Plummer mengatakan fenomena iklim El Nino di Samudra Pasifik, yang membawa kemarau parah ke Australia timur, bertanggung jawab atas sebagian besar perubahan tersebut, tapi itu mulai melemah.
Plummer said an El Nino weather event in the Pacific Ocean bringing severe drought to eastern Australia was responsible for much of the variation, but that was beginning to weaken.