A change in a sea-ice parameter in a global coupled climate model results i
n a reduction in amplitude (of about 60%) and a shortening of the predomina
nt period of decadal low frequency variability in the time series of global
ly averaged surface air temperature. These changes are global in extent and
also are reflected in time series of area-averaged SSTs in the equatorial
eastern Pacific Ocean, the principal components of the first EOFs of global
surface air temperature and sea level pressure, Asian monsoon precipitatio
ns and other quantities. Coupled ocean-atmosphere-sea ice processes acting
on a global scale are modified to produce these changes. Global climate sen
sitivity is reduced when ice albedo feedback is weakened due to the change
in sea ice that makes it more difficult to melt. The changes in the amplitu
de and time scale of the low frequency variability in the model are traced
to changes in the base state of the climate simulations as affected by modi
fications associated with the changes ill sea ice. Making sea ice more diff
icult to melt results in increased sea-ice area, colder high latitudes, inc
reased meridional surface temperature gradients, and, to a first order, str
onger surface winds in most regions which strengthen near-surface currents,
particularly in the Northern Hemisphere, and decreases the advection time
scale in the upper ocean gyres. Additionally, in the North Atlantic there i
s enhanced meridional overturning due to increased density mainly in the Gr
eenland Sea region. This also contributes to an intensified North Atlantic
gyre. The changes in base state due to the sea ice change result in a more
predominant decadal time scale of near 14 years and significantly reduced c
ontributions from lower frequencies in the range of 15-40 year periods.