Future sea surface temperatures in Large Marine Ecosystems of the Northwest Atlantic

We analysed projections of future sea surface temperatures (SSTs) for six Large Marine Ecosystems (LMEs) of the Northwest Atlantic: the West Greenland Shelf, the Newfoundland-Labrador Shelf, the Scotian Shelf, the Northeast US continental shelf, the Southeast US continental shelf, and the Gulf of Mexico. We used state-of-the-art global climate models (CSIRO-Mk3.6, GISS-E2-R) and earth system models (CanESM2, HadGEM2-ES) and representative concentration pathways (RCPs) 8.5 and 4.5 that represent a range in possible future concentrations of atmospheric CO2. Our analysis focuses on average February and August SSTs from the period 2071-2100 as the low and high temperatures of these months generally define the thermal habitat of a species. SSTs will increase in most, but not all, waters of the LMEs, and seasonality will increase in all LMEs. The difference in SSTs from the Gulf of Mexico to the Scotian Shelf may be reduced but differences will increase from the Scotian Shelf north. Although past SST changes have been greatest on the Newfoundland-Labrador Shelf, ensemble average projections indicate that the greatest future change will occur on the Scotian Shelf. The variation in future SSTs is greater among models than between RCPs, suggesting that impact studies limited to a single model may be biased.