Systems Thinking Through Climate Change — 5 Positive Feedback Loops
So far most of my systems have been pretty simple so I thought I’d try something with a few more moving parts. I think this falls under my domain since I remember reading that we shouldn’t do anything about climate change because of the economy. Carbon emissions are an externality, a cost to be paid by all of the world’s citizens as opposed to the producers and consumers. The lack of response is not due to a lack of technical knowledge, but a lack of political will or more candidly an unjust distribution of power.
Originally I made one more all encompassing systems map, but I later realized that some of the positive feedback loops that emerged deserved a separate explanation. These aren’t new, but it was certainly interesting to see how they fit together. I’ll note beforehand it is possible to sort of reduce greenhouse gases, radiative forcing, and global temperature to basically the same thing, but I think the distinctions are important here for reasons I’ll explain. Remember dotted lines indicate a negative relationship.
First some definitions so we’re all on the same page.
Radiative Forcing here represents the energy imbalance of Earth. When there is an imbalance in energy, the earth’s temperature slowly rises (or falls) until equilibrium is reached. Since this takes a long time there is a delay as you can see. (The double lines)
Albedo (reflectivity of Earth’s surface) prevents energy from being absorbed, so more albedo means lower radiative forcing. Greenhouse gases prevent energy from going out so more greenhouse gases means more radiative forcing.
First Reinforcing Feedback Loop (R1): Radiative forcing raises temperatures, which reduces ice. Ice is white, and sea water is a much darker, more absorbent color. When there is less ice, there is less albedo, which increases radiative forcing, and the cycle continues.
Second Reinforcing Feedback Loop (R2): Higher temperatures lead to permafrost melt which leads to more greenhouse gases, higher radiative forcing higher temperatures and so on.
Third Reinforcing Feedback Loop (R3): Wildfires, which here could functionally be replaced with desertification and rainforest drying which can release large amounts of CO2, and take in less CO2 as time goes on. These could represent R5 and R6, but they would feel redundant to me since the mechanism of action is the same. Heat can negatively effect plant life which ultimately leads to higher GHG concentrations.
Fourth Reinforcing Feedback Loop (R4): This one is the hardest to explain since the mechanism isn’t as well known. It is one of the least understood potential positive feedback loops due to the contradicting effects of clouds on climate. What makes this a potential positive feedback loop is that when acidification rises it can actually have a negative effect on albedo. This loop is one of the reasons why the distinction between Greenhouse Gases and radiative forcing is so important. More greenhouse gases lead to ocean acidification while positive radiative forcing and climate change in isolation do not.
From Nature.com “Acidification would lead certain marine organisms to emit less of the sulphur compounds that help to seed the formation of clouds and so keep the planet cool.” Clouds reflect sunlight, particularly when lower in altitude. Clouds are composed partially of compounds released by marine life.
SO… greenhouse gases lead to ocean acidification which reduces albedo, which increases radiative forcing, which increases global temperature, which increases permafrost melting, which increases greenhouse gases and we start all over again.
Fifth Reinforcing Feedback Loop (R5): Heat waves lead to less ice which reduces albedo which increases radiative forcing which increases global temperatures which increases the frequency and severity of heat waves.
Now we have the environmental part out of the way we get to the part we actually care about: How it affects us.
Gray elements are environmental issues most of which we already covered. Maroon elements are the tangible effects on humanity. (That we know of.) Blue elements are how we can respond. Green and Red are pretty self explanatory.
We’ve already covered most of the elements on the left so let’s start with Global Temperatures and go counter clockwise starting with Desertification.
Desertification, which has been called “the greatest environmental challenge of our time” is one of the effects of the changes in precipitation that will take place in a future of climate change. Heat waves, wildfires, and droughts can all lead to desertification, so as temperatures continue to increase the rate of desertification may accelerate aided more and more by multiple elements.
In theory desertification could raise albedo, and help reduce radiative forcing, but I’m not quite sold on deliberately increasing desertification in the interest of protecting the planet. The increase in greenhouse gases would more than offset any reflective benefits.
Heat Waves: Higher global temperatures also lead to heat waves, which lead to droughts and also plain old death especially for the old, and/or poor.
I thought about connecting death to greenhouse gases with a negative connection since when people die their propensity to emit greenhouse gases goes down, but I decided not to. First it’s not a conclusion I care to encourage. Secondly I doubt the most severe victims of climate change are significant emitters to begin with.
Drought: More drought leads to more refugees, and a lower food supply which leads back to more refugees and also death again.
Mosquito Prevalence: Higher global temperatures also mean mosquitoes which are limited by latitude and cold seasons will… well are increasing in range and number. This leads to disease spread, even in regions not conventionally affected by them and thus more death.
Hurricanes: More hurricanes have a negative impact on infrastructure as well both directly from wind and indirectly from floods.
Floods: Higher global temperatures also lead to more floods, which would in turn lead to more favorable conditions for insects and so on. They can also increase the spread of waterborne diseases. Floods also have a negative effect on infrastructure/property… kind of a lot. So if massive human death and suffering isn’t bad enough, there’s also property damage to consider.
Water Mass: When temperatures increase water takes up more space which means sea levels go up more in addition to the increase from melting ice. Higher sea levels hurt infrastructure increase refugees etc.
Permafrost Melting: We covered this in the first map, but I thought it was worth mentioning again since it could also have a human cost outside of its positive feedback loop. Something I only learned recently is that permafrost melting also has the potential to uncover dormant bacteria thousands of years old that could lead to disease. I doubt this concern will be addressed before it’s too late but we might get a decent apocalypse movie out of it.
Now as for the blues Mitigation is pretty straightforward; reduce greenhouse gas emissions. Adaptation is more about shoring up infrastructure to prevent the worst effects of climate change. Geoengineering is the most complicated and controversial one but most methods seem to amount to finding ways to remove greenhouse gases from the atmosphere and to increase planetary albedo in various ways.
So what’s the point?
Well I had fun making the maps. I guess my point is if you squint, or even if you don’t it seems most of the second map was maroon. This is a human issue as much as an environmental issue. A lot of elements have connections pointing to stuff like “Death,” “Disease,” and “Food Supply” which seems not good.
It also makes it clear that all those people who say we can’t predict the impacts of climate change are right in a way. These elements seem to be interconnected in a way that makes the full scope of the effects of climate change on humanity impossible to predict. Unpredictability however does not mean we should be bashful in our response. It means the opposite. Since we don’t know the full effects of climate change on our future existence, we would do well to take it seriously.
