Everything I find is a bit too confusing or leaves out too much or whatever it is that I’m just not getting it, but it sounds bad
In: 840
I’m sure someone else can explain it much better than I can, but el nino and subsequently la nina are in a constant cycle that brings large weather pattern and localised climate changes to a number of different countries. They can introduce larger number of storms and pressure changes due to the climate and atmospheric pressure drops. You have likely experienced a couple of la nina and el nino cycles in your life already and shouldn’t be anything to worry about
Firstly, you have to understand that weather patterns often follow what occurs in the water around them – because clouds/rain comes from bodies of water.
El Nino and La Nina events are caused by a body of water within the Pacific Ocean that is regionally warmer and moves along the equator between the western Pacific to the Eastern Pacific and back. Warm water tends to evaporate quicker and thus creates more water in the air thus more rainfall than average leading to flooding. But the whole thing is a cycle so if it’s raining in one place there will be drier air in the other and less rainfall and droughts.
There is more to it, and how it interacts with other weather patterns but this is the general overview of this particular pattern.
Edit: someone please correct me if I’m wrong, this is just going off memory
So the El Nino and La Nina cycle themselves are not of concern they’re the normal cyclical pattern of weather for multiple countries that border the pacific ocean. Others have given a more technical explanation but the more layman one is: “When it is El Nino, places such as Canada and northern half of USA experience warmer/drier weather, the south eastern corner becomes quite dry, countries such as Australia experience dry spells and lower rainfall while southern half of USA experience increased rainfall. When it is La Nina this almost flips, with Canada and north half of USA experiening cold weather and increased rainfall while the southern ends of NA warm and dry up. Australia and eastern Pacific regions experience increased rainfall, cooler weather”
Why it is concerning is the effects of climate change are amplifying the effects of these weather patterns. So what once might have been a once in 50 years drought is now becoming “once in a decade” drought and catastrophic bush-fires are becoming a almost yearly event for the dry side of the cycle, meanwhile on the wet side those “once in 50 years flood” is becoming a biannual occurrence.
We’re coming off a particularly long La Nina period, so Canada, Australia/South Pacific and northern USA are bracing for the inevitable droughts and fires that climate change are amplifying which have plenty of fuel to burn after years of cool weather with plenty of rainfall to encourage plant growth.
Meanwhile the southern half of USA is bracing for flooding and more intensive cyclones.
From a California standpoint:
Our oceans have circular currents, which are guided by winds (tradewinds) During El Nino, the trade winds decrease.
So going to back California. The pacific ocean current in the northern hemisphere goes clockwise. Warm equatorial water rises up to japan, gets colder, then comes down from Alaska. (That’s why California’s ocean is usually below 60 degrees).
But in El Nino, the decrease is trade winds causes the warm water at the equator to rise up central and North america, instead of going to Japan/Alaska first. I remember El Nino 1998. The water was so warm off the coast of So Cal.
The change in trade winds and change in ocean temperature causes jet stream patterns to change and that changes the weather.
How does the ocean get cooler or warmer than usual?
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Will actually try to explain like I would to a 5 year old, all the replies are great but somewhat more technical.
Think of two little kids playing tug of war, except instead of one straight rope, they are each on one end of a lasso loop. They are ALWAYS playing tug of war in this lasso, and as they are playing the rope rotates around them.
When El Niño strengthens, that kids side of the lasso gets warmer, creating ripples in the rope that change the shape and pattern of the rope (changing the shape and patterns of the weather). When La Niña strengthens, that other kids side of the rope cools down the heating that was occurring on El Niños side. Sometimes, in between these two kids battling, they both take a break, and we call this neutral, not much is happening.
This always happens and is super normal. What’s not normal is the amount of strength that El Niño is exerting nowadays to warm up their side of the rope, and in return, La Niña seems to be also using more strength as well. The strength these two kids are using is changing how much the shape and pattern of the rope goes through. When we were used to seeing “normal” strength, we could predict the pattern or shape the rope/lasso would take and how long it could stay there. Now that the kids are using more strength, we’re not able to guess what the rope/lasso will look like (this is the problem, strong El Niño and La Niña patterns create weather chaos) and when/if it potentially snaps, we really have no idea what’s going to happen afterwards. Will it bounce back? Can the rope be repaired? If another rope is used, will it behave in the same or similar way?
Wait …
That was la Nina when the Australian bush fires happened…?
Or did I mess it up… The calendar of events…?
Or is the global warming thing truly messed up…
On a global scale. La Nina has a generally cooling effect, El Nino, a warming effect. We have had a long period without El Nino, and despite that have been having record high temperatures.
The previous highest global temperatures before the recent past was 1997 and 1998 – strong El Nino years. That heating on top of the current trend could be really nasty.
Here is an excellent explainer video about El Niño and its effects on people. It is in Dutch (as it is from the national broadcast station) but you can watch it with english subtitles
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