Walker Circulation – El Niño conditions [image credit: NOAA]
The paper this article is based on informs us that ‘The Pacific Walker circulation (PWC) has an outsized influence on weather and climate worldwide. Yet the PWC response to external forcings is unclear’. Under a headline saying: ‘Greenhouse gases are changing air flow over the Pacific Ocean, raising Australia’s risks of extreme weather’, the article here offers almost nothing to support an argument for any human-caused climate effects ‘in the industrial era’. The paper is somewhat embarrassing for climate models: ‘Most climate models predict that the PWC will ultimately weaken in response to global warming. However, the PWC strengthened from 1992 to 2011, suggesting a significant role for anthropogenic and/or volcanic aerosol forcing, or internal variability’. So that role could be anything or nothing, but the models trended the wrong way anyway. The search for ‘anthropogenic fingerprints’ continues.
– – –
After a rare three-year La Niña event brought heavy rain and flooding to eastern Australia in 2020-22, we’re now bracing for the heat and drought of El Niño at the opposite end of the spectrum, says The Conversation (via Phys.org).
But while the World Meteorological Organization has declared an El Niño event is underway, Australia’s Bureau of Meteorology is yet to make a similar declaration. Instead, the Bureau remains on “El Niño alert.”
The reason for this discrepancy is what’s called the Pacific Walker Circulation. The pattern and strength of air flows over the Pacific Ocean, combined with sea surface temperatures, determines whether Australia experiences El Niño or La Niña events.
In our new research, published in the journal Nature, we asked whether the buildup of greenhouse gases in the atmosphere had affected the Walker Circulation. We found the overall strength hasn’t changed yet, but instead, the year-to-year behavior is different.
Switching between El Niño and La Niña conditions has slowed over the industrial era. That means in the future we could see more of these multi-year La Niña or El Niño type events. So we need to prepare for greater risks of floods, drought and fire. [Talkshop comment – alarmist psychobabble].
An ocean-atmosphere climate system
La Niña and its counterpart El Niño are the two extremes of the El Niño Southern Oscillation—a coupled ocean-atmosphere system that plays a major role in global climate variability.
The Walker Circulation is the atmospheric part. Air rises over the Indo-Pacific Warm Pool (a region of the ocean that stays warm year-round) and flows eastward high in the atmosphere. Then it sinks back to the surface over the eastern equatorial Pacific and flows back to the west along the surface, forming the Pacific trade winds. In short, it loops in an east-west direction across the equatorial Pacific Ocean.
But the Walker Circulation doesn’t always flow with the same intensity—sometimes it is stronger, and sometimes it is weaker.
. . .
So far, the Walker Circulation is what’s missing from the current El Niño event developing in the Pacific Ocean: it has not weakened enough for the Bureau to declare an El Niño event.
What’s happening to the Walker Circulation?
The Walker Circulation is a major influence on weather and climate in many places around the world, not just Australia.
A stronger-than-usual Walker Circulation even contributed to the “global warming slowdown” of the early 2000s. This is because a stronger Walker Circulation is often associated with slightly cooler global temperature.
So we need to know how it is going to behave in the future. To do that, we first need to know if—and if so, how—the Walker Circulation’s behavior has changed due to human activities. And to do that, we need information about how the Walker Circulation behaved before humans started affecting the climate system. [Talkshop comment – unsupported assertion].
We reconstructed Walker Circulation variability over the past millennium. We used global data from ice cores, trees, lakes, corals and caves to build a picture of how the Walker Circulation changed over time.
We found that on average, there has not yet been any industrial-era change in the strength of the Walker Circulation.
This was surprising, because computer simulations of Earth’s climate generally suggest global warming will ultimately cause a weaker, or
more El Niño-like, Walker Circulation.
Full article here..
– – –
Research paper: Forced changes in the Pacific Walker circulation over the past millennium (Aug. 2023)
Tallbloke's Talkshop 
[…] August 25, 2023kaykiser Walker Circulation study is a damp squib for climate worriers, contradicts models […]
Illustrates the problem with climatology now. There’s a huge and important part of the climate they do not understand but still they are “surprised” the models of it are wrong. How can you think you can model something you don’t understand?
And once again we see that the models are wrong in detail but still the models are right somehow. How can they point at the weather amd attribute heatwaves to climate change when the same whilst admitting that the models go in the wrong direction for things as important as this? It is farcical.
More pain for climate models…
Systematic Climate Model Biases in the Large-Scale Patterns of Recent Sea-Surface Temperature and Sea-Level Pressure Change
First published: 31 August 2022
Abstract
Observed surface temperature trends over recent decades are characterized by (a) intensified warming in the Indo-Pacific Warm Pool and slight cooling in the eastern equatorial Pacific, consistent with Walker circulation strengthening, and (b) Southern Ocean cooling. In contrast, state-of-the-art coupled climate models generally project enhanced warming in the eastern equatorial Pacific, Walker circulation weakening, and Southern Ocean warming. Here we investigate the ability of 16 climate model large ensembles to reproduce observed sea-surface temperature and sea-level pressure trends over 1979–2020 through a combination of externally forced climate change and internal variability. We find large-scale differences between observed and modeled trends that are very unlikely (<5% probability) to occur due to internal variability as represented in models. Disparate trends in the ratio of Indo-Pacific Warm Pool to tropical-mean warming, which shows little multi-decadal variability in models, hint that model biases in the response to historical forcing constitute part of the discrepancy. [bold added]
Key Points
— The patterns of observed sea-surface temperature and sea-level pressure trends differ significantly from CMIP5/6 historical simulations
— The rate of Indo-Pacific Warm Pool warming relative to tropical-mean warming is particularly anomalous in observations compared to models
— Patterns of observed changes that climate models do not reproduce are isolated with a signal-to-noise maximizing pattern analysis
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GL100011
It would help if they could actually define climate accurately first. The engineer in me wonders just how they hope to be able to describe a natural chaotic system without knowing how and why it changes.
In other words, they will never be able to model the climate but they have to continue trying or they will be thrown out of their plush air-conditioned offices and the money will stop.
Oldbrew, based on SOI figures -daily, 30d average, 90 day average and longer term trends the La Nina ended in February, but there is no indication that an El Nino has started. So, for maybe the first time BOM is correct by not going along with the useless WMO.
Many if not most articles in Phy.Org are wrong, basically because of wrong assumptions. As Ivan says that no one can make assumptions about systems or nature if one does not understand what is going on. Heat transfer is an engineering subject. If one does not understand heat transfer then for a start one can say nothing about global warming or climate conditions.
The word science only goes back to the mid nineteenth century to take in people like Charles Darwin who did scientific data collection and research before he came up with a theory. Engineering dates back maybe hundreds of thousand years to making tools and structures for shelter. Engineering involves thinking, logic, mathematics, experience, measurement, and testing.
I suggest that nearly everything put forward in the Conversation comes from people who have no engineering qualifications and have no understanding about the systems they are writing about. They write article to show their pretence of doing something.
Yes, The Conversation here tries to switch the focus to a threat of extreme weather in Australia, which has nothing to do with the study. But that’s their job – to keep the manufactured climate fear factor ahead of science discussion, while ignoring climate model fails.
“If one does not understand heat transfer then for a start one can say nothing about global warming or climate conditions.”
It would be interesting to know how many “climate scientists” had even heard of entropy…