Source: Yahoo El Nino Article
Example:
"If [PDO] transitions back into positive, we'd see a resumption in these more rapid rates of global warming," said Gerald Meehl, a climate scientist at the National Center for Atmospheric Research in Boulder, Colorado. "Having that shift in the background base state means that the peaks of the El Nino are going to be higher."
What exactly does "base state" mean?
Best Answer
Base state is a term used in statistics.
We have a measurable quantity, in this case the temperature of the sea.
We have an effect upon that quantity, El Nino increases the temperature and therefore the rainfall.
Each El Nino event may raise the temperature by a different amount. However, if the starting point from which the temperature is being raised - the Base State - is higher (due to global warming) then the peak caused by El Nino will be higher.
In effect, put very simply, the whole temperature graph goes up a bit.
The base state is the value of a variable before it is altered before an external event and to which it returns after that event.