What Humpty Dumpty and the Atlantic Have in Common

Did you know that, when it comes to what is happening in our future climate, the collapse of the Atlantic Meridional Overturning Circulation Current cannot be fully taken off the table? Meadows Center scientists think about this constantly. If you did not know about this, however, you are likely shocked, possibly even chagrined.

To avoid the further potential upset of your sensibilities and good person, our discussion will begin today with Humpty Dumpty. When I was very young, my parents turned me on to this nursery rhyme, which helped convince me of what I already felt to be the clear, evident, and undeniable truth: adults are weird. What was the point of this strange story about someone who fell off a wall and could not be put together again, even by all the king’s horses and, well, staff? It seemed more like a statement of the obvious. Perhaps this nursery rhyme is something that we innately understand to convey a simple but powerful and important life message that we should all keep in view from an early age—there are many things, some are essential things, that one cannot fix. Once disrupted, broken, destroyed, that’s it.

This concept relates to something that scientists refer to as tipping points, a critical system threshold, the passing of which leads to large and irreversible system changes. There are so many tipping point examples, it would be hard to know where to start. Certainly, a tipping point under current heated discussion (pun intended) regards the Earth’s climate system.

An event illustrating the tipping point concept that caught my attention was the 2021 Surfside/Miami condominium collapse. Engineer’s advice in 2018 noted damage to the concrete structure; a 2020 follow-up documented the rapid and increasing rate of deterioration. A building maintenance manager had been vocal with concerns. As with many tipping points, feedback processes were in operation—saltwater caused the concrete and rebar within the concrete to corrode. The more the concrete deteriorated, the greater the saltwater penetration into concrete elements. Weaker structural supports compromised the condominium’s structural integrity, and investigators from the U.S. National Institute of Standards and Technology have not ruled out that geological factors were also in play. The collapse, when it came, was sudden and deadly.

The aftermath of the Surfside condominium building collapse which occurred on June 24, 2021. Source: Miami-Dade Fire Rescue Department, Wikimedia Commons

While climate systems are inordinately more complex than a Florida condo, they are also governed by a web of feedback loops. One simple feedback loop describing the interdependence of ice caps and global temperature is shown in the scheme below. This is just a single feedback loop. Even a casual attempt to capture a more realistic picture of the actual complexity is difficult to follow (warning: the graphic on the other side of this link contains content that, being dry and complicated, may be distressing or traumatizing to some. Readers are advised to exercise extreme caution in accessing this content).

Source: The National Academies of Science, Engineering, and Medicine

One reoccurring theme that dates back as far as existing geological records is that Earth’s climate, the chemical composition of the atmosphere, and the life-sustaining nature of Earth’s systems have always been changing as an inextricably linked system. The Great Oxygenation Event, for instance, was a period associated with the increasing proliferation of photosynthetic/oxygen-producing cyanobacteria and changing climate. This is also sometimes known as the Oxygen Catastrophe because other organisms died out over the time of transition.

Pondering these things, I wonder, why all the hoo-haw over the Earth’s climate system? The geological record shows that climate, atmospheric composition, and life on Earth has been subject to change. If great greasy glutinous globs of unicellular microorganisms such as cyanobacteria are associated with large changes, why would it be a stretch to think that humans might be?

(left) Cyanobacteria, source: Deeper Blue (right) Microscopic view of cyanobacteria, source: Josef Reischig, Wikimedia Commons

This brings us back to the condo collapse as an example of feedback loops and tipping points. As humans, we can and do form committees to have long discussions and arguments about the merits of facts, mechanisms by which to effect “repair,” but time, the physical/chemical outcomes of our activities, the laws of our physical world, and the processes governed by these, continue their own way while we do so. We might argue that, due to uncertainties and feedback loop complexities, tipping points are notoriously difficult to predict with accuracy. Still, such an argument is separate from the issue of risk management.

Hypothetically advised that your condo needed structural repairs, you could delay repairs until engineers reduced uncertainties regarding the timing of a collapse, or you might heed the nursery rhyme and invest in repairs, even if costly, as soon as possible. What do you think—is this analogy valid? Why or why not? Let us know in the comments →

For those interested in reading a more detailed treatment of environmental feedbacks and tipping points, view the unadulterated treatment of this topic here.

 Additional Resources:

• Champlain Towers South Condominium Structural Field Survey Report
• Champlain Towers South Condominium Letter to Owners
• Ex-Maintenance Manager for Surfside Condo That Collapsed Recalls Saltwater Intrusion (Newsweek)
• 29, 2022, Update: Champlain Towers South Investigation Completes Site Testing, Announces Next Advisory Committee Meeting (National Institute of Standards and Technology)
• Great Oxygenation Event: How Oxygen Filled the Atmosphere (Earth How)
• Feedbacks and tipping points: Big uncertainties about future warming (E&E News)
• Guest Post: Understanding climate feedbacks (Carbon Brief)
• Problem solving activity: Climate change and feedback loops (NOAA)
• The Study of Earth as an Integrated System (NASA Global Climate Change)