Question

what is a an effect of El Niño?

Answer 1

Primary effects: these are directly caused.Alteration of weather patterns which include:
Temperature changes
Precipitation changes
Storm track changes and intensity
Alteration of currents and ocean temperature.

Secondary effects: these are some consequenses:Fires
Drought
Flooding
Economic changes, price of heating, food, etc.Political and social unrest
Crash of fisheries
Famine
Plagues (hanta virus)Insect population explosion leading to disease and plagues.
Crop failure

Answer 2

It changes atmospheric pressures to rain, wind patterns, sea surface temperatures :) 

Hope it helps you