Near-term Climate Change: Projections and Predictability

Cambridge University Press eBooks, Journal Year: 2014, Volume and Issue: unknown, P. 953 - 1028

Published: March 24, 2014

This chapter assesses the scientific literature describing expectations for near-term climate (present through mid-century). Unless otherwise stated, 'near-term' change and projected changes below are period 2016–2035 relative to reference 1986–2005. Atmospheric composition (apart from CO2; see Chapter 12) air quality projections 2100 also assessed.

Language: Английский

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Arctic sea ice in transformation: A review of recent observed changes and impacts on biology and human activity

Reviews of Geophysics, Journal Year: 2014, Volume and Issue: 52(3), P. 185 - 217

Published: May 15, 2014

Sea ice in the Arctic is one of most rapidly changing components global climate system. Over past few decades, summer areal extent has declined over 30%, and all months show statistically significant declining trends. New satellite missions techniques have greatly expanded information on sea thickness, but many uncertainties remain data long-term records are sparse. However, thickness observations other satellite-derived indicate a 40% decline due large part to loss thicker, older cover. The changes happening faster than models projected. With continued increasing temperatures, ice-free conditions likely sometime coming though there substantial exact timing high interannual variability will as decreases. already having an impact flora fauna Arctic. Some species face challenges future, while new habitat open up for species. also affecting people living working Native communities facing their traditional ways life, opportunities shipping, fishing, natural resource extraction. Significant progress been made recent years understanding its role climate, ecosystem, human activities. furthering knowledge processes, impacts, future evolution

Language: Английский

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A climate model projection weighting scheme accounting for performance and interdependence

Geophysical Research Letters, Journal Year: 2017, Volume and Issue: 44(4), P. 1909 - 1918

Published: Feb. 8, 2017

Abstract Uncertainties of climate projections are routinely assessed by considering simulations from different models. Observations used to evaluate models, yet there is a debate about whether and how explicitly weight model agreement with observations. Here we present straightforward weighting scheme that accounts both for the large differences in performance interdependencies, test reliability perfect setup. We provide weighted multimodel Arctic sea ice temperature as case study demonstrate that, some questions at least, it meaningless treat all models equally. The constrained ensemble shows reduced spread more rapid decline than unweighted ensemble. argue growing number characteristics considerable interdependence finally justifies abandoning strict democracy, guidance on when this can be achieved robustly.

Language: Английский

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Freshwater and its role in the Arctic Marine System: Sources, disposition, storage, export, and physical and biogeochemical consequences in the Arctic and global oceans

Journal of Geophysical Research Biogeosciences, Journal Year: 2015, Volume and Issue: 121(3), P. 675 - 717

Published: Oct. 12, 2015

Abstract The Arctic Ocean is a fundamental node in the global hydrological cycle and ocean's thermohaline circulation. We here assess system's key functions processes: (1) delivery of fresh low‐salinity waters to by river inflow, net precipitation, distillation during freeze/thaw cycle, Pacific inflows; (2) disposition (e.g., sources, pathways, storage) freshwater components within Ocean; (3) release export into bordering convective domains North Atlantic. then examine physical, chemical, or biological processes which are influenced constrained local quantities geochemical qualities freshwater; these include stratification vertical mixing, ocean heat flux, nutrient supply, primary production, acidification, biogeochemical cycling. Internal joint effects sea ice decline intensification have strengthened coupling between atmosphere wind drift stresses, solar radiation, moisture exchange), drainage basins discharge, sediment transport, erosion), terrestrial ecosystems greening, dissolved particulate carbon loading, altered phenology biotic components). External acts as both constraint necessary ingredient for deep convection subarctic gyres thus affects Geochemical fingerprints attained likewise exported neighboring systems beyond. Finally, we discuss observed modeled changes this system on seasonal, annual, decadal time scales mechanisms that link marine atmospheric, terrestrial, cryospheric systems.

