Amplifying Feedback

Eight feedbacks driving global heating

Global heating is causing more global heating.

Here are eight “amplifying feedbacks” driving this heating: Each feedback is a “self-reinforcing, circular chain of cause-and-effect”, like this “permafrost feedback cycle”.

The permafrost feedback

Higher air temperatures More melting of permafrost
More greenhouse heatingMore methane & CO2 in the air

If this feedback dominated, we would see:

  • higher air temperatures, causing
  • more melting of permafrost (ice containing frozen plant & animal matter), causing
  • more decay of thawing organic matter, releasing
  • more carbon dioxide & methane into the atmosphere, causing
  • more greenhouse heating, which closes the cycle by causing
  • higher air temperatures.

This permafrost feedback is dangerous as permafrost contains vast amounts of carbon: about 1.6 times more than our atmosphere.

It’s concerning that measurements show increases in every element of this feedback:

  • global air temperatures are rising,
  • permafrost temperatures deep within measurement boreholes are increasing, showing that permafrost melting is also increasing,
  • atmospheric carbon dioxide is surging, and
  • atmospheric methane is soaring.

These increases show that the permafrost feedback is active and may already be self-sustaining and unstoppable. We cannot tell if it’s self-perpetuating now because it is supported by:

  • human emissions of carbon dioxide and methane, &
  • other feedback cycles, which are also increasing global temperatures. (I briefly describe seven more example feedback cycles below.)

Humans are playing with fire by continuing to fuel these feedback cycles, and the critical question is, can humans stop this dangerous amplification of global heating?

For more on methane, see the methane feedback cycle on this website.

The ice cover feedback

Higher air temperaturesLess ice cover
*Less sunlight reflection & more absorption

This dynamic is reversible and could amplify cooling; see below.

See The dwindling Arctic sea ice on this website.

These causal linkages are tendencies

The cause-and-effect linkages in these feedbacks are tendencies or likely outcomes. External events often break the links in these feedback cycles, preventing the dominance of the feedback. For example, ash from a volcanic eruption could reduce the sunlight reaching the Arctic, so even with “less ice cover”, the Arctic could “absorb less sunlight”, not more sunlight.

The water vapour feedback

This feedback is powerful as:

  • water vapour is a potent greenhouse gas,
  • there is more water vapour in our atmosphere than any other greenhouse gas, and
  • this feedback operates fast because temperature changes rapidly change the amount of water vapour in the air.
Higher air temperatures(1) More evaporation & (2) Warmer air can hold more water vapour
More greenhouse heatingMore water vapour in the air

If this feedback dominated, we would see:  

  • higher global air temperatures, leading to
  • (1) more water evaporating from oceans, and (2) the air being able to hold more water vapour, causing
  • more water vapour in the air, causing
  • more greenhouse heating of the atmosphere, causing
  • higher air temperatures.

This cycle is reversible as global cooling would reduce water vapour in the atmosphere.

(Climate Change: Now or Never: New Scientist: 24 April 2021: page 37).

The phytoplankton feedback

Higher air temperaturesMore ocean surface heating
More carbon dioxide in the airLess nutrient upwelling
Less photosynthesis & Less carbon on the ocean floorReduced phytoplankton population

See the heating of the ocean surface and the phytoplankton feedback cycle on this website.

The forest fire feedback

Higher air temperaturesMore heat & drought
More carbon dioxide in the airMore forest fires

See fires intensifying climate change on this website

The ice-darkening feedback

Higher air temperaturesMore melting of the ice sheet surface
Less sunlight reflectionMore dark matter on the ice surface

If this feedback dominated, we would see:  

  • higher global temperatures cause
  • more ice sheet melting, which exposes
  • more dark matter on the ice surface, like ash from distant bushfires that was previously part of the glacier, which causes
  • the ice sheet to reflect less sunlight back into space, which closes the cycle by causing
  • higher global temperatures.

The glacier altitude feedback

More glacial surface meltingA drop in the altitude of the glacier surface
*A rise in average temperature at the glacier surface

This feedback occurs because the average temperature at the top of a mountain is lower than at sea level – and this is relevant because we have some deep ice sheets, e.g., up to 4.9 kilometres deep in Antarctica.

See glaciers in retreat on this website.

The populist politics feedback

Higher air temperaturesMore extreme weather
Less climate actionMore conflict over land, water, food & housing
More populist politicsMore migration

See right-wing populism feedback on this website.

Feedbacks that could limit global heating

The Arctic cooling feedback

The above “Arctic heating feedback” is reversible. It would become the “Arctic cooling feedback” and amplify cooling if cooling occurred.

Lower air temperaturesMore sea-ice cover
* More reflection & less absorption of sunlight

The current exceptionally high level of greenhouse gases in our atmosphere means that we are unlikely to see any global cooling, so we are unlikely to see any amplification of global cooling.

