Next time you get a moment, go outside. Stand in the sunshine, take a look around. Take in the magnificent scale of the natural world that surrounds us. It's rather amazing when you stop to think about it.
The planet Earth is big. It's really, really big, and its systems, from its orbit, the angle of its axis, plate tectonics, ocean currents, and climate, are vast beyond our capability to easily comprehend. There are vast cycles, some measured in decades, some in millennia, some even in millions of years. We can try to make some predictions as to what's next in these cycles, but the best models we can come up with are, by comparison, laughably crude.
Which brings us to an article in the UK Independent, spreading some more panic about something called the Atlantic Meridional Overturning Current, its predicted collapse, and how we must immediately panic over the resulting climate chaos. There's just one problem with this claim: It's hogwash.
First, the system itself, the Atlantic Meridional Overturning Current, or AMOC: What is it?
AMOC stands for Atlantic Meridional Overturning Circulation. The AMOC circulates water from north to south and back in a long cycle within the Atlantic Ocean. This circulation brings warmth to various parts of the globe and also carries nutrients necessary to sustain ocean life.
The circulation process begins as warm water near the surface moves toward the poles (such as the Gulf Stream in the North Atlantic), where it cools and forms sea ice. As this ice forms, salt is left behind in the ocean water. Due to the large amount of salt in the water, it becomes denser, sinks down, and is carried southwards in the depths below. Eventually, the water gets pulled back up towards the surface and warms up in a process called upwelling, completing the cycle.
This is the system sometimes called the "Atlantic salt conveyor," and as noted, it's a cycle that takes thousands of years. Even the climate scolds admit this. This is the system that climate scolds are warning us about.
Climate Realism's Anthony Watts has an issue with that characterization, noting that the predictions aren't based on observations, but rather (again) on models.
The Independent claims in “Vital Atlantic current likely to collapse with catastrophic consequences, scientists warn” that the Atlantic Meridional Overturning Circulation (AMOC) is significantly more likely to shut down within decades, plunging Europe into extreme winters and triggering global disruption. This is wrong-headed speculation. The article relies heavily on extreme computer model simulations built on high-emissions assumptions, ignoring the observational record of the AMOC, which shows little or no evidence of an imminent collapse.
The article asserts that AMOC “could pass the shutdown tipping point within the next couple of decades,” and that a slowdown of 42 to 58 percent by 2100 is “almost certain to end in collapse.” That strong claim is based solely on modeling exercises, not direct measurements of a system in free fall.
That's a problem. Even the piece in The Independent that Mr. Watts cites admits that this vast current isn't well enough understood for modeling to be really effective. A model, to be predictive, has to closely reproduce all of the various inputs, outputs, influences, and cycles in the process being modeled; we just plain don't know enough about what those inputs, outputs, influences, and cycles are.
Actual observations, though, tell another story.
Climate models are useful tools, but they are not reality. Their reliability in simulating ocean circulation over century timescales remains limited. Small changes in parameterization, freshwater flux, wind forcing, or vertical mixing can dramatically alter projected AMOC strength. That is why scientific literature shows divergence rather than convergence on the idea of a collapsing AMOC.
The observational record does not show a collapse. Direct measurements of AMOC strength from the RAPID array at 26.5°N, which has been operating since 2004, show variability but no clear long-term downward trend indicating imminent shutdown. Paleo proxies used in that study suggest multidecadal variability has always occurred.
The tipping-point rhetoric also deserves scrutiny. “Collapse” implies an abrupt and irreversible shutdown. But the article acknowledges that even studies showing significant weakening do not necessarily predict a full switch-off. Weakening is not collapse. Variability is not collapse. Modeling a threshold is not observing one.
Ay, there's the rub.
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The Intergovernmental Panel on Climate Change (IPCC), a branch of the United Nations, itself an organization prone to climate panic-mongering, even admits as much. As Mr. Watts describes this:
The Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report states that while AMOC weakening is likely happening under current high emissions scenarios, there is low confidence in a collapse before 2100. That cautious assessment stands in contrast to headlines suggesting shutdown within decades.
Extreme simulations produce extreme headlines, but extraordinary claims require extraordinary proof, and none have been presented here. Ocean circulation science is unsettled. Models disagree. Observations show variability. Published studies over the past decade have projected collapse, steady-state behavior, and even strengthening under certain dynamics.
What the climate scolds and panic-mongers don't understand is something that real, working scientists, people who are familiar with and adhere to the scientific method, take for granted: Sometimes we just don't know, and working backward from a conclusion is bad science. In fact, it's not science at all, but activism. What the Independent has done in this panic-mongering piece is not only bad science reporting, it's bad reporting, period. It's activism wrapped in sciencey-sounding terminology, reliant on models of vast systems, taking hundreds of years to complete one cycle, systems we just don't know well enough to model, and any objective examination of actual measurements leads to, at worst, ambiguity.
We don't, or at least, we shouldn't, base policy decisions on ambiguities. But that is the very heart of the climate scold agenda.
