the naughty little children who make the weather
Over the last couple of weeks we’ve heard much discussion of ‘El Nino’, a weather pattern with worldwide effects and which dates back thousands of years, returning with a vengeance but what is it exactly and, notwithstanding the recent catastrophic mudslide in Tibet/Nepal, do we truly need to fear its arrival?
El Nino, a phenomenon in which a band of warmer water develops in the central and eastern Pacific, was first noticed by Peruvian fishermen in the 1600s when this warmed water, which appeared around Christmas time, severely impacted their catch. They called it ‘El Nino de Navidad’ – The Little Boy of Christmas – and today the warming waters are recognised as part of a complex weather pattern that visibly influences conditions over large swathes of the Earth.
Normally, the pacific trade winds blow east to west but during an El Nino, for reasons not fully understood (though it is obvs linked to changing regional air pressures), this is reversed and every three-seven years great masses of warm water move easterly towards the Americas. At certain times, the opposite effect also occurs: the easterly trade winds strengthen and the Pacific is colder than usual and this is known as La Nina, ‘The Little Girl’. During an El Nino, dry regions of southern and central America (Peru, Chile, Mexico, southwest US) are often deluged with rain and snow, whilst rainfall in Asia and Australia is greatly reduced. This is reversed during La Nina.
Historically, it is accepted that El Nino played a significant role in the ending of the Moche civilisation in the 7th century and subsequently the Maya and Yucatan dynasties. It lead to the failed European crop yields in 1789 which ultimately sparked the French revolution. During the intense El Nino event in the winter of 1997-98 deluges and landslides left tens of thousands homeless, while on the other side severe drought and devastating forest fires were witnessed. Both la Nina and El Nino events undoubtedly change the odds of flood, drought, heatwave, fire and extreme cold on a worldwide basis. Increasingly countries such as Canada, Brazil, Thailand, Argentina and Turkey are feeling the impact of these two events.
The actual impact climate change has on these two events is unknown and difficult to predict. However, heating oceans has many effects: the severe warming of the 2015-16 El Nino put-paid to almost a third of the coral on the Great Barrie Reef. Scientists and meteorologists warn that its reappearance, on top of global warming, would probably trigger weather extremes and disasters of unprecedented scope and scale. “There’s a huge amount of heat stored below the surface that’s ready to erupt” said Dr. Michael McPhaden of the US National Oceanic and Atmospheric Administration and “the escalator’s only going up.”
