Abstract :
Atlantic tropical cyclones have been getting stronger recently with a trend that is related to an increase in the late
summer/early fall sea-surface temperature over the North Atlantic. Some studies attribute the increasing ocean warmth
and hurricane intensity to a natural climate fluctuation, known as the Atlantic Multidecadal Oscillation; others suggest
that climate change related to anthropogenic greenhouse gases emissions is the cause. Noting that the only difference
between these two hypotheses is the causal connection between global mean near-surface air temperature (GT) and
Atlantic sea-surface temperature (SST), the author previously showed how to use statistical tests to examine this
hypothesis. Here the author expands on this research. In particular, a more comprehensive explanation of the techniques
and additional tests and checks against misspecification are provided. The earlier results are confirmed in showing that
preceding GT anomalies have a significant statistical relationship to current SST anomalies but not conversely so that
if causality exists between Atlantic SST and global temperature, the causal direction likely goes from GT to SST. The
result is robust against a small amount of noise added to the data. Identical tests applied to surrogate time series fail to
identify causality as expected. The work underscores the importance of using data models to understand relationships
between hurricanes and climate.
