A new paper published in Geophysical Research Letters finds "In contrast to recent claims of a Gulf Stream slow-down, two decades of directly measured velocity across the current show no evidence of a decrease." The paper contradicts claims by the IPCC that the Gulf Stream has slowed down due to global warming and alleged secondary climate effects.
On the long-term stability of Gulf Stream transport based on 20 years of direct measurements
T. Rossby et al
In contrast to recent claims of a Gulf Stream slow-down, two decades of directly measured velocity across the current show no evidence of a decrease. Using a well-constrained definition of Gulf Stream width, the linear least square fit yields a mean surface-layer transport of 1.35x105 m2 s-1 with a 0.13% negative trend per year. Assuming geostrophy this corresponds to a mean cross-stream sea level difference of 1.17 m, with sea level decreasing 0.03 m over the 20-year period. This is not significant at the 95% confidence level, and it is a factor of 2-4 less than that alleged from accelerated sea-level rise along the U.S. coast north of Cape Hatteras. Part of the disparity can be traced to the spatial complexity of altimetric sea level trends over the same period.