Climate Systems and Feedback Loops

Introduction

Earth's climate is not controlled by a single cause. It emerges from interactions among the atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere, together with flows of energy and matter. In this aiMOOC, you will study the climate as a dynamic system: a network in which a change in one component can influence many others.

A central idea is the feedback loop. A feedback occurs when a change in the climate system triggers processes that then influence the original change. A positive feedback reinforces the initial change. A negative feedback opposes or damps it. The words positive and negative describe the direction of the response, not whether the outcome is desirable.

This distinction matters. Human activities such as greenhouse-gas emissions can create a forcing that disturbs Earth's energy balance. Feedbacks then shape how strongly and how quickly the climate responds. According to the Intergovernmental Panel on Climate Change, the combined effect of known radiative feedbacks amplifies the base warming response, while Earth's increasing emission of infrared radiation as it warms provides a strong stabilizing response.

By the end of the course, you should be able to trace causal chains, distinguish forcing from feedback, interpret energy-flow diagrams, explain major physical and carbon-cycle feedbacks, use simple quantitative models, evaluate uncertainty, and discuss how feedbacks relate to climate sensitivity and tipping points in the climate system.

Learning Goals

After completing this aiMOOC, you can:

Climate system: Explain how the atmosphere, ocean, ice, land, and living organisms interact across different spatial and temporal scales.
Earth's energy budget: Describe how incoming solar radiation and outgoing infrared radiation determine the planet's energy balance.
Radiative forcing: Distinguish an external or imposed forcing from a feedback that occurs in response to climate change.
Climate change feedbacks: Trace and classify important reinforcing and balancing feedback loops.
Climate sensitivity: Explain why feedback strength affects the amount of warming produced by a given forcing.
Systems thinking: Analyze interacting loops, delays, thresholds, uncertainty, and possible unintended consequences.

The Climate System as an Interconnected System

Five Major Components

The climate system contains five strongly interacting components. The atmosphere transports heat, moisture, and trace gases. The hydrosphere includes oceans, lakes, rivers, groundwater, and water vapour. The cryosphere includes snow, glaciers, ice sheets, sea ice, and frozen ground. The lithosphere provides land surfaces, rocks, soils, and topography. The biosphere includes organisms and ecosystems that exchange carbon, water, and energy with the rest of the system.

These components do not respond at the same speed. The atmosphere can change within hours or days, surface ocean conditions can evolve over seasons to decades, and the deep ocean and large ice sheets can take centuries or longer to approach a new equilibrium. This difference in response time creates lags and memory. A climate system may therefore continue changing after the original forcing has stabilized.

Ocean and atmospheric circulation redistribute energy from regions with net energy gain toward regions with net energy loss. The water cycle moves both matter and latent heat. The carbon cycle connects the atmosphere with vegetation, soils, oceans, sediments, and rocks. These transfers mean that a local change can influence distant parts of the Earth system.

Stocks, Flows, and State Variables

Systems thinking distinguishes a stock from a flow. A stock is an amount stored at a given time, such as carbon in a forest or heat in the ocean. A flow is a rate of transfer, such as carbon dioxide entering the atmosphere or heat moving from the surface to the atmosphere.

A state variable describes the condition of a system. Global mean surface temperature, sea-ice area, atmospheric carbon dioxide concentration, ocean heat content, and soil moisture are examples. Feedback loops connect these variables through causal relationships.

When you analyze a climate diagram, ask four questions: What variable changed first? Which process connects one variable to the next? Does the final effect reinforce or oppose the initial change? On what timescale does the response occur?

Earth's Energy Budget

The climate system is powered mainly by solar radiation. Some incoming sunlight is reflected by clouds, atmospheric particles, snow, ice, and bright land surfaces. The rest is absorbed by the atmosphere and surface. Earth then emits energy to space as infrared radiation.

If incoming absorbed energy exceeds outgoing energy, the climate system gains energy and warms. If outgoing energy exceeds incoming absorbed energy, it loses energy and cools. At equilibrium, the long-term global average energy entering the climate system is balanced by energy leaving it.