Language: Английский

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Climate change alters the structure of arctic marine food webs due to poleward shifts of boreal generalists

Proceedings of the Royal Society B Biological Sciences, Journal Year: 2015, Volume and Issue: 282(1814), P. 20151546 - 20151546

Published: Sept. 4, 2015

Climate-driven poleward shifts, leading to changes in species composition and relative abundances, have been recently documented the Arctic. Among fastest moving are boreal generalist fish which expected affect arctic marine food web structure ecosystem functioning substantially. Here, we address structural at level induced by shifts via topological network analysis of highly resolved webs Barents Sea. We detected considerable differences properties link configuration between webs, latter being more modular less connected. found that a main characteristic into region Sea is high generalism, property increases connectance reduces modularity web. Our results reveal habitats form natural boundaries for modules, generalists play an important functional role coupling pelagic benthic modules. posit these habitat couplers potential promote transfer energy matter habitats, but also spread pertubations, thereby changing considerably with implications dynamics functioning.

Language: Английский

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Ch. 2: Our Changing Climate. Climate Change Impacts in the United States: The Third National Climate Assessment

Published: Jan. 1, 2014

Language: Английский

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Arctic marine mammal population status, sea ice habitat loss, and conservation recommendations for the 21st century

Conservation Biology, Journal Year: 2015, Volume and Issue: 29(3), P. 724 - 737

Published: March 17, 2015

Arctic marine mammals (AMMs) are icons of climate change, largely because their close association with sea ice. However, neither a circumpolar assessment AMM status nor standardized metric ice habitat change is available. We summarized available data on abundance and trend for each species recognized subpopulation. also examined diversity, the extent human use, temporal trends in 12 regions by calculating dates spring retreat fall advance from satellite (1979–2013). Estimates varied greatly quality, few studies were long enough analysis. Of subpopulations, 78% (61 78) legally harvested subsistence purposes. Changes phenology have been profound. In all except Bering Sea, duration summer (i.e., reduced ice) period increased 5–10 weeks >20 Barents Sea between 1979 2013. light generally poor data, importance forecasted environmental changes 21st century, we recommend following effective conservation: maintain improve comanagement local, federal, international partners; recognize spatial variability subpopulation response to change; implement monitoring programs clear goals; mitigate cumulative impacts activity; limits current protected legislation. Estado de las Poblaciones Mamíferos Marinos del Ártico, la Pérdida Hábitats Hielo Marino y Recomendaciones Conservación para el Siglo XXI Los mamíferos marinos Ártico (MMA) son emblemas cambio climático, principalmente por su asociación cercana con hielo marino. Sin embargo, no se encuentran disponibles ni una evaluación estado los MMA medida estandarizada en hábitat Resumimos datos sobre abundancia tendencia cada especie reconocimos subpoblaciones. También examinamos diversidad especies, extensión uso parte humanos tendencias temporales marino doce regiones al calcular fechas retroceso hielos primavera avance otoño partir satelitales estimados variaron enormemente calidad pocos estudios fueron lo suficientemente largos como realizar un análisis tendencia. De subpoblaciones MMA, cazadas legalmente razones subsistencia. cambios fenología han sido profundos. En todas regiones, salvo Mar Bering, duración periodo verano (es decir, reducción hielo) incrementó semanas entre A razón generalmente pobres, importancia ambientales pronosticados XX1, recomendamos siguiente conservación efectiva MMA: mantener mejorar co-manejo socios locales, federales e internacionales; reconocer variabilidad espacial respuesta sub-poblaciones climático; implementar monitoreo programas objetivos claros; mitigar impactos acumulativos incremento actividad humana; límites legislación actual especies protegidas. The world's disproportionately threatened compared terrestrial counterparts (Schipper et al. 2008), 11 arctic particularly vulnerable due dependence (Laidre 2008a; Kovacs 2012; Reid & Laidre 2013). Some AMMs obligates, meaning life history events (e.g., reproduction, molting, resting) feeding depend ice, whereas others use but do not it completely 2008a). By mean that occur north Circle (66° 33′ N) most year ecosystem aspects selected seasonally inhabit waters may live outside part year. include 3 cetaceans (narwhal [Monodon monoceros], beluga [Delphinapterus leucas], bowhead [Balaena mysticetus] whales); 7 pinnipeds (ringed [Pusa hispida], bearded [Erignathus barbatus], spotted [Phoca largha], ribbon [Histriophoca fasciata], harp [Pagophilus groenlandicus], hooded [Cystophora cristata] seals walrus [Odobenus rosmarus]); polar bear (Ursus maritimus). Throughout much range, these animals important