Much ado about tipping points

Recent environmental news puts a significant focus on tipping points. Scientific and social tipping points are both discussed daily in various contexts. But what is a tipping point, and how can we know if we have reached one? 

A simple definition for a tipping point is: a critical point in a system or ongoing process, beyond which unstoppable or irreversible change takes place. This critical point is sometimes referred to as a threshold point.

Envision a day at the water park. The sun is beating down, and you have decided to venture up the winding stairs to the top of the water slide. After a wait, your time comes. You sit on your mat and inch forward towards the point where the slide starts to slope downward. You can still back out at this point, hang your head in shame, and descend via the stairs. But you press on, and at a single point in the process, your fate is sealed. As you move past the flat entry zone, the slide picks up some slope and gravity takes hold. Once you pass this point, there is no going back.

The threshold point, where gravity overcomes friction, is the tipping point of this system. Once you pass this tipping point, you can thrash, holler, and flail your limbs erratically, but you are going to the bottom whether you want to or not. There is no stopping until gravity has converted all of your potential energy into kinetic energy, and you splash into the receiving pool at the bottom of the slide.

Complex systems

The water park example is a rather simple system: a slide, water to reduce friction, and gravity. But environmental systems are more complex, and there are many variables creating ambiguity around threshold tipping points for those systems. Arctic warming is a case in point. Global temperatures are rising, but Arctic temperatures are rising faster. Ice reflects more solar energy that open ocean or land. So, as more ice melts, exposed water and land in the Arctic can absorb more heat and the rate of melting increases. This process is a cycle that can become self-sustaining. 

There is a point in this system where stopping the rise in atmospheric greenhouse gases will have no effect, and the process will continue on its own until all the polar ice melts. Physics dictates that a temperature-related tipping point exists, but the system is too complex to specify the exact threshold temperature.

Some people will take this uncertainty as a bold cue to press forward and ignore the consequences for the time being. Others may be more circumspect and reflect that we may not recognize the tipping point until we have passed it. By then, of course, it’s just too late. 

Environmental tipping points are a physical reality. The more complex a system, then the less we know about the exact location of the tipping point. In these complex systems, the sad news is that once we definitively recognize a threshold point, we are too late to stop the process.

ArcheanWeb:

Arctic Warming (Source: ArcheanWeb) – https://archeanweb.com/2019/12/05/arctic-warming-climate-change/ Also:

Sources

6 climate tipping points: How worried should we be? (Ilissa Ocko – Environmental Defense Fund) –  https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwjv5pevn-vmAhVIGTQIHWA-Cb8QFjAAegQIBRAB&url=https%3A%2F%2Fwww.edf.org%2Fblog%2F2015%2F05%2F28%2F6-climate-tipping-points-how-worried-should-we-be&usg=AOvVaw1hNT-Si2ulH5X-VDZ4BoU- Also:

Feature photo: Arctic Ice (alexi_sailingfish – earthorg – Instagram – Modified)