Other global heating feedback cycles are also reversible, e.g., the water vapour feedback. Other feedback cycles are not reversible, e.g., the methane release feedback.

The amplification of climate action

Here is a feedback cycle that could amplify climate action in Australia and thereby contribute to limiting global heating.

More popularity for the superpower vision
More benefits More progress toward the vision

In this feedback:

  • the increasing popularity of the vision of “Australia as a renewable energy superpower” tends to
  • increase progress towards that vision, which tends to
  • increase the resulting benefits, which tends to close the cycle by
  • further increasing the popularity of the superpower vision.

Focusing on the feedback cycle amplifying global heating can be demoralising. It can be more energising to focus on positives, like this “amplification of climate action feedback”, which could propel Australia towards an attractive future. For more on this, see:

No effective resistance to the current heating

James Lovelock (“The Revenge of Gaia”: 2006: page 35) writes that the observed rate of global warming is a grave concern. This rate suggests that no global climate dynamic will effectively resist the current warming and limit temperature increases to keep an environment safe for life as we know it.

Lovelock points out that the levels of methane and CO2 in the atmosphere in 2006 were comparable to those caused by natural releases of these gases fifty-five million years ago. At this time, temperatures rose between 5 and 8 degrees C, with consequences lasting 200,000 years.

There is no evidence of a climate dynamic emerging to limit temperature increases.

The danger of global heating amplification

Feedback cycles can produce exponentially increasing phenomena, e.g., the feedback you often get when a person is talking into a megaphone, and a slight hum rapidly turns into a painful shriek. And the various feedbacks reinforce each other, each adding to the heating and threatening our nurturing climate. So, these global heating feedback cycles threaten self-perpetuating, exponential increases in global temperatures. A critical danger is that:

  • one feedback increasing global temperatures becomes dominant, leading to a cascade of similar feedbacks becoming dominant,
  • these self-perpetuating dynamics increase global temperatures with increasing rapidity,
  • the heating releases vast amounts of the greenhouse gases carbon dioxide and methane from sources like forest fires and the thawing of permafrost,
  • humans cannot counter this heating as (1) stopping the use of fossil fuels only stops one source of carbon dioxide but does not decrease the levels of greenhouse gases in the atmosphere, and (2) geoengineering will not match the global scale of the many heating feedbacks, &
  • our nurturing environment disappears.

We have co-evolved with our climate, so our current climate system suits human beings and the rich diversity of life on our planet. We must protect our climate system because global heating threatens our current climate, the global economy, political stability, human health, and the environment.

Systems theory & feedback

Feedback: A well-established concept

Feedback is a long-established concept that is a central part of “Systems Theory”. You may know about amplifying feedback under other names, like:

Sound amplification systems & feedback

Here are some amplifying feedback examples that do not include climate change.

When a person speaks into a microphone with an amplifier and loudspeaker, they can kick off a soft hum, a sound that rapidly escalates into that painful, ear-piercing shriek called “feedback”. Here is an amplifying feedback cycle showing this process:

Louder microphone input
Louder loudspeaker outputAmplification

Destructive feedback: Road pothole formation

“A stitch in time saves nine”. This old saying is about stopping amplifying feedback from escalating problems and preventing more damage. Amplifying feedback can destroy things. For example, a road surface develops a slight defect that becomes a pothole and then the bigger the hole gets, the more cars hit the pothole and hit it with greater force.

The pothole gets bigger.Cars hit the pothole harder & more often.

Creative feedback: the emergence of a new interest

Amplifying feedback can also create new things of value. For example, when a person becomes interested in rocks at a beach, later they can read and develop expertise or even become a geologist.

More fascination with a subjectMore knowledge about the subject

Amplifying feedback & Chaos theory

Amplifying feedback offers an understanding of the “chaos theory” concept of the “butterfly effect”.

The butterfly effect puts forward the improbable example of something tiny causing something massive, i.e., the flap of a butterfly’s wing in Brazil causing a tornado in Texas. It is a way of announcing that systems can be super-sensitive in some regions and times so that something tiny can lead to something large. The butterfly effect accurately suggests that our world does not run predictably like clockwork. For example, a chance meeting or an unfortunate stumble can change people’s lives. Science used to regard the movement of the planets around the sun as predictable, but in the long term, even our planets are unpredictable.

When you use a microphone and get feedback, it’s hard to identify what triggers that shriek. Amplifying feedback often begins with an unnoticeable small change, and a repeating sequence of events amplifies this small initial change. Amplifying feedack can cause massive change, as suggested by the butterfly effect.

(Understanding the butterfly effect: American Scientist)

Negative Feedback

While amplifying feedback cycles tend to change systems, negative feedback prevents change. See the above Maruyama article or Wikipedia.

Site name: Feedback Reigns

The importance of “amplifying feedback cycles” led to this website’s name: “Feedback Reigns”.

The physics of tipping points and amplifying feedback

Updated: 4 April 2022

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