cultural nutritional resources indigenous nonindigenous peoples. Recent reviews outline vulnerabilities 2011). Warming over past decades has about 2 times greater than global (IPCC rate loss faster predicted models (Stroeve 2012), projections suggest an ice-free 2040 (Overland Wang Even if greenhouse gases, primary driver limited immediately, likely continue several Therefore, appears continued unprecedented habitats inevitable. reviewed what known population abundance, or stock. evaluated richness across quantified use. assessed provide first comparative measure change. Based our findings, make recommendations conservation relative gaps, forecasts, anthropogenic activities, complex social, economic, political context rapidly warming Arctic. compiled estimates published unpublished sources. Subpopulations included those management bodies advisory groups such as International Whaling Commission (IWC), North Atlantic Marine Mammal (NAMMCO), Union Conservation Nature (IUCN) specialist groups. Trends associated time frames reported authors noted. delineated regions, modified slightly Flora Fauna (CAFF) Circumpolar Biodiversity Monitoring Plan (CAFF 2011) (Fig. 1). central Basin was excluded paucity data. calculated number per region determining whether had legal commercial harvest. Habitat 1979–2013 daily concentration satellites (Supporting Information). date given when area fell below specific threshold, rose above same threshold. used region-specific threshold halfway March September areas baseline decade (1982–1991) characterize biologically transitions winter conditions. highest Baffin Bay, Davis Strait, Sea; lowest Okhotsk Beaufort Sea. availability quality here through 2015 widely (Table 1 Fig. 2). many cases, knowledge consisted single point estimate large uncertainty based expert opinion without formal bias. For cetaceans, 5 19 0 narwhal 4 subpopulations. Abundance ringed seal outdated, some small surveyed repeatedly seals. areas; however, represented only portion discreteness subpopulations uncertain. Trend suggested increased, stable declined. bears, 14, although out uncertainty. Current 10 derived projection untested assumptions Evaluation complicated unknown structure partial surveys seasonal aggregations. High survey methods, surveys, levels precision made summary difficult. Nonetheless, 35% 78 identified found taken nations Norway (including Svalbard). review subspecies, (n = 61) regularly 76% (74% belugas, 91% narwhals, 50% whales), including stocks which whales captured aquaria (White Sea). Approximately 80% pinniped walruses subsistence, purposes Norway, Canada, Russia (harp [Table 1]). Kara Laptev where illegal harvest occurs. Large occurred nearly habitats. Eleven showed statistically significant toward earlier retreat, later advance, and, consequently, longer summers 3, Supporting Only trend. effect 34-year season 2013 1979. largest 20 this period. sensitive choice they defined Information) typically fall. negatively correlated Climate widespread ecological (Rosenzweig 2008; Gilg Post 2013), yet its effects relatively underreported despite abiotic exceed temperate, tropical, montane biomes (ACIA 2005). quantitative evidence negative ice-obligate (Stirling 1999; Regehr 2007; Øigard 2010, 2013; 2010). species- subpopulation-specific responses vary space, evidenced delayed even positive (Moore 2006; Quakenbush 2011; Stirling Rode 2014; George 2015). Variability can arise differences exploitation histories, strategies, biological productivity, trophic interactions. Such heterogeneity respect systems, tend be more rich (Moritz Agudo Assessing mammal populations difficult wide distributions cryptic behavior compounded logistical challenges surveying remote areas. understanding identifying priorities, absent 3), lack will limit utility future assessments. Although expected lower carrying capacity ice-dependent species, currently recovering [George 2015], sport hunting [Schliebe 2006]) previously insufficiently managed prior 2000 West Greenland [Witting Born 2013]). short term, recovery previous overexploitation could mask reductions loss. addition, productivity could, period, offset potential result transient term increases (Quakenbush St Lawrence Estuary Cook Inlet beluga) show cessation harvesting (Wade 2012). modern world, rare wild mammals, particular top predators, support well-being communities, do. subspecies hunted commercially. Thus, intertwined renewable resource. responsibility resides federal state government agencies partners representing communities. Many under regional, national, agreements share decision-making power framework harvests supported national laws U.S. Protection Act, Nunavut Land Claims Agreement). comprehensive list, examples Alaska Native working United States Beluga Committee, Eskimo Commission, Walrus Nanuuq Ice Seal Committee. Inuvialuit Fisheries Joint Management Committee; Wildlife Boards Nunavut, Nunavik, Nunatsiavut; Polar Bear Administrative Chukotka (Russia), Associations Hunters (KNAPK) Association Traditional Chukotka, respectively, cooperate agencies. Furthermore, Greenland, carried local composed mainly ethnic Inuit. highly mobile undertake movements, resulting half 1) ranging regional boundaries, quantify movement poor. transboundary requires