Climate variable / Region
Pacific / Atlantic / Arctic
Air temperature / Increase of 1-3oC for coastal regions, and annual mean increase of ~3oC in offshore open ocean regions / Very likely increase in all seasons, with annual means increasing by 1-3.5oC. / Very likely increase by 0-3oC in summer and 3-7oC in winter
Precipitation / Increased precipitation over winter but Increasing summer drought, with more rain than snow over land. Slight increase in precipitation over open ocean waters / Likely increase in annual means by > 10%, with possible increase in extreme precipitation events / Likely slight increase in precipitation, less in summer than in winter
Winds and storms / Downwelling winter winds and summer upwelling winds of similar strength but slightly reduced duration / Likely poleward shift in storm tracks / Likely increase in storm strength and size; coastal erosion and loss of coastline
Streamflow / ~10% lower in summer and 10% higher other times of the year. / Very likely increases in annual discharge in some sub-basins but uncertain in others. Possible increase in extreme river discharge events / Likely increase of up to 50% in winter and fall flows, with decrease in summer; Increase in annual discharge from Greenland ice sheet; river ice break up 15-35 days earlier and freeze up 10-12 days later
Water temperature / Sea surface temp increase by 1.5-2oC except in summer / Very likely increase in surface temperature in all areas and all seasons / Very likely increase of 0-2oC in summertime sea surface temperature in ice-free areas
Sea surface salinity / Decline by 0.25-0.3 ppt and by up to 1 in coastal sub-basins, although this is subject to seasonal variation / Very likely decrease of 0.1-1.0 in all coastal, shelf, slope areas in all seasons. / Some decrease in sea surface salinity by 0-1.5ppt
Sea level / Local sea level rise is highly uncertain but not expected to deviate much (<5cm) from projected global mean increase of ~30cm / Very likely increases of 30-50cm in coastal mean sea level, exceeding global average / Anticipated rise in global sea level may be masked over much of the Canadian Arctic
Stratification / Greater stratification in spring and summer / Very likely increase in near surface stratification in all areas, but decrease in surface mixed layer depths / Likely strengthening of stratification
Currents and waves / Stronger currents / Likely increase in significant wave height in winter and spring / Likely small increase in mean significant wave height in summer; increased storm waves and sediment mobilization
Acidification / pH declines by 0.13 and aragonite saturation declines by 0.29 at a water surface density level of 1026.6 kg m3 / Very likely widespread reduction in pH of >0.1 in most areas / Very likely decrease in pH (0.1-0.2) and decreased saturation for aragonite
Oxygen concentration / Decline by ~36 μmol/kg at a water surface density level of 1026.6 kg m3. / Very likely widespread reduction in subsurface concentrations and saturation levels
Nutrients / No significant change in surface nitrate concentration / Likely widespread reduction in nutrient supply to euphotic zone / Likely no major changes in open ocean basins
Large scale ocean circulation / - / Uncertain changes in local and regional circulation and exchange; Likely northward shift of Gulf Stream, reduction in Atlantic Meriodional Overturning Circulation, and intensification of Labrador Current / Likely intensification of large scale circulation; reduction in volume and freshwater transport through the Canadian Arctic Archipelago
Sea ice / - / Very likely decrease in area, thickness, volume, concentration and duration in all areas. / Very likely continued decrease in mean sea-ice thickness (0.25-1.75m); decrease in summer ice extent by 10-80%; longer open water season; possible ice-free Arctic in late summer
Icebergs / - / Likely reduced occurrences of icebergs
Permafrost / - / - / Very likely continued permafrost degradation
REFERENCES
DFO (2013a) Risk based assessment of climate change impacts and risks on the biological systems and infrastructure within Fisheries and Oceans Canada’s mandate – PacificLargeAquaticBasin. DFO Can Sci Advis Sec Sci Resp 2013/016
DFO (2013b) Risk based assessment of climate change impacts and risks on the biological systems and infrastructure within Fisheries and Oceans Canada’s mandate – ArcticLargeAquaticBasin. DFO Can Sci Advis Sec Sci Resp 2012/042
DFO (2013c) Risk based assessment of climate change impacts and risks on the biological systems and infrastructure within Fisheries and Oceans Canada’s mandate – AtlanticLargeAquaticBasin. DFO Can Sci Advis Sec Sci Resp 2012/044