What El Nino And La Nina Actually Mean For Australia:
The butterfly effect theory is becoming popular these days; apparently when a butterfly in Amazon flaps its wings, tornados occur in Texas.
While this may sound outrageous, it’s only a mere joke that tries to signify that small changes in one part of the planet can negatively impact the rest of the world.
Picture yourself in a room one hot afternoon, then having to turn on your fan. At first instance, it will circulate the air directly before it but with time, the air in the room gets mixed up and the entire space gets affected. The fan impacts the atmosphere closest to it, but ultimately the entire room is affected albeit a little. Similarly, disturbances happening in one part of planet earth’s atmosphere will be felt in another region.
A single insect might be too minute to literally cause a huge global effect, however, the next sub-topic—the Walker Circulation, truly does.
So, what exactly is the Walker Circulation?
Before explaining all about the Walker Circulation, here is what you should know:
The Walker Circulation refers to the occurrence where air moves across the Pacific Ocean but when it gets to Indonesia, it rises.
The air then travels back across the Pacific Ocean before finally descending upon Central America to complete the cycle. This forms the neutral phase and is the most common phenomenon.
In the presence of a La Nina, the Walker Circulation grows intense, bringing about warmer oceans and wetter conditions to eastern parts of Australia. La Nina is the phase when a normal circulation experiences numerous Weetbix.
The air is absorbed more strongly across the Pacific Ocean, hence there is excess moist air rising over the Australian side of the Pacific, causing rainy weather conditions east of Australia. When in the presence of El Nino, the Walker Circulation gets reversed and pushes air downwards bringing dry conditions to Australia, and the west Pacific Ocean sea surface temperatures become cooler than normal.
On the other hand, the El Nino is the phase when the Walker Circulation becomes weaker or is reversed causing air to descend on the Australian side of the Pacific Ocean, thereby preventing lifts and bringing about dry, warm conditions for Australia.
ENSO is the ultimate result of a push and pull between the ocean and the atmospheric air over the Pacific. Generally in Australia, El Nino causes drier and hotter weather conditions, while La Nina causes cooler and wetter weather.
How weather affects health, economies and conflicts
As it is, even the smallest variations in pressure and temperature in the Pacific Ocean leads to flow-on effects across the globe. The link between ENSO and its effects on temperature and rainfall thereby causing bushfires, floods, cyclones and droughts, is well documented.
However, not all effects relating to ENSO are well known.
Pre-historic El Nino events have been linked with the construction and abandonment of temples in Peru between 5,800 and 2,800 years ago. Having said that, it’s worth noting that communities affected by ENSO are not just those in the ancient past.
Research findings by the University of Cambridge show that Australia, India, Chile, Japan, Indonesia, South Africa and New Zealand have suffered significant economic losses in the aftermath of El Nino events. Other regions like Europe and the United States believe El Nino can cause enhanced effects on economic activity.
The relationship between climate and economics is quite complex but may be considered as the connection between rainfall and agricultural productivity. ENSO also impacts health. For instance, El Nino has been seen to have significantly contributed to air pollution in parts of eastern China.
The steady, descending air brought about by the reversed Walker Circulation during 2015 El Nino event increased smog build-up in the heavily polluted Beijing atmosphere. Such negative effects can lead to severe outcomes.
According to a research published in Nature, ENSO is likely to have played a role in 21 percent of all civil conflicts that happened between 1950-2004, and that fresh civil conflicts within the tropics were twice more likely to happen during El Nino years than during La Nina.
Researchers recommend that the economic stress caused by El Nino, alongside stress emanating from El Nino-instigated natural disasters, can put pressure on the human psyche, leading to more violent behaviour.
It’s not all about ENSO
It’s worth noting that not all global or Australia’s weather is driven by ENSO only.
One of the major effects relating to El Nino include increased bushfire potential across Australia, not forgetting the Ash Wednesday (1983) which was linked to El Nino.
The famous Black Saturday of 2009 happened at the fall of a La Nina season, while the October 2013 bushfires in the Blue Mountains occurred on a neutral phase.
ENSO happens to be one of the main climate drivers that impact Australia.
The Indian Ocean Dipole is also another major annual driver besides the Pacific Decadal Oscillation, the Madden Julian Oscillation and the Southern Annular Mode, among others which play an active role.
These drivers are also triggered by climate change, as seasonal changes and single systems remain at the fore.
It’s certainly a jungle out there with so many butterflies in it.
The information contained in this article is of a general nature only. It does not take your specific needs, objectives or circumstances into consideration, and is not financial advice, legal advice or otherwise a recommendation to purchase any financial product or insurance policy. You should seek your own independent financial advice from a qualified financial and insurance adviser before making any financial decisions, and seek your own independent legal advice from a qualified solicitor before making any decisions of a legal nature.