collaboration. Currently, bears joint commissions Canada Greenland; Russia) information shared Inupiat-Inuvialuit Agreement Canadian Technical Committee (also Greenland). Scientific narwhals though Canada–Greenland Narwhal-Beluga NAMMCO. receive advice NAMMCO, catch Russia, States, set IWC. Advice coordinated Council Exploration Seas Organization. It well established declining every month monthly areal capture timing annual influence feeding, AMMs. therefore This meaningful approach other metrics appropriate 1979-2013, 17 days/decade 25 consistent findings Stammerjohn (2012), who methods similar ours, Stroeve (2014), detection liquid water surface snow obtain melt onset freezing regions. addition extent, thickness decreased substantially (Schweiger Continuation induce (Notz 2009) possibly weather anomalies warm strong storm) impact thin correlation transition 2) manifestation ice-albedo feedback, extra heat absorbed ocean during early must released into atmosphere before begin form. direct indirect comprehensively (2008a) (2011). Loss affected survival (Regehr Pinniped pup related breakup young need sufficient suckling weaning (Øigard 2010; Absence Pacific calf crushing at crowded haul-out sites (Jay Physical properties, roughness depth (which decreasing [Webster 2014]), suitability lairs (Furgal 1996; Iacozza Ferguson 2014). Timing linked accessibility foraging production bloom ultimately influences (Carmack Wassmann 2006). Indirect consequences overlap new predators competitors. Finally, both ability humans access them fraction takes place near edge affecting abate immediate future. At present, there agreement reduce emissions gasses, unabated versus aggressive mitigation scenarios substantively diverge until least years fixed regardless efforts greenhouse-gas emissions. reduction solution mitigating long-term warming, scientists, managers, conservationists, industry, communities dependent prepare deal Accordingly, conservation. Maintaining increasing governmental entities key component face climate-induced viability (see "Human Use" section). culture people throughout (Born Comanagement directly involve resource vested interest it. They lead community participation minimizing human–polar conflicts), collection traditional knowledge, compliance restrictions, identification science priorities opportunities scientific sampling. Arctic, activities benefits prohibitively expensive otherwise infeasible involvement. Future require balancing needs declines There scientifically incremental balance social If loss, responsible percentage [Runge 2009; 2015]) hold unlikely accelerate environmentally driven declines. either updated periodically conservative levels. precautionary warranted populations, whereby increasingly risk-averse applied decline size resilience. Given fast pace how respond, flexible adaptive critical. articulation goals targets. users managers reducing human-caused disturbance removals, harvests, one mechanisms (but necessarily offset) Species exhibit variable space (Post 2009, Moritz variation characteristics ice), species' move favorable habitats, phenotypic behavioral plasticity, genetic traits bolster managing scales 2012) should incorporated predictive plans. contrasting climate. Chukchi southern rates 2), body condition reproductive parameters historic values region, declined (Rode Samples subsistence-harvested northern 2000s indicate vital better 1960s 1970s 2011), 1992 2011 (Harwood seals, observed attributed productivity. whale shown growth concurrent Both Bering-Chukchi-Beaufort (BCB) low whaling >3%/year, theoretical maximum (Wiig Givens time, BCB improved 1989 (George 2015), extensive productive Though showing recent changes, forecasts next 50–100 (Wang Overland serious threats Models forecast century Amstrup Udevitz 2013) inform prescribe term. Part challenge broad resolutions frames. Pitfalls making decisions coarse-resolution missed opportunities, sustainable latter risk alienating stakeholders compromising efforts. that, possible, consider risks coarse fine scales. monitored determine scale. Measuring trend, indicator status, demographic analysis reproduction survival), elusive distribution AMMs, acquiring realistic; thus, develop samples provides opportunity, collaboration suite age maturity, pregnancy rate, condition, pollution, contaminant loads) serve broader indicators. Other feasible monitor sensing observation Gulland analyzed together regular areas, reasonable strategy. Long-term provided foundation Western Hudson Bay Southern [Stirling 2010]) conjunction hunters, amounts cost. Successful Department Fish Game's Bio-monitoring Program Slope Borough's sampling program Harvest biosampling successfully conducted Canada. plans drafted whales, 2008b; Simpkins Vongraven 2014), systematically implemented. factors insufficient funding, organization will, awareness plans, absence major economic incentives cooperation biodiversity often projects span agency interests authority. rigorous, any work outlined plan while concurrently performing focused necessary meet needs. With physical barrier interchange disappearing (Heide-Jørgensen complicates emphasizes analyses. On level, moving Assessment CAFF Program. range states preparing action auspices 1973 Bears. An example successful Ocean Antarctic

