Teleconnection is defined as the linkage between weather changes occurring in widely separated regions of the globe. Elaborating further, it means if one atmospheric element decreases or increases in one part of the world, as a consequence another element may decrease or increase in a faraway part of the world.
El Nino and La Nina
The most talked about example of teleconnection is El Nino or La Nina phenomenon. El Nino event occurs when the Oceanic waters on the coast of Peru and Equador warms up abnormally. The consequences could be a weak monsoon over the Indian sub-continent. In this case the converse is also true, i.e. a La Nina event signifies a normal monsoon.
Origin of Teleconnection
British meteorologist Sir Gilbert Walker first noted teleconnections in the late 19th century, through computation of the correlation between time series of atmospheric pressure, temperature and rainfall.
Though aerosol concentrations or density of pollutants in a particular place does affect rain and other forms of precipitation in faraway parts of the world, it is still to be accepted as teleconnections.
Thus, we can conclude that teleconnection is simply a theory of atmospheric science that refers to climate anomalies being related to each other at large distances, typically thousands of kilometres.
