japan and Peru/Chile Sardine Catch(Million Metric Tons)40033002200Japan110019001910192019301940195019601970198019902000What comes first?Sources: U.S. GLOBEC, FAO North Pacific Index (Atmos. Pressure)
31Where to get Information Intergovernmental Panel on Climate Change (IPCC):NMFS Pacific Fisheries Env LabU.S. Environmental Protection Agency (EPA):U.S. Global Change Research Program (USGCRP):UN Atlas of the Oceans:Primary ReferencesEverett, 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, WashingtonIPCC Working Group I, Climate Change 2001: The Scientific Basis. Document of the Intergovernmental Panel on Climate Change