In a climate model at two different resolutions, sulphate aerosols are shown to induce a fast cooling followed by a delayed warming in the subpolar North Atlantic. The delayed warming is stronger at higher resolution due to a stronger Atlantic Meridional Overturning Circulation (AMOC) response. This difference is due to the lower resolution model having more sea ice which insulates the ocean, showing that the North Atlantic response to external forcing is sensitive to regional differences.