23 Questions
In the context of equilibrium states, when is a system considered to be in a stable equilibrium?
When its response to a modest disturbance returns the system to its initial equilibrium state
What does the ball analogy illustrate about equilibrium states?
Low points are analogous to stable equilibria
How do system disturbances differ in terms of time scale?
A perturbation acts over a brief period, while a forcing acts over a long period
In the context of Daisyworld, what happens to daisy coverage as the sun brightens?
Daisy coverage expands
According to the text, how is stability defined in the context discussed?
Stability is defined as the inverse of the potential energy of the system.
In the context of stability, what type of state has low potential energy?
Highly stable state (deep valley)
In the context of stability, what type of state has high potential energy?
Unstable state (top of a hill)
What is the current position of the Earth System represented as in the provided illustration?
The small sphere on the red line close to the divergence between the Stabilized Earth and Hothouse Earth pathways.
What does the horizontal line in the middle of the figure represent in the provided illustration?
The preindustrial temperature level.
What is the relationship between sea level and temperature change, as described in the text?
Sea level follows temperature change relatively slowly through thermal expansion and the melting of glaciers and ice caps.
What does the proposed planetary threshold at ∼2 °C above the preindustrial level represent in the provided illustration?
A critical temperature level that may lead to significant environmental changes.
What do the letters A, B, C, and D along the Stabilized Earth/Hothouse Earth pathways represent in the provided illustration?
Four time periods in Earth’s recent past that may give insights into positions along these pathways.
What term describes large-scale subsystems of the Earth system that can be switched into a qualitatively different state by small perturbations?
Tipping element
What does hysteresis refer to in the context of thresholds?
A system transitioning to an alternate state may not return to its previous state by reversing the conditions
What is a characteristic of small perturbations to a system approaching a threshold?
They can lead to abrupt transitions
What is the Earth System on a pathway toward, driven by human emissions of greenhouse gases?
Hothouse Earth
What effect does increasing global photosynthesis rates have on atmospheric CO2 levels and Earth's temperature?
It can lower atmospheric CO2 levels but may also cool the Earth
What is a common feature of natural systems with feedback loops?
Self-regulation
What happens to daisy population and temperature rise if Daisyworld warms beyond the optimum for daisies?
Daisy population crashes and rapid temperature rise occurs due to positive feedback
What can external conditions affect in multi-stable ecosystems?
The resilience of multi-stable ecosystems to perturbation
What effect does expanding daisy coverage have on the extent of warming on Daisyworld as the sun brightens?
It reduces the extent of warming on Daisyworld
What is the term used to describe the melt of Greenland Ice sheet, Atlantic Meridional Overturning Circulation, and Arctic Sea Ice loss as parts of the climate system moving closer to potential thresholds?
Tipping elements
What does the Stabilized Earth pathway involve, guided by human-created feedbacks?
Guidance to a quasistable, human-maintained basin of attraction
Study Notes
Daisyworld Model and Climate Thresholds
- Daisyworld warms beyond the optimum for daisies, causing a crash in the daisy population and rapid temperature rise due to positive feedback.
- Planetary climate systems are not passive in the face of internal or external forcings and perturbations, and self-regulation is common in natural systems with feedback loops.
- Small perturbations to a system approaching a threshold can lead to abrupt transitions.
- Earth’s average temperature is influenced by atmospheric CO2 content, global temperature, and photosynthesis rates, which are interconnected.
- Increasing global photosynthesis rates can lower atmospheric CO2 levels but may also cool the Earth, affecting plant photosynthesis.
- As the sun brightens, daisy coverage expands, reducing the extent of warming on Daisyworld.
- Several parts of the climate system are moving closer to potential thresholds, including the Atlantic Meridional Overturning Circulation, melt of Greenland Ice sheet, and Arctic Sea Ice loss.
- The term "tipping element" describes large-scale subsystems of the Earth system that can be switched into a qualitatively different state by small perturbations.
- Thresholds can have hysteresis, meaning a system transitioning to an alternate state may not return to its previous state by reversing the conditions.
- External conditions affect the resilience of multi-stable ecosystems to perturbation.
- The Earth System is on a Hothouse Earth pathway driven by human emissions of greenhouse gases, leading to an irreversible pathway beyond a planetary threshold at ∼2 °C.
- Another pathway leads to Stabilized Earth, guided by human-created feedbacks to a quasistable, human-maintained basin of attraction.
Daisyworld Model and Climate Thresholds
- Daisyworld warms beyond the optimum for daisies, causing a crash in the daisy population and rapid temperature rise due to positive feedback.
- Planetary climate systems are not passive in the face of internal or external forcings and perturbations, and self-regulation is common in natural systems with feedback loops.
- Small perturbations to a system approaching a threshold can lead to abrupt transitions.
- Earth’s average temperature is influenced by atmospheric CO2 content, global temperature, and photosynthesis rates, which are interconnected.
- Increasing global photosynthesis rates can lower atmospheric CO2 levels but may also cool the Earth, affecting plant photosynthesis.
- As the sun brightens, daisy coverage expands, reducing the extent of warming on Daisyworld.
- Several parts of the climate system are moving closer to potential thresholds, including the Atlantic Meridional Overturning Circulation, melt of Greenland Ice sheet, and Arctic Sea Ice loss.
- The term "tipping element" describes large-scale subsystems of the Earth system that can be switched into a qualitatively different state by small perturbations.
- Thresholds can have hysteresis, meaning a system transitioning to an alternate state may not return to its previous state by reversing the conditions.
- External conditions affect the resilience of multi-stable ecosystems to perturbation.
- The Earth System is on a Hothouse Earth pathway driven by human emissions of greenhouse gases, leading to an irreversible pathway beyond a planetary threshold at ∼2 °C.
- Another pathway leads to Stabilized Earth, guided by human-created feedbacks to a quasistable, human-maintained basin of attraction.
Test your knowledge of the Daisyworld model and climate thresholds with this quiz. Explore concepts such as feedback loops, planetary self-regulation, tipping elements, hysteresis, and the impact of human emissions on the Earth system.
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