Projected impacts of climate change on Arctic marine ecosystems: a summary of key findings

from the IPCC 5th Assessment ReportAnne Hollowed

Alaska Fisheries Science Center

September 2014: SICCME Open Science MeetingLarsen, J.N., O.A. Anisimov, A. Constable, A.B. Hollowed, N. Maynard, P. Prestrud, T.D. Prowse, and J.M.R. Stone, 2014: Polar regions. In: Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part B: Regional Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Barros, V.R., C.B. Field, D.J. Dokken, M.D. Mastrandrea, K.J. Mach, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova,

B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken, P.R. Mastrandrea, and L.L. White (eds.)]. Cambridge University Press,Cambridge, United Kingdom and New York, NY, USA, pp. XXX-YYY.

Climate Change Assessment (IPCC - WGII Summary for Policy Makers)

What do we expect in the future? – See IPCC WG 1

Photo credit NOAA. (http://marinesciencetoday.com)

• Increased ocean temperature

• Increased stratification of Arctic Ocean and the SE Bering Sea in summer

• Reduced sea ice extent in Arctic Ocean in summer

• Reduced cold pool extent in the Bering Sea

• Changes in timing of sea ice breakup and set-up

• Naturally occurring interannual, decadal, and multi-decadal variations in climate will continue to influence the Arctic Ocean and its neighboring high latitude seas.

• Changes in bio-chemical properties of Arctic Ocean and eastern Bering Sea (including ocean acidification)

• Changes in the size distribution and abundance of selected phytoplankton and zooplankton

Projected Average Annual Surface Temperature (IPCC AR5 SPM, 2014)

Record Low Sea Ice Extent in September, 2012 Source: National Snow and Ice Data Center, Boulder

CO.

From http://nsidc.org/

Wang, Overland and Stabeno 2012 DSR II 65-70: 46-57

Projected Seasonal – Sea Ice Extent Over Chukchi Sea AR4

Red – Observed; Blue – Ensemble means under A1B scenarioPink – Ensemble mean under A2 scenario Gray curve – one realization of one model

Projected EBS July bottom temperatures in SE Bering Sea ( Al Hermann JISAO)

} “medium”

} “cold”

} “warm”

CGCM3MIROCECHOG

Regional Heterogeneity: Larsen et al. 2014

• “The impacts of climate change, and the adaptations to it, exhibit strong spatial heterogeneity in the polar regions because of the high diversity of social systems, biophysical regions, and associated drivers of change (high confidence). {28.2.2}”

Danielson et al. 2011. J. Geophys. Res.116: C120341

Major Currents

Sea ice 0 m

200 m

100 m

300 m

Sea ice

100 m

0 m

200 m

300 m

McBride et al. 2014. ICES J. Mar. Sci. Courtesy of Jack Cook: Woods Hole Oceanographic Institution

Winter Present Future?

Importance of latitudeJi et al. 2012 Prog. Oceanog. 40-56

Growth Season Start DateSeawifs-derived Chla

Growth Season lengthOnset of snow melt

Seasonal ice zone

Arrigo and van Dijken 2011 J. Geophys. Res., Vol. 116, C09011, doi:10.1029/2011JC007151

Local ResponseRates Differ

“Some marine species will shift their ranges in response to changing ocean and sea ice conditions in the polar regions (medium

confidence). • The response rate and the spatial extent of the shifts will

differ by species based on their vulnerability to change and their life history. {28.2.2, 28.3.2}

• Loss of sea ice in summer and increased ocean temperatures are expected to impact secondary pelagic production in some regions of the Arctic Ocean, with associated changes in the energy pathways within the marine ecosystem (medium confidence).

• These changes are expected to alter the species composition of zooplankton in some regions, with associated impacts on some fish and shellfish populations (medium confidence). {28.2.2.1}”

One Example of Evidence of Spatial ShiftDetecting temporal trends and environmentally-driven changes in the spatial distribution of bottom fishes and crabs on the eastern Bering

Sea shelf.Stan Kotwicki and Robert R. Lauth

• Data: Eastern Bering Sea (EBS) bottom trawl survey 1982 – 2011• First study that included cold years 2006 – 2010• Used GAMs and indices of co-location• Tested effects of time lag, population abundance and cold pool area using three

isothermal boundaries - 0°, 1°, and 2°C.

Ecosystem context: Larsen et al. 2014

• “The physical, biological, and socioeconomic impacts of climate change in the Arctic have to be seen in the context of often interconnected factors that include not only environmental changes caused by drivers other than climate change but also demography, culture, and economic development.”

Future Fisheries• Demand for protein• World markets• Range expansion to north uncertain• Infra-structure• Bio-economic considerations (fuel, risk)• Sustainable fisheries – Ecosystem Based Fisheries Management• International cooperation

Photo Credit: Sam Zmolek, NOAA Fisheries. Photo of Dutch Harbor, Alaska

Transportation

Other issues: Larsen et al. 2014

• “Shifts in the timing and magnitude of seasonal biomass production could disrupt matched phenologies in the food webs, leading to decreased survival of dependent species (medium confidence).”

• “Ocean acidification has the potential to inhibit embryo development and shell formation of some zooplankton and krill in the polar regions, with potentially far-reaching consequences to food webs in these regions (medium confidence).”

Core research questions

• Future stratification – impedes nutrient exchange • Future storm frequency and intensity – nutrient pulses • Role of spatial distribution and timing of ice algal

blooms • Vulnerability to shifts in onset of growing season

(onset and duration)• Grazing impacts• Pelagic – Benthic coupling• Vulnerability to Ocean Acidification• Population level impacts of Ocean Acidification