Tipping points: the russian roulette of climate change
Nele Vandersickel
Lineair versus non-lineair
Lineair versus non-lineair
Two options:
-
I will give you 1 euro per day for the next 30 days.
- I will give you a 0.001 cent on the first day, 0.002 cents on the second day, 0.004 cents on the third day, 0.008 cents on the fourth day, and keep doubling every day for a total of 30 days.
Lineair versus non-lineair
Two options:
-
I will give you 1 euro per day for the next 30 days = 30 euro
- I will give you a 0.001 cent on the first day, 0.002 cents on the second day, 0.004 cents on the third day, 0.008 cents on the fourth day, and keep doubling every day for a total of 30 days = 10.000 euro
Lineair versus non-lineair
If a pond has a lily pad that doubles in size daily and takes 30 days to cover the pond, When will half of the pond be covered?
Lineair versus non-lineair
If a pond has a lily pad that doubles in size daily and takes 30 days to cover the pond, When will half of the pond be covered?
Day 29
Lineair versus non-lineair
If you fold a piece of paper, how many times do you need to fold it to get to the moon?
Lineair versus non-lineair
If you fold a piece of paper, how many times do you need to fold it to get to the moon?
42 times!
Lineair versus non-lineair
Human brain: tends to think lineair
"Illusion of linearity": incremental change, little-by-little will get you to your destination
We predict the future on recent progress in a linear way
Lineair versus non-lineair
- But: most processes are non-linear!
- Most dangerous processes are the exponential growing processes
Lineair versus non-lineair
But the exponential changes can really catch us by surprise:
There is a pace misconception: in exponential growth, things can seem quiet before they explode.
Lineair versus non-lineair
Most famous example: the corona crisis - spread of disease is exponential in the beginning.
Lineair versus non-lineair
Most famous example: the corona crisis - spread of disease is exponential in the beginning.
The hospital is 1/4 full, in how many days is the hospital completely full, if the number doubles every 3 days?
Lineair versus non-lineair
Most famous example: the corona crisis - spread of disease is exponential in the beginning.
The hospital is 1/4 full, in how many days is the hospital completely full, if the number doubles every 3 days?
Just 6 days!
Feedback loops
Feedback loops
Positive feedback
Negative feedback
A positive value of a variable increase in that variable,
A negative value of a variable decrease (more negative)
A positive value of a variable decrease in that variable,
A negative value of a variable increase in that variable
Feedback loops
Examples: what is it?
Methane is a greenhouse gas 25 times more potent than CO2. Large amounts of methane are trapped in Arctic permafrost and at the bottom of the ocean. Rising temperatures cause this methane to be released, contributing to further temperature increases.
Feedback loops
Examples: what is it?
Methane is a greenhouse gas 25 times more potent than CO2. Large amounts of methane are trapped in Arctic permafrost and at the bottom of the ocean. Rising temperatures cause this methane to be released, contributing to further temperature increases.
Positive
Feedback loops
Examples: what is it?
Examples: what is it?
A person whose bank account is low might work overtime to bring it back up and then cut back on overtime when there is sufficient money in the account.
Feedback loops
Examples: what is it?
A person whose bank account is low might work overtime to bring it back up and then cut back on overtime when there is sufficient money in the account.
Negative
Feedback loops
Examples: what is it?
Animals have young, which increases the population. The larger the population is, the more babies are born, which makes the population even larger. As long as resources are available, the population will keep growing.
Feedback loops
Examples: what is it?
Animals have young, which increases the population. The larger the population is, the more babies are born, which makes the population even larger. As long as resources are available, the population will keep growing.
Positive
Feedback loops
Examples: what is it?
Practicing a sport or musical instrument. Practice makes you better at the activity, which makes you enjoy it more, which makes you practice more.
Feedback loops
Examples: what is it?
Practicing a sport or musical instrument. Practice makes you better at the activity, which makes you enjoy it more, which makes you practice more.
Positive
Feedback loops
Examples: what is it?
A thermostat that controls an air conditioner. When the temperature goes up, the air conditioner comes on, which causes the temperature to go down. The thermostat can also control a heater, in which case a decrease in temperature causes the heater to turn on, which raises the air temperature.
Feedback loops
Examples: what is it?
A thermostat that controls an air conditioner. When the temperature goes up, the air conditioner comes on, which causes the temperature to go down. The thermostat can also control a heater, in which case a decrease in temperature causes the heater to turn on, which raises the air temperature.
Negative
Feedback loops
Our climate system is full of positive and negative feedback loops
Positive feedback
Negative feedback
Feedback loops
Our climate system is full of positive and negative feedback loops
Positive feedback
Negative feedback
They create non-lineair (exponential) changes!
Tipping points
Tipping points
Tipping points are the most dangerous part in the whole story of climate change, and for our loss of biodiversity.
positive feedback = bad
Negative feedback = good
Tipping points
Tipping points are the most dangerous part in the whole story of climate change, and for our loss of biodiversity.
Earth system: complex system with positive and negative feedback loops: earth is in equilibrium
Tipping points: ice sheet collapse
Tipping points: AMOC
Tipping points: AMOC
Tipping points: AMOC
No consensus when?
But if it happens...
An AMOC collapse would be a massive, planetary-scale disaster.
- Cooling and increased storminess in northwestern Europe
- major additional sea level rise especially along the American Atlantic coast
- a southward shift of tropical rainfall belts (causing drought in some regions and flooding in others)
- reduced ocean carbon dioxide uptake, greatly reduced oxygen supply to the deep ocean
- likely ecosystem collapse in the northern Atlantic
- ...
Tipping points: all interconnected
Tipping points: hothouse earth
A “Hothouse Earth” climate will in the long term stabilize at a global average of 4-5°C higher than pre-industrial temperatures with sea level 10-60 m higher than today, the paper says.
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Tipping points: hothouse earth
What to do...
What to do
We must avoid any green house gas entering the atmosphere
Everything, everywhere,
all at once