The greenhouse effect is part of this energy system. Greenhouse gases absorb and emit infrared radiation. Increasing greenhouse-gas concentrations changes the altitude and conditions from which Earth effectively radiates energy to space, producing a positive radiative forcing. The surface and lower atmosphere warm until outgoing energy again balances incoming energy, with feedbacks modifying the size of that temperature response.

Forcing Versus Feedback

A forcing is an initial disturbance to Earth's energy balance that is not caused by the resulting change in global temperature. Examples include a change in solar input, volcanic aerosol loading, or an increase in greenhouse gases caused by human emissions. A feedback is a process that responds to the climate change and then alters the energy balance further.

This distinction is conceptual rather than absolute in every context. For example, carbon dioxide added directly by fossil-fuel burning is treated as a forcing, while additional carbon dioxide released because warming weakens a natural carbon sink can be treated as a carbon-cycle feedback.

A useful causal pattern is:

Forcing → temperature response → system change → additional energy-balance change → modified temperature response.

A Simple Quantitative Feedback Framework

Climate scientists often write a simplified top-of-atmosphere energy-balance equation as:

N = F + αΔT

Here, N is the net energy imbalance at the top of the atmosphere, F is the effective radiative forcing, ΔT is the change in global mean surface temperature, and α is the net feedback parameter in watts per square metre per degree of warming.

With the sign convention used here, a negative α means that warming increases the loss of energy to space. The largest stabilizing term is the Planck response: a warmer Earth emits more thermal radiation. Other feedbacks make the net value of α less negative or more negative.

At equilibrium, N = 0. The equation then shows why stronger amplifying feedbacks produce a larger equilibrium temperature response for the same forcing. In real climate models, feedbacks vary by region, season, climate state, and timescale, so this linear equation is a useful approximation rather than a complete model.

Feedback Loops: Core Concepts

Positive and Negative Feedback

A positive feedback is reinforcing. If the system warms and a process causes additional warming, that process is a positive feedback. If the system cools and the same process causes additional cooling, it is still positive because it reinforces the original direction of change.

A negative feedback is balancing. If warming triggers a process that increases heat loss or reduces heat gain, the feedback opposes the initial warming.

Positive feedback does not automatically mean unlimited runaway warming. The climate system also contains strong stabilizing processes. In Earth's present climate, the increase in outgoing infrared radiation with temperature is a major reason the planet tends toward a new energy balance after a forcing.

Loop Diagrams and Causal Signs

In a causal-loop diagram, an arrow marked with the same-direction relationship means that when one variable increases, the next tends to increase relative to what it otherwise would have done. An opposite-direction relationship means that an increase in one tends to decrease the next.

A loop with an even number of opposite-direction links is reinforcing. A loop with an odd number is balancing. However, sign counting is only the start. You must also consider the strength of each link, delays, spatial differences, and whether other processes interrupt the loop.

For example:

Temperature rises → snow and sea ice decrease → surface reflectivity decreases → solar absorption increases → temperature rises further.

That is the ice-albedo reinforcing loop.

Major Physical Climate Feedbacks

Water-Vapour Feedback

Warmer air can contain more water vapour when moisture is available. Water vapour is itself a greenhouse gas, so increased atmospheric water vapour reduces the rate at which infrared energy escapes to space at a given temperature. This leads to additional warming.

The causal chain is:

Initial warming → more atmospheric water vapour → stronger infrared absorption and emission within the atmosphere → reduced outgoing radiation at first → additional warming.

This is a positive feedback. It is a response to warming rather than the primary cause of current human-driven climate change. The atmospheric concentration of water vapour is strongly controlled by temperature and condensation, while carbon dioxide can remain in the climate system for much longer and acts as an important forcing.

The water-vapour feedback is often analyzed together with the lapse-rate feedback, because temperature and humidity changes are physically linked.

