El Nino Explained

If, like me, it’s been a long time since your last geography lesson then your understanding of how the world around us works may sometimes (rather embarrassingly) not be up to scratch. When natural phenomena occur, I acknowledge their significance but that tends to be as far as it goes; I rarely look for the reasons why that volcano erupted or how those tectonic plates shifted to create that earthquake.

But this time I’ve decided to go in search of some answers and find out why the El Niño phenomenon occurs and how it affects South America, particularly the Galápagos Islands.

So, first things first: what is El Niño?

El Niño (“The Boy”) is a natural event which occurs irregularly every 2–7 years; it is so called because the phenomenon often arrived in the region around Christmas and many people connected it to the birth of Christ. However, since its initial, religious nomenclature, scientists have discovered that rather than being an annual event, El Niño is actually a gradual warming of coastal waters in the Equatorial Pacific that can take place over a period of six to 18 months. The consensus (at the time of writing) is that this El Niño event is likely to continue through Northern Hemisphere winter 2015-2016, gradually weakening through spring 2016.

(For more information and updates: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.pdf)

Here’s how it works (in a nutshell):

The Humboldt Current is a cold water current which originates from the southern tip of Chile, flows north to Peru and then west along the Equator. It is rich in nutrients and feeds marine life off the northern coast of South America, including the Galápagos Islands. During normal years, westward-blowing trade winds drag warm surface waters away from the islands and allow these cold currents to rise to the surface and continue on their way northwards to nourish the Galápagos’ ecosystems. During an El Niño year, the trade winds are weakened, meaning the warm surface waters are not pulled westward but sent eastward towards South America, preventing the deeper, nutrient-rich cold water from rising to the surface and reaching the archipelago.

“I’ve heard that the 2015 El Niño event is set to be particularly strong; record-breaking, even”.

Whether a specific El Niño event is considered strong or weak depends on the rise in temperature. A weak El Niño would mean an increase of about 2-3 degrees Celsius and a strong El Niño might see increases of 8-10 degrees Celsius, which can cause climatic changes all over the world.

This then leads us to our next questions... What are the effects of El Niño and where are these effects felt?

No two El Niño events are identical, making it very hard to predict what the exact effects will be in terms of weather. In general, the coasts of Ecuador and Peru will likely experience a higher-than-average level of rainfall in the coming months, which will occur due to lower atmospheric pressure caused by the warmer ocean water. This heavy rainfall can lead to landslides, major flooding and a negative impact on industries such as fishing, which will suffer as the warmer waters diminish the supply of fish. The overall effect for countries such as Peru is often a damaged infrastructure and economy.

The effect on wildlife is a little more certain: we do know that the food chain will be disrupted. The small fish, plankton and algae that benefit from the cold, nutrient-rich water will die off as they cannot survive in such warm waters. This will have an adverse effect on marine life such as the sea turtles, marine iguanas and sea birds as these fish and algae are a main food source for them. Other wildlife such as sharks and sea lions will have to search for food in places they would usually avoid and breeding can become a problem, leading to reduced populations amongst these species.

However, there are other, land-based, species which benefit from warmer temperatures and increased rainfall. For example, land iguanas, giant tortoises, Darwin finches, Galápagos doves and mockingbirds will all thrive as the overall vegetation on the islands flourishes. The normally dry and desert-like landscape of the Galápagos Islands becomes lush and verdant, making for an excellent and unique opportunity to see the archipelago in a way that most visitors do not.

Overall, weather conditions during El Niño are difficult to forecast as there is no pattern of behaviour for the phenomenon. However, we can be sure that our local operators are continually monitoring the situation and are well placed to deal with any issues should they occur. And if you’re travelling to the Galápagos it’s a great idea to talk to your naturalist guide as they will help further your understanding of the climatic changes and the transformation that the islands undergo during this extraordinary natural phenomenon.