Understanding Climate Change and El Niño

Pacific weather conditions  are dominated by El Niño Southern Oscillation (ENSO). But what is this climate phenomena exactly and does it get altered with climate change?

What is El Niño?

The ENSO cycle is a natural climate variability in the Pacific region with cycles of about two to six years. During natural ENSO oscillations the sea level fluctuates of about 20 cm and causes large seasonal variations of precipitation patterns with long wet and dry periods between several years. In El Niño periods the Central and Eastern Pacific Ocean is warmer than average. More cyclones are occurring. In La Niña periods the Central and Eastern Pacific Ocean is colder than average. ENSO La Niña periods promote rather drought conditions in the South Pacific.

El Niño – Easy explained

You are not a scientist and need a simple explanation to grasp it? No problem. Watch this funny video of the climate crab and you understand the impacts of El Niño on the Pacific Island region:

 

Water scarcity in La Niña periods

In La Niña periods many islands experience situations of water shortage. Islands are not any more able to meet the citizens’ needs for drinking water. Water scarcity is a vital problem for many Pacific Island states. It is defined as lack of sufficient access to safe and affordable water for drinking, washing and livelihood. Since Pacific islands are poorly gifted with surface water and groundwater is too brackish to drink, many countries dependent on rainwater as primary water source. This makes the islands very vulnerable to variations of precipitation patterns.

How climate change affects ENSO

Climate change model projections show that ENSO events are becoming more intense and extreme with longer periods of drought and more frequent tropical cyclones. But model projections about rainfall pattern are inconsistent. Some preview an increase in rainfall, others predict reduced amounts of rainfall (Pacific Climate Change Science Program 2011, Power 2012). Though measurements do not show a significant trend for extreme weather events, the IPCC stated that it is very likely that small islands to the east of the dateline experience more frequent and intense and devasting tropical storms during El Niño events (Mimura, 2007).

© 2014 Heike Huntebrinker. All rights reserved.

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