Lapse-Rate Feedback

The lapse rate is the rate at which atmospheric temperature changes with altitude. In a warming climate, the vertical pattern of warming is not uniform. In the tropics, the upper troposphere tends to warm more strongly than the surface. Because warmer upper-air layers emit more infrared radiation to space, this pattern provides a globally negative lapse-rate feedback.

The lapse-rate and water-vapour feedbacks partially offset one another. Their combined effect is positive and is assessed as a major contributor to climate amplification.

Surface-Albedo Feedback

Albedo is the fraction of incoming solar radiation reflected by a surface. Bright snow and ice have high albedo, while open ocean and many land surfaces are darker and absorb more sunlight.

When warming reduces snow or sea-ice cover, darker surfaces are exposed. They absorb more solar energy, which causes additional warming and can lead to further melting. This is a positive feedback and contributes to strong warming at high northern latitudes.

A second concise explanation is provided by the University of St Andrews GeoBus project:

The albedo feedback is especially strong where snow and ice are close to their melting point and where sunlight is available. Its strength therefore changes by season and location.

Cloud Feedbacks

Clouds influence both shortwave and longwave radiation. They can cool Earth by reflecting sunlight and warm it by reducing infrared energy loss to space. The net effect depends on cloud height, thickness, phase, location, coverage, and how these properties change as the climate warms.

The current scientific assessment is that the net global cloud feedback is positive, meaning that cloud changes on balance amplify warming. Cloud feedback remains a major source of uncertainty in estimates of climate sensitivity because different cloud processes operate at small scales and interact with large-scale circulation.

A useful distinction is between the effect of clouds in today's climate and cloud feedback. Clouds currently have an overall cooling effect on Earth, but the feedback asks a different question: how does the net cloud radiative effect change as global temperature changes?

Planck Response: The Fundamental Stabilizer

Every object emits more thermal radiation as its temperature rises. For Earth, this means that warming increases outgoing infrared radiation to space. This response opposes the initial warming and is therefore a strong negative, or stabilizing, feedback in the energy-balance framework.

Without the Planck response, reinforcing feedbacks would be much more destabilizing. With it, the climate system generally approaches a new equilibrium after a sustained forcing, although that equilibrium can be substantially warmer than the initial state.

Carbon-Cycle and Ecosystem Feedbacks

The climate system and the carbon cycle are coupled. Human activities add carbon dioxide to the atmosphere, while land and ocean sinks remove a substantial fraction of those emissions. Warming can alter the strength of these sinks and sources, creating feedbacks.

Land Carbon Feedbacks

Plants take up carbon dioxide through photosynthesis, while respiration, decomposition, fire, and land-use change release carbon. Rising carbon dioxide can stimulate plant growth in some environments, which tends to increase uptake and act as a balancing carbon-cycle effect. However, nutrient limits, heat stress, drought, fire, pests, and ecosystem change can weaken or reverse this response locally.

A warming climate generally increases many biological rates, including respiration and decomposition, although moisture and nutrient availability strongly modify the result. The net land carbon response therefore depends on interacting physical and biological processes.

Ocean Carbon and Heat Uptake

The ocean absorbs both heat and carbon dioxide. Ocean heat uptake slows the rate of surface warming because some excess energy is stored below the surface. This does not remove the energy from the Earth system; it redistributes it and creates long response times.

Carbon dioxide dissolves in seawater and participates in chemical reactions that form dissolved inorganic carbon. As surface waters warm, carbon dioxide is generally less soluble, while changing circulation and biology can further influence ocean carbon uptake. The ocean's ability to take up carbon is therefore linked to climate state.

Ocean heat uptake is not identical to a radiative feedback in the standard top-of-atmosphere feedback decomposition, but it is crucial for understanding transient climate response and why surface temperature can continue adjusting for decades to centuries.

Permafrost Carbon Feedback

Permafrost stores large amounts of organic carbon in frozen soils. When permafrost thaws, previously frozen organic matter can be decomposed by microbes, releasing carbon dioxide and, in oxygen-poor environments, methane. These greenhouse gases can cause additional warming, which promotes further thaw.

