Climate Feedback Loops

Climate Feedback Loops

Systems Dynamics is a field that became famous with Jay Forrester, an engineer and systems scientist who taught at MIT and became the pioneer of the field. Donella Meadows, another MIT professor and environmental scientist, applied systems modeling to feedback loops in the climate vertical.

One of the greatest challenges we have with climate is that the loops take time to be perceivable.

Let's talk about duckweed, quoting Ed Seykota's book called Govopoly: "Traditional economists do not have much fluency with System Dynamic models. This does not mean system dynamic models do not work. It indicates 1) that economists do not know how to build them yet and 2) that the models recommend politically incorrect policies. Traditional economic models do not explain how simple cycles work. They do not explain bubbles. They do not explain the Great Depression. They do not generate curves that represent the behavior of the economy [...]. Building system dynamic models requires a grasp of basic engineering concepts such as feedback loops, oscillators, exponential growth and decay". Now, let's talk about the duckweed riddle.

Say you have one duckweed plant floating on a pond. Every day you find twice as many duckweeds as the day before. So, the second day you find two, then four, then eight and so on. Duckweed (like carbon dioxide in our atmosphere) grows exponentially. On the 40th day, you notice the duckweed completely covers the pond. Guess how many days it takes the duckweed to fill 1/2 of the pond.

Well, it takes 1 day for the duckweed to fill in the remaining 1/2 of the pond. When the situation becomes important and we finally become aware of it, we cannot do anything about it. Why is this important and how does it relate to climate?

Enter NASA's website: https://climate.nasa.gov/evidence/

For millennia, atmospheric carbon dioxide had never been above 400 parts per million. "The planet's average surface temperature has risen about 2.12 degrees Fahrenheit (1.18 degrees Celsius) since the late 19th century, a change driven largely by increased carbon dioxide emissions into the atmosphere and other human activities. Most of the warming occurred in the past 40 years, with the seven most recent years being the warmest. The years 2016 and 2020 are tied for the warmest year on record."

At +2 degrees celsius (due to the concentration of CO2 in the atmosphere and the correlated increase of the oceans' temperature), 99% of all global corals die. With dead corals, the fish that feed from them, also die. Then the big fish that eat the small fish, also die. Of course, this is not including overfishing, which increases the speed of the collapse of many species. At +3 degrees celsius, 50% of all species are at risk of extinction. We have less than 1 decade to prevent an increase of +2 degrees celsius. Once we reach that point, the feedback loops our natural ecosystems will experience cannot be modeled with "normal curves". The risk is at the fat tails.

If you want to learn more about Donella Meadows' work, check out the video above or read one of her books: Thinking in Systems. As for Jay Forrester, you find many videos of his lectures online. In the next posts we will cover some strategies to reduce and remove CO2 from our atmosphere as well as resources to get you started with climate tech.