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Explain how El Niño cycles can lead to drought. (5 marks)

El Niño cycles occur periodically, on average every 3- 7 years in the Pacific Ocean. Normally-descending air over the Eastern Pacific gives dry conditions that create the Atacama desert, whilst Western Pacific has warm moist ascending air, giving the region heavy convectional rainfall. However El Niño events involve a a drop in trade winds resulting in the reversal of climactic conditions in the equatorial pacific region-leading to descending air/ high pressure over the Western Pacific and moist air and wetter conditions in the Easter Pacific. Drop in trade winds leads to cooler water off Australia, thus less evaporation which can therefore cause drought.