This feedback operates over long and uneven timescales. Not all permafrost carbon is released at once, and the proportion emitted as carbon dioxide or methane depends on local conditions. The process is nevertheless important because it can add natural greenhouse-gas emissions on top of human emissions.

Interacting Feedbacks and Climate Sensitivity

Feedbacks rarely act alone. Water vapour affects clouds. Sea-ice loss changes heat exchange between the ocean and atmosphere. Vegetation change can alter albedo, evapotranspiration, and carbon storage. Fire can remove biomass, darken snow with soot, and release greenhouse gases. These interactions create a network rather than a set of isolated loops.

Climate sensitivity describes how much the global climate warms in response to a sustained forcing, especially a doubling of atmospheric carbon dioxide. Feedbacks are central to this concept. The direct warming response to carbon dioxide is amplified by the combined effect of water-vapour, cloud, and surface-albedo feedbacks, while lapse-rate and Planck responses provide stabilizing effects.

Uncertainty in climate sensitivity does not mean scientists do not know whether greenhouse gases warm the planet. It means that the exact magnitude of the full system response depends on feedback strengths, especially processes involving clouds and long-term Earth-system changes.

Equilibrium Climate Sensitivity and Transient Response

Equilibrium climate sensitivity, or ECS, is the long-term global mean surface warming expected after atmospheric carbon dioxide is doubled and the climate approaches equilibrium. Because the deep ocean takes a long time to adjust, equilibrium is not reached immediately.

Transient climate response, or TCR, describes warming at the time carbon dioxide doubles in an idealized experiment where concentration increases gradually. TCR is lower than ECS because the ocean is still taking up substantial heat during the transient period.

These two measures answer different questions. ECS helps describe long-term commitment; TCR is closely related to warming over policy-relevant decades under a steadily increasing forcing.

Tipping Points, Thresholds, and Nonlinearity

A tipping point is a threshold beyond which a small additional change can trigger a large or self-sustaining shift in part of the climate system. Tipping points may involve feedback loops, but a feedback loop and a tipping point are not the same concept.

A feedback can operate gradually without a threshold. A tipping element may remain relatively stable until a critical condition is crossed, after which internal feedbacks can drive a major transition. Examples studied by climate scientists include ice-sheet changes, ecosystem shifts, and large-scale ocean-circulation changes.

A nonlinear response occurs when doubling an input does not simply double the output. Nonlinearity can arise from thresholds, saturation, changing feedback strengths, or interactions among components. This is one reason systems thinking is essential in climate science.

Avoiding the Runaway Misconception

Positive climate feedbacks can strongly amplify warming, but they do not imply that Earth's current climate must enter a Venus-like runaway greenhouse state. The Planck response increases outgoing radiation as Earth warms, and many feedbacks weaken, strengthen, or change sign depending on state and timescale.

The scientifically useful question is not whether every reinforcing loop becomes infinite. It is how much each feedback changes the energy balance, how feedbacks interact, whether thresholds are crossed, and how quickly the resulting changes unfold.

Reading Evidence and Model Results

Climate feedbacks are studied using several independent lines of evidence: satellite observations of radiation and humidity, surface measurements, ocean heat observations, paleoclimate records, laboratory and field studies, process models, and global climate models.

A climate model represents physical laws and approximations on a numerical grid. Some processes, such as large-scale atmospheric motion, can be represented directly at model resolution. Smaller-scale processes, such as cloud microphysics, require parameterizations. Model uncertainty therefore comes partly from incomplete knowledge and partly from computational limits.

Scientific confidence increases when theory, observations, and models point toward the same mechanism. For example, the positive water-vapour feedback is supported by thermodynamics, satellite observations, and climate models. Cloud feedback has become better constrained, but it still contributes strongly to the uncertainty range of climate sensitivity.

Correlation Is Not Enough

Two variables changing together do not by themselves prove a feedback. To demonstrate a causal feedback, you need a plausible mechanism, correct timing, evidence that the intermediate steps occur, and ideally quantitative agreement between predicted and observed energy changes.

