What's really astonishing about this is that to increase sea surface temperature by 1.5 degrees C, you need to heat the whole ocean mixed layer, which in summer is around 50 meters deep. E = c_p * rho * h * dT ~ (4e3 J / kg K) * (10e3 kg / m^3) * (50 m) * (1.5 K) = 3e8 J / m^2. So over the whole North Atlantic, this is about a (4e14 m^2) * (3e8 J / m^2) = 1.2e23 Joules of energy that have been added to the North Atlantic. That's about the same amount of energy that the whole Earth absorbs from the sun in a month.