Flood Risk and Vulnerability Analysis Project - Atlantic Climate ...

e a higher incidence of tropical storms from the Atlantic Ocean potentially making landfall in
Newfoundland.
Another consequence of an increase in a positive NAO phase might be that it brings colder
water and air to the coastal regions of Labrador and of Newfoundland. As a result, general
warming in inland and western parts of Newfoundland and Labrador are likely to be faster than
that felt along the east coast (Bruce, 2011).
Regarding the variability of ENSO as a result of climate change, the IPCC found that all models
were showing continued ENSO interannual variability. Models exhibited a wide range of
behaviours, from little change to large changes in El Nino events. It is also difficult to discern
whether any changes in El Nino amplitude predicted by models are due to external forcing
resulting from global warming, or are simply a manifestation of internal multi-decadal variability.
The IPCC concludes that there is no consistent indication at this time of discernible future
changes in ENSO amplitude or frequency. In addition, a recent study simulating the effects of
climate change on ENSO (Stevenson et al, 2011), confirms the IPCC conclusions. However,
while it found no significant changes in the extent or frequency of ENSO, it also found that the
warmer and moister atmosphere of the future could make ENSO events more extreme, in
particular, stronger La Nina events. Since these are associated with higher winter precipitation
in Newfoundland; this result is consistent with the GCM outputs discussed earlier. Overall
though, as the ENSO regime is projected to remain quite similar to the present, its impact on
Newfoundland climate is not expected to change dramatically.
In summary, it can be stated that the ocean currents which exert a major influence on
Newfoundland and Labrador climate are not expected to change significantly as a result of
global warming over this century. The ocean-atmosphere oscillations that are responsible, to
some extent, for the observed decadal (and longer) cycles in warmer and colder periods and
periods with greater tropical storm intensity, continue through to the end of this century, if not
beyond. Their periodicity and intensity may change somewhat over the coming decades and
tracking those may help to predict climate anomalies in particular years or series of years in the
future. But because these planetary scale general circulation features are all likelihood well
handled by global climate models, the gradual upward trends in temperature and precipitation
seen out to 2050 and 2080 in the modeling section likely capture the long term effects of the
small changes in these large ocean currents and oscillations.
3.4.6 Worst Case Scenario Analysis
In the interest of preventing natural hazards from becoming natural disasters, one must also
consider worst case scenarios; intense phenomena that may occur in isolation or in combination
with other events or circumstances, that could lead to extreme water levels. This section
provides a preliminary, largely qualitative, assessment of scenarios that could lead to extreme
TA1112733 page 79