For example, observing both warming and sea-ice loss is consistent with ice-albedo feedback but does not alone quantify its strength. Researchers also measure changes in reflected solar radiation, absorbed energy, seasonality, and regional temperature response.

Uncertainty Is Part of the Science

Uncertainty is not ignorance. Scientists use probability ranges, confidence statements, ensembles, sensitivity tests, and comparisons among methods to describe what is known and what remains uncertain.

For decision-making, uncertainty can increase the need to evaluate risk rather than justify inaction. A system with uncertain thresholds and potentially long-lasting changes requires attention to both likely outcomes and high-impact possibilities.

A Systems-Thinking Toolkit

When you analyze a new climate problem, use this sequence:

System boundary: Define what is inside the system and what is treated as external.
State variable: Identify the variables that can change, such as temperature, ice area, carbon storage, or humidity.
Causal relationship: State how one variable influences another and why.
Feedback loop: Trace the pathway back to the original variable and classify the loop as reinforcing or balancing.
Time delay: Identify slow responses that can hide or postpone effects.
Nonlinearity: Ask whether the response changes strength at high or low values.
Evidence: Look for observations, theory, and model results that test each link.
Uncertainty: State what is known with high confidence and what remains uncertain.

Worked Examples

Example: Ice-Albedo Loop

Suppose spring temperatures rise in the Arctic. Snow melts earlier, exposing darker land and ocean. Darker surfaces reflect less incoming sunlight, so more solar energy is absorbed. The additional absorbed energy increases local warming, which favors further melting.

This is a positive feedback because the final effect reinforces the initial warming. The loop is strongest when sunlight is available and frozen surfaces are near the melting point. In polar winter, there is little or no incoming sunlight, so the shortwave albedo link is weak even though other processes continue.

Example: Water Vapour and Lapse Rate

A greenhouse-gas forcing raises surface temperature. A warmer atmosphere tends to contain more water vapour, increasing greenhouse trapping and amplifying warming. At the same time, the tropical upper troposphere tends to warm more than the surface, increasing infrared emission to space and providing a negative lapse-rate feedback.

The two processes are physically connected, so climate scientists often analyze their combined effect. The combined feedback is positive even though the lapse-rate part is negative.

Example: Permafrost Carbon

Warming thaws some carbon-rich frozen ground. Microbes decompose newly thawed organic matter. Carbon dioxide and methane enter the atmosphere. Their greenhouse effect produces additional warming, which can promote more thaw.

This is a reinforcing feedback. However, its rate depends on soil temperature, moisture, oxygen, vegetation, landscape change, and how deeply thaw penetrates. A good systems model therefore includes both the loop structure and the controls on each link.

Interactive Tasks

Quiz: Test Your Knowledge

What makes a climate feedback positive? (It reinforces the initial change) (!It always produces a beneficial outcome) (!It always causes infinite warming) (!It acts only in the atmosphere)

Which statement best distinguishes a forcing from a feedback? (A forcing initiates an energy imbalance while a feedback responds to climate change) (!A forcing is always natural while a feedback is always human caused) (!A forcing changes weather while a feedback changes only climate models) (!A forcing is always positive while a feedback is always negative)

Why is the Planck response stabilizing? (A warmer Earth emits more infrared energy to space) (!A warmer Earth receives less sunlight from the Sun) (!Clouds disappear completely as temperature rises) (!Oceans stop absorbing heat after warming begins)

Which process is a positive surface-albedo feedback? (Melting ice exposes darker surfaces that absorb more sunlight) (!Warming increases infrared emission to space) (!Volcanic aerosols reflect sunlight before temperature responds) (!The deep ocean stores some excess heat)

Why is water vapour considered a feedback in current climate change? (Its atmospheric amount increases in response to warming and then amplifies warming) (!It is emitted mainly by fossil fuel combustion) (!It remains fixed in the atmosphere for centuries) (!It prevents carbon dioxide from absorbing infrared radiation)

