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The Arctic Oscillation, ENSO and U.S. Winter Temperatures
Higgins, R.W., Leetmaa, A. and Kousky, V.E.  2002.  Relationships between climate variability and winter temperature extremes in the United States.  Journal of Climate 15: 1555-1572.

What was done
The authors examined the influence of two important sources of Northern Hemispheric climate variability - the El Niņo/Southern Oscillation phenomenon and the Arctic Oscillation (AO) - on winter (Jan-Mar) daily temperature extremes over the conterminous United States for the 50-year period 1950-1999.  Among other things, they determined how the numbers of extreme cold and warm days differed between El Niņo and La Niņa years.

What was learned
Considerable decadal variability in winter surface air temperatures was noted throughout the 50-year record.  During El Niņo years, the total number of extreme temperature days was found to decrease by around 10%, while during La Niņa years they increased by around 5%.  With respect to AO effects, there was basically no difference in the number of extreme temperature days between its positive and negative phases.

What it means
With respect to winter temperatures across the conterminous United States, the climate-alarmist contention that warmer global temperatures - such as are typically experienced during El Niņo years - will produce more extreme weather conditions is found to be false.  In this study, in fact, just the opposite was found to be true.

Reviewed 25 September 2002