El Niño Explained

[Jamie in Chile]

If you see anything about El Niño in the news re climate, here´s what you need to know.

There is a cycle of heat transfer between the ocean and atmosphere due to currents, winds etc. The total amount of heat in ocean+atmosphere remains constant.

When we are in El Niño phases, there is more heat in the atmosphere, and less in the ocean.
In La Niña phases, there is more heat in the ocean, and less in the atmosphere.
There are also neutral phases.
Phases can last one or multiple years.

Global temperatures increase by about 0.2C during an El Niño episode, and fall about 0.2C during La Niña.

Recently, since 2020, we have been in a La Niña phase. This means the effects of global warming are slightly reduced.

In 2023/2024, we are likely moving to a El Niño phase, probably by Northern Hemisphere summer/fall 2023. This likely means record breaking temperatures and a slight increase in the effects of global warming.

Some scientists think the 2023/2024 La Niña could be stronger than previous ones.

Global temperatures are currently about 1.25C above pre industrial levels. So, as we go through El Niño, they might rise quickly to 1.4 or 1.5C before staying at about that same level for a few years after that as we return to a La Niña or neutral phase.

 

[Amy SF]

For those of us on the West Coast of the United States, it means a cooler, wetter winter in Southern California and a warmer, dryer winter in the Pacific Northwest. So we here in SoCal, we’ll likely get a repeat of last winter.