What does the lapse-rate feedback describe? (Changes in the vertical pattern of atmospheric temperature) (!Changes in the speed of ocean currents only) (!Changes in the chemical lifetime of carbon dioxide) (!Changes in Earth orbital shape)

What is the current scientific assessment of global net cloud feedback? (It is positive overall) (!It is exactly zero) (!It is strongly negative with no uncertainty) (!It is unrelated to Earth energy balance)

Why does ocean heat uptake matter for transient warming? (It stores part of the excess energy below the surface and slows surface warming) (!It permanently removes energy from the Earth system) (!It turns infrared radiation into sunlight) (!It prevents greenhouse gases from affecting temperature)

Which statement about tipping points is correct? (A tipping point is a threshold that can trigger a large system change) (!Every positive feedback is automatically a tipping point) (!Tipping points occur only in the atmosphere) (!A tipping point means all uncertainty has disappeared)

What is the strongest way to support a proposed feedback mechanism? (Combine physical theory observations and model evidence) (!Use a single correlation between two variables) (!Rely only on one short weather event) (!Assume every simultaneous change has the same cause)

Memory Game

Forcing	An initial disturbance to the planetary energy balance
Albedo	The fraction of incoming sunlight reflected by a surface
Planck response	Increased thermal emission to space as temperature rises
Water-vapour feedback	Moisture increase after warming that strengthens greenhouse trapping
Climate sensitivity	Long-term temperature response to a specified radiative disturbance
Carbon sink	A reservoir or process that removes more carbon than it releases
Tipping point	A threshold beyond which a large system transition can be triggered

Drag and Drop

Match the correct terms.	Topic
Reinforcing feedback	Ice loss lowers reflectivity and increases solar absorption
Balancing feedback	Higher temperature increases outgoing infrared radiation
Carbon-cycle feedback	Thawing frozen soil releases additional greenhouse gases
Transient response	Surface warming while the ocean is still taking up substantial heat
Threshold behaviour	A small additional change triggers a much larger system shift

...

Crossword Puzzle

Albedo	What one-word term means the fraction of incoming sunlight that a surface reflects?
Cryosphere	Which one-word term names Earth's frozen-water component?
Amplification	What one-word term describes making an initial climate response stronger?
Permafrost	What one-word term names ground that remains frozen for at least two consecutive years?
Sensitivity	Which one-word term completes the phrase climate ___ for the temperature response to forcing?
Radiation	What one-word term describes energy transmitted as electromagnetic waves?

LearningApps

Cloze Text

Earth's climate behaves as a connected

in which changes can spread between the atmosphere, ocean, ice, land, and living organisms. A change that disturbs the top-of-atmosphere energy balance is called a

. A process that responds to climate change and then modifies that change is a

. When a feedback reinforces the original change, it is described as

. Bright snow and ice have high

because they reflect a large fraction of incoming sunlight. Warming can increase atmospheric

, which strengthens greenhouse trapping and amplifies the initial temperature rise. The increase in outgoing infrared energy as Earth warms is known as the

. Thawing

can expose frozen organic carbon to microbial decomposition and add greenhouse gases to the atmosphere. The long-term temperature response to a sustained radiative disturbance is related to climate

. A threshold beyond which a small additional change can trigger a major system transition is called a

.

Open-Ended Tasks

Easy

Feedback loop sketch: Draw a causal-loop diagram for ice-albedo feedback, label every arrow, and explain in 120 to 180 words why the loop is reinforcing.
Energy budget explanation: Create a one-page illustrated explanation of Earth's energy budget for a younger student, including incoming sunlight, reflection, absorption, infrared emission, and greenhouse gases.
Media analysis: Choose one video in this aiMOOC and produce a fact-check table with at least five scientific claims, the evidence shown, and one question you would ask the creators.
Local climate interview: Interview an adult about a climate-related change they believe they have noticed, then separate personal observation from evidence needed to establish a long-term climate trend.