Language: Английский

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The urgency of Arctic change

Polar Science, Journal Year: 2018, Volume and Issue: 21, P. 6 - 13

Published: Nov. 27, 2018

This article provides a synthesis of the latest observational trends and projections for future Arctic. First, Arctic is already changing rapidly as result climate change. Contemporary warm temperatures large sea ice deficits (75% volume loss) demonstrate states outside previous experience. Modeled changes cryosphere that even limiting global temperature increases to near 2 °C will leave much different environment by mid-century with less snow ice, melted permafrost, altered ecosystems, projected annual mean increase +4 °C. Second, under ambitious emission reduction scenarios, high-latitude land melt, including Greenland, are foreseen continue due internal lags, leading accelerating level rise throughout century. Third, may in turn impact lower latitudes through tundra greenhouse gas release shifts ocean atmospheric circulation. Arctic-specific radiative heat storage feedbacks become an obstacle achieving stabilized climate. In light these trends, precautionary principle calls early adaptation mitigation actions.

Language: Английский

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Recent Arctic Ocean sea ice loss triggers novel fall phytoplankton blooms

Geophysical Research Letters, Journal Year: 2014, Volume and Issue: 41(17), P. 6207 - 6212

Published: Aug. 19, 2014

Abstract Recent receding of the ice pack allows more sunlight to penetrate into Arctic Ocean, enhancing productivity a single annual phytoplankton bloom. Increasing river runoff may, however, enhance yet pronounced upper ocean stratification and prevent any significant wind‐driven vertical mixing upward supply nutrients, counteracting additional light available phytoplankton. Vertical is key process that will determine fate marine ecosystems. Here we reveal an unexpected consequence loss: regions are now developing second bloom in fall, which coincides with delayed freezeup increased exposure sea surface wind stress. This implies during fall indeed significant, at least enough promote further primary production. The Ocean seems be experiencing fundamental shift from polar temperate mode, likely alter ecosystem.

Language: Английский

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On the future navigability of Arctic sea routes: High-resolution projections of the Arctic Ocean and sea ice

Marine Policy, Journal Year: 2016, Volume and Issue: 75, P. 300 - 317

Published: Feb. 4, 2016

The rapid Arctic summer sea ice reduction in the last decade has lead to debates maritime industries on possibility of an increase cargo transportation region. Average sailing times North Sea Route along Siberian Coast have fallen from 20 days 1990s 11 2012–2013, attributed easing conditions coast. However, economic risk exploiting shipping routes is substantial. Here a detailed high-resolution projection ocean and end 21st century forced with RCP8.5 IPCC emission scenario used examine navigability routes. In summer, opening large areas Ocean previously covered by pack wind surface waves leads cover evolving into Marginal Ice Zone. emerging state features more fragmented thinner ice, stronger winds, currents waves. By mid century, season route via Pole are estimated be 13–17 days, which could make this as fast Route.

Language: Английский

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