etlands will decrease; sharply where there is shore protectionHigher wave energy; faster erosion*USNA= US National Assessment
19 PrecipitationObs 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
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 & 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
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 reestablishedMany 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 sensitiveFishers 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 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
26 Important 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
27 Important 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 