Standard

Albedo experiment: Use equal containers or surfaces with light and dark coverings under the same lamp, measure temperature change at regular intervals, graph the results, control variables, and discuss how the model differs from real sea ice and ocean.
Carbon cycle investigation: Build a systems map linking atmosphere, vegetation, soil, ocean, and human emissions, then identify at least two reinforcing and two balancing processes and explain the limits of your map.
Climate data poster: Use a reliable public dataset to create a poster or infographic connecting one observed climate variable with a plausible feedback mechanism, clearly distinguishing correlation from causal evidence.
Feedback comparison video: Produce a three-to-five-minute video comparing water-vapour, lapse-rate, cloud, and surface-albedo feedbacks, including which are reinforcing, which are balancing, and where uncertainty is greatest.

Advanced

Energy-balance model: Create a spreadsheet or short program implementing a simplified equation of the form N = F + αΔT, test several values of forcing and feedback strength, and explain how equilibrium temperature changes.
Feedback network research: Develop a network diagram that combines at least six climate feedbacks, include delays and cross-links, then write a 700-word analysis of where cascading effects or nonlinear responses could occur.
Scientific literature briefing: Read one recent peer-reviewed paper or major assessment chapter on cloud, permafrost, or carbon-cycle feedbacks and prepare a structured briefing that compares its methods, evidence, uncertainty, and conclusions with this aiMOOC.
Tipping-point policy simulation: Design and run a classroom decision simulation in which teams must choose mitigation strategies under uncertain thresholds, delayed climate responses, and limited carbon budgets, then evaluate how uncertainty changed the decisions.

Learning Assessment

Causal reasoning assessment: Given an unfamiliar climate process, construct a causal chain, classify the loop, justify the classification, and identify at least one missing variable that could alter the result.
Forcing and feedback assessment: Analyze a scenario containing volcanic aerosols, carbon dioxide emissions, sea-ice loss, and water-vapour change, then separate forcings from feedbacks and defend each choice.
Quantitative energy-balance assessment: Use a provided forcing and feedback parameter in the simplified energy-balance equation, calculate the equilibrium temperature change, and explain how the answer changes when the feedback parameter becomes less negative.
Evidence evaluation assessment: Compare a correlation-based claim about sea ice with a mechanism-based study that also measures reflected solar radiation, then judge which provides stronger evidence for feedback strength and why.
Systems transfer assessment: Apply the concepts of reinforcing loops, balancing loops, delays, and thresholds to a non-climate system such as an ecosystem, economy, or engineered control system, and explain both useful similarities and misleading differences.
Uncertainty and decision assessment: Write a reasoned recommendation for decision-makers facing an uncertain climate threshold, showing how probability, potential impact, reversibility, and response time should influence action.

Evidence of Learning

Important evidence of learning includes:

Knowledge: Accurate explanations of Earth's energy budget, forcing, major physical feedbacks, carbon-cycle feedbacks, climate sensitivity, nonlinearity, and tipping points.
Skills: Clear causal reasoning, interpretation of diagrams and graphs, simple quantitative modelling, comparison of timescales, evaluation of evidence, and communication of uncertainty.
Products: Causal-loop diagrams, experimental reports, data visualizations, explanatory media, research briefings, models, and reflective evaluations.
Transfer: The ability to apply feedback concepts to unfamiliar climate processes and to distinguish useful systems analogies from oversimplifications.
Scientific practice: Use of reliable sources, transparent assumptions, reproducible calculations, careful distinction between correlation and causation, and revision of conclusions when evidence changes.

OERs on the Topic

The English Wikipedia article on the Climate system provides an accessible overview of interacting climate components and links to related topics:

For deeper study, compare the explanations in Climate change feedbacks, Climate sensitivity, Earth's energy budget, Ice–albedo feedback, Cloud feedback, Carbon cycle, and Tipping points in the climate system.

Reliable external references for advanced learners include the IPCC Sixth Assessment Report Working Group I chapter on Earth's energy budget, climate feedbacks, and climate sensitivity; NASA resources on Earth's energy budget and water-vapour feedback; and the UCAR Center for Science Education overview of feedback loops and tipping points.