What is El Niño?
El Niño is a natural phenomenon in which the ocean surface temperatures in the central to eastern Pacific become warmer than usual. It affects weather systems around the world, causing more rain in some regions, and none in others. It also causes temperatures to rise and more cyclones.
Extreme weather caused by El Niño results in severe droughts and floods, often in the same region. Countries in eastern and southern Africa, the Pacific, south-east Asia and Central America are most at risk. The United Nations says that over 60 million people will be impacted by El Niño this year.
El Niño happens every 3-7 years, however the 2015-16 phenomenon was one of the strongest in 50 years. Although this recent El Niño event has officially ended, the worst of its effects may be yet to come.
La Niña is the cooling phase which sometimes follows an El Niño. It tends to have the opposite climate effects to those of an El Niño, but it can have a more devastating impact as the coping capacities of communities are already overwhelmed. There is a 75 percent chance of La Niña occurring, most likely in late 2016 and early 2017.
Effects of El Niño
Extreme weather is severely impacting agricultural and fishing industries, causing crops to fail and livestock to die. Food production is depleted and water supplies are scarce in many parts of the world.
Food and water shortages are causing hunger, high rates of child malnutrition - which can have permanent effects on their physical and intellectual development - and the spread of waterborne diseases, such as cholera.
With no food at home, children are unable to concentrate at school or are forced to drop out to find work, leaving them vulnerable to exploitation and abuse.
Food insecurity caused by El Niño is predicted to peak in early 2017, meaning children and families will need life-saving assistance well into next year.
El Niño and climate change
It is not clear exactly how El Niño interacts with climate change. El Niño events are not caused by climate change, as they occur naturally. But scientists believe the effects of El Niño may be becoming more intense as a result of climate change.
According to the World Meteorological Organization the naturally occurring El Niño and human-induced climate change may interact and modify each other in ways which have never been experienced.